Confirmed case of Pneumocystis pneumonia in a Maltese Terrier × Papillon dog being treated with toceranib phosphate

Abstract

Case report A 7-year-old female-neutered Maltese Terrier × Papillon dog was presented with tachypnoea and weight loss following 12 months of therapy with toceranib phosphate for a metastatic, histologically-low-grade mast cell tumour.The dog was diagnosed with Pneumocystis canis based on PCR with supportive clinical, radiographic and cytological findings. No other clinical evidence of immunocompromise was identified through assessment of haematology and immunoglobulin quantification. Clinical signs completely resolved with a short course of potentiated sulfonamides and discontinuation of the toceranib.Conclusion To the authors' knowledge this represents the first case of Pneumocystis in a dog secondary to immunomodulatory drug therapy. It is also the first case of opportunist infection secondary to a tyrosine kinase inhibitor in dogs.

Pneumocystis Colonization in Dogs Is as in Humans

“…To diagnose primary PCP, consistent clinical findings, characteristic changes in radiographs and CT scans (ideally high-resolution CT), and an unequivocal response to specific therapy with TMS, in addition to a positive qPCR result are required. In contradistinction, the presence of Pneumocystis cysts (ascii) or zoites (trophic forms) in stained smears of BALF is strongly associated with presence of symptomatic PCP; such cases are not included here but have been described previously [ 14 , 22 ] and are tabulated with the observed C T values for purposes of comparison to the cases presented in this study ( Table 2 ).…”

“…Unlike the situation with P. jirovecii in humans, prevalence data for Pneumocystis in animal species is far less well documented. Canine cases of florid Pneumocystis pneumonia (PCP) have been fully described in only 53 dogs to date [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ].…”

In this issue ‐ May 2019: West Nile virus in horses · Treating horses with dexamethasone via nebulisation · Animal hoarding in NSW · Dangers of powdered washing soda for emesis in dogs · Pneumocystis in a dog following toceranib phosphate · Oxalate nephrosis in koalas

“…6 Toceranib phosphate is a tyrosine kinase inhibitor that blocks receptors associated with angiogenesis and the dog had been on an extended course for a resected cutaneous mast cell tumour. infection in a dog that was secondary to powdered treatment with toceranib phosphate.…”

“…infection in a dog that was secondary to powdered treatment with toceranib phosphate. 6 Toceranib phosphate is a tyrosine kinase inhibitor that blocks receptors associated with angiogenesis and the dog had been on an extended course for a resected cutaneous mast cell tumour. It presented with 6 weeks of lethargy, panting and weight loss.…”

X‐linked CD40 ligand deficiency in a 1‐year‐old male Shih Tzu with secondary Pneumocystis pneumonia

“…2 In dogs, pneumocystosis has occurred with suspected inherited immunodeficiencies, [3][4][5][6] secondary to distemper 7 and with administration of a tyrosine kinase inhibitor. 8 The exact mechanisms of humoral and cell-mediated immunity protective against pneumocystosis in humans and domestic animals still are being elucidated, but over a dozen genes encoding for proteins critical for immune responses have been identified in people. 9 Deficiency of 1 of these proteins, cluster of differentiation 40 ligand (CD40L), is linked to pneumocystosis in experimental murine models 10,11 and in humans, 12 but not in dogs.…”