Tuberculosis Flashcards
Define Tuberculosis (TB)?
Granulomatous disease caused by Mycobacterium tuberculosis
What is Primary TB?
Initial infection may be pulmonary or (more rarely) gastrointestinal
What is Miliary TB?
Results from haematogenous dissemination of TB
What is Post-Primary TB?
Caused by reinfection or reactivation
What is the aetiology of TB?
Mycobacterium tuberculosis is an intracellular organism
It survives after being phagocytosed by macrophages
What is the epidemiology of TB?
Annual mortality = 3 million (95% in developing countries)
Annual UK incidence = 6000
Asian immigrants are the highest risk group in the UK
What are the symptoms and signs of Primary TB?
Mostly asymptomatic Fever Malaise Cough Wheeze Erythema nodosum Phlyctenular conjunctivitis
What are the symptoms and signs of Miliary TB?
Fever
Weight loss
Meningitis
Yellow caseous tubercles spread to other organs
What are the symptoms and signs of Post-Primary TB?
Fever/night sweats Malaise Weight loss Breathlessness Cough Sputum Haemoptysis Pleuritic chest pain Signs of pleural effusion Collapse Consolidation Fibrosis
Who does Non-Pulmonary TB normally affect?
The immunocompromised
What are the effects on the Lymph nodes as a result of TB?
Suppuration of cervical lymph nodes leading to abscesses or sinuses
What are the CNS symptoms and signs of TB?
Meningitis
Tuberculoma
What are the symptoms and signs on the skin of TB?
Lupus vulgaris (jellylike reddish-brown glistening plaques
What are the symptoms and signs on the heart as a result of TB?
Pericardial effusion
Constrictive pericarditis
What are the GI symptoms and signs of TB?
Subacute obstruction Change in bowel habit Weight loss Peritonitis Ascites
What are the Genitourinary symptoms and signs of TB?
UTI symptoms Renal failure Epididymitis Endometrial or tubal involvement Infertility
What are the Bone/Joint symptoms and signs of TB?
Osteomyelitis
Arthritis
Vertebral collapse (Pott’s disease)
Spinal cord compression from an abscess
Why do we do Sputum/Pleural Fluid/Bronchial Washings for TB?
MC&S
Culturing TB takes a long time (around 6 weeks)
Why do we do Tuberculin Tests for TB?
Positive if the patient has had previous exposure to M.tuberculosis or BCG
What is the Mantoux Test?
A purified protein derivative (PPD) is injected intradermally
Erythema occurs after 72 hrs
What is the Heaf Test?
Place a drop of PPD on the forearm
Fire a spring-loaded needle gun
Check again after 3-7 days
Graded according to papule size and vesiculation
Why do we do Interferon Gamma Tests for TB?
Useful in latent TB
Exposure of host T cells to TB antigens leads to release of interferon
What do we see on a CXR for Primary Infection of TB?
Peripheral consolidation
Hilar lymphadenopathy
What do we see on a CXR for Miliary Infection of TB?
Fine shadowing
What do we see on a CXR for Post-Primary TB?
Upper lobe shadowing Streaky fibrosis and cavitation Calcification Pleural effusion Hilar lymphadenopathy
What other investigations can we do for TB?
HIV Testing CT Lymph Nodes Pleural biopsy Sampling of other affected systems
