Formic Acid Poisoning in a Tertiary Care Center in South India: A 2-Year Retrospective Analysis of Clinical Profile and Predictors of Mortality

Survival of formalin intoxication in a 13-year-old Thoroughbred gelding

BACKGROUND

Formalin intoxication via the gastrointestinal route has not been previously reported in the horse. Whereas ingestion of formalin in humans, although rare, is well documented. Majority of human cases are either accidental, suicidal or homicidal and often lead to fatality, with a reported lethal formaldehyde dose equating to 0.12 - 0.16 g/kg bwt.

OBJECTIVES

To describe a single case report of the clinical management of an adult horse referred to a veterinary teaching hospital following accidental administration of 10% formalin via nasogastric tube.

METHODS

A 13-year-old Thoroughbred gelding originally presented to the referring veterinarian for colic where 1.8 L of 10% formalin was accidentally administered instead of mineral oil via nasogastric intubation, a potentially lethal dose of formaldehyde (0.12 g/kg bwt). Approximately 20-hours following 10% formalin administration the horse was admitted to the referral hospital with moderate tachycardia, occasional ectopic beats, tacky and hyperaemic mucous membranes, delayed capillary refill time, reduced borborygmi, and pronounced digital pulses. Diagnostic investigations included laboratory blood analysis, urinalysis, electrocardiogram, abdominal ultrasound, palpation per rectum and gastroscopy.

RESULTS

Patient assessment found evidence of toxicity to the gastrointestinal tract, hypovolaemia and risk for laminitis. Intensive care included fluid and electrolyte therapy, anti-inflammatories and analgesia, continuous digital cryotherapy, gastro-protectants and other methods of gastrointestinal support. The horse was discharged from hospital on day 14 with no long-term complications and the client-veterinarian relationship was preserved.

DISCUSSION

In human cases of ingestion, gastrointestinal injury is typically accompanied by severe metabolic acidosis and multiple organ dysfunction syndrome due to toxicity of other body systems that can contribute to non-survival. Formaldehyde toxicity in the present case predominantly affected the gastrointestinal tract, most likely a direct result of the route of administration. Aside from gastrointestinal injury, primary toxicity of other body systems was not confirmed. To prevent this medical error recurring, the referring veterinary clinic revised their labelling and storage of 10% formalin.

CONCLUSION

This is the first report of systemic formalin intoxication in the horse. Following a high dose of 10% formalin (0.12 g/kg bwt formaldehyde) enterally, the horse survived having received intensive supportive care based on human guidelines for ingested formalin.

Outcome of early emergency intubation and early emergency dialysis in deliberate self-harm with formic acid in a tertiary care center in South India: A retrospective cohort study

OBJECTIVE

The objective is to evaluate the outcome of early emergency intubation and early dialysis in formic acid (FA) poisoning and to determine the clinical features associated with its mortality.

METHODS

It is a retrospective cohort study of 78 patients who presented to the emergency medicine department from July 2008 to June 2015 with alleged history and clinical features of FA poisoning. The outcome of early intubation and early dialysis was studied in terms of 7-day and 30-day mortality. The outcome was compared in severe and not severe groups separately. Severity was graded according to Med-Tu chart used for corrosive poisoning.

RESULTS

In the severe group (n = 53), early dialysis was done in 15 patients. There was 53% (n = 8) 30-day mortality. In the group where early dialysis was not done there was a significant increase in mortality 92.1% (n = 35). This was statistically significant with a P = 0.003. In a similar fashion 7-day mortality was analyzed in the severe group where mortality was higher when early dialysis was not done. In not severe group early dialysis has minimally decreased the mortality. Early intubation in severe group did not demonstrate any mortality benefit. Patients who were intubated early and not intubated early had equally high mortality. In not severe group, intubation could not make any significant difference in mortality.

CONCLUSION

In this retrospective study, we observed that early dialysis in the severe group has a better outcome in terms of 7-day and 30-day mortality.

