Gout in poultry

Gout is a metabolic disease characterized by deposition of urates on the surfaces of various internal organs, or various joints

1. Gout Gout is a metabolic disease characterized by deposition of urates on the surfaces of various internal organs, or various joints Both in broiler and layer chicks, gout can be seen from 4th day onward and can be a serious problem between 2nd and 3rd week Birds usually die from kidney failure

2. Types of gout Visceral gout  – deposition of uric acid crystals in visceral organs like kidney, liver, heart and gut. It is the acute and more common form of gout reported in poultry. It causes huge mortality in poultry ranging from 15-35 per cent. It is observed in young poultry . Articular gout  – deposition of uric acid crystals in joints, ligaments and tendon sheath. It is chronic form of gout and has some genetic predisposition. It is rarely seen in poultry

3. pathogenesis Uric acid is the end product of purine and protein metabolism in poultry. Uric acid is formed in the liver and excreted by kidneys . Birds are uricotelic , lack the enzyme uricase and this along with the process of water conservation, allows them to excrete urine in the form of semi-solid uric acid in the faeces .   Disruption in the metabolic process of excretion of uric acid leads to gout . So,gout can arise either due to production of uric acid over the capacity of kidneys to excrete it, or due to compromised kidney function failing to excrete the produced uric acid

4. Postmortem Findings Presence of white chalky deposits on the surfaces of heart, liver, kidneys, proventriculus , and lungs. These deposits are seen as white chalky coating

5. 2. The chalky deposits first begin on the heart and then spread 3 . Kidneys are swollen, congested , and typically gouty (greyish white in colour ) . 4. One or both ureters may be distended with white material. 5.In the articular gout, when joints are opened, the tissue surrounding the joints is white due to urate deposition

6. Diagnosis Joint fluid test.  Your doctor may use a needle to draw fluid from your affected joint. Urate crystals may be visible when the fluid is examined under a microscope Blood test.  Your doctor may recommend a blood test to measure the levels of uric acid and creatinine in your blood. Blood test results can be misleading, though. Some people have high uric acid levels, but never experience gout. And some people have signs and symptoms of gout, but don't have unusual levels of uric acid in their blood . X-ray imaging.  Joint X-rays can be helpful to rule out other causes of joint inflammation . Ultrasound.  Musculoskeletal ultrasound can detect urate crystals in a joint or in a tophus

7. Differential diagnosis Pseudogout (calcium pyrophosphate deposition disease) The definitive diagnosis is finding calcium pyrophosphate crystals in the synovial fluid. These are rhomboid-shaped, weakly positively birefringent crystals. Chondrocalcinosis (radiographic calcification of cartilage in certain joints) is usually present. Septic arthritis Synovial fluid microscopy and culture may be Gram positive and show growth. Blood cultures may grow the causal bacteria   Trauma Synovial fluid is usually bloody and has no monosodium urate crystals. Rheumatoid arthritis (RA) Synovial fluid is inflammatory (WBC count >2000/mm^3), but no monosodium urate crystals are found Reactive arthritis X-rays may show soft-tissue swelling