Cladophialophora encephalitis in an alpaca

Abstract

A 4-year-old Huacaya hembra was evaluated for acute neurologic signs including recumbency and a left head tilt. Cranial nerve examination revealed a left ear droop, muzzle deviation to the right, mydriasis of the left eye, an absent menace response, bilateral absent pupillary light reflex when light was directed into the left eye, and bilateral horizontal nystagmus with fast phase to the right. Multifocal intracranial lesions were suspected. Computed tomography revealed an intracranial mass. Postmortem examination, histopathology, and sequencing of a polymerase chain reaction product confirmed a diagnosis of phaeohyphomycotic meningoencephalitis caused by Cladophialophora bantiana. Key clinical message: Advanced diagnostic imaging (computed tomography) was useful in achieving a diagnosis of an intracranial mass in an alpaca with acute neurological signs, later confirmed to be central nervous system (CNS) phaeohyphomycosis. Although uncommon, intracranial fungal infection should be considered as a differential diagnosis in camelid patients exhibiting CNS signs, particularly if they do not respond to initial antimicrobial and anthelmintic therapy.

Figure 1

A — Transverse CT image (soft tissue displace algorithm) shows an ill-defined mass (yellow arrows) in the region of the right thalamus that extended caudally, ventral to the falx tentorium to the level of the cerebellum and caused a leftward midline shift. The mass was heterogenous, slightly hyperdense and caused dorsal and lateral compression of the right lateral ventricle. B — Transverse, C — sagittal, and D — dorsal CT images (soft tissue displace algorithm) showing the ill-defined mass previously noted in A is now contrast enhancing, consistent with an abscess or a granuloma.

Figure 2

A — Prosencephalon at the level of the thalamus and hippocampus. There is a large, brown to black central area of necrosis that unilaterally effaces 60% of the gray and white matter and compresses the adjacent neuroparenchyma. B — Thalamus 1000 × H&E stain; bar = 50 μm. Yeast cells (arrow) are ovoid, 7 to 20 μm in diameter, with dark brown cell walls, clear to pale brown cytoplasm, and a central basophilic nucleus. Hyphae (arrowhead) are 5 to 10 μm wide, septate with irregular, dichotomous and nondichotomous with acute angled to right angled branching, and thin, pigmented, nonparallel walls.