Tuberculosis Flashcards
Which drug used in the treatment of TB targets actively growing organisms?
Isoniazid
Which drug used in the treatment of TB targets semi-dominant organisms inhibited by an acid environment?
Pyrazinamide
Which drug used in the treatment of TB targets semi-dormant organisms with. spurts of metabolism?
Rifampicin
Which drug used in the treatment of TB targets completely dormant organisms?
These organisms are not killed by standard drugs
What staining method is used to detect m.tuberculosis?
Zheil-neelsson
M.tuberculosis is a fast growing organism. T/F?
False
Give an example of a molecular test which can identify TB directly from samples
Gene XPert
Which protein which is anchored to the inner cytoplasmic membrane of M.tuberculosis is a major immune stimulator during infection?
Mannose-capped lipoarabinomannan (LAM)
Which cytokine is particularly important in the immune response to TB infection?
Interferon gamma
What patient factors may result in an increased likelihood of reactivation of TB?
Immunosuppression
HIV infection
Smoking
Describe the Mantoux test for the diagnosis of TB
A standard dose of tuberculin is injected intradermally and. read 48-72 hours later
A person who has been exposed to the bacteria is expected to. mount an immune response in the skin containing the bacteria proteins
The reaction is read by measuring t he diameter of induration (palpable, raised, hardened area) across the forearm in mm.
Describe the T spot test for TB diagnosis
Counts the number of anti-TB effector T cells which produce INF-gamma in a sample of blood. Gives overall measurement of immune response against TB, which can reveal the presence of even latent TB infection.
The Montaux test is less influenced by previous BCG vaccination than the T spot test. T/F?
False - the opposite is true
What is the quatiferon Tb test?
This is a whole blood test which is used to diagnose TB infection, including latent TB by mixing blood samples with. antigens and controls
Where in the tuberculous granuloma are foam cells most commonly found?
At the rim of the necrotic centre
Where in the tuberculous granuloma are bacteria most commonly found?
In the central necrotic area of the granuloma
Other than macrophages, what cell types may populate the tuberculous granuloma?
Neutrophils Dendritic cells B cells T cells NK cells Fibroblasts
What does a Ghon. complex consist of?
A Ghon focus and a pulmonary lymphadenopathy within a nearby pulmonary lymph node
A Ghon complex is a source. of long-term TB infection. T/F?
True
What type of necrosis occur within a Ghon focus?
Caseous necrosis
What are the signs and symptoms of tuberculosis?
Fever Night sweats Fatigue Loss of appetite / weight. loss Lymphadenopathy Cough +/- haemoptysis Dyspnoea Meningitis Choirditis Constrictive percarditis Dysuria / haematuria Ileocaecal/abdominal pain Lupus vulgaris
What are the risk factors for the development of active tuberculosis?
Untreated HIV Immunosuppression due to transplantation Silicosis Chronic renal failure requiring dialysis Recent TB infection Abnormal CXR INF-alpha inhibitors Steroids Diabetes mellitus Young age when infected Underweight Cigarette smoker
What imaging should be conducted on a patient with suspected TB?
CXR
How should adults and children with latent TB be treated?
Isoniazid for 6 months
How should children <15 with latent TB in from countries with a high TB incidence be treated?
Rifampicin and isoniazid daily for 3 months
How should adults with latent TB in from countries with a high TB incidence be treated?
Rifampicin. and isoniazid weekly for three months
How is active TB treated?
Rifampicin and isoniazid for 6 months
Ethambutol and pyrazinamide for 2 months
What are the drug interactions / adverse events which can occur with rifampicin?
CYP450 inducer
Turns bodily secretions orange
Flu-like illness
What are the drug interactions / adverse events which can occur with isoniazid?
Liver injury
What are the drug interactions / adverse events which can occur with ethambutol?
Toxic optic neuropathy
What are the drug interactions / adverse events which can occur with pyrazinamide?
Liver injury
Raised lactate
How can resistance of Tb to both rifampicin and isoniazid be detected rapidly?
Molecular testing. (gene Xpert)
How is multi drug resistant TB treated?
18 months to 2 years. of treatment with pyrazmdamide alongside fluoroquinolone, 2nd line injectable, ethionamid/prothionamide and cycloserine/p-aminosalicyclic acid for >8 months
How should multi drug. resistant TB which is also resistant to flurorquinolone be treated?
No standard treatment
Surgical intervention should be considered
Tb has a predilection for bones of the vertebral column. This can extend to form which complications?
Spinal/paraspinal abscess +/- cord compression
Extension of TB infection into the of the psoas muscle
What are the two main types of infection which can occur if TB spreads to the brain?
TB meningitis
Cerebral TB
What is TB meningitis?
A slow progressive condition with altered consciousness and progressive lower cranial nerve palsies
What is cerebral TB?
A foci of infection in the cerebrum which can behave as a space-occupying lesion with seizures and venous system signs
Other than the lungs, brain and bones, what organ systems can TB typically affect?
Renal tract Testes/ovaries Larynx Skin Eye Liver
