Of course, diagnosis has as its prime purpose the direction of therapy. The treatable causes of coma are drug and alcohol intoxications, shock from infection, cardiac failure, or systemic bleeding, uremia, epidural and subdural hematomas, brain abscess, bacterial and fungal meningitis, diabetic acidosis or hyperosmolar state, hypoglycemia, hypoor hypernatremia, hepatic coma, hypercalcemia, uremia, status epilepticus, Wernicke disease, Hashimoto encephalopathy, and hypertensive encephalopathy. Also treatable to a varying degree are cerebellar hemorrhages, which can be removed successfully; edema from massive stroke, which may be ameliorated by hemicraniectomy; and hydrocephalus from any cause, which may respond to ventricular drainage.
Management of the Acutely Comatose Patient
Seriously impaired states of consciousness, regardless of their cause, are often fatal not only because they represent an advanced stage of many diseases but also because they add their own particular burdens to the primary disease. The physician’s main objective, of course, is to find the cause of the coma and to treat it appropriately. It often happens, however, that the disease process is one for which there is no specific therapy; or, as in hypoxia or hypoglycemia, the acute, irreversible effects have already occurred before the patient comes to the attention of the physician. Again, the problem may be highly complex, for the disturbance may be attributable not to a single cause but to several factors acting in unison, no one of which could account for the total clinical picture. In certain circumstances two processes contribute to depressing consciousness, particularly head injury combined with drug or alcohol intoxication, and focal lesion(s) combined with inevident seizures. In lieu of specific therapy, supportive measures must be used; indeed, the patient’s chances of surviving the original disease often depend on the effectiveness of these general medical measures.
The successful management of the insensate patient requires the participation of a well-coordinated team of nurses and a physician. Necessary treatments must be instituted rapidly, even before all the diagnostic steps have been completed; diagnosis and treatment may have to proceed concurrently. The following is a brief outline of the principles involved in the treatment of such patients. The details of management of shock, fluid and electrolyte imbalance, and other complications that threaten the comatose patient (pneumonia, urinary tract infections, deep venous thrombosis, etc.) can be found in Harrison’s Principles of Internal Medicine.
1. Shallow and irregular respirations, stertorous breathing (indicating obstruction to inspiration), and cyanosis require the establishment of a clear airway and delivery of oxygen. The patient should initially be placed in a lateral position so that secretions and vomitus do not enter the tracheobronchial tree. Secretions and vomitus should be removed by suctioning as soon as they accumulate; otherwise they will lead to atelectasis and bronchopneumonia. Arterial blood gases should be measured and further observed by monitoring of oxygen saturation.
A patient’s inability to protect against aspiration and the presence of either hypoxia or hypoventilation dictate the use of endotracheal intubation and a positive-pressure respirator.
2. The management of shock, if present, takes precedence over all other diagnostic and therapeutic measures.