Delayed postoperative neurological deterioration from prolonged sodium nitroprusside administration. Case report

Sodium nitroprusside is commonly used for the induction of hypotension during neurosurgical procedures. Its toxicity stems from hemodynamic compromise as well as from its metabolites, especially the formation of cyanide. A patient is described who underwent craniotomy for hypertensive intracerebral hemorrhage. He gradually recovered following the operation, but needed continued administration of sodium nitroprusside for control of hypertension. On the 7th postoperative day, he deteriorated into coma with evidence of severe edema and herniation on the computerized tomography scan. Cessation of sodium nitroprusside and treatment for cyanide poisoning resulted in resolution of his symptoms within hours. The potential toxicity of sodium nitroprusside, measures to prevent toxicity, and therapeutic steps are discussed.

[Acute cyanide poisoning in an infant]

An infant of 9 months was admitted to hospital in comatose condition; cyanide poisoning was suspected. This poisoning was caused by the desorption of hydrocyanic acid from building materials after the house had been fumigated with hydrocyanic acid under strict supervision and observed safety measures. Administration of 4-dimethyl-aminophenol, a methaemoglobin inducer, and sodium thiosulphate together with supportive measures, led to complete recovery of the infant, although the general hypotony persisted for a few weeks.

Vaginally administered cocaine overdose in a pregnant woman

The deleterious effects of cocaine have been described in the adult population and in the neonate. Documentation of adverse effects in pregnant patients has been limited. We report the first known fatal vaginal administration of cocaine.

Physostigmine in the treatment of intrathecal baclofen overdose. Report of three cases

The expanding use of intrathecal baclofen for spasticity has raised a concern about the treatment of overdose in these patients, since no specific baclofen antagonist is available. Since physostigmine has been reported to reverse the respiratory depression and somnolence due to opiates, the drug was tried for the treatment of baclofen overdose. In three cases, intravenous physostigmine (2 mg) completely reversed the respiratory depression and coma caused by boluses of 80 to 800 micrograms of lumbar intrathecal baclofen. Physostigmine, although not a specific antagonist, should provide increased safety for patients receiving intrathecal baclofen.

Cyanide poisoning successfully treated without 'therapeutic methemoglobin levels'

A 24-year-old woman ingested an unknown amount of potassium cyanide in a suicide attempt. Coma and metabolic acidosis developed. Administration of the Lilly Cyanide Antidote kit (Eli Lilly and Co, Indianapolis) resulted in prompt resolution of symptoms and full recovery. Whole blood cyanide level was 13 micrograms/mL approximately one hour after ingestion. The highest measured methemoglobin level after sodium nitrite administration was 9.2%, demonstrating that attaining a "therapeutic methemoglobin level" of 25% is unnecessary to insure a satisfactory clinical outcome. Because severe hypotension or excessive methemoglobinemia can be caused by the sodium nitrite component of the Lilly kit, only enough to produce an acceptable clinical response should be administered.

Trial of prednisolone for prevention of melarsoprol-induced encephalopathy in gambiense sleeping sickness

In a prospective randomised trial, 620 patients who had Trypanosoma brucei gambiense trypanosomiasis with central nervous system involvement were treated either with prednisolone plus melarsoprol or with melarsoprol only. 598 patients were evaluable: morbidity and death associated with melarsoprol-induced encephalopathy was reduced in patients who were given prednisolone. The two groups did not differ either in the incidence of other complications of melarsoprol therapy or in relapse rate after melarsoprol therapy. The cost of prednisolone would be outweighed by savings on the treatment of encephalopathies in such patients.

Valproic acid induction of coma in rats: synergism with NH4+ and pentobarbital

Dose-response curves for the incidence of coma after intraperitoneal injections of various doses of valproic acid (VP) and octanoic acid (OA) showed that, mole for mole, valproic acid was less toxic than octanoic acid. However, a simultaneous subcoma dose of pentobarbital (PB) enhanced the toxicity of VP more than that of OA. The dose-response curve for NH4Cl was affected by simultaneous subcoma doses of VP and OA but not by PB. VP enhanced the toxicity of the NH4+ by 52%; OA enhanced the toxicity by 12%. PB added significantly to the toxicity of VP and NH4+ when the three were given simultaneously. Doses of 0.7 mmol NH4+ and 0.5 mmol VP given separately had little or no encephalopathic effect, with blood ammonias of 250-1250 micrograms/dl. When given simultaneously they induced a deep coma and raised the blood ammonia threefold, to about 3600 micrograms/dl. Similar doses of OA and NH4+, induced a similar deep coma, but blood levels of ammonia were not as high. Simultaneous injections of 250 mg glucose did not alter the results. Thus VP toxicity is enhanced substantially by its synergistic interactions with PB and the NH4+.

Studies of ammonia loading: effects of rate of delivery and enhanced removal of NH4 on blood levels of ammonia and coma induction

Using dose-response curves, the dose of NH4Ac inducing coma in one-half of the animals was increased by 60 to 80% after 1 mmol of arginine. The larger increase occurred in larger rats but was not proportional to the increase in weight. Incremental subcoma doses of NH4 raised the amount of NH4 required for inducing coma and the brain level of ammonia at the point of coma. After a portacaval shunt the results were similar, although lower doses of NH4 were required from the beginning. Blood ammonias after a loading dose (1.25 mmol) of NH4 were influenced by the duration of a preinfusion of NH4 and by the preinjection of various amino acids involved in the disposal of NH4 in the urea cycle. The amount of reduction in blood ammonia by ornithine and arginine compounds was less the longer the preinfusion of NH4. Blood ammonia was not lowered by glutamate at any time but was increased with longer preinfusion periods. Hepatectomy (Hx) reduced the removal of an NH4 load. After a modest load (0.85 mmol) of NH4, blood ammonia increased 5-fold, over that of sham-operated rats, with 70% Hx and 15-fold with 90% Hx. Ornithine reduced these blood ammonias by about 50%. Arginine had no effect. These studies indicate ways of reducing toxicity of NH4 and factors that predispose to or enhance toxicity.

