637 Postgrad Med J: first published as 10.1136/pgmj.24.278.637 on 1 December 1948. Downloaded from THE DIFFERENTIAL DIAGNOSIS OF COMA By PATRICK J. SWEENEY, M.D., M.R.C.P.I., M.R.C.P. Latelv First Assistant, Department of Medicine, Roval Victoria and West Hants Hospital, Bournemnozuth The difficulties in the diagnosis of the uncon- Case Report scious state are known to all. As an adequate A male, aged 45, admitted March 30, I948 with history is so often lacking, physical examination a history of severe headache for a week. must be exhaustive and the first essential is the Examination revealed a semicomatose patient. accurate assessment of the degree of unconscious- Pupils equal and light reactive, fundi normal, ness present. The term coma implies a state of muscle tone increased and reflexes generally unconsc;ousness from which the patient cannot increased. No neck rigidity or fascial weakness. be roused. Painful stimuli, e.g., firm pressure Bilateral extensor plantar response. over the. supraorbital foramen, have no effect. The Heart and lungs normal. Blood-pressure I20/70. corneal and pupillary reflexes, muscle tone, and Pulse 62. Temperature 980. the deep reflexes, are frequently abolished. Milder Lumbar puncture revealed a clear fluid under degrees of coma exist where, although the patient a pressure of 28o mm. Slight increase of protein, is unconscious, pupillary and corneal reflexes are and io white cells per cu. mm., mostly lympho- obtained and painful stimuli provoke a reaction. cytes. Two hours after the lumbar puncture, the Stupor indicates a state of partial loss of conscious- patient was sitting up in bed, quite rational, feeling ness where the response to external stimuli is well, but rather euphoric and unduly talkative. Protected by copyright. markedly diminished and is also characterized by During the next three days, his condition a tendency to resist interference and to catalepsy. remained unchanged, but he complained of It is extremely important to record carefully the occasional headache and was subject to periods of degree of unconsciousness present at the initial drowsiness. No abnormal signs could be detected examination of the patient, in order to establish in the nervous system. a base line and follow the course of the condition. On April 5, I948, the lower limb reflexes were The slow development of cerebral compression found to be brisker on the left side, and the left following a head injury, e.g. ruptured middle plantar response extensor. (The first localizing meningeal artery, illustrates the importance of signs.) this point. Particular attention must therefore be On April 7, 1948, he again became unconscious, paid to the pupils, fundi, muscle tone, deep with twitching and rigidity of all extremities. reflexes, plantar responses, pulse rate and tem- Both plantar responses were extensor. Blood sugar perature. Other points such as the odour of the and blood calcium normal. Repeat lumbar punc- breath, the type of breathing etc., are well known ture revealed a clear fluid under slightly increased to all, and will not be stressed here. pressure, with a marked increase of protein, and http://pmj.bmj.com/ The common causes of comatose, semi-coma- 29 white cells per cu. mm. The fundi remained tose and stuporose states will now be considered. normal. He was seen by a surgical colleague who sug- Trauma gested a diagnosis of right subdural haematoma. Unconsciousness following concussion is short- Ventriculography was carried out with negative lived, but prolonged coma may follow cerebral result, and the patient died on April I0, 1948. contusion or laceration. Bleeding from the nose Post mortem examination revealed a soft vas- or ears, or subconjunctival haemorrhage, may cular tumour in the right occipital lobe, which on on October 2, 2021 by guest. indicate a fractured skull and the need for radio- section proved to be a spongioblastoma of varied graphy. Lumbar puncture should be performed in pleomorphic structure. all cases, as the presence of blood in the cerebro- spinal fluid is often unsuspected. It should be remembered that an alcoholic Periods of drowsiness, stupor or coma from aroma is no guarantee that a cerebral injury has which recovery takes place with subsequent not occurred. Coma from a slowly developing relapse, and localizing pyramidal tract signs of subdural haematoma, the result of rupture of the type mentioned in this case, together with a cortical veins, is often difficult to differentiate from a slow pulse, are considered typicaf features of a brain tumour, especially as the original injury may. subdural haematoma. Cellular increase in the have been trivial and disregarded by the patient. cerebro-spinal fluid is not a feature, but is more 638 POST GRADUATE MEDICAL JOURNAL December I948 Postgrad Med J: first published as 10.1136/pgmj.24.278.637 on 1 December 1948. Downloaded from suggestive of cerebral abscess or tumour, as in the in order to exclude other medical or surgical case described causes of coma. To quote Walshe, 'alcoholic coma is diagnosed most safely by a process of Intoxications and Poisons