19th January 2024

A 32-year-old female presents with a 3-month history of back pain and stiffness, which is worse in the morning.

A 32-year-old female presents with a 3-month history of back pain and stiffness, which is worse in the morning. She often takes ibuprofen for the pain which helps, but is finding it increasingly difficult to carry out her job as a cashier due to the pain. She has also noted pain and stiffness at the bottom of her calves in the morning. She does not recall any history of trauma, and is otherwise well, aside from suffering with mild eczema. A set of bloods are taken:

Hb 120 g/L (130-180)

MCV 93.5fL (80-96)

WCC 8.0 x 10⁹/L (4.0-11.0)

CRP 15 mg/L (<10)

Sodium 140 (133–146 mmol/L)

Potassium 4.8 (3.5–5.3 mmol/L)

Creatinine 72 (45–84 μmol/ L)

EGFR >90 

LFTs normal 

ESR 1

Rheumatoid factor 5 (0-20 u/mL)

Antinuclear antibody positive 

Anti-CCP negative 

What is the most likely diagnosis?

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