Question 1

A 32-year-old woman is hospitalized with left leg pain and swelling two weeks after an uneventful vaginal delivery of a healthy baby girl.  She is diagnosed with a left lower extremity deep venous thrombosis and is started on intravenous heparin.  On the second day of her hospitalization, she develops left-sided weakness and a facial droop.  A non-contrast CT scan of the head reveals no intracranial bleeding but suggests an ischemic infarction in the territory of the right middle cerebral artery.  Which of the following is most likely to reveal the cause of this patient's symptoms?

Accepted Answer

Explanation: This young woman has a new ischemic stroke in the setting of a lower extremity deep venous thrombosis (DVT), suggesting that a paradoxical embolus may be responsible. Typically, embolic strokes occur when a mural thrombus from the left atrium or a plaque from a carotid artery embolizes and lodges in the cerebral circulation. However, patients may develop embolic strokes with origins in the venous system as well. This can occur when an intracardiac communication like a patent foramen ovale or atrial septal defect is present and allows a dislodged venous clot to travel into the arterial circulation. These so-called paradoxical emboli are often responsible for embolic strokes in younger patients. A transthoracic or transesophageal echocardiogram with a bubble study will reveal such an intracardiac shunt. (Choice A) There is no physical exam evidence of a right lower extremity DVT. Moreover, a right lower extremity DVT would not put her at significant risk of an embolic stroke unless she had an intracardiac communication. (Choice B) Venography can be used diagnose lower extremity DVTs when the diagnosis is unclear. As described above, there is little to suggest a right lower extremity DVT and, even if one was present, there would also have to be an intracardiac communication for it to cause a stroke. (Choice C) Carotid artery atherosclerosis increases one's risk of developing a stroke. It is more common in older patients than in young ones, and this patient already has a compelling embolic source. (Choice E) 24-hour cardiac monitoring is used to diagnose arrhythmias. Atrial fibrillation is a leading cause of embolic strokes; however, this young woman who developed a stroke in the setting of a lower extremity DVT is more likely to be suffering from a paradoxical embolus. Educational objective: Paradoxical emboli are those that originate in the venous system and enter the arterial system via an intracardiac shunt. They are a more common cause of stroke in the young than in the elderly. They can be diagnosed with an echocardiogram and bubble study.

Question 2

A 69-year-old man comes to the emergency department with 1 hour of sudden vision loss in his right eye.  The patient has no headache, eye pain, itching, or discharge.  He has a history of coronary artery disease, type 2 diabetes mellitus, hypertension, and hyperlipidemia.  The patient was diagnosed with prostate cancer 6 months ago and treated with radiation therapy.  Physical examination shows severely compromised vision in the right eye.  He can recognize hand motion but cannot count fingers.  Funduscopic findings are shown below.  Which of the following is the most likely diagnosis?

Accepted Answer

Explanation: 11ec2b69_c196_f925_8f63_bf6f8a49b872_MD0005_00 This patient's presentation-acute, painless monocular vision loss-suggests central retinal artery occlusion (CRAO), which usually affects patients age >60 with underlying cardiovascular risk factors. CRAO is most commonly due to carotid atherosclerosis as the central retinal artery is a branch of the ophthalmic artery, which arises from the internal carotid artery. Other etiologies include cardiac embolism, small vessel disease (eg, hypertension, diabetes), and vasculitis (eg, giant cell arteritis). Funduscopic examination usually shows diffuse ischemic retinal pallor and a cherry red spot at the macula (due to preserved circulation via posterior ciliary arteries). Evaluation includes laboratory studies to exclude giant cell arteritis (erythrocyte sedimentation rate, C-reactive protein), carotid artery imaging, and cardiac evaluation in patients with a suspected cardioembolic source. cherry red spot CRAO can cause irreversible retinal damage within 90-100 minutes. As a result, patients require urgent ophthalmology consultation and interventions to lower intraocular pressure (eg, ocular massage, anterior chamber paracentesis, intravenous acetazolamide or mannitol). Long-term management includes atherosclerotic risk factor modification (lipid-reducing and antiplatelet agents) for prevention of recurrent vascular events. Prognosis is poor in patients with severe vision loss at the time of presentation. (Choice A) Acute angle-closure glaucoma typically presents with vision loss, severe eye pain, headache, nausea, and vomiting. Patients may also report seeing light halos. Examination shows conjunctival redness and a dilated, poorly reactive pupil. Acute angle-closure glaucoma (Choice C) Central retinal vein occlusion can also present with painless, acute, or subacute monocular vision loss. Central retinal vein occlusion is usually due to nonembolic causes. Examination can show tortuous and dilated veins, diffuse hemorrhages, disk swelling, and cotton wool spots. Central retinal vein occlusion (Choice D) Macular degeneration usually presents with progressive distortion and loss of vision, primarily in the center of the visual field (central scotomas). The "dry" form can have cellular debris (drusen) accumulate between the retina and the choroid, which sometimes leads to retinal detachment. The "wet" form is more severe, with blood vessels growing up from the choroid behind the retina, which can cause retinal detachment. Macular degeneration (Choice E) Retinal detachment presents with vision loss (peripheral followed by central) and photopsia with showers of floaters. It is usually associated with trauma, previous eye surgery, aging, and severe myopia. Retinal detachment Educational objective: Central retinal artery occlusion presents with acute, painless, monocular vision loss. Funduscopy shows diffuse ischemic retinal pallor and a cherry red macula. Management includes urgent Ophthalmology consultation and measures to lower intraocular pressure. References: A review of central retinal artery occlusion: clinical presentation and management. (http://www.ncbi.nlm.nih.gov/pubmed/23470793)

Question 3

A 62-year-old woman is brought to the physician by her son due to progressive forgetfulness over the last year.  She has been less active than normal and is having some difficulty walking.  The patient has no urinary incontinence.  Her past medical history is significant for exertional angina and hypertension.  She has recently been depending on her son to manage her medications, which include metoprolol, amlodipine, and aspirin.  She does not smoke or consume alcohol.  Her father had hypertension and stroke, and her mother had Alzheimer disease.  The patient is oriented to person and place, but not time.  She has difficulty with 3-word recall.  Her gait is slightly unstable and she has problems balancing when she closes her eyes.  Examination of the lower extremities show decreased vibratory sensation, spastic paresis, and hyperreflexia bilaterally. 
Further evaluation of the patient shows a mild indirect hyperbilirubinemia.  Which of the following is the most likely explanation of this finding?

