Canis ISSN: 2398-2942

Pulmonary tuberculosis

Synonym(s): Pulmonary TB, active tuberculosis/TB

Contributor(s): Conor O'Halloran

Introduction

  • Rare primary disease in dogs.
  • Dogs primarily develop respiratory form of disease.
  • Cause: infection with Mycobacterium tuberculosisMycobacterium bovis may also occasionally be isolated.
  • Signs: weight loss, cough, depression, lymphadenopathy (local or generalized), anorexia. Occasionally dyspnea.
  • Diagnosis: biopsy with histology and special stains, culture/PCR and diagnostic imaging.
  • Treatment:
    • Euthanasia. Always indicated for M. tuberculosis infections due to risk to public health.
    • Long-term and potentially toxic chemotherapy can be used for TB complex infections other than M. tuberculosis. Often not attempted.
  • Prognosis: guarded or poor.

Pathogenesis

Etiology

  • Infection with Mycobacterium tuberculosis Mycobacterium tuberculosis or another member of the mycobacterium tuberculosis-complex, usually M. bovis.

Predisposing factors

General

  • Contact with human case. Also (but more rarely) contact with other sources, eg cattle or wildlife.
  • Immunocompromise, although evidence for this in dogs is anecdotal.

Pathophysiology

  • Dogs are usually infected with mycobacteria via inhalation of infective agent and so tend to develop respiratory disease.
  • Wildlife infections can occur by inoculation into the skin via bite wounds and so result in skin granulomas.
  • Most canine cases are the result of contact with human carriers or, occasionally, other sources.
  • Organism multiplies locally inducing granuloma (or tubercle) formation.
  • Infection will be spread to local lymph nodes.
  • Immune system activation at this stage may result in a degree of regression of lesions.
  • Lesions may progress over time to have a degree of central cavitation with cessation.
  • If cell mediated immune response fails or wanes, infection may spread or generalize.

Timecourse

  • Chronic disease with insidious onset over months.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Aranaz A, Liébana E, Pickering X, Novoa C, Mateos A & Domínguez L (1996) Use of polymerase chain reaction in the diagnosis of tuberculosis in cats and dogs. Vet Rec 138 (12), 276-280 PubMed.
  • Clercx C et al (1992) Tuberculosis in dogs - a case report and review of the literature. JAAHA 28 (3), 207-211 VetMedResource.
  • Trujillo-Rojas R A (1967) Pulmonary tuberculosis in dog diagnosed by a positive culture of Mycobacterium tuberculosis from laryngeal swab. Am Rev Respir Dis 95 (4), 674-675 PubMed.

Organisation(s)

  • Clinical advice: Professor Danielle Gunn-Moore, Royal (Dick) School of VeterinaryStudies, University of Edinburgh, UK. Email: companion.animalTB@ed.ac.uk.
  • Regional Center for Mycobacteriology (PHLS), Llandough Hospital, Penlan Road, Renarth, Cardiff CF64 2XX, UK. Tel: +44 (0)2920 716408.
  • Mycobacteria Unit, City Hospital, Edinburgh EH10 5SB, UK.
  • Mycobacteria Unit, St James Hospital, St James Street, Dublin 8, Ireland.


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