Tuberculosis Flashcards
How many people develop TB each year and how many die from it?
10 million cases of active be TB
1.7 million deaths
Global incidence is falling by 2% each year
What causes TB?
Mycobacterium tuberculosis
M. Bovis can also cause TB
How is TB transmitted and what factors increase transmisibility?
Airborne droplet
Susceptibility (age, HIV etc)
Exposure
Infectiousness (bacillary load, AGPs, cavitation)
Environment (low UV, ventilation, overcrowding)
After exposure to TB what proportion of patients with clear with innate immunity and what proportion will become latent?
70% clear
30% latent
After latent TB has occurred what proportion will clear the infection with adaptive immunity?
Over 90%
What is the BCG and who gets it?
Live attenuated vaccine from M bovis
Provides protection against military and TBM in children.
Given to all children in high TB prevalence countries unless HIV +be
What are the risk factors for developing active TB?
HIV TB exposure in last 2yrs <2yrs old Malnutrition DM Alcohol Poverty
What are the symptoms of pulmonary TB?
Cough Fever Haemoptysis Weight loss Very few clinical chest signs
What are the symptoms of lymphatic TB?
Neck or axilla, often solitary LN
Tender, slightly warm and fluctuant
May have sinus formation
PCR and smear +ve, also histology
What are the symptoms and signs of pleural TB?
Pleural effusion
Straw coloured exudate
PCR +ve, smear -ve
What are the signs and symptoms of TB meningitis?
Prodrome then reduced GCS CN palsies common Seizures from tuberculomas High opening pressure PCR+ve, culture +ve
What are the signs and symptoms of GU TB?
Anywhere along tract
Sterile pyuria - culture positive
Infertility in women
Epididymitis
What are the signs and symptoms of pericardial TB?
Large globular heart
Tamponade- pulsus paradoxus
What are the signs and symptoms of MSK TB?
Most commonly spine-Potts disease
Back pain, tender and fever
Gibbus formation from wedge collapsed vertebrae
What e the diagnostic tests for TB and when are they useful?
Sputum smear -2xsamples in clinic with LED fluorescence microscopy
GeneXpertMTB/RIF- resistance, under 2hrs, more sensitive than smear (+ve in 75% of smear -ve)
Line probe assay- test for resistance in smear +ve
Urinary LAM- best for advanced HIV
Culture- gold standard but slow
What are tuberculin skin tests used for?
Epidemiological surveys to determine TB prevalence
Identification of candidates for LTBI Tx
Tells you previous, latent or active TB or BCG
What are IGRAs used for?
Latent TB testing, no false +ves from BCG but may be negative in HIV
What is the treatment for TB?
Rifampicin isoniazid pyrazinamide and ethambutol for 2 months then RI for 4 months
TBM and TB bone- RI for 10months
DOT
Fixed dose tablets
What are the side effects of the standard TB drugs?
R- interacts with OCP + ART (need to increase dolutegravir dose), orange discolouration, liver tox
I- peripheral neuropathy, liver tox
P- liver tox, arthralgia
E- ocular tox
How do you manage drug induced liver injury in TB?
Dx if ALT 5x upper limit or 3x upper limit with Sx
Stop Tx and restart with R+E, if no worse add in I, then a fluoroquinolone if still ok
What are the different levels to drug resistant TB?
MDR- resistance to R+I
Pre XDR- MDR + a fluroquinolone
XDR- MDR + a fluroquinolone+ a group A drug
TDR- resistance to all first and second line drugs
What proportion of TB patients have MDR and where are they?
5%
20% among retreatment cases
China, India, Soviet Union and Eastern Europe
Who can use the shorter regimen for MDR-TB and what is it?
No fluroquinolone resistance, no extrapulmonary TB, less than 1 month exposure to any of the drugs already Bedaquiline (or amikacin) Ethionamide Isoniazid Pyrazinamide Levofloxacin/moxi Ethambutol Clofazimine BEIPLEC for 4-6months PLEC for 5 months
What is the longer regime for MDR TB?
Individualised depending on resistance 5 drugs for 8months then 4 for 1yr 3 from group A At least one group B Group C when A or B can't be used
What are the group A and B drugs for MDR TB?
A Levo or moxi Bedaquiline Linezolid B Clofazimine Terizidone
What are the group C drugs in MDR TB?
Ethambutol Delaminid Pyrazinamide Meropenem Amikacin Ethionamide
Who gets treated for latent TB?
HIV +ve
Household contacts if symptomatic (but no active TB), or asymptomatic and under 5yrs or over 5yrs with a positive TST/IGRA
What is the treatment for latent TB?
Isoniazid and pyridonxine daily for 6 months
Or
Weekly rifapentine and isoniazid for 3 months
How does active case finds in TB work?
Systematic screening of PLHIV, household contacts, prisoners
Screen with
-cough, fever, night sweats, weight loss? For HIV
-Sx, CXR, RDT
What is the WHO definition of cured from TB?
A bacteriologically confirmed TB that’s smear or culture negative in the last month and on one other occasion
What is the WHO definition of Tx completed in TB?
Completed Tx without evidence of failure but also no evidence of cure
What is the WHO definition of Tx failed?
Smear or culture is positive at month 5 or later
Which countries account for 2/3 of new TB cases?
India China Indonesia Phillipines Pakistan Nigeria Bangladesh SA
What are the pillars of the WHO End TB Strategy?
- Integrated patient centred care and prevention
- early Dx incl. drug resistance and screening
- Tx all and Pt support
- TB/HIV collaboration
- preventative Tx of high risk and vaccination - Bold policies and supportive systems
- political commitment with adequate resources
- engagement of communities
- universal health coverage and case notification
- poverty alleviation - Intensified research and innovation
- develop new tools and strategies
- research to optimise implementation
What are the indicators of the WHO End TB strategy?
95% reduction in TB deaths by 2035 (from 2915)
90% reduction in TB incidence
Zero TB affected families facing catastrophic costs due to TB
