Lethal intoxication with hydrofluoric acid

Abstract

Intoxication with hydrofluoric acid is a very rare but mostly lethal clinical condition. It is mainly caused by dermal exposure, with ingestion extremely rare. Hydrofluoric acid is one of the strongest acids known that has a strong lipophilic ability. Ingestions of more than 20 mg/kg body weight are considered a lethal dose. Even after dermal exposure, the fatal prognosis is caused by severe electrolyte disturbances, especially hypocalcemia. We report on a 50-year-old female with endogenous depression who swallowed approximately 30 ml hexafluorosilicate (hydrofluoric acid) during a night-time attempt to commit suicide. In the early morning, the woman was found somnolent in a condition of circulatory shock. She complained of severe abdominal pain. She had to be intubated by the emergency doctor and was admitted to the hospital. Physical examination of the mechanically ventilated patient only revealed conjunctival irritation. Laboratory investigations showed severe electrolyte disturbances (hypokalemia, hypocalcemia, hypophosphatemia decreased magnesium levels) as well as severe metabolic acidosis. Within the next few hours, disseminated intravascular coagulation and hyopalbuminemia developed. Serum fluoride levels were 0.099 mmol/l or 1.98 mg/l (normal values 0.0005–0.02 mmol/l or 0.1–0.4 mg/l). Urine fluoride levels were 1.94 mg/l (normal values <1.0 mg/l). Gastroscopy showed necrotic gastric mucosa without signs of bleeding. Topical instillation of calcium was not performed due to the long time interval from burn to treatment but intravenous calciumgluconate was substituted immediately. Despite fluid resuscitation, correction of the electrolyte abnormalities, stabilisation of coagulation and substitution of albumin, the clinical condition worsened. The patient had to be defibrillated due to ventricular fibrillation about 30 times. Later on, these episodes of ventricular fibrillation were becoming less responsive to defibrillation although the electrolyte threshold had already been corrected. After 12 hours, the patient died under cardiopulmonary resuscitation. On autopsy, severe burns were found in the esophageal and gastric mucosa, hyperemic lesions were seen in the renal tubular system as well as necrotic lesions in the cardiac musculature. Besides the poor prognosis of a fluoride intoxication in this dosis, the long time interval until treatment could be started seems to be the main reason for the fatal outcome of this case.