A case of renal amyloidosis associated with udder cleft dermatitis in an adult dairy cow

Abstract

Amyloidosis is a group of disorders characterised by the injurious deposition of abnormal proteins in tissues. Most common in cattle and other animals is secondary or reactive systemic amyloidosis associated with chronic inflammation, resulting in deposition of acute-phase serum amyloid A (SAA) in organs like the kidneys, liver, and spleen. While chronic diseases like mastitis, metritis and pododermatitis are usually the most common diseases identified as inflammatory sources, any persistent inflammation can trigger this disorder. Cattle affected by amyloidosis often exhibit symptoms like weight loss and kidney dysfunction. Here we present the case of a five-year-old Holstein Friesian referred to the University of Glasgow for weight loss and chronic diarrhoea. Clinical examination revealed low body condition score, watery diarrhoea, mild dehydration (5%), mild submandibular oedema, left renomegaly, and udder cleft dermatitis. Biochemistry and urine analysis indicated hypoalbuminemia with normal globulin levels and marked proteinuria. Gross post-mortem findings suggested a diagnosis of secondary amyloidosis, and histopathology confirmed SAA deposition in the glomeruli and renal medullary interstitium. In the absence of another grossly appreciable chronic inflammatory focus/ foci the udder cleft dermatitis was considered the likely contributing comorbidity.