Private gilbert's syndrome clinic in London, same-day endocrinology.

What is happening

Bilirubin is produced continuously as old red blood cells are broken down. An enzyme in the liver processes it for excretion. In Gilbert's syndrome that enzyme works at around 30% of normal capacity — ample under ordinary conditions, but not quite enough when production rises or the liver is under stress. Bilirubin then accumulates mildly, and may cause a faint yellow tinge to the whites of the eyes.

What makes the level rise

• Fasting or skipping meals — including the fast before a blood test, which is a common reason it is discovered
• Illness or infection, including a simple cold
• Dehydration, and vigorous or prolonged exercise
• Alcohol, and lack of sleep
• Stress, and in women, menstruation
• Levels typically fluctuate between normal and mildly raised, which is itself characteristic

What it means for you

• It is not liver disease. It does not progress, does not cause cirrhosis, and does not affect life expectancy.
• No treatment is needed, and no dietary restriction is required.
• Some people report fatigue or vague abdominal discomfort during episodes. Whether this is caused by Gilbert's is debated, but eating regularly and staying hydrated helps.
• It is inherited, so relatives may have it too — useful to know if their results are ever questioned.
• Tell any clinician about it, so a raised bilirubin in future is not misinterpreted as new liver disease.

The one practical implication

The same enzyme processes certain medicines, so a small number are handled more slowly and can cause more side effects. The most relevant are irinotecan (a chemotherapy drug), atazanavir (an HIV medicine), and occasionally paracetamol at high doses over long periods. This is rarely an issue in ordinary life, but it is worth having recorded in your notes.