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?

Question

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?

Quizplus · 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)

A 36-Year-Old Man Has Had Weakness in His Right Arm