Accepted Answer

Explanation: Ineffective erythropoiesis is a well-known phenomenon that occurs in patients with vitamin B12 deficiency. The mechanism that leads to this phenomenon involves defective DNA synthesis with megaloblastic transformation of bone marrow and intramedullary hemolysis. Although intense erythroid hyperplasia occurs, the erythroid cells do not mature normally and subsequently die in the bone marrow. Markers of hemolytic anemia (eg, elevated lactate dehydrogenase, low haptoglobin, indirect hyperbilirubinemia) may become evident, but reticulocyte response is typically absent in such patients. (Choice A) Impaired bile excretion can occur with extrahepatic cholestasis (eg, choledocholithiasis, malignant obstruction, biliary stricture) or intrahepatic cholestasis (eg, primary biliary cirrhosis, primary sclerosing cholangitis). However, direct hyperbilirubinemia is expected in these conditions. (Choice B) Impaired hepatic conjugation is observed in patients with Gilbert syndrome, a benign hereditary condition that can result in isolated indirect hyperbilirubinemia. This patient's age and manifestations of vitamin B12 deficiency make the diagnosis unlikely. (Choice D) Intravascular hemolysis may result in indirect hyperbilirubinemia but is typically associated with microangiopathic hemolytic anemia (eg, thrombotic thrombocytopenic purpura), blood transfusions (eg, ABO incompatibility), or paroxysmal nocturnal hemoglobinuria. Reticulocyte count is usually elevated in these conditions. (Choice E) Liver parenchymal damage (eg, viral hepatitis, drug-induced liver injury, ischemic hepatopathy) usually causes direct hyperbilirubinemia. Educational objective: Vitamin B12 deficiency may cause erythroid hyperplasia and ineffective erythropoiesis in the bone marrow, which can result in markers of hemolytic anemia (eg, elevated lactate dehydrogenase, low haptoglobin, indirect hyperbilirubinemia) and an absent reticulocyte response. References: Hemolysis and hyperhomocysteinemia caused by cobalamin deficiency: three case reports and review of the literature. (http://www.ncbi.nlm.nih.gov/pubmed/19094231)

Question 4

A 36-year-old man has had weakness in his right arm and leg as well as difficulty walking over the past 2 weeks.  This was preceded for several days by mild headaches and dizziness that have not recurred.  He is an ex-smoker with a 10-pack-year history.  The patient experimented with cocaine in college although never intravenously, and he has used no illicit drugs in the last 10 years.  He has a history of multiple sexual partners and has been treated twice in the past several years for gonococcal urethritis.  He also reports an ulcerative lesion on his penis "a while ago," that resolved.  The patient has no history of diabetes or hypertension.  His family history is negative for stroke or premature coronary artery disease.  He is afebrile, his blood pressure is 132/80 mm Hg, and his heart rate is 85/min with a regular rhythm.  There is no murmur on cardiac examination.  His reflexes are hyperactive on the right side.  Electrocardiogram shows normal sinus rhythm.  A urine toxicology screen is negative.  Brain MRI demonstrates a subacute stroke in the left frontal lobe.  HIV test is negative.  Cerebrospinal fluid analysis results are as follows:  Cerebrospinal fluid Gram stain shows no organisms.  Which of the following is most likely to indicate the underlying etiology of this patient's symptoms?

Accepted Answer

Explanation: 11ec2b69_c192_b35e_8f63_f176f7bb898b_MD0005_00 This patient has right-sided weakness and hyperactive reflexes with an MRI showing a subacute infarct in the left frontal lobe, consistent with stroke. However, given his young age and lack of family history of cerebrovascular disease, etiologies other than atherosclerosis should be entertained. In particular, infectious causes of stroke should be considered in light of this patient's sexual history and his penile ulcerative lesion concerning for a syphilitic chancre. This patient likely has meningovascular syphilis, a condition in which low-grade infection in the subarachnoid space can affect the intracranial vessels and potentially result in stroke. Confusion, headache, and stiff neck are seen less frequently than in the more common meningitis form. Serum reactive plasma reagin (RPR) and cerebrospinal fluid (CSF) Venereal Disease Research Laboratory (VDRL) testing should be performed to confirm the diagnosis of syphilis. Intravenous penicillin is the appropriate treatment. (Choice A) Potential fungal etiologies causing meningitis and stroke are Cryptococcus and endemic mycoses (eg, coccidioidomycosis, histoplasmosis). The normal CSF glucose and the lack of immunosuppression make a fungal central nervous system infection less likely. (Choice B) The subacute presentation over 2 weeks is less consistent with herpes simplex virus (HSV) encephalitis. Classically, HSV encephalitis presents with hemorrhagic infarction of the temporal lobe, with elevated red blood cells seen on CSF analysis. MRI findings in HSV encephalitis most frequently show temporal lobe enhancement, sometimes with associated mass effect. (Choice C) This patient is young for atherosclerotic stroke and has no family history to suggest inherited dyslipidemia. The abnormal CSF cell counts also make atherosclerotic stroke less likely. (Choice E) Although mycotic aneurysms from cardiac valvular vegetation may present with stroke, this patient has no stigmata of endocarditis and is afebrile, making this diagnosis less likely and a transesophageal echocardiogram less useful. Mycotic aneurysms would also likely be seen on MRI. Educational objective: Alternate causes of stroke should be considered in patients who are young and without traditional cardiovascular disease risk factors, particularly those with risk factors for unusual infections. Meningovascular syphilis can present with stroke due to intracranial arteritis. The diagnosis can be confirmed with cerebrospinal fluid Venereal Disease Research Laboratory (VDRL) testing; penicillin is the appropriate treatment. References: Neurosyphilis in the modern era. (http://www.ncbi.nlm.nih.gov/pubmed/15548491) Treatment of neurosyphilis. (http://www.ncbi.nlm.nih.gov/pubmed/16569377)

Question 5

A 35-year-old Caucasian male with no significant past medical history presents to the emergency department complaining of severe pain in his left eye.  Earlier that afternoon he was working on his boat when he dropped a heavy metal crate onto the boat's wooden deck.  Immediately after he dropped the crate, he felt one or more small foreign objects enter his left eye.  The eye began to water profusely and he was unable to open it sufficiently to examine the cornea.  He states that he does not wear contact lenses.  Physical examination of the left eye reveals edema of the upper eyelid, conjunctival hyperemia, diffuse corneal inflammation, and corneal abrasion.  After a topical anesthetic was applied to the injured eye, irrigation with saline was successful in removing all debris.  What organism is most commonly cultured from corneal foreign bodies?

