Signs of Coma, Diagnosis, and Differential Diagnosis
When conducting a differential diagnosis of comatose states, the following key signs should be considered:
- Endotoxic Coma: This type of coma often develops subacutely over several hours or days, sometimes more slowly. It is frequently preceded by stupor, drowsiness, and sometimes psychomotor agitation.
- Hyperthermia: This is characteristic of coma due to overheating, infectious diseases of the nervous system (primarily purulent meningitis), general infections (severe influenza, typhoid fever, etc.), and sometimes somatic bacterial diseases (lobar pneumonia, etc.). Hyperthermia can also occur in epileptic coma.
- Skin and Mucous Membrane Color Changes: These can be indicative of the underlying condition leading to coma:
- Jaundice suggests hepatic coma.
- Cherry-red coloration indicates carbon monoxide poisoning.
- Facial hyperemia points to apoplectic coma.
- Pale gray skin color is associated with coma due to nutritional dystrophy, cancer, or Addison’s disease (bronze skin color).
- Dry skin with scratch marks is seen in uremic and diabetic (hyperglycemic) comas.
- Ammonia odor from the mouth is characteristic of uremic coma, while the smell of acetone is indicative of hyperglycemic coma.
- Papilledema: Combined with albuminuric retinitis and high blood urea levels indicates eclamptic (pseudo-uremic) coma.
- High Blood Pressure: Recorded in cases of apoplectic coma (cerebral hemorrhage).
- Bradycardia: Observed in apoplectic and traumatic comas (with intracranial hematoma), coma associated with brain tumors, atrioventricular block, and exotoxic comas related to poisoning with beta-blockers, digitalis, or hyperkalemia.
- Mydriasis (Pupil Dilation): Seen in coma related to poisoning by anticholinergic substances (atropine, belladonna, cyclodol, etc.), carbon monoxide poisoning, and nutritional-dystrophic coma.
- Miosis (Pupil Constriction): Characteristic of hyperglycemic (diabetic) coma, uremic coma, and coma due to morphine and opiate poisoning.
- Anisocoria (Unequal Pupil Size): Typically seen in destructive coma, most commonly apoplectic and traumatic comas.
- Seizures: Characteristic of epileptic and eclamptic comas, they can also be observed in destructive comas of any origin.
- Myoclonic Jerks: Indicative of uremic and anoxic-ischemic comas.
- Hormetonia: Along with persistent focal neurological symptoms, particularly hemiparesis, indicates destructive coma, most commonly apoplectic and traumatic.
- Early Tendon Areflexia: Observed in the precoma state (stupor, drowsiness) and in the first stage of coma, it is specific to alcoholic and diabetic comas.
- Vegetative State (Apathetic Syndrome): This is termed a chronic vegetative state if it lasts more than a month. It is usually the result of extensive brain damage — cortex, limbic system, and basal ganglia — with the brainstem remaining intact. Patients maintain spontaneous breathing and cardiovascular function. The state is characterized by alternating periods of apparent wakefulness and sleep. Despite the lack of motor activity (except for responses to stimuli or random movements), patients periodically open their eyes, though they do not perceive their surroundings or respond to verbal stimuli. Recovery from a chronic vegetative state is extremely rare, and higher mental and social functions are not restored.
In conclusion, the diagnosis and differential diagnosis of coma involve careful observation of specific clinical signs and a thorough differential diagnosis to determine the appropriate treatment for each case.