History and Physical
A 17-year-old right-handed male consults for a daily and persistent headache over 2 weeks. Headaches are predominantly left unilateral, with retroorbital and throbbing pain. They are associated with photophobia, phonophobia, and nausea and vomiting. In addition, he reports blurred vision in the left eye without tearing or conjunctival injection.
On the day of presentation, the headache is severe (8–9/10) and associated with sudden-onset paresthesias in the right hemibody. The paresthesias rapidly spread from fingers to hand, arm, and face. This is accompanied by dysarthria and word-finding difficulties. Symptoms worsen over a 10-minute period, to the point where he is unable to feel his face and right arm. These symptoms resolve within an hour, but he subsequently develops paresthesias and slight weakness in his right arm, lasting 2 hours. He recalls a similar but milder episode 6 months earlier. Family history is negative for migraine, stroke, or other illnesses.
In the emergency department, the patient is oriented in time and space. He is able to follow orders but not comfortably. The neurological examination shows mild dysarthria but preserved language function with good understanding, repetition, and meaning of words. The young man does not have any sensory deficits, but strength in the hand and right arm is approximately 4/5, and deep reflexes are difficult to obtain. No facial or lower limb weakness is observed. The rest of the exam is normal.
Diagnostic Workup
MRI stroke protocol performed 2 hours after the onset of symptoms is negative for acute infarct but shows asymmetric decrease in left cerebral perfusion and cortical venous susceptibility ( Fig. 6.1 ).
Hemiplegic migraine. Brain MRI, (A) arterial spin labeling (ASL) demonstrates decreased perfusion throughout the left cerebral hemisphere with increased signal in overlying arteries, reflecting arterial transit artifact ( arrow ). (B) Susceptibility-weighted imaging (SWI) shows decreased asymmetric signal in left hemispheric cortical veins ( arrow ).
Clinical Differential Diagnosis
Stroke and transient ischemic attack: Strokes, especially of the hemorrhagic type, can present with headaches. Urgent investigation is required, including MRI with stroke protocol and laboratory tests to evaluate for risk factors.
Focal seizures with Todd paralysis: Paralysis after a focal seizure is usually sudden, and most patients have a history of prior motor seizures.
Hemiplegic migraine: Development of neurological symptoms in hemiplegic migraine is progressive (usually more than 20 minutes). Clinical and radiologic abnormalities are generally reversible. Hemiplegic migraine occurs around the first or second decade of life.
Alternating hemiplegia of childhood: Children with this disorder have intermittent episodes of hemiplegia affecting one or both sides. Age of onset is usually before 18 months.
Tumors and hydrocephalus: Space-occupying lesions can present with headaches and motor deficits. These generally follow a subacute time course, though a longer deterioration is possible.
Sturge-Weber syndrome (SWS): Children with SWS have headache, seizures, and hemiplegic episodes. Type 3 SWS affects the brain without facial vascular malformations. Type 1 to 2 SWS are easier to diagnose due to the overlying facial port-wine stains.
Infection: Meningoencephalitis can manifest with asymmetric focal deficits and headaches. Patients present with fever and CSF abnormalities.
Mitochondrial disorders: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) can cause headaches and motor deficits, typically self-resolving.
Imaging Differential Diagnosis
Stroke: Arterial ( Fig. 6.2 ) and venous strokes can present with decreased perfusion in vascular distributions but not involving an entire hemisphere. A global anoxic event can produce bilateral infarcts, but again not in a hemispheric distribution.
Acute stroke with autoregulation. Brain MRI, (A) axial FLAIR, (B) DWI, and (C) ADC show right parietal infarct with restricted diffusion in the cortex and subcortical white matter ( arrowheads ). (D) MR angiography shows dilation of the distal right middle and posterior cerebral artery branches ( arrows ), reflective of cerebral autoregulation. ADC , Apparent diffusion coefficient; DWI , diffusion weighted imaging; FLAIR , fluid-attenuated inversion recovery.