Accepted Answer

Explanation: Although rarely sent for culture in practice, corneal foreign bodies are known to frequently test positive for pathogens. Studies have shown that the most common pathogen isolated from these cultures is coagulase negative Staphylococcus (Choice B). Other common pathogens include Streptococcus, Haemophilus, and Pseudomonas. Therefore, the treatment for all foreign-body associated corneal abrasions should include empiric broad-spectrum antibiotic eye drops or ointments (e.g., erythromycin, sulfacetamide, ciprofloxacin, ofloxacin). Staphylococcus Streptococcus Haemophilus Pseudomonas Pseudomonas (Choice A) is a common cause of bacterial infection in contact lens wearers. Pseudomonas Neisseria gonorrhoeae (Choice C) can penetrate intact corneal epithelium and cause bacterial keratitis. This is one of many possible manifestations of gonorrheal infection resulting from sexual transmission or passage through the birth canal. Neisseria gonorrhoeae Sporotrichosis (Choice D) is a fungal infection most often found in persons handling thorny plants, sphagnum moss, or baled hay. It typically manifests as nodules on the skin that ulcerate and are slow to heal. Candidal (Choice E) infection of the eye is most often found in immunosuppressed patients or those with chronic diseases of the ocular surface. Educational Objective: The most common pathogen isolated from cultures of corneal foreign bodies is coagulase negative Staphylococcus. Other common pathogens include Streptococcus, Haemophilus, and Pseudomonas. Staphylococcus Streptococcus Haemophilus Pseudomonas

Question 6

A 34-year-old Caucasian female presents to the emergency department (ED) with a 24-hour history of headaches, myalgias and low-grade fever.  She grades the intensity of her headaches as 6-7 on a 10-grade scale, and states that she has never had such symptoms before.  She does not know what could have brought these symptoms on.  Nobody in her family, or among her co-workers, has recently had similar symptoms.  She has no history of recent travel.  Her past medical history is significant for an episode of severe pyelonephritis one year ago.  CT scan of the head without contrast does not reveal any abnormality.  A lumbar puncture is performed, and the CSF findings are as follows:  CSF analyses on cryptococcal antigen, Lyme titer, bacterial stains, as well as bacterial cultures, are pending.  Which of the following is most consistent with the CSF findings in this patient?

Accepted Answer

Explanation: The CSF findings in this patient are most consistent with traumatic lumbar puncture (LP), which results from accidental damage of a blood vessel during the procedure. A RBC count exceeding 6,000/mm3 may indicate traumatic LP, but other important causes, mainly subarachnoid hemorrhage (SAH), should be ruled out. WBC elevation in traumatic LP is commonly explained by the blood leak if approximately one WBC is present per 750-1000 RBCs. The protein level is elevated in the presence of traumatic LP, and the glucose level is typically high. (Choice C)Important findings that help to differentiate traumatic LP from SAH are xanthochromia and discoloration of centrifuged CSF due to hemoglobin breakdown. These are characteristic for SAH, and appear 2 to 4 hours after RBCs enter the subarachnoid space. These are present in more than 90% of patients within 12 hours of SAH. (Choices A, B and D)Interestingly, in one study, a WBC/RBC ratio not exceeding 0.01 has almost 100% negative predictive value for meningitis. Educational Objective: Traumatic lumbar puncture (LP) results from accidental damage of a blood vessel during the procedure. A high RBC count without xanthochromia is characteristic.

Question 7

A 50-year-old woman with type 2 diabetes mellitus, hypertension, and obesity comes to the emergency department with left-sided vision loss that started 45 minutes ago.  She has no fever, headache, eye pain, or tearing.  On examination, she can only see hand motion with her left eye and cannot count fingers.  Visual acuity in the right eye is normal.  Funduscopic findings are shown below.  Which of the following is the most likely cause of this patient's condition?

Accepted Answer

Explanation: 11ec2b69_c196_83f3_8f63_cfcc4d69efd3_MD0005_00 This patient with cardiovascular risk factors and acute visual loss likely has central retinal artery occlusion (CRAO). The most common cause of CRAO is carotid artery atherosclerosis. Other less frequent etiologies include cardiogenic embolism, clotting disorders, carotid artery dissection, and vasculitis (eg, giant cell arteritis). CRAO is characterized by acute-onset, painless, monocular vision loss. Patients may lose the ability to make fine distinctions (eg, finger counting), but can frequently identify objects (eg, hands). Typical examination findings include an afferent pupillary defect and funduscopy showing a pale, ischemic fundus with a "cherry red spot". Initial management should include measures to reduce intraocular pressure (eg, ocular massage, acetazolamide) and urgent ophthalmology consultation to avoid irreversible visual loss. "cherry red spot" (Choice B) Elevated intracranial pressure from tumor or idiopathic intracranial hypertension (pseudotumor cerebri) can cause visual impairment. However, this patient's lack of headache and absence of papilledema on funduscopy make the diagnosis less likely. (Choice C) Acute angle-closure glaucoma can present with acute monocular visual loss; however, it is usually associated with eye pain, headache, nausea/vomiting, and conjunctival erythema. Also, angle-closure glaucoma would not explain this patient's funduscopic findings. Acute angle-closure glaucoma (Choice D) Optic neuritis typically causes subacute (hours to days) monocular vision loss associated with eye pain that worsens with eye movement. Patients can have an afferent pupillary defect, but funduscopy characteristically shows optic disc edema. optic disc edema (Choice E) Proliferative retinopathy due to diabetes mellitus typically results in progressive visual loss in its late stages. Acute visual loss may take place in the setting of a complication such as vitreous hemorrhage; however, this patient does not have evidence of neovascularization or hemorrhage on funduscopy, making the diagnosis unlikely. Proliferative retinopathy Educational objective: Central retinal artery occlusion is most commonly caused by carotid artery atherosclerosis and presents with acute, painless, monocular vision loss. Patients typically have an afferent pupillary defect on examination and funduscopy may show a pale, ischemic fundus with a "cherry red spot." References: A review of central retinal artery occlusion: clinical presentation and management. (http://www.ncbi.nlm.nih.gov/pubmed/23470793) Ocular emergencies. (http://www.ncbi.nlm.nih.gov/pubmed/17910297)

Question 8

A 60-year-old woman comes to the emergency department complaining of a severe, sudden-onset headache accompanied by nausea.  She has had mild diplopia for the past 3 months.  The patient has a long history of hypertension and diabetes mellitus type 2.  Her blood pressure is 160/90 mm Hg and heart rate is 80/min.  Physical examination shows right-sided ptosis, mild anisocoria, and nuchal rigidity.  There is no ataxia.  Which of the following is the most likely diagnosis?

