MRCP2-4546

MRCP2-4546

A 28-year-old microbiologist presents with persistent fevers of >39°C, severe joint pains, and swelling of the hands and feet.

She complains of a pale pink macular rash, which she thinks may be secondary to the antibiotic her GP prescribed for fever.

On examination, you find a palpable splenic tip and a single lymph node in the posterior cervical region.

Blood tests are as follows:

Haemoglobin 113 g/L (100-160)

Sodium 136 mmol/L (133-146)

ESR 110 mm/hr (0-9)

White Cell Count 11.3 ×109/L (3.5-10.9)

Potassium 4.0 mmol/L (3.5-5.3)

CRP 322 mg/L (<5) Neutrophils 9.0 ×109/L (1.9-9.0) Creatinine 83 µmol/L (44-80) Platelets 495 ×109/L (150-450) Urea 5.0 mmol/L (2.5-7.8) Ferritin >3000 µg/L (13-300)

RF Negative

ANA Negative

Serum electrophoresis Normal

HIV Negative

EBV serology Negative

Blood film Normal

TFTs Normal

What is the most likely diagnosis for this 28-year-old microbiologist?