Editing Tuberculosis


The disease caused by Mycobacterium tuberculosis

== Presentation ==

* Wide spectrum of disease - asymptomatic to severe, active

== Pathophysiology ==

* Transmitted by aerosol droplets, leading to one of two responses:
** Immediate clearance of the organism
** TB infection (previously called latent TB)
* TB infection
** Tuberculous bacilli proliferate inside alveolar macrophages
** A nodular granulomatous structure (tubercle) forms (seen as a Ghon focus radiologically)
** The tubercle enlarges and bacilli enter the lymphatic drainage system, leading to lymphangitis and enlarged regional nodes
** An effective cell-mediated response eventually develops in most patients, containing organisms
** Caseous necrosis can be seen in this context
* Primary TB disease
** Immediate onset of TB disease following exposure in a previously naïve host
** Caused by failure to mount an effective response
** Progressive tissue destruction - bacilli migrate away from lungs, producing disseminated TB
** More common with immunosuppressed people
* Reactivation disease
** Occurrence of TB after a period of clinical latency
** Lifetime risk of 5-10%
** Associated with HIV, organ transplant, silicosis, immunosuppressive drugs, diabetes, CKD
** Tends to be localised to lung apices

== Abdominal TB ==

* Can present with involvement of peritoneum, stomach, GIT, HPB, perianal area, and lymph nodes
* Can occur via reactivation of latent TB or by ingestion of bacilli, or can develop via miliary spread of active pulmonary TB
* Presents with fever, weight loss, abdominal pain/distension, ascites, hepatomegaly, diarrhoea, WBO, and abdominal mass
* GIT: most commonly ileocaecal. 
* Management:
** Anti-tuberculous therapy (same as pulmonary TB)
** Surgical indications:
*** Perforation
*** Abscess
*** Fistula
*** Bleeding
*** High-grade obstruction (most common)
** Surgery should be as conservative as possible. Bypass should be avoided due to blind loop syndrome.



== Scrofula/tuberculous lymphadenitis ==

* One of the most common extrapulmonary manifestations of TB - responsible for about 40% of lymphadenopathy in third-world countries
* Treat with multidrug antimycobacterial therapy - often two months of rifampicin, isoniazid, ethambutol and pyrazinamide

== Complications ==

* Haemoptysis
* Pneumothorax
* Bronchiectasis
* Broncholithiasis
* Extensive pulmonary destruction
* Respiratory failure
* Septic shock
* Malignancy
* VTE
* Chronic pulmonary aspergillosis

[[Category:Infectious diseases]]