Accepted Answer

Explanation: 11ec2b69_c192_653c_8f63_cb5610472656_MD0005_00 The patient's symptoms are suggestive of a subarachnoid hemorrhage. The constellation of sudden-onset headache, nausea, and nuchal rigidity is characteristic. She demonstrates signs of right cranial nerve III (CN III) palsy (ptosis and anisocoria), a typical finding with posterior communicating artery aneurysms (about 20% of cerebral aneurysms) due to the proximity of the nerve to the artery's path. This finding can also be seen in cavernous-carotid aneurysms, but these are uncommon. The patient's history of diplopia may have been due to right CN III neuropathy (mass effect from the unruptured aneurysm). (Choice A) Brainstem gliomas present with signs and symptoms of progressive brainstem involvement, including ataxia, cranial nerve palsies, and motor and/or sensory abnormalities. (Choice B) Lacunar strokes manifest as relatively limited neurologic dysfunction (eg, pure motor strokes), but headache and nuchal rigidity are not typically present. (Choice D) Posterior inferior cerebellar artery aneurysms frequently result in ataxia and bulbar dysfunction. (Choice E) Trigeminal neuralgia presents as recurrent brief attacks of facial pain in the distribution of CN V. Educational objective: Cranial nerve III palsy is a typical finding in patients with a posterior communicating artery aneurysm. References: Oculomotor nerve palsy by posterior communicating artery aneurysms: influence of surgical strategy on recovery. (http://www.ncbi.nlm.nih.gov/pubmed/22937927) Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography. (http://www.ncbi.nlm.nih.gov/pubmed/16378842)

Question 9

A 45-year-old African-American woman presents to the emergency department with the complaint that "my eye hurts, and it's far too bright in here."  She has one hand cupped over her left eye.  She denies any history of trauma or the presence of a foreign body sensation in either eye.  Physical examination reveals significant redness at the junction between the cornea and sclera of the left eye.  The left pupil is irregular and constricted and she recoils when the penlight is shined in either eye.  Visual acuity is reduced in the left eye. Slit lamp examination shows the presence of leukocytes in the anterior segment of this eye.  What is the cause of this woman's symptoms?

Accepted Answer

Explanation: Anterior uveitis (iritis) is characterized by pain, redness, variable visual loss, and a constricted and irregular pupil. To properly distinguish iritis from other causes of a red eye, it is important to visualize the anterior segment of the eye with slit lamp examination. If leukocytes are seen in the anterior segment, which contains the aqueous humor found between the cornea and the lens, then the diagnosis of iritis (Choice D) is confirmed. A hazy "flare," which is indicative of protein accumulation secondary to a damaged blood-aqueous barrier, may also be seen. Treatment for iritis depends on the etiology of the condition, and typically includes antimicrobial therapy for viral or bacterial causes and topical corticosteroids for noninfectious causes. Acute closed angle glaucoma (Choice A) may cause symptoms similar to those found in iritis, but is confirmed by documenting elevated intraocular pressure. Conjunctivitis (Choice B) is a diagnosis of exclusion, and is made in a patient with red eye and discharge only if vision is normal and there is no evidence of glaucoma, iritis, or keratitis. Infectious keratitis (Choice C) is characterized by severe photophobia and difficulty in keeping the affected eye open. Penlight examination reveals a corneal opacity or infiltrate. A red eye can result from the presence of a foreign body or a corneal abrasion resulting from trauma (Choice E), but such information is normally provided in the patient's history. Penlight examination should provide confirmation. Educational Objective: Anterior uveitis (iritis) is characterized by pain, redness, variable visual loss, and a constricted and irregular pupil. Visualization of leukocytes in the anterior segment confirms the diagnosis.

Question 10

A 10-year-old Caucasian boy is brought to the emergency department (ED) after a major car accident.  He was unresponsive when the ambulance arrived to the site, but regained consciousness soon after arrival to the ED.  He is oriented to time and space, and is able to move his extremities and obey commands.  Careful inspection reveals several deep scalp lacerations and a horizontal laceration of the right upper lateral eyelid with deep fat tissue in the wound.  The right eyelid is swollen.  The pupils are symmetric and reactive to light.  Which of the following structures is most likely injured as a result of the eyelid laceration in this patient?

Accepted Answer

Explanation: Knowedge of basic orbital anatomy is important in assessing eyelid lacerations. Horizontal lacerations of the upper eyelid may involve the orbital septum, a structure that separates orbital content from the lid tissue. The presence of orbital fat tissue in the wound indicates a high probability of septum injury and a possible levator palpebrae injury. Levator function should be tested in this patient by asking him to look up and down. The other structures listed are located on the medial side, and are less likely to be injured. (Choices B, A, D and E)Canaliculi are most susceptible to medial laceration of the eyelids, but other structures such as the punctum, nasolacrimal duct and lacrimal sac can also be injured. Educational Objective: The presence of orbital fat tissue in the wound indicates a high probability of septum injury and a possible levator palpebrae injury.

Question 11

A 16-year-old Caucasian male presents with decreased hearing and several subcutaneous nodules.  His past medical history is insignificant.  His family history is significant for a father with bilateral deafness that was treated with surgery.  Physical examination reveals two hypopigmented spots on his back.  MRI scans of the head with gadolinium enhancement show bilateral cerebellopontine angle masses.  Which of the following cell types is responsible for these findings?

