When to get a CT Head
When to get a head CT?
How do you know when to order a head CT? A patient presents with headache or confusion: should you get a scan now? Here is a mnemonic that can help you know when to get a head CT on a patient with neurological symptoms.
SCAN – NOW. Get a CT Head if . . .
Seizure: new onset seizure
Confusion, or any change in mental status
Acute onset: a “new and different” headache
Nuchal rigidity: the stiff neck of meningitis or subarachnoid hemorrhage
Neuro deficit: any focal neuro change, like unequal pupils or pronator drift
Optic papilledema: a sign of increased intracranial pressure
Worrisome history: like malignancy, anticoagulants, or prior bleed or known lesion
For the patient with complaint of headache, always ask, “Is this the same old headache that’s bothered you so long … or IS THIS NEW AND DIFFERENT?” The “new and different headache” needs a CT.
For the headache patient, always perform a funduscopic exam, looking for optic papilledema, a sign of increased intracranial pressure. Every headache workup needs a funduscopic exam!
Nuchal rigidity is a classic sign of meningitis and is caused by the irritation of the meninges caused by bacteria and white blood cells in the CSF. This irritation is heightened by flexion of the neck, as the meninges are stretched. In a subarachnoid hemorrhage, red blood cells in the CSF cause a similar irritation of the meninges, aggravated by neck flexion. This nuchal rigidity is also associated with Kernig’s sign and Brudzinski’s sign. Any patient with headache and nuchal rigidy requires an immediate CT of the head. (And in the presence of acute illness or fever suggesting meningitis, immediate administration of antibiotics, even before the diagnostic workup is completed.)