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Table 16-3

Differential Diagnosis of Coma

  1. Diseases that cause no focal or lateralizing neurologic signs, usually with normal brainstem functions; CT scan and cellular content of the CSF are normal.
    1. Intoxications: alcohol, sedative drugs, opiates, etc.
    2. Metabolic disturbances: anoxia, hyponatremia, hypernatremia, hypercalcemia, diabetic acidosis, nonketotic hyperosmolar hyperglycemia, hypoglycemia, uremia, hepatic coma, hypercarbia, Addisonian crisis, hypo- and hyperthyroid states, profound nutritional deficiency
    3. Severe systemic infections: pneumonia, septicemia, typhoid fever, malaria, Waterhouse-Friderichsen syndrome
    4. Shock from any cause
    5. Postseizure states, status epilepticus, nonconvulsive status epilepticus
    6. Hypertensive encephalopathy, eclampsia
    7. Severe hyperthermia, hypothermia
    8. Concussion
    9. Acute hydrocephalus
  2. Diseases that cause meningeal irritation with or without fever, and with an excess of WBCs or RBCs in the CSF, usually without focal or lateralizing cerebral or brainstem signs; CT or MRI shows no mass lesion.
    1. Subarachnoid hemorrhage from ruptured aneurysm, arteriovenous malformation, trauma
    2. Acute bacterial meningitis
    3. Viral encephalitis
    4. Miscellaneous: fat embolism, cholesterol embolism, carcinomatous and lymphomatous meningitis, etc.
  3. Diseases that cause focal brainstem or lateralizing cerebral signs, with or without changes in the CSF; CT and MRI are abnormal
    1. Hemispheral hemorrhage (basal ganglionic, thalamic) or infarction (large middle cerebral artery territory) with secondary brainstem compression
    2. Brainstem infarction due to basilar artery thrombosis or embolism
    3. Brain abscess, subdural empyema
    4. Epidural and subdural hemorrhage, brain contusion
    5. Brain tumor with surrounding edema
    6. Cerebellar and pontine hemorrhage and infarction
    7. Widespread traumatic brain injury
    8. Metabolic coma (see above) with preexisting focal damage
    9. Miscellaneous: Cortical vein thrombosis, herpes simplex encephalitis, multiple cerebral emboli due to bacterial endocarditis, acute hemorrhagic leukoencephalitis, acute disseminated (postinfectious) encephalomyelitis, thrombotic thrombocytopenic purpura, cerebral vasculitis, neurologic paraneoplastic syndromes, gliomatosis cerebri, pituitary apoplexy, intravascular lymphoma, etc.