Acromegalic Arthropathy Masquerading as Rheumatoid Arthritis- A Diagnostic Challenge

Introduction:
Acromegaly is a disorder related to the excessive production of growth hormone after puberty. The estimated incidence of acromegaly is approximately 3/10,00,000 persons per year. Although figures in the literature vary, the diagnosis of acromegaly is often delayed by 7-10 years from the onset of symptoms. Increased provider recognition allows for early diagnosis and treatment, which may prevent long-term complications of acromegaly. This case highlights the importance of increased provider awareness of the condition, and it’s clinical features.

Case Description:
A 50-year-old female presented to primary care with several years of progressive joint pain in the hands with associated swelling and morning stiffness. On examination, she had synovitis in her PIP and MCP joints. Ultrasound of her hands revealed diffuse synovial fluid complexes and tenosynovitis. She was referred to Rheumatology and was diagnosed with seronegative rheumatoid arthritis. She was trialed on MTX, HCQ, and SSZ, followed by several biologics (Adalimumab, Etanercept, Abatacept) without clinical improvement. This prompted re-evaluation of her diagnosis. The rheumatologist recognized clinical features suggestive of acromegaly- mild frontal bossing, enlarged hands and dactylitis. A serum IGF1 level was elevated, which was confirmed on repeat testing upon establishing care with Endocrinology. MRI brain revealed a 7 mm pituitary microadenoma. The patient has been referred to neurosurgery and is awaiting surgical intervention.

Discussion:
The clinical manifestations of acromegaly include frontal bone bossing, jaw prognathism, acral overgrowth, osteoarthritis, diabetes mellitus, hypertension, respiratory and cardiac failure. With untreated, prolonged disease, concentric myocardial hypertrophy develops, and diastolic heart failure occurs, which are not reversible. Skeletal disorders cause significant functional disability and compromised quality of life in patients with acromegaly. 70% of such patients have large-joint and axial arthropathy that includes thickened articular cartilage, periarticular calcifications, osteophyte overgrowth, and synovitis. About 40% of cases are initially diagnosed by an internist, and the rest are diagnosed when patients are seen by ophthalmologists for visual disturbances, by dental surgeons for bite disorders, by gynecologists for menstrual dysfunction and infertility, by rheumatologists for osteoarthritis, or by sleep-disorder specialists for obstructive sleep apnea.

In conclusion, high suspicion of the diagnosis, along with early diagnosis, is critical in possibly preventing the morbidity associated with acromegaly and improving long-term outcomes.