TB & Pleural Infection Flashcards
What organisms cause TB? Name them. Where in the immune system do they hide? How do they appear on gram stain? What is the buzzword associated with them?
Mycobacterium tuberculosis complex: - Mycobacterium tuberculosis - Mycobacterium bovis - Mycobacterium africanum - Mycobacterium microti Thy are intracellular pathogens which infect mononuclear phagocytes. They only stain weakly on gram stain. *Zeihl-neesen stain for acid fast bacilli*
What is the immunology and pathophysiology associated with the progression of TB?
Which main cells are involved?
What forms as a result?
What type of hypersensitivity reaction occurs?
What then forms?
What is the initial focus of disease called?
How does this show on CXR?
Dendritic cell - innate response.
T cell - adaptive response.
Once inhaled into the lung, alveolar macrophages ingest the bacteria where they proliferate.
Macrophages present the antigen to the T lymphocytes with the development of a cellular immune response.
A delayed type hypersensitivity reaction occurs (type IV).
A granuloma then forms, containing the infection.
A Ghon focus - on CXR it is a small calcified nodule in the midzone.
What are the symptoms of TB?
Productive cough Haemoptysis Weight loss Fevers Sweats Hoarse voice Pleuritic pain if pleura is inflamed
What is the 2nd commonest site for TB?
How does this present initially and as the disease progresses?
Lymph node TB - presents as a firm non-tender enlargement of cervical lymph nodes, which becomes necrotic centrally and can liquefy and be fluctuant if peripheral.
What procedure should always be performed in miliary TB?
Why?
Lumbar puncture to test for CNS involvement, unless contraindicated
What is the standard treatment of pulmonary TB? Give SE(s) of the medications.
2 months of Rifampicin, Isoniazid, Pyrazinamide, Ethambutol
+ 4 months of Rifampicin, Isoniazid
Rifampicin - stains body fluids orange/pink
Isoniazid - polyneuropathy & hepatitis
Pyazinamide - hepatic toxicity & gout
Ethambutol - Optic problems
What test should any patient with TB be given and vice versa?
HIV test
How does chronic kidney disease relate to TB?
CKD is a risk factor for developing TB due to relative immune paraesis. Patients due to undergo renal transplantation may need to be screened for LTBI and need to be given complete chemoprophylaxis if necessary before undergoing the procedure.
What two tests are available for latent TB?
Tuberculin skin test
Inferon-gamma release assays
What type of vaccination is the BCG?
Live attenuated
What pathology does primary TB cause?
Ghon focus in the periphery of mid zone of lung
Large hilar nodes (granulomatous)
What pathology does secondary TB cause?
Fibrosing and cavitating apical lesion
What is lights criteria for diagnosing transudate vs exudate pneumothorax?
35g of protein it is exudate.
Transudate is usually due to forces in the chest e.g. heart failure, cirrhosis
Exudate is usually from inflammatory conditions & lung cancer
Pleural fluid examination Straw coloured Bloody Turbid/milky Foul smelling Food particles Bilateral
Straw - cardiac failure, hypoalbuminaemia
Bloody - trauma, malignancy, infection, infarction
Foul smelling - anaerobic empyema
Food particles - oesophageal rupture
Bilateral - LVF, PTE, drugs, sympathetic path
Define primary and secondary pneumothorax.
A primary pneumothorax is one that occurs spontaneously without an apparent cause and in the absence of significant lung disease, while a secondary pneumothorax occurs in the presence of existing lung pathology.
