In pure alcoholic coma the presence of the special features of coma from other causes will be absent. It must be remembered, however, that alcoholic coma may be combined with other kinds, and the more serious form should be kept in mind. Where there is the slightest doubt in the diagnosis, one‘s procedure should be ruled by the possibility of the graver cause.
Opium or Narcotic Poisoning.—The skin is usually perspiring freely, moist and cold; the countenance placid, pale and ghastly, the lips livid. The eyes are heavy, and the pupils contracted to a pin-head and equal, the conjunctival reflex usually present. There is the odour of opium in the breath. The pulse is slow, and the respiration stertorous and slow. There is no paralysis, and the person can be momentarily roused by a sharp question or blow.
Apoplexy.—The person is with difficulty, if ever, temporarily aroused. The face is red and bloated. Respiration suspirious and stertorous, and there is often Cheyne-Stokes breathing. The pupils are dilated or irregular; in pontine hæmorrhage, contracted. The temperature may at first be subnormal but gradually rises.
There may be rigidity of the limbs, or hemiplegia. The pulse is full and bounding, often of high tension with hardened arteries.
Albuminuria may be present.
Uræmia.—This is less profound than in cerebral hæmorrhage; the patient may be temporarily aroused; the onset is usually gradual. There is albuminuria with casts; albuminuric retinitis may be present. The pupils may be contracted or dilated. The breath has a peculiar so-called “uræmic odour.” The pulse is generally slow, the tension high, and the heart enlarged. The respirations are slow and sighing, and may be Cheyne-Stokes in type. There is no paralysis. There may have been preceding convulsions, and the coma may alternate with these attacks.
Anasarca may be present.
Diabetic Coma.—This may come on suddenly, and may occur unexpectedly in a person in whom diabetes has not been discovered up to the time of coma. There is sighing respiration, “air hunger.” The odour of acetone in the breath is present, and sugar in the urine.
Epilepsy.—Unconsciousness is profound, and comes on immediately with rigidity, followed by convulsions, unilateral, limited to the side of the face, jaws, head and neck or arm, or generalised. Bloody froth exudes from the mouth, the tongue being bitten. The eyes are wide open, the pupils dilated and insensible to light. Micturition may occur. After the convulsive attack has passed off, post-epileptic coma may remain, though usually for a short time only.
Syncope.—This has been described under modes of dying ([p. 38]).