[A hypophysis-abscess-syndrome in cattle III. Pathogenesis (author's transl)].

The pathogenesis of a hypophysis-absces-syndrome in cattle is discussed on the basis of clinical (Espersen 1975) and pathomorphological (Møller and Espersen 1975) investigations. It is concluded that several pathogenetic mechanisms are possible. A remarkable high incidence of the syndrome in recently ringed bulls point to the possibility of a porogenous spread from the nasal septum to the meninges and brain. The often occurring traumatic horn lesions with subsequent sinusitis suggest a porogenous spread from the sinus to the meninges and brain. On the other hand, traumatic horn lesions seem more often to occur as a secondary event and caused by automutilation, as a consequence of the pain, which is thought to accompany a primary meningo-encephalitis. The localization of the abscess in the hypophysis seems, in the majority of cases, to be a result of a primary, purulent meningo-encephalitis, with accumulation of pus from the brain ventricles to the infundibulum and pituitary cleft, due to gravitational forces. In some cases possibly as an extension from a basal meningitis. A direct, hematogenous metastasis to the frontal lobe of the pituitary is a further possibility. Ascending infection through a persistent cranio-pharyngeal duct and infection due to a primary cranial fracture represents other hypothetical, pathogentical possibilities. They have not been shown to occur. Severe clinical symptoms seem to be absent until the inflammation in the basal meninges and in the pituitary region attacks the adjacent cranial nerves, causing a paresis/paralysis.