Hemiplegia is paralysis of one side of the body and is almost invariably the result of damage to the pyramidal tract somewhere along its course from the upper cervical cord to the cerebral cortex. Recall of the many causes can be facilitated by the mnemonic VITAMIN.
· V—Vascular disease would help recall cerebral hemorrhage, thrombosis, and embolisms. When these occur in the vertebral–basilar artery distribution, quadriparesis or paraplegia is more common. Aneurysm and arteriovenous malformation can be associated with paraplegia. Anterior spinal artery occlusions are more likely to be associated with paraplegia.
· I—Inflammatory disease would suggest cerebral abscess, cortical vein thrombophlebitis, encephalomyelitis, viral encephalitis, and some form of meningitis.
· T—Trauma brings to mind epidural, subdural, and intracerebral hematomas resulting from trauma. Although uncommon, a high cervical cord lesion due to a fractured cervical spine with cord compression may cause hemiplegia.
· A—Autoimmune disorders that may cause hemiplegia include multiple sclerosis, possible Schilder disease, and collagen disorders.
· M—Malformation brings to mind porencephalic cysts, cerebral agenesis, and Sturge–Weber syndrome.
· I—Intoxication is not likely to cause hemiplegia, but ischemia would suggest the transient ischemia of carotid stenosis and migraine.
· N—Neoplasms of brain (causing hemiplegia) include meningiomas, gliomas, and metastatic carcinoma. An early meningioma of the high cervical cord may rarely be associated with hemiplegia. N for neurosis will help to recall the hemiplegia of conversion hysteria.
Approach to the Diagnosis
The history is very important in determining the diagnosis of hemiplegia. An acute onset without a history of trauma would suggest a cerebral embolism, hemorrhage, or thrombosis, whereas a gradual onset would indicate a possible neoplasm or other space-occupying lesion. Intermittent occurrence of hemiplegia might suggest migraine, multiple sclerosis, or carotid artery insufficiency. A history of fever may indicate a cerebral abscess or subacute bacterial endocarditis. The physical examination may also be helpful. A carotid bruit points to carotid stenosis. A cardiac arrhythmia suggests cerebral embolism. Hypertension points to cerebral hemorrhage. A central facial palsy or other cranial nerve signs indicate a brain or brainstem lesion as opposed to a cervical cord insult. The initial diagnostic workup would include a CBC, sedimentation rate, VDRL, ANA, and chemistry panel.
More definitive studies such as a CT scan or MRI will almost certainly be necessary, but a neurologist should be consulted first. If a vascular lesion is suspected, MRI, a carotid duplex scan, and four-vessel cerebral angiography may be indicated. Blood cultures would be helpful in ruling out bacterial endocarditis. Spinal fluid analysis should be done if multiple sclerosis or neurosyphilis is suspected.
Other Useful Tests
1. Endocarditis (cerebral embolism)
2. Electrocardiogram (EKG) (myocardial infarction with mural thrombosis, atrial fibrillation)
3. Somatosensory evoked potential (SSEP), brainstem-evoked potential (BSEP), VEP (multiple sclerosis)