exclusion.' Opium poisoning is seldom seen During the past year, 40 per cent. of the coma- nowadays. Its chief features are a cold, clammy tose patients admitted to the medical wards of this skin, a slow respiration rate, and pin-point pupils. hospital were suffering from, in the following In all cases of suspected poisoning, gastric lavage frequency, carbon monoxide, barbiturate and should be performed and the gastric contents aspirin poisoning. An indication, perhaps', of kept for analysis. Lead poisoning is a rare cause present day conditions, when coupled with the of coma, and as a rule a preceding history of vomit- fact that alcoholic coma was not encountered. ing, abdominal colic, headache and constipation Carbon monoxide poisoning is usually obvious will be obtained. If suspected, the gums should from the history. It should be noted however, be exarmined for the well known blue line, the that the typical cherry-red colour of the face and blood for punctate basophilia and evidence of lips is not always present, and that even a mild anaemia, which may be haemolvtic in type, and degree of carbon monoxide poisoning may precipi- the urine analysed for lead. tate cardiac failure and pulmonary oedema with resultant coma, in a patient with pulmonary or Cerebral Vascular Lesions cardiac disease. A simple clinical test for carboxy- Coma resulting from cerebral haemorrhage, haemoglobin is to dilute-one drop of the patient's embolism or thrombosis is characterized by hemi- blood in a test tube of water, and compare with a plegia in the great majority of cases. Usually control from a normal person. A carmine tint will there is conjugate deviation of the head and eyes be evident if there is much carboxyhaemoglobin towards the side of the lesion, the paralysed cheek present. A diagnosis of barbiturate or aspirin flaps in and out with respiration, which is ster-Protected by copyright. poisoning is more difficult. Deep coma, sweating torous, and a positive Babinski sign is obtained on and extensor plantar responses are common to the hemiplegic side. Where lesser degrees of both. A raised temperature, cyanosis and pul- coma exist, a unilateral diminution or abolition monary oedema are typical findings in barbiturate of the corneal reflex is of value in distinguishing poisoning, as exemplified in the following case. apoplexy from other conditions. Where the pupils are unequal, it is always well to remember that Case Report the larger pupil is usually on the side of the A female aged 35 was admitted on October i9, haemorrhage. Syphilis must always be kept in I947. She was found unconscious in her flat with mind as a cause of cerebral thrombosis. Cerebral a bottle of nembutal capsules beside her. There embolism is suggested by the presence of heart were three capsules left out of a possible original disease such as mitral stenosis and auricular fibril- total of twenty-five. lation. Pontine haemorrhage results in homo- She was deeply comatose, i.e., ' corneal and lateral cranial nerve palsy and contralateral hemi- pupillary reflexes absent, deep reflexes absent, plegia, but all four limbs are soon paralysed as a limbs flaccid, no response to painful stimuli. rule. A high temperature and pin-point pupils http://pmj.bmj.com/ Bilateral extensor plantar responses. Cyanosed. further characterize this condition. In my experi- Moist skin. Breathing noisy and bubbly with ence, subarachnoid haemorrhage, the ' apoplexy moist sounds throughout both lungs, obscuring of young people,' has been the commonest the heart sounds. Blood pressure iIo0/90. Pulse individual disorder aniongst the cerebral vascular go. Temperature I00°. With large doses of cora- accidents admitted during the past year. The diag- mine and picrotoxin intravenously, the pupillary nosis is seldom difficult. Neck rigidity is the out- reflexes returned after three hours, but it was standing feature as a rule, but in some deeply three days before the patient became fully con- comatose patients, this is absent, and the diagnosis on October 2, 2021 by guest. scious and rational. is only apparent on lumbar puncture. Retinal .* * * haemorrhages, usually near the disc, vitreous and If no history is available, barbiturates can be subhyaloid haemorrhages, papilloedema, and 3rd detected in the urine and cerebrospinal fluid, using and 6th nerve palsies with resultant squint, are Millon's reagent. occasional features of a subarachnoid haemorrhage. Aspirin poisoning is characterized by evidence Frequently, bilateral extensor plantar responses of vomiting, profuse sweating, and deep breathing are obtained. The unne may-contain sugar and which may resemble the air hunger of diabetic albumin, and a rise of temperature up to ioo is coma. The ferrichloride test for salicvlates in the a common finding. urine is positive. Where alcoholic coma is sus- Hypertensive encephalopathy should-be thought pected, a careful physical examination is necessary of in the comatose patient with an extremely December I948 SWEENEY: Differential Diagnosis of Coma 639 Postgrad Med J: first published as 10.1136/pgmj.24.278.637 on 1 December 1948.