ABDOMINAL PAIN AND JAUNDICE

The history can be very helpful in establishing whether jaundice is caused by a pre-hepatic, hepatic or posthepatic problem. Bilirubin is produced by degradation of haem and is initially unconjugated, and hence water-insoluble. Unconjugated bilirubin is transported bound to albumin and is conjugated in the liver parenchymal cells to make it water-soluble and excretable in bile. Conjugated bilirubin is excreted and converted to urobilinogen, urobilin and stercobilinogen in the gut, which can be reabsorbed, leading to the enterohepatic circulation of bile pigments. These pigments give stool its normal coloration. If there is increased unconjugated bilirubin production from increased red cell destruction (e.g. haemolysis) then there will be jaundice with normally pigmented stool and urine. If there is obstruction to bile excretion (e.g. common bile duct stone), conjugated bilirubin accumulates (which causes itching), overflows into urine (causing it to appear dark), and does not reach the gut (resulting in pale stools). Hepatic causes may produce a combination of these patterns. Thus it is important to ask about stool and urine colour, as well as factors that may predispose to each type of cause. In this case, a full travel history is necessary and additional questions should be asked about pre-travel immunization and drug history.

Differential diagnosis of abdominal pain and jaundice

Pre-hepatic

• Abdominal pain is an uncommon feature

• Possible causes: malaria, sickle cell crisis

Hepatic

• Often pale stools and dark urine will be present

• Acute hepatitis due to infection, drugs, toxins

Posthepatic

• Pale stools and dark urine

• Bile duct stones, cholecystitis, choledochal cyst

• Cholangitis must be considered in a febrile child

Additional tests should include urine dipstick to confirm bilirubinuria, amylase, determination of the conjugated and unconjugated fractions of serum bilirubin, serological investigation for viral hepatitis (most importantly, hepatitis A IgM), a clotting profile and abdominal ultrasound. The most likely diagnosis is hepatitis A, which is uncommon in the UK but endemic throughout much of the world and is most likely to cause symptomatic acute hepatitis in older children and adults. There is usually a flu-like prodromal phase, with nausea and anorexia starting 2–6 weeks after exposure, followed by an icteric phase when there may be tender hepatomegaly. Usually children make a complete recovery. Other infections (e.g. hepatitis B, or C, and Epstein–Barr virus) can also cause acute hepatitis but are less common. Hepatitis A can be prevented by immunization and good hygiene practices, as it is transmitted by the faeco-oral route.

KEY POINTS

• Always ask about urine and stool colour in a jaundiced child.

• Hepatitis A is endemic throughout much of the world.

• Hepatitis A is most likely to cause symptomatic disease in older children and adults