MRCP2-2701

MRCP2-2701

A 35-year-old man presented with a 4-week history of oedema and occasional tingling in his right leg. He had experienced painful muscle cramps in his legs and abdomen 3 months ago and had noticed swelling and numbness in his right leg. He had traveled to Thailand 10 months ago and had significant exposure to fresh water during his trip. On examination, he had a non-tender hepatomegaly of 4 cm without splenomegaly. Papular erythematous lesions were present on both legs, and there was pitting oedema in his right lower leg. Sensation to light touch over the right lower leg was reduced. The following results were obtained from his investigations:
White cell count (WCC) 14.8 × 109/l 4.0 – 11.0 × 109/l
Lymphocytes 3.5 × 109/l 1.5 – 4.0 × 109/l
Neutrophils 6.2 × 109/l 1.5 – 7.0 × 109/l
Eosinophils 5.1 × 109/l 0.04 – 0.4 × 109/l
Haemoglobin (Hb) 142 g/l 115 – 160 g/l
Platelets (PLT) 320 × 109/l 150 – 400 × 109/l

What is the most probable diagnosis?