(Infection)

Overview

• An infectious, chronic granulomatous disease caused by Mycobacterium tuberculosis
• Typically affects lungs (esp. upper lobes) however infection may spread haematologically to any organ, causing extrapulmonary TB
• In many patients, M tuberculosis is dormant before it progresses to active TB (primary TB = asymptomatic)
  • Primary TB ⇒ non-immune host who is exposed to m.tuberculosis. In immunocompetent individuals, this will usually heal.
  • Secondary TB ⇒ If the host becomes immunocompromised the initial infection may become reactivated.
• Activation of the infection can occur in immunocompromised individuals
• Risk Factors → exposure to infection, immunosuppression (diabetes, cushings, steroid use), silicosis (form of lung fibrosis), malignancy, birth in an endemic country (India/Bangladesh/Sub Saharan Africa), HIV, overcrowded areas

Making Diagnosis

Clinical Features:

• Cough → productive (may have haemoptysis), doesn't respond to conventional antibiotic therapy
• Fever
• Weight Loss
• Night Sweats
• SOB
• Anorexia
• Malaise