TB Flashcards
What are some differentials for:
2month history of weight loss, low grade fever and Haemoptysis
Lung cancer
TB
PCP pneumonia
Sarcoidosis
ILD (silicosis)
Sarcoidosis
What type of organism is Mycobacterium tuberculosis?
Gram +ve acid fast rod shaped bacilli
Aerobic organism
Which part of the lungs does TB typically infect?
Apex of the lungs
What are the 3 causes of homogenous opacity on plain chest radiograph?
Fluid
Lung collapse
Solid mass like tumour
How is TB transmitted?
DROPLET TRANSMISSION
Overcrowding
Poor sanitation
Poor ventilation
Spitting in public
What are the risk factors for catching TB
Overcrowding
Poor sanitation
HIV
Malnourishment
Alcoholism
Chronic steroid use
Chemotherapy
Anti-TNF (infliximab)
Malignancy
Anything that causes Immunosupression
What is the clinical presentation of TB infection?
Chronic productive cough
Low grade
Fever
Weight loss
Haemoptysis
Systemic features
What systemic complications can TB cause ?
Intestinal TB
Genitourinary TB
TB ascites
What are stages of infection of TB?
Most peoples innate immunity clear the infection
Immunocompromised get infection
If TB is contained = LATENT TB
If not cleared becomes PRIMARY TB INFECTION
What happens if a patient becomes immunocompromised with latent TB?
Develops to secondary TB
How does the immune system contain TB causing latent TB?
Forms granulomas
What is the name of the structure which shows up on chest X-ray with latent TB?
Ghons complex
Ghons focus
What is a Ghons complex?
When granuloma spreads to the hilar lymph nodes so you can see consolidations
What is considered disseminated TB?
When theres infection of 2 or more non contiguous sites
What will the results be for a skin prick test if a patient has latent TB?
+ve skin prick test
What investigations would you do for a patient presenting with a 2month history of cough, weight loss and low grade fever?
SPUTUM SAMPLE
FBC
U+E
LFT
CRP
INR
HIV serology
Hepatitis serology
HbA1c
Blood glucose
What imaging is first used if you want to investigate chronic cough, weight loss and low grade fever?
CXR
What investigations are done on the sputum sample for chronic cough, weight loss and low grade fever?
MC and histology
NAAT (Nucleic Acid Amplification Test)
What is the utility of using gene xpert on the sputum sample when assessing TB?
Checks the TB resistance for the TB agent Rifampicin
What are the 4 key antibiotics for treating TB infection?
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
What is the regime for antibiotics for a non CNS involved TB infection?
2months of: Rifampicin + Isoniazid + Pyrazinamide + Ethambutol
Then
4months: Rifampicin + Isoniazid (?pyrazinamide)
What supplement do you also give to the patient when treating them for TB and why?
Pyridoxine (Vit B6)
Isoniazid causes peripheral neuropathy
What conservative changes do you encourage a patient to do while they’re being treated for TB?
Encourage high protein diet
What additional mediations do you give to a patient with CNS involved TB infection?
Steroids
Anti-epileptics