Unusual cutaneous presentation in a corrosive acid ingestion

Corrosive digestive tract injuries are considered to be a source of morbidity and mortality worldwide. The cases of acid ingestion in Forensic Medicine practice are not infrequent. Corrosive ingestion usually presents with injuries over the face, oropharynx, esophagus, and gastrointestinal tract. We report a case of a 65-year-old woman who was brought to the emergency department with a history of ingestion of toilet cleaner at her home. Following this, she developed blackish-brown discoloration over the abdomen. The patient survived for less than one day. An autopsy confirmed the perforation of the stomach and small intestine. 500 ml of blackish fluid was present in the peritoneal cavity which resulted in corrosive peritonitis. The chemical examiner's report showed corrosive mixtures comprising sulfate, nitrate, and chloride ions in the peritoneal contents. This case report highlights atypical cutaneous presentation over the abdomen following corrosive acid ingestion, which has not been reported previously. The possible explanation for this cutaneous manifestation was corrosive effects of the underlying viscera due to its close proximation to the abdominal wall and presence of minimal intra-abdominal fat. A direct physical connection between perforation and cutaneous findings was not identified. The case emphasizes the need for a comprehensive approach in managing such cases, analyzing ingested material, and following standard autopsy protocols in case of death.

Carbon monoxide poisoning and pulmonary injury from the mixture of formic and sulfuric acids

CONTEXT

The inhalation of carbon monoxide produced by the incomplete combustion of carbon remains a popular method of suicide. A much less common method of producing carbon monoxide for suicide is by mixing formic and sulfuric acids.

CASE DETAILS

We describe a patient who attempted suicide by mixing formic and sulfuric acids. He presented with a depressed level of consciousness, chemical burns of his airway and skin, and respiratory distress. He was found to have a metabolic acidosis, a carboxyhemoglobin of 36.8%, hyperkalemia, and rhabdomyolysis. His hospital course was notable for copious pulmonary secretions and hypoxia, but he ultimately recovered with supportive care.

DISCUSSION

The case highlights the potential toxicity, particularly from inhaled carbon monoxide and formic acid, with this method of suicide.

Formaldehyde and methylene glycol equivalence: critical assessment of chemical and toxicological aspects

Due largely to the controversy concerning the potential human health effects from exposure to formaldehyde gas in conjunction with the misunderstanding of the well-established equilibrium relationship with its hydrated reaction product, methylene glycol, the concept of chemical equivalence between these two distinctly different chemicals has been adopted by regulatory authorities. Chemical equivalence implies not only that any concentration of methylene glycol under some condition of use would be nearly or completely converted into formaldehyde gas, but also that these two substances would be toxicologically equivalent as well. A relatively simple worst case experiment using 37% formalin (i.e., concentrated methylene glycol) dispels the concept of chemical equivalence and a review of relevant literature demonstrates that methylene glycol has no inherent toxicity apart from whatever concentration of formaldehyde that might be present in equilibrium with such solutions.

Acute formic acid poisoning in a rubber plantation worker

Among the workers in a rubber plantation in South India, ingestion of formic acid either accidentally or with suicidal intention is a common problem. Formic acid is diluted and used for coagulation of rubber latex. Easy availability makes formic acid a common poison. The aim of this article is to study the case of formic acid poisoning, its complications and management. Patient was managed symptomatically. Antidote was not used and no nasogastric aspiration was done. Patient had dysphagia; nutrition was maintained with open gastrostomy done on day 5 and subsequent enteral feeding. Measures to prevent anticipated complications were undertaken. Stricture of the esophagus is a common complication leading to long-term morbidity. After initial management, all patients should be on follow-up for prevention and management of strictures. Workers should be educated on complications of formic acid poisoning and easy availability should be curtailed by enforcing remedial measures.

Fatal course of a suicidal intoxication with hydrochloric Acid

Suicidal ingestion of undiluted hydrochloric acid is a rare but live-threatening event. We report on the dramatic and fulminant course of a 61-year-old woman who drank 200 ml of 30–33% hydrochloric acid. On admission to our intensive care unit she was alert and oriented with stable vital signs. Gastroscopy demonstrated complete necrosis from the hypopharynx to the pylorus, which was flushed continuously via drainage catheters. At that time point perforation was not evident. Shortly thereafter she developed an acute abdomen and a tension pneumothorax which was decompressed. CT scan demonstrated esophageal and intestinal perforation with massive mediastinal necrosis. On emergency laparostomy she showed complete necrosis of the intestine and stomach. The patient died 10 h after admission from multiorgan failure. The therapeutic options are critically discussed in comparison to previously reported cases in the literature.