A 42-year-old woman is brought to the emergency department by her husband due to a sudden-onset, severe headache that began 3 hours ago. She describes it as the "worst headache of my life." Her medical history is unremarkable, and she takes no daily medications. Vital signs show a blood pressure of 150/90 mm Hg, heart rate of 92/min, and respiratory rate of 16/min. Neurological examination reveals no focal deficits, but she reports mild photophobia and neck stiffness. A non-contrast computed tomography (CT) scan of the head reveals no evidence of acute hemorrhage or mass effect. Which of the following is the most appropriate next step in the diagnostic workup?
- Lumbar punctureCevap
- BMagnetic resonance imaging of the brain
- CComputed tomography angiography of the head
- DCerebral angiography
- EDischarge with a prescription for a triptan
Cevap
Lumbar puncture is the correct next step because a negative head CT does not definitively rule out a subarachnoid hemorrhage in a highly suspicious presentation.
The correct answer is a lumbar puncture. In a patient presenting with a sudden-onset "thunderclap" headache highly suspicious for a subarachnoid hemorrhage (SAH), a non-contrast head CT is the best initial test. However, head CT can be falsely negative, especially if performed several hours after symptom onset, if the patient is anemic, or in cases with a very small amount of bleeding. Therefore, if the CT is negative and clinical suspicion remains high, a lumbar puncture is mandatory to evaluate for xanthochromia (bilirubin in the cerebrospinal fluid) and red blood cells to definitively confirm or rule out the diagnosis.
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Anahtar Kavram
In patients with a suspected subarachnoid hemorrhage and a negative non-contrast head CT, a lumbar puncture is the required next step in the diagnostic sequence.
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