Acute pancreatitis secondary to treatment with isotretinoin

We present the case of a 14-year-old male who attended our hospital following hours of epigastric abdominal pain and vomiting. There was no associated choluria, jaundice or change in bowel habits. Prior history of interest included treatment with isotretinoin 30 mg/day for the last three months.

The physical examination found the patient to be afebrile and tachycardic, with a blood pressure of 100/66 mmHg. He experienced epigastric pain upon palpation of the abdomen, with no peritonism and no other findings of interest. No relevant abnormalities were observed in the abdominal X-ray. The blood tests revealed abnormal pancreatic clinical chemistry values (amylase 584 U/l and lipase 1392 U/l) with a normal lipid, phosphorus and calcium profile. An abdominal ultrasound found no significant biliary abnormalities, ruling out the presence of intra-abdominal collections or masses.

In light of these findings, mild acute pancreatitis (BISAP 0) of probable toxic-drug-induced aetiology secondary to treatment with isotretinoin was diagnosed. The patient's progression was satisfactory after withdrawal of the medicinal product, with no abnormal findings in the subsequent clinical examination, bloods and ultrasound.

Isotretinoin is a medicine used to treat severe and nodular cystic acne. Although its mechanism of action is unknown, it is believed to induce apoptosis in the sebaceous gland cells.

Acute pancreatitis induced by the ingestion of isotretinoin is an extremely rare and generally mild adverse effect.¹ Most cases are caused by an idiosyncratic reaction (as in our case), with a small percentage of cases attributable to secondary hypertriglyceridaemia.² It usually manifests between six weeks and six months after the start of treatment, with onset possible at any time.³ It cannot be prevented, with the systemic monitoring of triglyceride levels during treatment having been shown to be an ineffective tool.

Despite being a rare side effect, acute pancreatitis should be taken into account when treating a patient with abdominal pain who is taking isotretinoin.

Acknowledgements

We are grateful for the support of the entire Hospital Universitario Rio Hortega Gastroenterology Department, and our particular thanks go to Dr Raúl Torres and Dr Félix García, and to the rest of the staff who handled this case.