A seven-year-old male castrated Labrador Retriever was referred to the Cornell University Hospital for Animals (CUHA) for a two-week history of anterior uveitis in the left eye and a four-five month history of hemorrhagic large bowel diarrhea. Refractory clinical signs and exhaustion of non-invasive diagnostics prompted referral for an upper and lower GI endoscopy performed on 4/14/15 at the Veterinary Medical Center in Syracuse. Biopsy results and fungal serology were sent to Texas A&M College of Veterinary Medicine. Results were pending at the time of presentation.
On presentation to the CUHA Ophthalmology service, the dog was bright, alert and responsive. Ophthalmic exam revealed absent direct pupillary light reflex OS (left eye), absent menace OS, and 3+ flare of the anterior chamber. The intraocular pressures were 10 OD (right eye) and 35 OS (mmHg). The fundus displayed chorioretinitis with multifocal areas of subretinal hemorrhage and retinal edema OD and complete bullous retinal detachment with intraretinal white lesions OS. The dog had a left sided head tilt and mild kyphosis of the thoracolumbar spine. The remainder of the physical exam was unremarkable.
These ophthalmic findings, coupled with the left sided head tilt and several month history of refractory colitis, were suggestive of protothecosis. Additional diagnostics including urine culture, cytology of subretinal aspirates, and culture of the subretinal aspirate were performed. All tests confirmed presence of P​rototheca s​pp. The dog was hospitalized and treatment with amphotericin B and itraconazole was initiated. Intravenous fluid therapy was utilized to mitigate nephrotoxicity secondary to amphotericin administration. The dog was maintained on antibiotics (metronidazole and doxycycline), antacids and antiemetics and ocular medications. The patient’s condition remained relatively static over 5 days of hospitalization with some improvement with respect to hematochezia. He was discharged on 4/27/15 to the care of his owner. The patient continued to receive amphotericin therapy with his primary veterinarian. Over the course of several days, the patient became blind in both eyes. Due to the lack of response to medical management and the grave prognosis associated with this disease, euthanasia was elected.
This report will describe the pertinent clinical findings, diagnostics and treatment in a dog with disseminated protothecosis.