Accepted Answer

Explanation: Acoustic neuromas observed in patients with neurofibromatosis, as well as sporadic, unilateral acoustic neuromas, result from the proliferation of Schwann cells (schwannomas). Schwann cells are responsible for the myelinization of peripheral nervous system axons, including axons of most cranial nerves. (Choice B)Oligodendrocytes are responsible for the myelinization of CNS axons, including axons of optic nerves. (Choice A)Astrocytes are supportive cells of the CNS. They give rise to the majority of glial tumors. (Choice D)Microglia are composed of phagocytic cells . (Choice E)In spite of the name 'neuroma,' acoustic neuromas do not arise from neural cells . Educational Objective: Acoustic neuromas result from the proliferation of Schwann cells (schwannomas).

Question 12

A 45-year-old man comes to the physician because of difficulty walking.  Over the last several months, he has had increased falls due to feeling off balance.  He also has shooting and burning pains in his legs.  He does not have a recent history of fevers/chills, trauma, headache, visual changes, slurred speech, or trouble swallowing.  The patient also has no history of insect bites, skin rash, or genital lesions.  He works as a truck driver in the Mid-Atlantic region of the United States.  His temperature is 36.7 C (98 F), blood pressure is 140/90 mm Hg, and pulse is 92/min.  His neurologic examination reveals bilateral small pupils that reduce in size with accommodation but not when exposed to bright light.  His muscle bulk and strength are normal.  He has reduced sensation to pain, temperature, vibration, and proprioception in the lower extremities.  Ankle reflexes are absent bilaterally.  He is unstable during the Romberg test.  Which of the following is most likely to establish the diagnosis?

Accepted Answer

Explanation: 11ec2b69_c193_288f_8f63_d5f958c1221b_MD0005_00 This patient is presenting with late neurosyphilis, which typically manifests years after Treponema pallidium infection and can be characterized by tabes dorsalis and Argyll Robertson pupils. Tabes dorsalis is a neurodegenerative condition that involves the posterior spinal columns and nerve roots. Posterior spinal column involvement results in impaired vibration/proprioception, sensory ataxia, and instability during the Romberg test. Nerve root involvement can contribute to diminished pain/temperature sensation and areflexia. Patients might complain of lancinating pains, described as brief shooting or burning pain in the face, back, or extremities. Tabes dorsalis can also be associated with Argyll Robertson pupils, which are characterized by normal pupillary constriction with accommodation but not with light. (Choices A, C, and D) Chronic alcohol use and diabetes mellitus can result in a symmetric sensory peripheral neuropathy that presents similarly to what is seen in this patient. Lyme disease has a high incidence in the Mid-Atlantic region of the United States and can also have variable neurologic manifestations (eg, meningitis, cranial neuritis, and radiculoneuritis). However, Argyll Robertson pupils are not commonly associated with these conditions. (Choice B) Vitamin B₁₂ deficiency can result in peripheral neuropathy and/or subacute combined degeneration (SCD). SCD is a myelopathy characterized by both posterior spinal column disease and lateral corticospinal tract disease, the latter of which causes spastic paresis and hyperreflexia. Folic acid deficiency usually does not cause neurologic symptoms. Deficiencies in these vitamins are not typically associated with Argyll Robertson pupils. ₁₂ Educational objective: Late neurosyphilis can present with tabes dorsalis (sensory ataxia and lancinating pains) and Argyll Robertson pupils (constriction with accommodation but not with light). References: The Argyll Robertson pupil. (http://www.ncbi.nlm.nih.gov/pubmed/20103017) Neurosyphilis. (http://www.ncbi.nlm.nih.gov/pubmed/24365430)

Question 13

A 14-year-old girl is brought to the office due to recurrent headaches. The headaches began 2 weeks ago while she was studying for end-of-semester exams. Since then, the patient has had headaches almost daily but has been able to continue school and other daily activities. The headaches are of moderate intensity, bifrontal, non-throbbing, exacerbated by loud noise, and relieved by sleep. She has had no nausea or vomiting. Her mother has a history of migraine. Vital signs are within normal limits. BMI is 28 kg/m². Nasal and oropharyngeal mucosae and tympanic membranes are normal. Neurological examination shows normal bilateral pupillary response and normal motor strength, sensation, and deep tendon reflexes. There is no neck rigidity. Which of the following is the most likely cause of this patient's headaches?

Accepted Answer

Explanation: 11ec2b69_c193_9dc0_8f63_6f69ddce5c50_MD0005_00 This patient developed headaches during a period of stress and now has periodic, bifrontal, non-throbbing headaches, suggesting tension-type headache (TTH). TTHs are the most common form of headache in children, occurring 2-3 times more frequently than migraines. Unlike migraines, TTHs tend to be non-throbbing, bilateral, and band-like. Daily activities are rarely affected, and abdominal pain, nausea, and vomiting are unusual. Phonophobia or photophobia may occur, but the presence of both indicates an alternate diagnosis. Patients with TTH typically have a normal neurologic examination but may have tenderness or trigger points in the musculature at the base of the occiput. Diagnosis is made based on characteristic clinical findings. Treatments with pharmacologic (eg, acetaminophen), behavioral, or stress-reductive therapies are often helpful. (Choice A) Intracranial tumors may present with symptoms similar to those of TTH. However, intracranial tumors often cause headaches in the occipital region that progressively worsen over time. In addition, neurologic function is often affected. This patient with intermittent, bifrontal headaches and a normal neurologic examination is more likely to have TTH. (Choice B) Frontal sinusitis can cause headaches, but patients usually have prominent nasal symptoms (eg, purulent discharge, congestion). This patient's nasal examination is normal. (Choice C) Idiopathic intracranial hypertension primarily occurs in obese women of childbearing age and is usually associated with severe, throbbing, unilateral headache, papilledema, and vision changes (eg, diplopia, blurriness). This child with a bifrontal, non-throbbing headache that does not interfere with daily function and a normal neurologic examination is unlikely to have idiopathic intracranial hypertension. (Choice D) Migraine headaches are also common in children but are usually throbbing and disabling and are more likely to be associated with nausea, vomiting, and both phonophobia and photophobia. Educational objective: Tension headaches are typically non-throbbing, bilateral, and band-like. Daily activities are rarely affected and nausea and vomiting are unusual. Patients may occasionally have associated phonophobia or photophobia but do not have both together.

