Radiographic Findings in Cats with Mycobacterial Infections

Abstract

This study describes radiographic changes associated with mycobacterial infection in 33 domestic cats confirmed by culture or interferon-gamma testing. Infection was seen most frequently in adult (average age 5.7 years; range 1.5-12 years), non-pedigree (87%; 27/31), neutered male cats (69%; 22/32). The most common infections were Mycobacterium microti (60%; 18/30) and Mycobacterium bovis (37%; 11/30); Mycobacterium avium and Mycobacterium malmoense were infrequently cultured (3% of each; 1/30). Radiographs were available for the thorax (24 cats), abdomen (eight), appendicular skeleton (11) and head (three). Radiographic changes affected the thorax most commonly, consisting of bronchial (46%; 11/24), alveolar (38%; 9/24), nodular unstructured interstitial (38%; 9/24) or unstructured interstitial (25%; 6/24) lung patterns, which were often mixed. Perihilar or sternal lymphadenopathy were common (42%; 10/24), particularly perihilar lymphadenopathy (25%; 6/24). Skeletal changes were found in the distal antebrachium (three), pes (two), maxilla, scapula, spine, manus, femur, and tarsus (one each). Changes were typically osteolytic (73%; 8/11), often permeative osteolytic (64%; 7/11). Osteoproliferative changes were seen in three cats and soft tissue swelling in five cats, which were adjacent to the bony abnormality in four cats. Other changes included submandibular soft tissue swelling, marked aortic, aortic root and brachiocephalic trunk calcification, and soft tissue swelling with calcification in the distal antebranchium which was not involving bone. Abdominal changes were uncommon (seen in 2/8 cats) and consisted of hepatomegaly and hepatosplenomegaly. In summary, radiographic changes were varied, no lesion was pathognomic for mycobacterial infection, and pathology was seen most commonly in the thorax.

Mycobacterial Infections

“…Bronchial, alveolar, nodular interstitial, and unstructured interstitial patterns predominate in cats, and perihilar lymphadenopathy can be present. 20,26 Calcification of pulmonary lesions or lymph nodes may be evident in dogs or cats. Hepatomegaly, splenomegaly, or lymphadenopathy, with or without ascites, may be present on abdominal radiography, or abdominal radiographs may be unremarkable.…”

“…Hepatomegaly, splenomegaly, or lymphadenopathy, with or without ascites, may be present on abdominal radiography, or abdominal radiographs may be unremarkable. 26 Radiographic evidence of osteomyelitis (especially osteolysis) can occur in cats infected with M. microti or M. bovis, often in association with overlying cutaneous lesions. 26…”

Applying the One Health Concept to Mycobacterial Research – Overcoming Parochialism

“…NTM are capable of contaminating the natural environment leading to both human and animal infections (Rhodes et al., ; Falkinham, ; Halstrom et al., ; Ngeow et al., ). Food‐producing animals and pet animals act as reservoir hosts for a variety of NTM species, many with documented zoonotic potential (Katoch, ; Bennett et al., ; Greene, ; Schrenzel, ; Woerde et al., ). Many NTM are virulent in animals, but their human disease potential is poorly understood (Bono et al., ; Komijn et al., ; Hoefsloot et al., ; Richter and Saviola, ).…”

Incidence of Mycobacterial Infections in Cats in Great Britain: Estimate from Feline Tissue Samples Submitted to Diagnostic Laboratories

“…Unfortunately, many aspects of mycobacteriosis in this species remain unknown. While recent studies from Great Britain (GB) have advanced our overall understanding of these infections (reviewed in Gunn‐Moore, 2010; Bennett et al., 2011; Gunn‐Moore et al., 2011a,b; Lalor et al., 2012; Rhodes et al., 2011; Rüfenacht et al., 2011; reviewed in Greene and Gunn‐Moore, 2012), their current prevalence remains unknown.…”