E024 Doctor my back hurts... an unusual cause for lower back pain

Back pain is a common musculoskeletal symptom with multiple differential diagnoses. Thorough medical workup is vital for accurate diagnosis and effective management. Sarcoidosis is a granulomatous disease of unknown aetiology, characterized by the formation of immune granulomas in various organs. It has a prevalence of approximately 10-60 cases per 100,000 people in the United States and Europe. A recent systematic review revealed that sarcoidosis commonly affects the ankle, hand, and knee joints. Here, we report an unusual and unreported presentation of sarcoidosis.

A 63-year-old Caucasian female, with a background of asymptomatic hyperuricaemia and mild renal failure, presented in clinic with few weeks’ history of worsening episodes of nocturnal lower back pain. Other red-flag symptoms such as incontinence, radiating pain, constitutional symptoms, were not present. Thorough clinical examination did not identify any inflammatory pathology.

An initial MRI scan revealed multiple lesions within the vertebral marrow and vertebrae (T11, L3-4), suspected to be metastatic in nature. Baseline investigations revealed ALP 131 IU/L (30-130) and CRP 30.8 mg/L (<5), with normal immunoglobulins and no paraprotein identified. Subsequent urgent CT-CAP failed to identify a primary site, but instead showed multicompartmental supra and infra-diaphragmatic lymphadenopathy, highly suggestive of hematogenous malignancy lymphoma. Lymph node biopsy was negative for TB Ziehl-Neelsen staining, and Hodgkin’s lymphoma was not identified. Instead, histology confirmed a florid non-caseating granuloma. Further blood tests included an ACE level of 133 IU/L (16-85) and adjusted calcium of 2.77 mmol/L (2.20-2.60). EBUS confirmed the clinical diagnosis of sarcoidosis.

Sarcoidosis is a rare and unusual cause for lower back pain. Spinal involvement as an extra-pulmonary manifestation is also uncommon. In this case, the thorough diagnostic process allowed for targeted treatment with oral steroids, alongside bone and gastric protection. This resulted in significant improvement of the patient’s back pain and prevented future symptoms of hypercalcaemia. Therefore, it is important rheumatologists and other clinicians are aware of this unusual articular manifestation of sarcoidosis, to aid holistic assessment of patients presenting with lower back pain.

V. Sankar: None. D. Livingston: None. V. Rodwell: None. P. Gladston: None. A. Moorthy: None.