Question 14

A 78-year-old man is brought to the office due to recurrent falls.  The patient is a nursing home resident, and the nursing home staff noticed that he has a progressive decrease in vision.  The patient has not had any double vision, dizziness, nausea, vomiting, headache, or vertigo.  Medical problems include Alzheimer dementia, peptic ulcer disease, diverticulosis, and degenerative joint disease.  Vital signs are stable.  On examination, he has decreased vision in both eyes, and bilateral anterior cortical cataracts.  Which of the following associated conditions is most likely contributing to his decreased vision?

Accepted Answer

Explanation: The common causes of decreased vision in elderly patients (especially age >75) are cortical cataracts and associated age-related macular degeneration (AMD). The prevalence of cataractsin this age group is almost 40%, and that of associated AMD is 20%. Cataracts represent slow, progressive opacification of the lens, progressing to painless blurry vision with generally intact visual fields. AMD refers to degeneration of the central portion of the retina (possibly due to chronic inflammation or infection), leading to loss of central vision. Early changes are often asymptomatic but can progress to difficulty reading, scotomas, or needing brighter light for visualization. Drusen (cellular debris) may be visible in early stages (dry AMD). With wet AMD (choroidal neovascularization), the presentation can be more acute. Visual loss related to AMD may be irreversible, unlike that related to cataract. scotomas Drusen Patients with cataracts should be thoroughly evaluated for the severity of AMD, as they may not benefit from cataract surgery alone (eg, lens extraction); AMD management (eg, oral eye vitamin, potential intravitreal therapy in case of wet AMD) may be warranted. Cataract surgery may also increase the risk of AMD progression (possibly because the opacified lens provided some protection from AMD); therefore, decisions about cataract surgery in patients with AMD should be based on an assessment of the potential gain from lens extraction. (Choices A and B) Although the prevalence of glaucoma increase with age, it is still <10%. In addition, closed-angle glaucoma usually causes severe eye pain and headache. (Choice C) Proliferative retinopathy is usually seen in patients with diabetes. Without a history of diabetes, this diagnosis is very unlikely. (Choice E) Retinal detachment usually presents with a sudden onset of unilateral loss of vision. Educational objective: Cataracts and associated macular degeneration are extremely common in the elderly population and often result in visual impairment. Elderly patients should be thoroughly evaluated for the severity of macular degeneration, as they may not benefit from cataract surgery.

Question 15

A 34-year-old previously healthy man comes to the office due to severe back pain.  Two days ago, the patient was working on the lawn and experienced sudden-onset low back pain while moving a bag of soil.  The pain worsens with movement and radiates to his left leg.  He also reports weakness of the left leg.  He has had some improvement in the pain after taking NSAIDs and resting.  Physical examination shows spasm of lower paraspinal muscles.  There is weakness of left ankle dorsiflexion and toe extension.  Ankle and knee reflexes are normal.  Sensory examination shows loss of pinprick sensation over the dorsum of the left foot.  Rectal tone is normal, and the remainder of the examination shows no abnormalities.  Which of the following is the most likely cause of this patient's current condition?

Accepted Answer

Explanation: 11ec2b69_c191_2cb8_8f63_c51ecaf5693f_MD0005_00 This patient with sudden-onset low back pain that radiates to the left leg associated with sensory and motor deficits most likely has a lumbosacral radiculopathy due to a herniated vertebral disc. The sensory deficits over the dorsum of the foot in combination with weakness of foot dorsiflexion and great toe extension are consistent with L5 nerve root compression. The manifestations of lumbar radiculopathies vary based on the involved nerve root, but they typically include low back pain associated with sensory and motor changes in a dermatomal and myotomal distribution. In the case of L5 nerve root compression, pain and sensory loss typically affect the buttocks, lateral thigh and calf (eg, lateral shin), and dorsal foot (eg, loss of pinprick sensation over left foot dorsum in this patient); dermatomal radiation of pain is also common. Weakness (and potentially atrophy) occurs in muscles innervated by fibers from the L5 spinal root, which include the tibialis anterior (foot dorsiflexion and inversion), peroneus (foot eversion), and extensor hallucis longus (great toe extension). dermatomal (Choice A) Acute spinal cord compression can cause back pain and weakness, but would be expected to cause bilateral deficits at all levels below the area of injury, rather than deficits confined to a portion of one leg. In addition, upper motor neuron signs (eg, hyperreflexia, increased muscle tone) would also be present. (Choice B) The common peroneal nerve originates from L5-S1, so there can be overlapping features with L5 radiculopathy. Common peroneal nerve entrapment can cause weakness of foot dorsiflexion and toe extension; however, it would not cause back pain that radiates to the leg. (Choice C) L2 vertebral disc herniation could result in back pain with radiation. However, sensory deficits would be seen in the thigh, and motor deficits would include hip flexion, hip adduction, and knee extension. (Choice E) Compression of the lower sacral nerve roots would cause sensory deficits in the perineum and dysfunction of the urinary or rectal sphincters. Educational objective: L5 radiculopathy often presents with low back pain that radiates down the leg associated with sensory loss over the lateral thigh, calf, and dorsal foot, and weakness of great toe extension and foot dorsiflexion, inversion, and eversion.

Question 16

A 16-year-old boy is brought to the emergency department by his mother after a single episode of generalized tonic-clonic seizure.  The patient has been staying up late studying for midterm exams and has been feeling "more tired than usual" for the last few days.  For the last 6 months, he has had occasional jerking arm movements in the morning but was not medically evaluated as they were brief and he otherwise "felt fine."  The patient has had no recent fevers, vomiting, or headaches.  He does not use alcohol or illicit drugs.  His mother describes him as "anxious," but he has no chronic medical conditions and takes no medications.  Temperature is 37.2 C (99 F), blood pressure is 120/60 mm Hg, and pulse is 72/min.  On physical examination, the patient is drowsy but responsive to commands and oriented to person, place, and time.  Cardiac examination reveals a regular rate and rhythm without murmurs.  Cranial nerves II-XII are intact; there are no focal deficits.  Deep tendon reflexes are normal in the upper and lower extremities, and plantar responses are flexor.  There are no rashes or petechiae.  Electroencephalogram shows bilateral polyspike and slow wave discharges.
Which of the following is the best next step in management of this patient's condition?

