Although hemiplegia is the typical manifestation of stroke, cerebrovascular disease may manifest itself by signs that spare the motor pathways but have the same serious diagnostic and therapeutic implications. The following stroke syndromes tend to be overlooked.
Sometimes disregarded is a leaking aneurysm presenting as a sudden and intense generalized headache lasting hours or days and unlike any headache in the past. Examination may disclose no abnormality except for a slightly stiff neck and raised blood pressure. Failure to investigate such a case by imaging procedures and examination of the CSF may permit the occurrence of a later massive subarachnoid hemorrhage. Small cerebral hemorrhages, subdural hematomas, and brain tumors figure into the differential diagnosis, which is usually settled by a CT or MRI.
A second nonobvious stroke is one caused by occlusion of the posterior cerebral artery, usually embolic. This may not be recognized unless the visual fields are carefully tested at the bedside. The patient himself may not be aware of the difficulty or will complain only of blurring of vision or the need for new glasses. Accompanying deficits are inability to name colors or recognize manipulable objects or faces, difficulty in reading, etc. MRI or CT usually corroborates the clinical diagnosis, and therapy is directed against further emboli or extension of the thrombosis.
An inapparent stroke that may be mistaken for psychiatric disease is an attack of paraphasic speech from embolic occlusion of a branch of the left middle cerebral artery. The patient talks in nonsensical phrases, appears confused, and does not fully comprehend what is said to him. He may perform satisfactorily at a superficial level and offer socially appropriate greetings and gestures. Only scrutiny of language function and behavior will lead to the correct diagnosis. Infarction of the dominant or nondominant temporal lobe and rarely of the caudate may produce an agitated delirium with few focal findings. This may be mistaken for a toxic or withdrawal state.
Parietal infarctions on either side (usually nondominant hemisphere) are often missed because the patient is entirely unaware of the problem or the symptoms create only a subtle confusional state, drowsiness, or only subtle problems with calculation, dialing a phone, reaching accurately for objects, or loss of ability to write. Extinction of bilaterally presented visual or tactile stimuli gives a clue; marked asymmetry of the optokinetic nystagmus response is sometimes the only definite sign.
A cerebellar hemorrhage may at first be difficult to recognize as a stroke. An occipital headache and complaint of dizziness with vomiting may be interpreted as a labyrinthine disorder, gastroenteritis, or myocardial infarction. A slight ataxia of the limbs, inability to sit or stand, and mild gaze paresis may not have been properly tested or have been overlooked. The entire syndrome may be missed if the patient is not asked to get off the gurney and walk. Early intervention by surgery may be lifesaving; but once the syndrome has progressed to the point of coma with pupillary abnormalities with bilateral Babinski signs, surgery is usually less likely to result in a good outcome. Similarly, a lateral medullary infarction causing incessant vomiting and dizziness may be mistaken for gastroenteritis unless nystagmus and gait ataxia are appreciated.
The Comatose Stroke Patient