aetiology and pathogenesis

Last reviewed 01/2018

Mycobacteria usually enter the body via the respiratory tract. Infection through the alimentary tract is uncommon in the UK but does occur in developing countries. Infection through the skin is a very rare occurrence.

The infection may be asymptomatic. The severity of the clinical features depend on:

  • the degree of natural immunity
  • state of nourishment
  • coexisting disease e.g. malignancy or diabetes mellitus
  • immunosuppression
  • age

The pathogenesis of tuberculosis can be described in terms of:

  • primary
  • post-primary
  • miliary tuberculosis