TB Flashcards
Symptoms of TB
General
- Weight loss
- Fever
- Night sweats
- Anorexia
- Malaise
Pulmonary
- SOB
- Productive cough
Symptoms of extra-pulmonary TB
- Swollen lymph nodes = lymphatic TB
- Bone or joint pain/swelling = joint/spinal TB
- Constipation/bowel obstruction = genitourinary or gastrointestinal TB
- Headache, vomiting, irritability, confusion = meningitis TB
- skin lesions = cutaneous TB
Which organism causes TB?
Mycobacterium tuberculosis
Risk factors of TB
- Born in high prevalence areas
- Children less than 5 years of age
- Close contacts
- Hx of untreated or inadequately treated active TB infection
- Immunocompromised patients
- Hx of excessive alcohol, injecting drug users, and smokers
When to start treatment in a patient with suspected active TB?
Immediately without waiting for culture results
What is considered treatment success?
Completion of therapy with negative follow-up on sputum smears
People have been in contact should have screening for latent TB.
Who would be considered a high risk contact?
All household members.
Close contacts (partner, house visitors, and close workplace contacts) if the person with TB has a positive sputum smear result.
Casual contacts (such as most work colleagues) if the index person with TB is particularly infectious
Immunocompromised people
People who are new entrants to the UK from a high TB prevalence country
People who are new NHS emplyees
People who have evidence of TB scarring or untreated fibrotic changes on chest X-ray
What is the usual total duration of treatment?
6 months
How is TB spread?
Through inhaling infected respiratory droplets from a person with infectious TB
What medications are used in the initial phase treatment?
RIPE
Rifampicin
Isoniazid (with pyridoxine)
Pyrazinamide
Ethambutol
What is the duration of the initial phase treatment?
2 months
What medications are used for the continuous phase treatment?
Rifampicin
Isoniazid (with pyridoxine)
What is the duration of the continuous phase treatment?
4 months
TB self management
- Provide sources of information e.g., www.patient.info and tbalert.org
- Encourage adherence to the treatment regimen
- Lifestyle measures e.g., smoking cessation and alcohol reduction
- Contact tracing is necessary for high-risk contacts of people with pulmonary and laryngeal TB
What is active disease?
Evidence of symptomatic or progressive disease of the lung and/or other organs
Symptoms are specific to the site involved
What is latent disease?
Persistent immune response stimulation by Mycobacterium tuberculosis antigens
No evidence of clinically active TB
What is the treatment of latent TB for patients with HIV?
3 months of isoniazid with pyridoxine and rifampicin
OR
6 months of isoniazid with pyridoxine
What is the treatment of latent TB for patients <35 years old?
3 months of isoniazid with pyridoxine and rifampicin if hepatotoxicity is a concern
What should patients with latent TB aged 35-65 years old be tested for?
Hepatotoxicity
What is the treatment of latent TB for patients aged 35-65?
Where no concern of hepatotoxicity = no treatment
Treatment of single-drug resistant TB without CNS involvement
- Resistance to isoniazid
Initial phase: 2 months
- Rifampicin
- Pyrazinamide
- Ethambutol
Continuation phase: 7 months (10 for extensive disease)
- Rifampicin
- Ethambutol
Treatment of single-drug resistant TB without CNS involvement
- Resistance to pyrazinamide
Initial phase: 2 months
- Rifampicin
- Isoniazid (with pyridoxine)
- Ethambutol
Continuation phase: 7 months
- Rifampicin
- Isoniazid (with pyridoxine)
Treatment of single-drug resistant TB without CNS involvement
- Resistance to ethambutol
Initial phase: 2 months
- Rifampicin
- Isoniazid (with pyridoxine)
- Pyrazinamide
Continuation phase: 4 months
- Rifampicin
- Isoniazid (with pyridoxine)
Treatment of single-drug resistant TB without CNS involvement
- Resistance to rifampicin
Offer at least 6 anti-TB drugs which the mycobacterium is likely to be sensitive
What is the general CNS TB treatment?
Initial high dose dexamethasone or prednisolone then slowly withdrawn over 4-8 weeks
Standard treatment with initial phase (RIPE) for 2 months
Continuation phase drug should be continued for a further 10 months treatment
How does pericardial TB treatment differ to conventional TB treatment?
Initial high dose of prednisolone should be offered in those with active pericardial TB then slowly withdrawn over 2-3 weeks
Why is pyridoxine (vitamin B6) used alongside treatment?
Peripheral neuropathy prophylaxis
Specific side effects of rifampicin
Discolours contact lenses and bodily fluids orangey-red colour
Hepatotoxicity
Report signs of liver disorder
Specific side effects of isoniazid
Peripheral neuropathy
Be aware that it is also a CYP enzyme inhibitor = CYP450 interactions
Specific side effects of pyrazinamide
Hepatotoxicity - report signs
Specific side effect of ethambutol
Visual impairment and ocular toxicity
Which aminoglycoside is active against TB?
Streptomycin (used when resistant to other treatment)
Why can’t aminoglycosides be given orally?
Metabolised too quickly by GI tract so must be injected
How does rifampicin interact with hormonal contraceptives?
Effectiveness of hormonal contraceptives are reduced - alternative method required
How many antibacterials are used in the initial phase of TB treatment and how long for?
4
2 months
How many used in continuous phase of tb? How long?
2
4 months
If someone is taking isoniazid, what else must be prescribed and why?
Pyridoxine (Vitamin B6) as peripheral neuropathy prophylaxis
After 2 months of RIPE treatment for TB, what antibiotics are continued for a further 4 months?
Rifampicin
Isoniazid
Directly Observed Treatment (DOT) TB therapy should be offered to which groups of people?
People who are at high risk of not completing their TB treatment e.g.,
- Hx of non-adherence
- Substance misuse
- Homelessness
- Previously been treated for TB
- Have cognitive impairment
- Too ill to self-administer
Daily dosing is preferred
3 times weekly dosing schedule can be considered
Patient with HIV and TB how long should the TB treatment be for? What is the exception to this?
Should not routinely exceed 6 months
Unless TB has CNS involvement then should not exceed 12 months
6 toxicity syndromes associated with intermittent TB treatment?
GI
Cutaneous toxicity
Neurological toxicity
Ocular toxicity
Haematological toxicity
Hepatotoxicity
A break in TB treatment of how many weeks is classed as a treatment interruption?
2 weeks during the initial phase
OR
Missing >20% of prescribed doses
Treatment interruptions due to drug-induced hepatotoxicity
Stop treatment and only reintroduce once LFTs in range and patient has no symptoms of hepatotoxicity
Start with:
- Ethambutol and either isoniazid (with vit B6) or rifampicin
Patients with severe or highly infectious TB -
Consider continuing treatment with 2 drugs with low risk of hepatotoxicity e.g.,
- Ethambutol and streptomycin
Treatment interruptions due to cutaneous reactions
Patient with severe or highly infectious TB -
Consider continuing treatment with 2 drugs with low risk of cutaneous reactions e.g.,
- Ethambutol and streptomycin
Why is ethambutol cautioned in young children?
Can cause optic neuritis which can lead to vision loss
Children are more susceptible to this side effect because their optic nerves are still developing
