The respiratory response to CO2 and O2 in patients with coma due to voluntary intoxication with barbiturates and carbamates

We have investigated the respiratory response to CO2 and to O2 in comatose subjects self intoxicated with barbiturates and carbamates. The chemical drive of 12 such patients with coma was compared with that of comparable normal subjects. The ventilatory response to CO2 was depressed but the P0.1 response was of the same order of magnitude as in normals. O2 had little effect on the ventilatory parameters and occlusion pressure. There was no difference between the two groups of patients, indicating that the respiratory changes observed were more dependent on the intensity of the intoxication than on the nature of the drugs. In addition, mechanical factors seem mainly responsible for the depressed ventilatory response to CO2.

The transition between apnoea and spontaneous ventilation in patients with coma due to voluntary intoxication with barbiturates and carbamates

We have investigated the transition from apnoea to spontaneous breathing in five comatose patients self intoxicated with barbiturates and carbamates. All patients were apnoeic on admission, and were studied throughout the course of recovery. The transition between the first respiratory movements and a stable and nearly normal ventilation (stable respiratory activity) ranged from 15 to 105 min, a very short time compared to the duration of the apnoeic state that lasted 6 to 72 h from admission. Minute ventilation and occlusion pressure during the first respiratory movements were 6.3 +/- 2.7 l.min-1 and 1.35 +/- 0.45 kPa, respectively. These values increased by roughly 50 and 100% by the time stable respiratory activity was achieved. The increase in minute ventilation was entirely due to an increased inspiratory flow, in relation to a proportionate increase in occlusion pressure, and without significant changes in the respiratory times or in the effective elastance. We conclude that the transition between apnoea and stable respiratory activity is characterized by its rapidity, by the fact that respiratory times are fixed throughout the recovery process, and by the fact that effective elastance is high.

Cerebral embolization and coma after hysterosalpingography with oil-soluble contrast medium

A case of coma due to embolization after HSG, using oil-soluble contrast medium is presented. The patient was in a comatose state 11 days and then spontaneously regained full consciousness. The safety of oil-contrast medium for HSG is questionable.

Nonsteroidal anti-inflammatory drugs and coma: a case report of fenoprofen overdose

We present the case of a 17-year-old girl who ingested 24 to 36 g fenoprofen as a suicidal gesture. She presented with coma, hypotension, metabolic acidosis, and respiratory depression within four hours of ingestion. The most common adverse effects of the nonsteroidal anti-inflammatory drugs occur in both therapeutic and toxic doses and include gastrointestinal upset, blood dyscrasias, and analgesic nephropathy. The propionic acid derivatives of nonsteroidal anti-inflammatory drugs, including fenoprofen and ibuprofen, are rarely associated with severe toxic effects. This is the first report of pure fenoprofen overdose presenting as coma and metabolic acidosis.

The diagnostic utility of flumazenil (a benzodiazepine antagonist) in coma of unknown etiology

The use of flumazenil, a benzodiazepine antagonist, was studied in two patients with coma of unknown etiology. One patient ingested 20.5 mg alprazolam before crashing his truck into parked automobiles. The patient was awakened by flumazenil administration, and the severity of his injuries was evaluated reliably. A second patient ingested 7.5 mg triazolam and attempted suicide with carbon monoxide from car exhaust. His coma resolved completely after the administration of the double-blind study drug, obviating treatment with hyperbaric oxygen. Flumazenil had a clear diagnostic and therapeutic role in the treatment of these patients and should be a useful tool for emergency physicians and toxicologists.

Isopropyl alcohol intoxication

Three patients had neurologic signs due to isopropyl alcohol (IPA) intoxication. Over a several-week period, a known alcoholic developed apathy, confusion, ataxia, and hyperreflexia. During this period, there was no ethanol available to him, and he denied use of other intoxicants. He was found stuporous in the hospital after drinking IPA and admitted to IPA abuse during the preceding weeks. Two other men were admitted in a stupor after large ingestions of IPA. Intoxication with IPA has two different presentations: stupor in a known alcoholic and encephalopathy of unknown cause in individuals who hide their addiction. Ethanol, methanol, IPA, and ethylene glycol intoxications are associated with different clinical and laboratory findings.

Accidental self administration of xylazine in a veterinary nurse

A 19 year old male veterinary nurse accidentally injected himself with 200 mg of xylazine (a muscle relaxant and sedative used in veterinary practice). He subsequently became comatose, hypotensive, bradycardic and acidotic. He required intensive supportive therapy, and made a full recovery over the next few hours. Xylazine toxicity in humans is very rare, and the effects are discussed.

