A 42-year-old woman presented to the ED with headache and posterior
neck pain of one and a half hour’s duration. The onset
of the headache was sudden and was accompanied by one episode of
She had seen a physician two days earlier for neck pain and was
told she had a “pinched nerve.”
On examination, she was an overweight female in mild distress
due to her headache. The patient was fully alert and oriented with
no focal neurological deficits. She resisted full flexion of her neck.
A noncontrast head CT was obtained and interpreted as normal
- What should be done next?
The next day, the official CT reading diagnosed subarachnoid
- What are the CT findings of subarachnoid
hemorrhage on this CT?
Because the patient’s headache had characteristics suspicious
for subarachnoid hemorrhage (SAH)—sudden onset, association
with vomiting, and mild nuchal rigidity—and because CT
can occasionally miss SAH, a lumbar puncture was performed in the
ED. The spinal fluid was blood tinged and, after centrifugation,
the supernatant fluid had xanthochromia. She was admitted to the hospital
for further evaluation of SAH.
Subarachnoid hemorrhage is a potentially
life-threatening cause of headache. In 85% of cases, SAH
is due to leakage or rupture of an aneurysm at the base of the brain
(circle of Willis). The patient classically presents with an abrupt
onset of severe headache (“thunder-clap”), which
may be accompanied by an altered level of consciousness, seizure,
or focal neurological deficits. When there is a large hemorrhage, the
gravity of illness is obvious both clinically and on CT.
When a lesser quantity of blood leaks from the aneurysm, the
patient may present solely with headache. The clinical and CT findings
can be subtle and the diagnosis can potentially be missed. Such
misdiagnosis can have devastating consequences when the patient
later suffers a massive hemorrhage causing permanent neurological
disability or death.
In up to 50% of cases, a small bleed causing a “sentinel” or “warning” headache
precedes a large hemorrhage by hours, days, or weeks. Half of these
patients may have sought medical attention and may have been misdiagnosed,
i.e., up to 25% of SAH are missed on initial presentation (Kowalski
2004, Mayer 1996). Patients with such small bleeds benefit most
from prompt diagnosis and treatment because they are neurologically
intact at the time of initial presentation and ...