An 18-year-old woman is brought to the emergency department due to a severe headache. Her symptoms began suddenly an hour ago while she was moving into her college dorm room. The patient rested and took acetaminophen; the pain remains severe, and she has vomited once. Her only medication is an oral contraceptive. Temperature is 37.3 C (99.1 F), blood pressure is 156/90 mm Hg, and pulse is 100/min. The patient appears uncomfortable. Neurologic examination shows intact cranial nerves. Strength and sensations are equal bilaterally. Cerebellar examination is normal. CT scan of the head shows no focal abnormalities. Results from cerebrospinal fluid analysis are as follows: There is no difference in cell counts between the first and the last collection tubes. Which of the following is the most likely diagnosis in this patient?

Question

An 18-year-old woman is brought to the emergency department due to a severe headache.  Her symptoms began suddenly an hour ago while she was moving into her college dorm room.  The patient rested and took acetaminophen; the pain remains severe, and she has vomited once.  Her only medication is an oral contraceptive.  Temperature is 37.3 C (99.1 F), blood pressure is 156/90 mm Hg, and pulse is 100/min.  The patient appears uncomfortable.  Neurologic examination shows intact cranial nerves.  Strength and sensations are equal bilaterally.  Cerebellar examination is normal.  CT scan of the head shows no focal abnormalities.  Results from cerebrospinal fluid analysis are as follows:  There is no difference in cell counts between the first and the last collection tubes.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d542_94a6_bc81_492b50642936_MD0003_00 This patient's sudden-onset headache and cerebrospinal fluid (CSF) analysis are consistent with subarachnoid hemorrhage (SAH). Bleeding is typically due to a ruptured intracranial aneurysm, which may occur spontaneously or be triggered by physical exertion (ie, acute rise in blood pressure). Risk factors for SAH include smoking, hypertension, and certain genetic conditions (eg, autosomal dominant polycystic kidney disease). SAH classically presents with an acute, severe headache often described as "the worst of my life." Brief loss of consciousness and/or vomiting can occur, and patients are often hypertensive. Meningeal signs (eg, stiff neck, photophobia) may develop because blood in the CSF irritates the meninges, but focal neurologic deficits are typically absent. Noncontrast CT scan of the head is the first step in evaluation but may not detect a low-volume bleed, as in this patient. When clinical suspicion for SAH remains high, lumbar puncture (LP) is warranted to confirm the diagnosis. Characteristic findings include an elevated opening pressure and increased red blood cells (RBCs) that, in contrast to those from a traumatic LP, do not clear with successive CSF samples. In addition, RBC breakdown products (eg, bilirubin) in the CSF can lead to xanthochromia (yellow CSF) and slightly elevated protein. CT scan of the head After stabilization, management of SAH involves surgical repair (eg, clipping) of the aneurysm to prevent rebleeding. (Choices A and B) Bacterial meningitis (eg, Neisseria meningitidis) and herpes simplex virus (HSV) meningoencephalitis can present with acute headache and vomiting in adolescents. HSV encephalitis can also cause erythrocytes in CSF (as well as temporal lobe necrosis). However, fever and elevated white blood cells in the CSF would be expected. (Choice C) Idiopathic intracranial hypertension is most common in obese women of childbearing age and is characterized by headache, vision changes, and an elevated opening pressure. Increased RBCs in this patient's CSF make this diagnosis unlikely. (Choice D) Although oral contraceptives increase the risk of ischemic stroke, patients usually have focal neurologic deficits (eg, weakness) on examination. In addition, CSF cell counts are typically normal. Educational objective: Subarachnoid hemorrhage classically presents with a sudden-onset, severe headache. Lumbar puncture is warranted if clinical suspicion remains high despite a normal CT scan of the head. Characteristic findings include an elevated opening pressure, xanthochromia, and an elevated red blood cell count that does not decline with successive samples. References: Subarachnoid hemorrhage. (http://www.ncbi.nlm.nih.gov/pubmed/27741994)

An 18-Year-Old Woman Is Brought to the Emergency Department Due