A 46-year-old woman comes to the emergency department due to sudden-onset, severe occipital headache and nausea. The patient has a history of hypertension and cigarette smoking. Physical examination shows mild disorientation but no focal weakness, sensory loss, or cranial nerve abnormalities. Noncontrast CT scan of the head reveals diffuse hyperdensity in the subarachnoid space. CT angiography reveals a ruptured anterior communicating artery aneurysm. The patient undergoes endovascular coiling of the aneurysm. Four days later, there is sudden deterioration in her level of consciousness and new, right-sided hemiparesis is observed. Repeat CT scan shows no significant changes. Which of the following is the most likely cause of this patient's neurological deterioration?

Question

A 46-year-old woman comes to the emergency department due to sudden-onset, severe occipital headache and nausea.  The patient has a history of hypertension and cigarette smoking.  Physical examination shows mild disorientation but no focal weakness, sensory loss, or cranial nerve abnormalities.  Noncontrast CT scan of the head reveals diffuse hyperdensity in the subarachnoid space.  CT angiography reveals a ruptured anterior communicating artery aneurysm.  The patient undergoes endovascular coiling of the aneurysm.  Four days later, there is sudden deterioration in her level of consciousness and new, right-sided hemiparesis is observed.  Repeat CT scan shows no significant changes.  Which of the following is the most likely cause of this patient's neurological deterioration?

Quizplus · Accepted Answer

Subarachnoid hemorrhage (SAH) is a life-threatening condition that most commonly results from rupture of a saccular (berry) aneurysm. It classically manifests with the abrupt onset of severe headache (thunderclap headache); confusion, loss of consciousness, and meningismus may also occur. Noncontrast head CT scan reveals blood in the subarachnoid space (between the arachnoid and pia mater). If the patient survives the initial SAH, a number of complications (eg, rebleeding, hydrocephalus, seizures) may occur in the following days to weeks. The most common is arterial vasospasm, which occurs due to the release of vasoconstrictive factors from damaged erythrocytes in the subarachnoid space and the inability of damaged vascular endothelial cells to produce vasodilators (eg, nitric oxide). The resultant unopposed vasoconstriction can cause delayed cerebral ischemia, which manifests as a change in mental status and/or new focal neurological deficits 3-12 days after the SAH. CT scan usually reveals no significant changes despite the severity of the ischemia following vasospasm. Nimodipine, a selective calcium channel blocker, is used after SAH to promote vasodilation and prevent calcium-dependent excitotoxicity, which improves outcomes by reducing the incidence and extent of ischemia due to cerebral vasospasm. (Choices A, B, and E) Although arterial thrombosis, embolism, and vascular inflammation could all cause a change in mental status and focal neurologic deficits, they are not significant complications of SAH. (Choice C) Hydrocephalus may occur hours to days after SAH due to blood breakdown products obstructing the flow of cerebrospinal fluid or clogging the arachnoid villi. Patients develop signs of elevated intracranial pressure (eg, nausea/vomiting), and neuroimaging demonstrates ventricular dilation. (Choice D) Rebleeding after initial SAH carries a high mortality rate and usually occurs early (<24 hours) after the initial bleed. Although symptoms can include a sudden change in level of consciousness and appearance of new neurological deficits, rebleeding is very rare 4 days after a successfully repaired aneurysmal rupture and CT scan would demonstrate newly extravasated blood. Educational objective: The most common complication of aneurysmal subarachnoid hemorrhage is vasospasm, which typically occurs 3-12 days after the initial insult and can cause delayed cerebral ischemia (eg, sudden change in mental status, new focal neurological deficits). The CT scan usually remains unchanged, unlike with rebleeding.

A 46-Year-Old Woman Comes to the Emergency Department Due to Sudden-Onset