A 30-year-old woman is brought up to the emergency department at 2 pm by her husband. He is worried that she has taken some tablets in an attempt to harm herself. She has a history suggestive of depression since the birth of her son 3 months earlier. She has been having some counselling since that time but has not been on any medication. The previous evening about 10 pm she told her husband that she was going to take some pills and locked herself in the bathroom. Two hours later he persuaded her to come out and she said that she had not taken anything. They went to bed but he has brought her up now because she has complained of a little nausea and he is worried that she might have taken something when she was in the bathroom. The only tablets in the house were aspirin, paracetamol and temazepam which he takes occasionally for insomnia. She complains of a little nausea although she has not vomited. She has had a little abdominal discomfort. There is no relevant previous medical or family history of note. She worked as a social worker until 30 weeks of the pregnancy.
Examination On examination she is mentally alert. She says that she feels sad. Her pulse is 76/min, blood pressure is 124/78mmHg and respiratory rate is 16/min. There is some mild abdominal tenderness in the upper abdomen but nothing else abnormal to find.
Normal Haemoglobin 12.7g/dL 11.7–15.7g/dL Mean corpuscular volume (MCV) 87fL 80–99fL White cell count 6.8 109/L 3.5–11.0 109/L Platelets 230 109/L 150–440 109/L Prothrombin time 18s 10–14s Sodium 139mmol/L 135–145mmol/L Potassium 3.8mmol/L 3.5–5.0mmol/L Urea 4.6mmol/L 2.5–6.7mmol/L Creatinine 81amol/L 70–120amol/L Alkaline phosphatase 88IU/L 30–300IU/L Alanine aminotransferase (AAT) 37IU/L 5–35IU/L Gamma-glutamyl transpeptidase 32IU/L 11–51IU/L Glucose 5.1mmol/L 4.0–6.0mmol/L INVESTIGATIONS
Question • What should the management be now?
ANSWER
It is not evident from the history that the patient herself has been asked about any tablets or other agents she has taken. This would be an important area to be sure of. Of the three agents mentioned, the only one likely to be relevant is paracetamol. Aspirin and temazepam would be likely to produce more symptoms in less than 14h if they have been taken in significant quantity. However, the salicylate level should certainly be measured; in this case it was not raised. In the absence of drowsiness at this time, it is not necessary to consider temazepam any further. Paracetamol overdose causes hepatic and renal damage, and can lead to death from acute liver failure. The severity of paracetamol poisoning is dose related with a dose of 15g being serious in most patients. Patients with pre-existing liver disease and those with a high alcohol intake may be susceptible to smaller overdoses. The only significant abnormality on the blood tests is a slightly high prothrombin time and minimally raised alanine aminotransferase (AAT). The prothrombin time increase (expressed alternatively as the international normalized ratio or INR) is a signal that a paracetamol overdose is likely. It is often the first test to become abnormal when there is liver damage from paracetamol overdose. If the INR is abnormal at 24h, then a significant problem is very likely. There are few symptoms in the first 24h except perhaps nausea, vomiting and abdominal discomfort. This may be associated with tenderness over the liver. The liver function tests usually become abnormal after the first 24h. Maximum liver damage, as assessed by raised liver enzymes and INR occurs at days 3–4 after overdose. Acute liver failure may develop between days 3 and 5, and renal failure occurs in about 25 per cent of patients with severe hepatic damage. Rarely, renal failure can occur without serious liver damage. The paracetamol level should be measured urgently; it was found to be high. The evidence of early liver damage from the INR would in itself suggest that treatment with acetylcysteine would be appropriate. The earlier this is used the better but it is certainly still worthwhile 16h after the ingestion. In this case a level of paracetamol of 64mg/L confirmed that treatment was appropriate and that the risk of severe liver damage was high. Further advice can always be obtained by ringing one of the national poisons information services. The electrolyte, renal and liver function tests and the clotting studies should be monitored carefully over the first few days, and referral to a liver unit considered if there is marked liver dysfunction. Patients with fulminant hepatic failure are considered for urgent liver transplantation. The other areas that need to be addressed in this case are the mental state and the safety and care of the son and any other children. This is a serious drug overdose. She should be seen by a psychiatrist or other appropriately trained health worker. The question of any possible risk to the baby should be evaluated before she returns home.