A general practitioner (GP) refers a 21-year-old man, who had been previously fit and well, for
a second opinion. He had presented with a 6-week history of flitting arthralgia and myalgia.
Prior to the onset of this problem, he had been on holiday in the Far East where he had
unprotected sexual intercourse on one occasion only.
On general examination, there was no evidence of arthritis but it was noted that the patient
had bilateral cervical lymphadenopathy. Investigations showed a white cell count at the lower
end of normal, mild anaemia, normal urea and electrolytes, and abnormal liver function tests
with all the liver enzymes elevated. Urethral swabs for chlamydia and gonococcus were
negative.
Which is the most likely diagnosis?