Zolpidem intoxication mimicking narcotic overdose: response to flumazenil

Zolpidem is a recently introduced sleep-inducer which is thought to act on the central-type benzodiazepine receptors. This observation is the first report of drug poisoning with this compound. The toxic response was characterized by the development of a profound but short-lasting coma, associated with pin-point pupils and respiratory depression, as observed in a narcotic overdose. These clinical signs were not influenced by the administration of naloxone, but responded dramatically to flumazenil. Some analytical data on zolpidem toxicokinetics are presented.

Alkaline diuresis for acute poisoning with chlorophenoxy herbicides and ioxynil

The relation between blood chlorophenoxy herbicide and ioxynil concentrations and toxicity, and the effect of alkaline diuresis on outcome, have been studied in 41 patients. More than one herbicide was found in 38 cases. 6 of 30 patients who had ingested chlorophenoxy compounds alone died; 16 patients (mostly in grade 3-4 coma) had alkaline diuresis and 15 survived. 7 of 11 patients who had co-ingested ioxynil died; 3 had alkaline diuresis and all survived. Alkaline diuresis reduced plasma chlorophenoxy half-lives to values observed after doses that had no adverse effects (ie, below 30 h), but did not influence ioxynil clearance. Alkaline diuresis should be used to treat acute poisoning with chlorophenoxy herbicides or ioxynil in the presence of coma or other poor prognostic indicators, such as acidaemia, or if plasma total chlorophenoxy concentrations are 0.5 g/l or more.

Early blindness and coma during intrathecal chemotherapy for meningeal carcinomatosis

A 35-year-old woman was treated with intraventricular methotrexate (MTX) with a total dose of 70 mg followed by cytosine arabinoside (Ara-C) with a total dose of 80 mg for meningeal metastasis of breast carcinoma. Radiation therapy was not given. Despite a response of the meningeal tumor the patient developed in the third week of MTX treatment a progressive visual loss and loss of consciousness which worsened during subsequent Ara-C treatment and led to death within 3 weeks. Postmortem examination revealed only minimal neoplastic infiltration of the meninges. Multiple foci of axonal degeneration and demyelination were found in the optic nerves and chiasm, the superficial layers of the brainstem, and spinal cord and to some extent in other cranial nerves and spinal nerve roots. The possible causes of this previously unreported early complication are discussed.

Severe self-poisoning with oxetorone: report of one case

The authors report a case of severe self-poisoning with oxetorone. Plasma concentration of the drug assessed by HPLC was a thousand times higher than therapeutic levels. Coma, convulsions, and cardiac conduction defects were observed, similar to those noted with tricyclic and tetracyclic antidepressant poisoning. Similar cardiac disorders consisting of conduction defects had not been previously described during oxetorone intoxication.

Non-randomised study comparing toxicity of Escherichia coli and Erwinia asparaginase in children with leukaemia

Seven hundred fifty-eight unselected children entered into the United Kingdom Medical Research Council acute lymphoblastic leukaemia UKALL VIII Study and Trial were studied for differences in early treatment-related toxicity according to the type of intramuscular L-asparaginase received. Two hundred seventy-five received a product obtained from Escherichia coli and 483 the enzyme from Erwinia chrysanthemi. The E. coli patients had a significantly higher incidence of neurotoxicity, pancreatitis, and life-threatening sepsis (4%, 2%, and 20%, respectively) when compared with the Erwinia group (2%, 0%, and 18%). Severe hypersensitivity was seen in one patient from both groups and the incidence of glucose intolerance was not significantly different. These findings indicate that E. coli asparaginase may be more toxic. With a minimum follow up of 4 1/2 years there is no evidence that either product has made a significantly different contribution to disease-free survival.

