34th Annual Scientific Meeting proceedings

Objectives:

In human medicine, arthropathy, characterised by highly viscous non-inflammatory joint effusions, has been recognised and reported as one of the clinical states of acquired primary hypothyroidism. In dogs however, there is only one published case report describing non-inflammatory joint effusions as a presenting sign of hypothyroidism, with more common presentations including metabolic and dermatological abnormalities and less commonly reproductive, neurologic, cardiovascular and ophthalmic abnormalities. It has been proposed however, that excess thyroid stimulating hormone (TSH) production activates adenylate cyclase in synovial membranes, stimulating increased cellular production of synovial fluid within the joint and thus causing joint effusion.

Methods:

A 2 year-old female neutered Akita presented for stiffness, lameness and bilateral tarsal effusion. Grossly, there was marked increase in viscosity of the tarsal joint fluid obtained by arthrocentesis, however there was no evidence of inflammatory or infectious components. Radiographs demonstrated mild circumferential soft tissue swelling of the tarsi. TSH was increased, total thyroxine was decreased, and thyroglobulin autoantibody test showed a positive result. This supported a diagnosis of acquired primary hypothyroidism.

Results:

Oral Levothyroxine 400 mcg twice daily was prescribed for treatment of the diagnosed hypothyroidism. Three weeks later, the owner reported a vast improvement; the patient was tolerating long walks and had no lameness or stiff gait noted. On physical examination the bilateral tarsal effusion was markedly improved.

Conclusions:

Based on the findings outlines, hypothyroidism should be considered as a potential cause when a dog presents with non-inflammatory joint effusions.