Accepted Answer

Explanation: 11ec2b69_c191_a1ea_8f63_31053c105fc1_MD0005_00 Juvenile myoclonic epilepsy (JME) is a common pediatric epilepsy syndrome that usually presents in otherwise healthy adolescents. In about one-third of patients, JME begins with absence seizures (eg, staring spells) up to 5 years before other seizure types. During adolescence, the classic presentation involves myoclonic jerks of the arms within the first hour of waking that can be aggravated by sleep deprivation and alcohol intake. Generalized tonic-clonic (GTC) seizures occur later in the disease course in almost all patients and may be the event leading to diagnosis. Up to half of patients have a concomitant psychiatric diagnosis (eg, anxiety). Electroencephalogram (EEG) classically demonstrates bilateral polyspike and slow wave discharges during the interictal period. Neuroimaging (eg, MRI) is typically normal and not needed for diagnosis when the clinical presentation and EEG are classic for JME. Valproic acid is the first-line treatment for all types of JME, and patients should be educated on sleep hygiene and avoidance of other precipitants. (Choice A) Although observation and reassurance are appropriate for a first unprovoked seizure, this patient's GTC seizure was preceded by multiple morning myoclonic seizures. Seizure recurrence is expected with JME, and antiepileptic therapy should be initiated without delay. (Choice B) Meningitis can cause seizures and is confirmed with lumbar puncture; however, this patient's lack of fever, headache, and nuchal rigidity makes meningitis unlikely. (Choice C) Infantile spasms are an epileptic disorder of infancy characterized by symmetric spasms, developmental delay, and hypsarrhythmia on EEG. Corticotropin (ACTH) and vigabatrin are the gold-standard treatments for infantile spasms but have no role in the treatment of JME. (Choice D) Ethosuximide is the first-line treatment for typical absence seizures but is not effective for GTC seizures. Educational objective: Juvenile myoclonic epilepsy should be suspected in healthy adolescent patients with upper extremity morning myoclonus and subsequent generalized tonic-clonic seizures. Electroencephalogram classically demonstrates bilateral polyspike and slow wave discharges during the interictal period. First-line treatment is valproic acid. References: Management of juvenile myoclonic epilepsy. (http://www.ncbi.nlm.nih.gov/pubmed/23756489)

Question 17

A 60-year-old man comes to the physician complaining of shaking of his right hand. This problem began several months ago and has progressed over time. He says it is worse while watching TV, but that he frequently forgets about it while working or doing his regular daily activities. He is an accountant who works at a bank. His past medical history is significant for left hip osteoarthritis for which he occasionally takes naproxen to relieve the pain. His mother has diabetes mellitus. His father died of a heart attack at age 60. His blood pressure is 125/68 mm Hg in both arms and heart rate is 72/min. His BMI is 27 kg/m². Physical examination shows a right hand tremor that diminishes with movement, and involuntary resistance to flexion of the right wrist and right arm. No sensory abnormalities are present. Muscle strength is preserved on both sides. Plantar reflexes are flexor bilaterally. Which of the following is the most accurate tool that can be used to diagnose this patient's disease?

Accepted Answer

Explanation: Parkinson disease (PD) is a clinical diagnosis that depends on the ability to recognize characteristic symptoms and physical signs. Bradykinesia and tremor or rigidity are essential features for diagnosis; however, these physical findings can have a diagnostic accuracy of only 26% at an initial visit. Bradykinesia is eventually seen in practically all patients, tremor is seen in about 79%-100% of patients, and rigidity occurs in approximately 90% of patients. A significant improvement in symptoms with dopaminergic medications is also highly supportive and improves diagnostic accuracy. Other features that are suggestive of the disease include a unilateral onset and persistent asymmetry of symptoms. Conventional brain MRI is of limited value in making a diagnosis of PD (Choice D). However, it should be performed to evaluate for alternate conditions such as stroke and hydrocephalus. The striatal dopamine transporter scan (DaTSCAN) is a nuclear medicine scan that uses ioflupane -123 (¹²³I), a radioactive isotope with a high affinity for dopamine transporters located in the striatal region of the brain. Low uptake of ¹²³I in the striatal region has a diagnostic accuracy equal to that of physical examination and is typically reserved for patients in which the diagnosis is equivocal. ¹²³ ¹²³ (Choices A, B, and C) Other diagnostic evaluations such as autonomic testing, electroencephalography, and lumbar puncture have a limited role in the diagnosis of PD but can help to exclude other diagnoses. Educational objective: Parkinson disease is a clinical diagnosis that requires the presence of bradykinesia in addition to tremor or rigidity. A brain MRI is usually performed to exclude alternate diagnoses; the striatal dopamine transporter scan can be considered when the diagnosis of Parkinson disease is equivocal. References: Parkinson disease: an update. (http://www.ncbi.nlm.nih.gov/pubmed/23418798)

Question 18

A 70-year-old Caucasian male presents to clinic complaining of "some very disturbing whirling attacks."  He says that on three occasions in this past week, he suddenly began to feel dizzy, nauseated, and found himself unable to walk or speak properly.  During these episodes he also noticed a tingling sensation in his lips and that he had double vision.  The symptoms resolved gradually after lasting approximately eight to ten minutes.  The episodes happened at different times of day, both while at rest and during activity.  His medical history is significant for diabetes mellitus, chronic obstructive pulmonary disease, hypertension, hypercholesterolemia, and a remote myocardial infarction.  His current medications include metformin, enalapril, hydrochlorothiazide, simvastatin, albuterol, and aspirin.  He has a fifty-pack-year smoking history and drinks 1-2 beers per night.  He denies having ever used recreational drugs.  His temperature is 36.7C (98F), blood pressure is 142/88 mm Hg, pulse is 82/min, and respirations are 14/min.  Funduscopic examination shows some neovascularization of the retinal surfaces.  Tympanic membranes are translucent and the light reflex is present.  Heart sounds are normal.  Auscultation of the chest reveals wheezing and diffusely decreased breath sounds.  He is barrel-chested.  Abdomen is nontender and bowel sounds are present.  Mild peripheral edema is evident.  There is a loss of vibratory sensation and altered proprioception and impairment of pain, light touch, and temperature in a bilateral stocking-glove distribution.  Ankle reflexes are decreased.  His most recent laboratory evaluation included the following:  What is the most likely diagnosis?

