Generalised granulomatous disease in a horse

Area of Science:

• Veterinary Pathology
• Equine Medicine
• Immunology

Background:

• A 6-year-old gelding presented with a 3-month history of recurrent fever, inappetance, lethargy, and weight loss.
• Initial clinical findings included depression, thrombophlebitis, scrotal nodules, leukocytosis, hyperfibrinogenaemia, and hyperglobulinaemia.

Observation:

• The horse exhibited worsening signs, including continued weight loss, recurrent fever, and multifocal skin lesions (scales, crusts, nodules) on the face, neck, and limbs.
• Thoracic ultrasonography revealed pleural fluid and lung consolidation, initially suggesting chronic respiratory disease.

Findings:

• Histological evaluation of skin biopsies indicated a granulomatous reaction.
• Further thoracic ultrasonography showed multiple hypoechoic lesions consistent with granulomas in both lungs.
• Necropsy confirmed widespread fibrotic granulomatous inflammation in multiple organs, including the lungs, heart, liver, gastrointestinal tract, and mesenteric lymph nodes.

Implications:

• The case demonstrates a rare instance of generalized granulomatous disease in a horse.
• Accurate diagnosis required advanced imaging and histopathology, underscoring the complexity of diagnosing systemic inflammatory conditions in horses.
• This case contributes to the understanding of granulomatous diseases in equine medicine and their potential for multi-organ involvement.