Orchitis

• INFLAMMATORY (Orchitis)

Orchitis is inflammation of the testes. One or both testes may be affected.

Aetiology:

1. Release of sperm into interstitial tissue - granulomatous response.
2. Infections. May arise by three routes:
   • Haematogenous bacterial/viral infection.
   • Secondary infection following localised trauma.
   • Retrograde infection from accessory glands and/or epididymis.

Various organisms involved classically, Brucella spp. Brucella abortus, A. pyogenes, M. tuberculosis in cattle
B. canis in imported dogs
B. suis in pigs

The epididymis and seminal vesicles may also be affected in animal species with well developed accessory glands - i.e. bull and boar.

Histologically:Range of severity depending on the extent of vascular occlusion and/or pathogenic organism.

Early stages:necrosis of seminiferous epithelium and desquamation ± haemorrhagic or fibrinopurulent exudate if there is bacterial infection.

Chronic:fibrosis ± calcification.

Granulomata are often a feature of severe orchitis due to Brucella spp. infection.

Information by kind permission of Professor R W Else