Lake Nyos disaster, Cameroon, 1986: the medical effects of large scale emission of carbon dioxide?

Carbon dioxide was blamed for the deaths of around 1700 people in Cameroon, west Africa, in 1986 when a massive release of gas occurred from Lake Nyos, a volcanic crater lake. The clinical findings in 845 survivors seen at or admitted to hospital were compatible with exposure to an asphyxiant gas. Rescuers noted cutaneous erythema and bullae on an unknown proportion of corpses and 161 (19%) survivors treated in hospital; though these lesions were initially believed to be burns from acidic gases, further investigation suggested that they were associated with coma states caused by exposure to carbon dioxide in air. The disaster at Lake Nyos and a similar event at Lake Monoun, Cameroon, two years previously provide new information on the possible medical effects of large scale emissions of carbon dioxide, though the presence of other toxic factors in these gas releases cannot be excluded.

Isopropanol ingestion: case report with pharmacokinetic analysis

An unusual case of acute isopropanol overdose which occurred within the confines of the emergency department is reported. Serial serum concentrations of isopropanol and its metabolite acetone were followed for 43 hours. Pharmacokinetic analysis is presented, as well as a brief literature review of diagnosis and management. CNS toxicity was related mainly to isopropanol concentrations. The calculated half-life of isopropanol was 7.3 hours. Because of the pharmacokinetic profile of isopropanol, management decisions regarding the use of hemodialysis should be made within one to two hours of patient presentation.

Pine oil cleaner ingestion

We report the cases of 22 patients who were hospitalized for pine oil cleaner ingestion. The toxic manifestations most commonly observed were mucous membrane and gastrointestinal irritation. Ataxia, which did not occur in adults, was a frequent presenting sign of intoxication in children. Fifty-nine percent of patients who ingested only pine oil cleaner developed central nervous system depression, and three of these developed coma. Three of five children and three of 17 adults developed acute hydrocarbon pneumonitis. Unlike aspiration pneumonitis, which follows petroleum distillate ingestion, chemical pneumonitis from pine oil cleaner may occur from gastrointestinal absorption of pine oil and deposition in lung tissue. However, recovery from pneumonitis in our patients was typically rapid and complete. Only two adults developed secondary bacterial pneumonia; no patient died. Ingestion of pine oil cleaner was rarely life threatening; most patients needed only gastrointestinal decontamination and minimal supportive care.

Drug-induced hypoglycemia. A review of 1418 cases

The present review catalogues 1418 reported cases of drug-induced hypoglycemia. The main findings are that sulfonylureas (especially chlorpropamide and glyburide), either alone or with a second hypoglycemic or potentiating agent, still account for 63% of all cases; that alcohol, propranolol, and salicylate, either singly or with another hypoglycemic drug, are the next most frequent offenders (19% of the total); and that one older drug (quinine) and three new ones (pentamidine, ritodrine, and disopyramide) have caused an additional 7% of all episodes of severe hypoglycemia. The clinical factors that set the stage for drug-induced hypoglycemia are still restricted food intake, age, hepatic disease, and renal disease, both individually and even more so in combination. Drug-induced hypoglycemia continues to be so common that virtually every unconscious patient should be considered hypoglycemic until immediate estimation of the blood sugar level rules it in or out. If ruled in, the clinician should promptly start 10% intravenous glucose and plan to maintain it uninterruptedly for 1 or more days, with added glucagon, hydrocortisone, and diazoxide administration if necessary, until sustained hyperglycemia guarantees that all drug effects have worn off.

Cyanide and arsenic poisoning by intravenous injection

A 29-year-old man was found unresponsive a few minutes after self-injecting undetermined amounts of potassium cyanide and sodium arsenite intravenously in a suicide attempt. Treatment with the Lilly Cyanide Antidote kit rapidly resolved the initial coma, despite a whole blood cyanide level of 4.4 micrograms/mL. A 12-hour urine arsenic collection begun on admission showed 10,065 micrograms arsenic/12 hr. The patient received intramuscular BAL initially, which was followed by two ten-day courses of oral D-penicillamine. Complications included upper gastrointestinal tract bleeding requiring transfusion, transient elevations of liver function tests, self-limited complaints of decreased vision with conjunctival hyperemia and photophobia, and an abscess at the injection site. Although specific antidote therapy completely resolved the cyanide toxicity, early and prolonged arsenic chelation did not prevent a mild sensory peripheral neuropathy from developing with onset about 17 days after self-injection.

[Cerebral complications in chronic acetylsalicylic acid poisoning]

A 60-year-old woman who for many years had been taking salicylate-containing tablets for headaches, was admitted to hospital, in a somnolent state, because of increasing weakness, tiredness, memory and speech disorders, and tinnitus. Laboratory tests revealed a decompensated metabolic acidosis (pH 7.25), renal insufficiency (creatinine 2.3 mg/dl) and a decreased Quick value (63%). Whole-blood acetylsalicylic acid concentration was markedly elevated to 330 micrograms/ml. After treatment of the acidosis with bicarbonate and forced diuresis she at first regained consciousness, but clouding of consciousness again occurred eight hours later progressing to coma with unequal pupils and seizure potentials in the electroencephalogram. Status epilepticus without motor component was diagnosed, perhaps the result of a dysequilibrium of acid-base balance between blood and cerebrospinal fluid. The signs and symptoms were quickly reversed under treatment with clonazepam.