Long‐term cure of disseminated Mycobacterium avium infection in a cat

Abstract

Mycobacterium avium-intracellulare, a member of the M avium complex (MAC), is a ubiquitous, saprophytic, slowgrowing, acid-fast bacillus that is widely distributed in the environment (Greene and Gunn-Moore 2006). Clinical signs associated with MAC infection are typically organ-specific, depending on the route of infection.Dissemination can occur in immunocompromised hosts. The treatment of localised disease consists of surgical removal of the infected tissue, with or without medical therapy (Kaufman and others 1995, Malik and others 1998). The treatment of disseminated MAC infection in cats has recently been reported to be successful with a variety of combination drug regimens, including clofazimine and clarithromycin as essential components (Baral and others 2006). This short communication describes the treatment of a cat with disseminated M avium infection with a multidrug regimen and the associated side effects.A five-year-old, male neutered Abyssinian cat was evaluated by a private veterinarian because of a history of weight loss and anorexia. Physical examination revealed an abdominal mass, which was removed surgically. Pyogranulomatous inflammation was observed on histopathological examination of the mass. Tests for feline leukaemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibody were negative. Treatment with prednisone was initiated, but within two weeks the cat became tachypnoeic and was referred to the University of Georgia Veterinary Teaching Hospital.Thoracic radiography revealed a diffuse, nodular interstitial lung pattern. Pyogranulomatous inflammation without visible microorganisms was detected on bronchoalveolar lavage (BAL) and on transthoracic lung aspirates. The results of aerobic bacterial and fungal cultures and tests for cryptococcal antigen (latex agglutination test), toxoplasmosis antibodies (immunoglobulin M [IgM] and immunoglobulin G [IgG] ELISAs) and coronavirus antibody (immunoflourescent antibody test), were negative. On an empirical basis, the cat was discharged on 10 mg/kg clindamycin and 5 mg/kg itraconazole, both administered orally every 12 hours.Two months later, the cat was re-presented because of persisting anorexia and tachypnoea. At that time (day 0) the cat was thin (bodyweight 2·7 kg) and had a normal rectal temperature and a markedly increased respiratory rate, with increased expiratory effort. Thoracic auscultation revealed increased normal breath sounds bilaterally, and abdominal palpation revealed a 6 x 7 cm, irregular, non-painful mass in the mid-abdomen. Laboratory abnormalities included mild neutrophilia (15,768 cells/µl, reference range [RR], 2500 to 12,500 cells/µl) with left shift (bands, 1944 cells/µl, RR 0 to 300 cells/µl), hyperglobulinemia (51 g/l, RR 30 to 34 g/l) and hypercalcemia (total calcium 4·0 mmol/l, RR 2·25 to 2·7 mmol/l; ionised calcium 1·59 mmol/l, RR 1·22 to 1·3 mmol/ l). A severe bronchointerstitial lung pattern was detected on thoracic radiography (Fig 1). Abdominal ultrasonography revealed multiple irregularly marginated h...

Mycobacterial Infections

“…Most affected dogs or cats have had mild to moderate nonregenerative anemia, neutrophilia with bandemia, lymphopenia, hypoalbuminemia, hyperglobulinemia or hypoglobulinemia, and sometimes hypercalcemia, hyperbilirubinemia, and increased liver enzyme activities. 48,54,57 An absence of hematologic or biochemical abnormalities has also been described.…”

“…In cats, disease resembles that caused by M. bovis or M. microti, with cutaneous lesions (especially on the head and limbs) in some cats, osteomyelitis, pulmonary involvement with tachypnea or cough, peripheral and abdominal lymphadenomegaly, and gastrointestinal, liver, splenic, renal, omental, and uncommonly CNS or marrow involvement. 41,42,[44][45][46][47][48][49][50] Gastrointestinal involvement may initially manifest as weight loss despite a good appetite. 41 Dogs with MAC infections often develop marked peripheral or abdominal lymphadenopathy, tonsillar enlargement, hepatosplenomegaly, and/or osteomyelitis.…”

“…41,48 Diffuse interstitial patterns may be present in the absence of clinical signs of respiratory involvement. Thoracic lymphadenopathy or mediastinal masses may be present in dogs.…”

“…36,41,48 As for infection with MTBC organisms, the use of two or three drugs in combination is recommended to prevent emergence of resistance. The availability of macrolides (especially clarithromycin) has greatly improved outcome for human patients with MAC infections, so inclusion of clarithromycin or azithromycin is important.…”

Something old, something new

“…[111][112][113] The recommended first choice treatment is clarithromycin with clofazimine (4-8 mg/kg q24h) or rifampicin or doxycycline (5-10 mg/kg q12h) based on the few cases reported with good outcomes [EBM grade iV]. [114][115][116] Limited clinical experience with pradofloxacin suggests that it is more effective than the older fluoroquinolones. 110 Most cats with feline leprosy can be cured by surgery (small lesions), and treatment with combinations of rifampicin, clofazimine, clarithromycin and pradofloxacin for several months [EBM grade iV].…”