Delerium and Coma / Mental Status Change

Department of the Navy
Bureau of Medicine and Surgery
Peer Review Status: Internally Peer Reviewed

One of the most frightening and confusing problems for the physician onboard a ship or in an isolated deployment is a patient with altered mental status. For some reason, the first concern of most physician is brain tumor or masses, a relatively rare cause of altered mental status (in the absence of trauma) in a military population. First, keep in mind the fundamentals of neurologic diagnosis. Focal disease causes focal deficits. Non-focal, that is generalized diffuse disturbance of the brain, just as anywhere in the nervous system, is due to:

History and sometimes basic laboratory tests will discriminate among these last three. The mental status examination is discussed elsewhere in this manual and will not be repeated here.

The main features that distinguish organic from psychiatric causes of mental reactions are the level of alertness and orientation. Orientation is the more useful of the two, clinically because the patient with depressed alertness is already obviously organic. When presented with a patient who is irrational or whose behavior raises the question of psychological or organic disturbances, the following considerations should come to mind: Are the patient’s sensory functions intact? Can the patient see and hear? Can the patient speak? Is the apparent strange behavior a manifestation of aphasia? Then determine the patient's ability to attend and concentrate with recall of digits or repetition of a sequence of gestures. If these are done well, the orientation to time, place, and situation are the main discriminators of organic vs. psychiatric mental disturbance. Obviously a stiff neck, asymmetry of reflexes, or a Babinski sign indicate organic disease.

Hallucinations may be signs of schizophrenia or mania, but they may be seen in organic disease as well. Visual hallucinations usually indicate organic disease, and hallucinations of small animals or bugs, especially in large numbers, indicate toxic encephalopathy. This is particularly common with drug toxicity and alcohol withdrawal.

The commonest causes of delirium (acute organic brain syndrome) are drug overdoses or chemical ingestion. Hallucinogenic drugs as well as amphetamines have to be considered, as well as narcotics and alcohol. At sea, there is plentiful access to a number of solvents. Inhalation of fluorocarbon (Freon) solvents and lubricants are occasional recreational drugs. Other ingestion may not be intentional. In a military or industrial setting, metal toxicity from lead, arsenic, and more rarely beryllium need to be considered. Many hydrocarbon solvents and fuels can be chronically and acutely absorbed through the skin and induce an organic brain syndrome. A careful history of the patient's work and recreational environments must include interviews with coworkers and bunkmates. The physician and preventive medicine techs must review the materials and chemicals used in the individual's workspace.

Acute metabolic causes of delirium include hyponatremia and hyperthermia.

Other causes of delirium without focal neurologic disease include hyperthermia, encephalitis, cerebral vasculitis, and endocrine disturbances, especially myxedema and thyrotoxicosis.

The first step in treating the patient with delirium is to identify the cause, if possible, and treat it. If the patient is agitated, phenothiazines may be the most useful agents and are less likely to be sedating than benzodiazepines. Consultation should be sought from a neurologist or psychiatrist, and if a remediable cause cannot be found, a MEDEVAC should be arranged as soon as it can be done safely.

These are the most extreme degrees of organic disturbance of consciousness. Stupor, sometimes called "semi-coma," is the state of unresponsiveness and lack of awareness of self and environment from which the patient can be aroused to brief primitive responses only by noxious stimuli. Coma is that condition in which the patient has no response to even noxious stimuli other than primitive brain stem or spinal reflexes.

For the patient in a coma, the most important consideration is to maintain the airway and provide ventilatory support. Circulation is the next consideration, so hydration, cardiac rhythm, and blood pressure must be maintained. The most common causes of coma in the general population are toxic and metabolic conditions.

• Poisoning: drugs, vapors, ingestion of chemicals.

• Hypoxia: anoxia, choking, and cardiac arrest.

• Organ failure: especially hepatic and renal.

• Hypoglycemia.

• Endocrine disease: myxedema, parathyroid disease, and adrenal failure.

• Nutritional (thiamine deficiency - Wernicke's syndrome).

After establishing the airway, breathing and circulation (ABC’s), the patient should be given intravenous thiamine and glucose, as well as supplemental oxygen. Blood should be drawn to measure electrolytes, liver and renal function, and thyroid function.

• In a military setting, head trauma and mass lesions are important considerations. The optic fundi must be checked for papilledema, and a detailed neurologic examination should look for signs of focal lesions. If available, imaging should be done as soon as possible. If it is not available, and there are no signs or history of trauma, and the patient has no focal or lateralized signs, stronger consideration should be given to the possibility of subarachnoid hemorrhage and infection. The physician must immediately do a lumbar puncture.

• As soon as ventilation and circulation can be stabilized and assured, the patient should be evacuated. An endotracheal tube and urinary catheter should usually be inserted for the transport, as well as a capable medical escort trained in Advanced Cardiac Life Support (ACLS); either an independent duty corpsman, a nurse, or a physician.