Computed tomographic analysis of calvarial hyperostosis in captive lions.

Osseous malformations in the skull and cervical vertebrae of lions in captivity are believed to be caused by hypovitaminosis A. These often lead to severe neurologic abnormalities and may result in death. We describe the characterization of these abnormalities based on computed tomography (CT). CT images of two affected and three healthy lions were compared with define the normal anatomy of the skull and cervical vertebrae and provide information regarding the aforementioned osseous malformations. Because bone structure is influenced by various factors other than the aforementioned disease, all values were divided by the skull width that was not affected. The calculated ratios were compared and the most pronounced abnormalities in the affected lions were, narrowing of the foramen magnum, thickening of the tentorium osseus cerebelli and thickening of the dorsal arch of the atlas. CT is useful for detection of the calvarial abnormalities in lions and may be useful in further defining this syndrome.

Sub-occipital craniectomy in a lion (Panthera leo) with occipital bone malformation and hypovitaminosis A.

Neurologic dysfunction accompanied by malformation of both the skull and the cervical vertebrae has been previously described in lions kept in captivity worldwide, and this dysfunction and malformation were most often related to vitamin A deficiency. Diagnosis of the bone malformation and its effects on the neural tissue was until recently limited to postmortem examination, with characteristic thickening of the bones of the cranial vault, cerebellar herniation, compression of the foramen magnum, and enlargement of the lateral ventricles. For some mildly affected lion cubs with neurologic signs, improvement was reported with excessive vitamin A supplementation. However, definitive diagnosis was only available for those that eventually died or were euthanized. This case documents the antemortem diagnosis of the disease using computed tomographic imaging and liver biopsy. While conservative treatment failed, suboccipital craniectomy removed the thickened occipital bone and was demonstrated to be a successful surgical intervention that can be used to treat more severely affected lions.

Comparison of simultaneous splenic sample PCR with blood sample PCR for diagnosis and treatment of experimental Ehrlichia canis infection.

This report presents evidence that dogs recover from acute canine monocytic ehrlichiosis (CME) after 16 days of doxycycline treatment (10 mg/kg of body weight every 24 h). Blood PCR was as valuable as splenic aspirate PCR for early diagnosis of acute CME. Splenic aspirate PCR was, however, superior to blood PCR for the evaluation of ehrlichial elimination.