Carbamazepine overdose: a prospective study of serum levels and toxicity

A cooperative prospective study of consecutive cases of carbamazepine overdose was conducted to determine if serum levels were predictive of toxicity and if risk factors such as age, chronic exposure, or previous disorder or cardiovascular disease could be used as prognostic indicators. Seventy-three consecutive cases were collected from two regional certified poison control centers from January 1989 to August 1989. There were 25 exposures in children less than 6 yrs., 11 exposures in adolescents, and 37 exposures in adults. Ten adult cases and one adolescent case were excluded from the study due to the presence of coingestants or inadequate information. Peak measured serum levels ranged from 0.3 to 56 mcg/ml. Using the presence of coma, seizure activity or respiratory depression requiring mechanical ventilation as measures of toxicity, we found poor correlation between rising serum levels of carbamazepine and toxicity. Increased serum levels of carbamazepine did appear to correlate with increased hospital stay, but not with ICU stay. History of a seizure disorder appears to pose increased risk of a seizure in carbamazepine overdose. In this series chronic exposure to carbamazepine did not appear to increase the risk of coma or respiratory depression for a given toxic serum level and may add some protective effect. Serum levels below 40 mcg/ml do not appear to accurately predict the severity of toxicity. Cardiac conduction defects were rare (one child). Anticholinergic findings, as evidence by decreased bowel motility and sinus tachycardia were common. Previous cardiovascular disease and age did not appear to be important prognostic indicators.

Lithium toxicity and myxedema coma in an elderly woman

The development of hypothyroidism as a side effect of lithium therapy is a well recognized phenomenon. However, the presentation of myxedema coma after lithium intoxication has not been previously documented. In this case lithium toxicity may have exacerbated preexisting hypothyroidism to the point of respiratory arrest. Based on this case, we recommend periodic monitoring of thyroid function in an effort to detect preexisting hypothyroidism or lithium-induced hypothyroidism.

Skin blisters as a manifestation of oxazepam toxicity

A 75 year-old comatous patient was admitted after ingestion of 200 mg oxazepam. Skin blisters, attributed to oxazepam toxicity, appeared on the left forearm the following day and regressed spontaneously nine days later.

Carbamate and organophosphate poisoning in early childhood

Twenty-five infants and young children intoxicated by carbamate and organophosphorus compounds are described. Presenting signs and symptoms in children differed from those described in adults and were mainly related to severe CNS depression, coma and stupor, dyspnea, and flaccidity. Other clinical signs such as miosis, excessive salivation and tearing, sweaty, cold skin, and gastrointestinal symptoms were less frequent, while fasciculations and bradycardia were quite uncommon on arrival. Only two patients presented with all typical signs of organophosphate poisoning as described in adults. Signs of carbamate poisoning were indistinguishable from those of organophosphate poisoning and included signs of myoneural and CNS cholinergic receptor involvement, in addition to parasympathetic muscarinic dysfunction. Atropine sulfate was found to have a clear beneficial CNS effect in addition to its known peripheral antimuscarinic effect. Our data suggest that the clinical presentation of carbamate and organophosphate poisoning in early childhood and its response to therapy are quite different from those of adults and older children.

Ingestion of cannabis: a cause of coma in children

Previous reports of accidental ingestion of cannabis by children are rare. None has reported coma, although one described a stuporous state that required assisted ventilation. Over the past four years, the staff of British Columbia's Children's Hospital has managed six children with cannabis toxicity, three of whom presented in coma, including one with airway obstruction. Recurring diagnostic features included rapid onset of drowsiness, moderate pupil dilation, hypotonia, lid lag, and the presence of small granules or leaves in the mouth. Confirmation was obtained by positive urine screening for cannabinoids. The six cases described emphasize the need for emergency physician awareness of possible diagnostic criteria, the potential severity of intoxication, and the need for prevention through parent education.

Methanol poisoning: factors associated with neurologic complications

Hospital records of thirty patients with methanol poisoning were studied. Neurologic manifestations at presentation including coma, seizures and decreased visual acuity were seen in nineteen patients. The mean blood pH at presentation was significantly lower in the patients with these neurologic signs and symptoms than in the eleven patients without them (p less than 0.05). Methanol levels at presentation tended to be higher in patients with neurologic manifestations at presentation and these patients tended to present later after methanol ingestion than those patients without neurologic manifestations. Fifteen patients with methanol poisoning developed serious neurologic sequelae or died. The mean blood pH was significantly lower in this patient group than in those who survived without neurologic sequelae (p less than 0.05). Methanol levels at presentation were not different in the patients who developed neurologic sequelae or died as compared to those who did not. The time from ingestion of methanol to presentation at the hospital was however significantly longer in those patients who developed neurologic sequelae or died (p less than 0.05). Initiation of treatment within eight hours of ingestion of methanol was associated with a better clinical outcome.

Hyperosmolality due to antacid treatment

Magnesium trisilicate mixture is an antacid used commonly in our Intensive Care Unit in the prevention and treatment of stress ulcers. In this case the administration of large doses over a period of time led to the development of massive hyperosmolality, cerebral dehydration and coma. Management with hypotonic fluid resulted in complete recovery.