WHAT IS TUBERCULOSIS
infectious disease caused by various strains of mycobacteria,
usually Mycobacterium tuberculosis. ( gram positive bacteria)
It is a chronic granulomatous disease.
Tuberculosis typically attacks the lungs, but can also affect
other parts of the body. It is spread through the air when
people who have an active TB infection cough, sneeze, or
otherwise transmit respiratory fluids through the air.
The classic symptoms of active TB infection are a chronic
cough with blood-tinged sputum, fever, night sweats,
and weight loss . Infection of other organs causes a wide range
radiology commonly chest X-rays
microbiological culture of body fluids.
SIGNS AND SYMPTOMS
most commonly occurs in the lungs (known as pulmonary
tuberculosis).Extrapulmonary TB occurs when tuberculosis
develops outside of the lungs, although extra pulmonary TB
may coexist with pulmonary TB as well.
fever, chills, night sweats, loss of appetite, weight loss,
and fatigue. Significant finger clubbing.
it most commonly involves the lungs (in about 90% of cases).
Symptoms may include chest pain and a prolonged cough
producing sputum. About 25% of people may not have any
symptoms (i.e. they remain "asymptomatic").
Occasionally, people may cough up blood in small amounts, and
in very rare cases, the infection may erode into thepulmonary
artery, resulting in massive bleeding (Rasmussen's aneurysm).
Tuberculosis may become a chronic illness and cause extensive
scarring in the upper lobes of the lungs. The upper lung lobes are
more frequently affected by tuberculosis than the lower ones.
The reason for this difference is not entirely clear.
It may be due either to better air flow, or to poor lymph drainage
within the upper lungs.
n 15–20% of active cases, the infection spreads outside the lungs,
causing other kinds of TB.
Extrapulmonary TB occurs more commonly
in immunosuppressed persons and young children. In those with HIV,
this occurs in more than 50% of cases.
Notable extrapulmonary infection sites include the pleura (in
tuberculous pleurisy), the central nervous system (in
tuberculous meningitis), the lymphatic system (inscrofula of the neck),
the genitourinary system (in urogenital tuberculosis), and the bones and
joints (in Pott's disease of the spine), among others. When it spreads to
the bones, it is also known as "osseous tuberculosis".
a form of osteomyelitis. Sometimes, bursting of a tubercular abscess
through skin results in tuberculous ulcer. An ulcer originating from
nearby infected lymph nodes is painless.
Transmission: air born disease , When people with active
pulmonary TB cough, sneeze, speak, sing, or spit, they expel
infectious aerosol droplets 0.5 to 5.0 µm in diameter. A single
sneeze can release up to 40,000 droplets.
Pathogenesis:TB infection begins when the mycobacteria
reach the pulmonary alveoli,
WHO expert gp has farmed clear cut treatment guidelines
for different categories of TB patient
The dose of drug std on the basis of body weight.
The regimens have two phase
Inititial intensive phase: lasting 2 3 month ,amied to rapidly
kill the TB bacilli
Continuation phase : lasting for 4-6 months ,estimated bacilli
relapse dose not occur
Category wise treatment regimens
Category 1: untreated T.B
CATEGORY 2: RELAPSE, INTERRUPTED TREATMENT
CATEGORY3: LESS SEVERE FORMS OF
CATEGORY 4: THESE ARE CHRONIC CASE WHO HAVE
REMAINED OR HAVE BECOME +VE AFTER
COMPLETING FULLY SUPERVISED RETREATMENT
How is TB treated?
Several antibiotics need to be taken over a number of months to
prevent resistance developing to the TB drugs. The great majority
of TB bacteria are sensitive to the antibiotics used.
1st line drug : have high antitubercular efficacy,low toxicity
2nd line drug: low antitubercular effficacy ,low toxicity
Name of antibiotic used:
Discription of antibiotic used:
Cycloserine: 2nd line drug
Max: 1 gm in day
B12 ,FOLIC ACID DEFIciency, inhibit s phenytoin metabolism
& may increase of risk of epileptic seizuers, alcohal increase of
convulsions, increase cns toxicity.
ADR: megaloblastic anaemia, convulsions (dose related)
Drowsiness, vertigo, depression.
ETHAMBUTOL:1st line drug
Max dose: 15mg/kg/day
Interaction: synergistic effect wd other antitubercular agent
ADR: reduced renal clearance of urates.
ETHIONAMIDE: 2nd line drug
Max dose: 1gm/day
Interaction: increase hepatotoxicity wd rifampicin, increase
cns toxicity wd cycloserine
ADR: ANOREXIA, excessive salivation, metallic TASTE,
ISONIAZID: 1st line drug
Max dose: 300 mg daily
Interaction: may increase toxicity of carbamazepine
,ethosuximide, phenytoin, diazepam, triazolam, theophylline,
ADR: peripheral neuritis ,optic neuritis, psychotic reaction
Protionamide: 2ND LINE drug
Max dose: 1gm daily
Interaction: increase neurotoxic effect wd cycloserine,
increase hepatotoxicity wd rifampicin
ADR: thrombocytopenia, gyanecomastia , stomatitis
Pyzinamide: multi drug regimen
1st LINE DRUG
Max dose: 3gm DAILY
INTERACTION: excretion may be blocked by probencid
ADR : hyperureicaemia
1ST line drug
Max dose : 600 mg /day
Interaction: absorption may be decrease when taken wd
antacids, opioid, ketokonazole,
ADR: Abnormalities of liver , influenza like symptoms, reddish
Multi drug therapy
& combinations of drugs
OTHER ANTI T.B AGENT: DAPSONE,
MULTIDRUG RESISTANT (MDR) T.B
RESISTANCE TO BOTH ISONIAZID AND RIFAMPIN
MDR TB has a more rapid course ( some die in 4-16 weeks)
1st nd 2nd line drug are given for 12 to 24 months
Regimen of dose depend on associated disease
For isonizid resistance: rifampin
,pyrozinamide,ethambutol given 12 months
For isoniazid +rifampin resistance:
ofl/can be used.
The only currently available vaccine as of 2011 is bacillus
Calmette–Guérin (BCG) which, while it is effective against
disseminated disease in childhood, confers inconsistent
protection against contracting pulmonary TB.
Drug-resistant forms of the bacteria require treatment for
than six months. MDR TB is particularly serious, requiring
prolonged (up to 24 months) treatment, with the infectious
period lasting much longer.
Treatment in pregnant women:
isoniazid,ripampin,pyrazinamide to safe for foetus
(2HRZ+4HR) RECOMMMENTED FOR STD 6 MONTHS
SOMETIMES Z CREATE TERATOGENICITY EFFECT