Peer-reviewed veterinary case report
Widespread Mycobacterium avium infection affecting multiple organs
By Teh, A et al.·Published in Australian veterinary journal·2025·Sydney School of Veterinary Science, Australia·View original on PubMed →
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Original publication title: Atypical presentation of disseminated mycobacteriosis due to Mycobacterium avium in an aged cat.
- Species:
- cat
Plain-English summary
A 10-year-old American Shorthair cat was brought in for not eating and losing weight. An ultrasound showed a large mass on the left kidney, and tests confirmed it was caused by a type of bacteria called Mycobacterium avium. Unfortunately, the cat had widespread infection affecting multiple organs, including the kidneys, liver, and thyroid. The cat likely had a weakened immune system, which may have been worsened by steroid treatment. Despite the findings, the outcome of the case was not detailed, but this type of infection can be serious and requires veterinary attention.
People also search for: cat weight loss · cat kidney mass · Mycobacterium avium in cats · cat not eating treatment · cat immune system problems
Abstract
In cats, mycobacteriosis tends to present in a syndromic manner, with cases either being due to tuberculosis (TB) (in countries where TB is endemic), one of the "leprosy-like" diseases affecting the skin and subcutis, panniculitis caused by infection of subcutaneous tissues generally with rapidly growing Mycobacteria spp. or widely disseminated granulomatous disease, which is usually caused by members of the Mycobacterium avium-intracellulare complex (MAC). Disseminated MAC disease is rare, but when it occurs, usually develops in immunocompromised hosts with defective cell-mediated immunity. This report describes a case of widely disseminated mycobacteriosis in a 10-year-old American Shorthair cat with an atypical multi-organ distribution including rarely documented thyroid gland involvement. The cat presented for a chronic history of inappetence and weight loss. Abdominal ultrasonography revealed a large mass on the left kidney, and an aspirate (FNA) from this mass showed abundant negative-staining bacilli which were confirmed to be acid-fast with Ziehl-Neelsen (ZN) staining. This was consistent with a mycobacterial aetiology. Necropsy revealed mycobacterial granulomas and/or granulomatous inflammation in the kidneys, thyroid gland, liver, spleen, lungs and left mandibular lymph node, with abundant intralesional acid-fast bacilli in all these tissues. Polymerase chain reaction (PCR) and culture on samples of all affected tissues were positive for M. avium. Collectively, the findings are consistent with disseminated mycobacteriosis due to M. avium with atypical distribution of lesions. Very likely, the cat had underlying immunodeficiency of undetermined cause, exacerbated by the administration of depot corticosteroid.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/39710507/