Delerium and Coma /
Mental Status Change
Introduction
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.
Organic Brain Syndrome /
Delirium
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 patients 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.
Stupor and ComaThese 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 (ABCs), 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.
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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.
Reviewed by CAPT J. F. Morales, MC, USN, Neurology Specialty Leader, Neurology
Department, NNMC, Bethesda, MD (1999).
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Preface
· Administrative Section
· Clinical Section
The
General Medical Officer Manual , NAVMEDPUB 5134, January 1, 2000
Bureau
of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C.,
20372-5300
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