Cavernous sinus syndrome in dogs and cats: case series (2002-2015)

Canine Intracranial Venous System: A Review

The intracranial venous system (ICVS) represents in mammals a complex three-dimensional structure, which provides not only for adequate brain perfusion, but has also a significant impact on: cerebrospinal fluid (CSF) resorption, maintaining of the intracranial pressure (ICP), and brain thermoregulation. An intimate understanding of the anatomy and physiology of ICVS is fundamental for neurological diagnostics, selection of therapeutic options, and success of neurosurgical procedures in human and veterinary medicine. Since the intracranial interventions in dogs are recently performed more frequently than twenty or thirty years ago, the authors decided to review and report on the basic knowledge regarding the complex topic of morphology and function of the canine ICVS. The research strategy involved an NCBI/NLM, PubMed/MED-LINE, and Clarivate Analytics Web of Science search from January 1, 1960, to December 31, 2021, using the terms “canine dural venous sinuses” and “intracranial venous system in dogs” in the English language literature; also references from selected papers were scanned and relevant articles included.

Orbital apex syndrome secondary to an orbital sarcoma in a dog

A 12-year-old castrated male cocker spaniel dog was presented with a 4-week history of left episcleral injection and pawing at the face. Clinical examination findings included left internal and external ophthalmoplegia, left dorsal strabismus, pain opening the mouth, and intermittent amaurosis. Imaging studies revealed a left orbital apex mass with adjacent sphenoid bone lysis and extension into the cranial cavity. A left exenteration was performed and histopathology confirmed an orbital soft tissue sarcoma. Key clinical message: This report describes an orbital tumor causing orbital apex syndrome. This condition should be differentiated from cavernous sinus syndrome as the latter does not course with optic neuropathy.

Persistent Bilateral Mydriasis Associated With a Pituitary Adenoma in a Horse

Severe bilateral mydriasis and bilaterally decreased vision were observed in a 23-year-old crossbred warmblood gelding with a history of pituitary pars intermedia dysfunction. Ten years after the onset of clinical signs, it was killed humanely because of worsening of clinical signs and loss of therapeutic responsiveness. Postmortem examination of the head was performed to confirm the suspected pituitary neoplasm and to investigate secondary oculomotor lesions. Pathomorphologic examination revealed an expansile space-occupying pituitary adenoma and degenerative changes in the preganglionic oculomotor nerve, ciliary ganglion, and optic chiasm. The ocular clinical findings share features of a cavernous sinus syndrome.

Peripheral cranial neuropathies consistent with cavernous sinus syndrome caused by extracranial nasopharyngeal lymphoma in a cat

Cavernous sinus syndrome is a unique constellation of cranial nerve deficits occurring typically as a result of pathologic infiltration of the cavernous sinus, which is located in the lateral sellar compartment of the calvarium. This case report describes a polyneuropathy consistent with cavernous sinus syndrome as a result of a lesion outside of the cavernous sinus. The cat was presented with right internal and external ophthalmoplegia, loss of right corneal sensation, inspiratory stridor, dysphagia, dysphonia, tongue weakness, and weight loss. Magnetic resonance imaging identified a large nasopharyngeal mass along the base of, but without extension into, the calvarium. The histologic diagnosis was nasopharyngeal lymphoma. Focal extracranial masses should be considered as differential diagnoses for multiple cranial nerve deficits, including the constellation of clinical signs recognized as cavernous sinus syndrome.