ANSWER 29
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 14 h 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 overdosecauses 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 15 g
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 over-
dose 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 24 h, then a significant problem is very likely.
There are few symptoms in the first 24 h except perhaps nausea, vomiting and abdominal dis-
comfort. This may be associated with tenderness over the liver. The liver function tests usu-
ally become abnormal after the first 24 h. 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 acetylcys-
teine would be appropriate. The earlier this is used the better but it is certainly still worth-
while 16 h after the ingestion. In this case a level of paracetamol of 64 mg/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 ser-
vices. 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.
- Intravenous acetylcysteine and oral methionine are effective treatments for paracetamol
overdose if started early enough. - Paracetamol levels can be used to predict problems and guide treatment if the time
since overdose is known. - Paracetamol overdose should be suspected in any patient admitted with deranged liver
function tests and clotting, if no obvious alternative cause is apparent.