Accepted Answer

Explanation: Vertebrobasilar insufficiency (Choice C) is a term for reduced blood flow in the base of the brain, typically secondary to emboli, thrombi, or arterial dissection. The labyrinth and brainstem are commonly affected, and symptoms may include vertigo, dizziness, dysarthria, diplopia, and numbness. The vertigo often resolves on its own, but the condition should not be taken lightly. Risk factors for vertebrobasilar insufficiency include diabetes mellitus, hypertension, hypercholesterolemia, arrhythmia, coronary artery disease, circulatory problems, and a history of smoking cigarettes. Labyrinthitis (Choice A) is a mild, often self-limited condition characterized by vertigo, tinnitus, nausea, and a loss of balance. The disorder often follows a viral illness (eg, influenza). Labyrinthitis may also be caused by trauma, bacterial infection, allergies, benign tumors, and certain medications. Benign paroxysmal positional vertigo (Choice B) is an abnormal feeling of motion triggered by certain provocative positions. The condition is most often attributed to the presence of calcium debris within the posterior semicircular canal. Nystagmus is commonly seen. Panic attacks (Choice D) are discrete periods of intense fear or discomfort. Symptoms may include palpitations, sweating, trembling, shortness of breath, a choking sensation, chest pain, nausea, dizziness, paresthesias, and a fear of dying or losing control. Cataplexy (Choice E) is a sudden, temporary loss of muscle tone that can result in collapse. It is often caused by intense emotions, including laughter. Educational Objective: Vertebrobasilar insufficiency is typically secondary to emboli, thrombi, or arterial dissection. The labyrinth and brainstem are commonly affected, and symptoms may include vertigo, dizziness, dysarthria, diplopia, and numbness.

Question 19

A 62-year-old woman is brought to the physician by her son due to progressive forgetfulness over the last year.  She has been less active than normal and is having some difficulty walking.  The patient has no urinary incontinence.  Her past medical history is significant for exertional angina and hypertension.  She has recently been depending on her son to manage her medications, which include metoprolol, amlodipine, and aspirin.  She does not smoke or consume alcohol.  Her father had hypertension and stroke, and her mother had Alzheimer disease.  The patient is oriented to person and place, but not time.  She has difficulty with 3-word recall.  Her gait is slightly unstable and she has problems balancing when she closes her eyes.  Examination of the lower extremities show decreased vibratory sensation, spastic paresis, and hyperreflexia bilaterally. 
What is the most likely cause of this patient's condition?

Accepted Answer

Explanation: Vitamin B12 deficiency is relatively common in older adults and can present with dementia and subacute combined degeneration (SCD). This patient's dementia is represented by progressive memory impairment that is interfering with her daily activities (eg, medication management). She also has signs of dorsal spinal column dysfunction (eg, impaired vibration, positive Romberg sign) and lateral corticospinal tract abnormalities (eg, spastic paresis, hyperreflexia), which are fairly specific for SCD. Vitamin B12 levels should be checked in all patients with suspected dementia and/or SCD as these conditions are reversible with vitamin supplementation in the majority of cases. (Choice A) Alzheimer dementia can present with impaired cognition and diffuse cortical atrophy on neuroimaging. However, motor abnormalities are normally a late manifestation of the disease, and signs of dorsal spinal column dysfunction are not typical. (Choice B) Normal-pressure hydrocephalus is associated with ventriculomegaly and typically presents with gait abnormalities, cognitive dysfunction, and urinary incontinence. This patient's signs of dorsal spinal column dysfunction and lack of urinary incontinence make the diagnosis less likely. (Choice C) Wilson disease can result in copper accumulation in the brain and present with cognitive and gait dysfunction. However, the majority of cases are diagnosed at age 5-35, and the most common neurologic symptom is dysarthria. (Choice D) Although this patient has risk factors for stroke, her bilateral neurologic findings are consistent with myelopathy due to subacute combined degeneration. Educational objective: Dementia and subacute combined degeneration are potential complications of vitamin B12 deficiency that are reversible with vitamin supplementation in the majority of cases. References: Cobalamin deficiency: clinical picture and radiological findings. (http://www.ncbi.nlm.nih.gov/pubmed/24248213) Vitamin B(12) deficiency with bilateral globus pallidus abnormalities. (http://www.ncbi.nlm.nih.gov/pubmed/22332180)

Question 20

A 26-year-old Caucasian male presents to the emergency department with a three day history of dull back pain, progressive difficulty in walking, and urinary retention.  He had a mild upper respiratory infection one week ago, but he is otherwise healthy.  He is not taking any medications and denies drug abuse.  His temperature is 36.7 C (98 F), blood pressure is 120/76 mmHg, pulse is 80/min, and respirations are 16/min.  Neurologic examination reveals a decreased muscle strength (2/5) bilaterally in the lower extremities, hyporeactive knee and ankle reflexes, and decreased pain sensation up to the umbilical level.  Which of the following is the most likely diagnosis of this patient?

Accepted Answer

Explanation: Rapidly progressive weakness of the lower extremities following an upper respiratory infection, accompanied by sensory loss and urinary retention, is characteristic for transverse myelitis. Dull back pain may be present. Neurologic examination initially reveals muscle flaccidity and hyporeflexia, but spasticity and hyperreflexia develop subsequently. In patients presenting with acute transverse myelopathy, other causes (especially compressive lesions) should be ruled out by obtaining a careful history and performing the appropriate imaging procedures. (Choice A)A herniated intervertebral disk is characterized by an abrupt onset of neurologic deficit and may be related to strenuous activity. A straight-leg raising test will be positive. (Choices B and C) Although an epidural abscess or an acute subdural hemorrhage may develop in otherwise healthy individuals, an underlying cause is usually present (e.g., IV drug abuse or treatment with anticoagulants). (Choice D) Spinal cord compression from a metastatic tumor may present acutely, but the history of systemic malignancy is typical. Educational Objective: Rapidly progressive weakness of the lower extremities following an upper respiratory infection, accompanied by sensory loss and urinary retention, is characteristic for transverse myelitis.

Exam 2: Foundations of Independent Practice