27th May 2025

A 22-year-old female presents with a few-month history of pain and swelling in her right hip and shoulder.

A 22-year-old female presents with a few-month history of pain and swelling in her right hip and shoulder. She also has had back pain for the past 6 months, for which she takes ibuprofen. She reports feeling generally fatigued, and occasionally reports loose stools when stressed, but has no other symptoms. She works as a pharmacist and is finding it increasingly hard to carry out her job due to her symptoms. She has a family history of rheumatoid arthritis. Blood test results showed the following.

Hb 133 g/L (130-180)

MCV 93.5fL (80-96)

WCC 6.0 x 10⁹/L (4.0-11.0)

CRP 11 mg/L (<10)

Sodium 142 (133–146 mmol/L)

Potassium 4.6 (3.5–5.3 mmol/L)

Creatinine 76 (45–84 μmol/ L)

EGFR >90 

ESR 20

LFTs normal 

Rheumatoid factor 25 (0-20 u/mL)

Anti-CCP negative 

Faecal calprotectin 79 (50-200 μg/mg)

An x-ray of her joints has been requested. What is the most likely diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.