Pulmonary tuberculosis (TB) is caused by the bacteria Mycobacterium tuberculosis (M.
tuberculosis). You can get TB by breathing in air droplets from a cough or sneeze of an infected
person. This is called primary TB.
In the United States, most people will recover from primary TB infection without further
evidence of the disease. The infection may stay asleep or non-active (dormant) for years.
However, in some people it can reactivate.
Most people who develop symptoms of a TB infection first became infected in the past.
However, in some cases, the disease may become active within weeks after the primary
Tuberculosis (TB) is a chronic bacterial infection that primarily affects the lung, although
it may involve any part of the body.
Currently estimated about half of the world's population (3.1 billion) is infected with
Estimated from the year 2000 to 2020, nearly one billion people will be newly infected,
200 million people will get sick, and 35 million will die from TB - if control is not further
Primarily, Pulmonary Tuberculosis is caused by Mycobacterium Tuberculosis.
Mycobacterium Tuberculosis shape is long, slender, straight or curved rods. It is an aerobic
which usually colonizes on high oxygen area part of human body and that is apex of the lung. It
is decolorized by acid or alcohol which was then called by the name of “acid fast bacilli”.
Incubation period for the organism 4-6 weeks after initial contact.
Optimal conditions for transmission include the overcrowding of places, poor personal
hygiene, poor public hygiene. People with active disease (bacilli) expel them into the air by
coughing, sneezing, shouting, singing or any other way that will expel bacilli into the air.
Direct invasion through mucous membranes or breaks in the skin may occur, but
extremely rare. It can also be transmit via ingestion theoretically if the milk of the infected
animal is ingested but rarely occur.
1.6. Clinical Categories
Post primary TB (Secondary/reinfection TB)
Disseminated TB (extrapulmonary TB)
1.7. Primary Tuberculosis
infection in a person without specific immunity to TB and is called “childhood TB”.
The initial focus of infection is a small subpleural granuloma accompanied by granulomatous
hilar lymph node infection. Together, these make up the Ghon complex.
In nearly all cases, these granulomas (fibrocalcific nodules) resolve and there is no
further spread of the infection. The patient will heal and a scar will appear in the infected loci.
There will also be a few viable bacilli/spores may remain in these areas (particularly in the lung).
The bacteria at this time goes into a dormant state, as long as the person's immune system
remains active and functions normally.
1.8. Secondary Tuberculosis
Result from reactivation of primary infection or re- infection. Seen mostly in adults,
particularly when health status declines or immunocompromise person. Spreads by lymphatics
and delayed hypersensitivity reaction occurs.
The granulomatous inflammation is much more florid and widespread. Lesions are often
bilateral and usually cavitated and most connected to fibrocalcific scars. Typically, the upper
lung lobes (posterior/apical segment) are most affected.
1.9. Miliary Tuberculosis
Acute diffuse dissemination of tubercle bacilli occurs through the bloodstream.
Numerous small granulomas (contain mycobacteria) form in many organs, with the highest
number found in the lungs. Usually it is from the result of a delay in diagnosis or commencement
of treatment. Result from the consequence of either primary or secondary TB and universally
fatal without treatment.
1.10. Signs and Symptoms
Prolonged cough (non-productive/productive ) >> 3 weeks
Loss of appetite
Loss of weight
A working diagnosis can be made by:
Tuberculin test / Mantoux Test
Culture (Gold Standard)
Bronchoscopy is useful if no sputum is available.
Biopsy from pleura, lymph nodes and solid lesions within lung may be necessary.
1.11.1. Tuberculin Test or Mantoux Test
It is used as a diagnostic tool for tuberculosis. Used to detect latent Tuberculosis
infection, to detect recent infection (as shown by conversion of the Mantoux from negative to
positive) and as part of the diagnosis of Tuberculosis disease. Not recommended for those who
had a past Mantoux reaction of 15 mm or greater or in people who have had previous
1.11.2. Chest X-Ray
Classical radiograph appearance Infiltration,
cavitation, fibrosis with traction, enlargement of hilar and
mediastinal lymph node.
In reactivation of TB Classically fibrocavitary apical disease
Primary TB Middle or lower lobe consolidation
But no chest X-ray pattern is absolutely typical of TB. At about 10-15% of culture-
positive TB patients is not diagnosed by X-ray. And 40% of patients diagnosed as having TB on
the basis of x-ray alone do not have active TB.
1.11.3. Acid Fast Bacilli/Stain
Strongly consider TB in patients with
smears containing acid-fast bacilli
(AFB). Results should be available within 24 hours of
specimen collection. Presumptive diagnosis of TB.
The result is:
Not specific for M. Tuberculosis
It is gold standard for TB diagnosis which is use to confirm diagnosis of TB.Culture all
specimens, even if smear is negative. Results in 4 to 14 days when liquid medium systems used.
Solid mediumà 4-8 wks
Liquid medium à 2 wks
1.12. Differential Diagnosis
Solitary pulmonary nodule
0.1ml intradermal dose
Decrease the risk of developing TB up to 70%
Once vaccinated à subsequent Tuberculin test will be (+ve)
Tracing of close cantacts to limit spread of the disease as well to identify at an
Divided into :
i. Initial or extensive phase
○ At least 2 months
ii. Continuation or maintenance phase
○ At least 4 months
2 months of daily doses
2 SHRZ @ 2 EHRZ @ 2HRZ
H 5mg/kg/day (max 300mg daily)
R 10mg/kg/day (max 600mg daily)
S 15mg/kg/day (max 1000mg daily)
E 15-25mg/kg/day (max 1200mg daily)
Z 25mg/kg/day (max 2000mg daily)
Don’t give/limit S and E for babies, young child, elderly and severe renal impairment.
S, H and R
All 15mg/kg biweekly (2/52)
S and H max 1000mg/kg
R max 600mg/kg