TUBERCULOSIS

ICD-10 A15-A19

Dr. Nadia Aziz

C.A.B.C.M
Department of community medicine
Baghdad medical college
 Objectives
1- Define the tuberculosis

2- Identify the causative agent

3- Identify the mode of transmission & the high

risk group

4- Identify the ways of prevention &

management
 Identification
TUBERCULOSIS is a major cause of
disability and death in most of the world,
especially developing countries.
The initial infection usually goes unnoticed,
tuberculin skin test sensitivity appears within
2–10 weeks.
Early lung lesions commonly heal, except
occasional pulmonary or tracheobronchial
lymph node calcifications.
 TUBERCULOSIS

10% of those initially infected will eventually

develop active disease, half of them during the
first 2 years following infection.

90% of untreated infected individuals will never

develop active TB.
 TUBERCULOSIS
In infants and in immunosuppressed individuals
(HIV-positive) initial infection may progress
rapidly to active tuberculosis

In infants the disease is often disseminated

(miliary) or meningeal.
 TUBERCULOSIS
Extra pulmonary TB occurs less commonly (30%)
than pulmonary TB (70%).
TB disease may affect any organ or tissue, in
order of frequency:
lymph nodes, pleura, pericardium, kidneys, bones
and joints, larynx, middle ear, skin, intestines,
peritoneum, eyes.
 TUBERCULOSIS
65% of patients with sputum smear-positive

pulmonary tuberculosis, if untreated will die

within 5 years, most of them within 2 years.
 TUBERCULOSIS
A smear positive for acid-fast bacilli (AFB) is
indicative of high infectiousness.
Fatigue, fever, night sweats and weight loss
may occur early or late.
Localizing symptoms of cough, chest pain,
hemoptysis and hoarseness become prominent
in advanced stages.
 Diagnosis

1- Radiography of the chest reveals pulmonary

infiltrates, cavitations and fibrotic changes with
volume loss, almost commonly in the upper
segments of the lobes.
 Diagnosis
2- Tuberculin skin test

Immunocompetent people who are or have

been infected with Mycobacterium

Tuberculosis usually react to an intermediate

strength tuberculin skin test.
 Diagnosis
A positive reaction of tuberculin skin test is
defined as a 5, 10, or 15 mm induration
according to the risk of exposure or disease.
Among persons with active TB disease
10%–20% may have no reaction to PPD(purified
protein derivative) a negative skin test does not
therefore rule out active TB disease.
 Diagnosis
An induration of tuberculin skin test of 5 mm or
more is considered positive among

• HIV-infected persons

• Persons on immunosuppressive treatment

• Persons showing fibrotic lesions on chest X-rays

• Recent close contacts of infectious TB patients.

 Diagnosis

A diameter of 10 mm or more is considered

positive among persons with high-risk
conditions (e.g. diabetes mellitus,
hematological disorders, injection drug use,
end-stage renal disease, rapid weight loss).
 Diagnosis

Any reaction of 15 mm or more should be

considered positive among low-risk persons.
 Tuberculin skin test
In some persons with TB infection, delayed
hypersensitivity to tuberculin may wane with
time & they may show a negative reaction

The skin test may boost to react to tuberculin and

cause a positive reaction in subsequent tests.
 Boosted reaction
The “boosted” reaction may be mistaken for a new

infection.

Boosting also reported in persons who have received

BCG.

A 2-step testing procedure 1–3 weeks apart will

distinguish boosted reactions and reactions due to

new infection.
 Tuberculin skin test

Two-step testing should be used for initial skin

testing of adults who will be retested

periodically (e.g. health care workers)
 Diagnosis

3- Demonstration of acid-fast bacilli in

stained smears from sputum or other body
fluids in a clinical and epidemiological
situation suggestive of TB.
 Diagnosis
4- Isolation of organisms of the Mycobacterium
tuberculosis complex on culture confirms the
diagnosis.
In the absence of bacteriological confirmation,
active disease can be presumed if clinical,
histological or radiological evidence is
suggestive of TB
 Infectious agents
Mycobacterium tuberculosis complex includes:
M. tuberculosis
M. africanum
M. canettii
all primarily from humans
and M. bovis primarily from cattle.
 Occurrence
Worldwide

with a high prevalence of HIV infection a

prevalence of tuberculosis have increased.

TB mortality and morbidity rates increase with

age, and higher in males than in females.
 Occurrence

In regions with rising incidence, morbidity is

highest among working-age adults.
 MDR-TB

Multidrug-resistant TB

is resistance to at least Isoniazid and Rifampicin

 MDR-TB
Effective measures in combating and preventing
multidrug resistant strains includ:

1- Strict enforcement of infection control guidelines

2- Case-finding

3- Contact investigations

4- Measures to ensure completion of appropriate

treatment regimens
 Reservoir

Primarily humans, rarely primates, diseased

cattle, badgers, swine and other mammals
are infected.
 Mode of transmission
Exposure to tubercle bacilli in airborne

droplet nuclei, 1 to 5 microns in diameter,

produced by people with

pulmonary or respiratory tract tuberculosis during

expiratory efforts (coughing, singing or
sneezing).
 Mode of transmission
Health care workers are exposed during

procedures such as bronchoscopy or intubation

and at autopsy.

Laryngeal tuberculosis is highly contagious but

rare.
 Mode of transmission

Bovine tuberculosis, a rare event, results from

exposure to tuberculous cattle, usually
through ingestion of unpasteurized milk or
dairy products
Extrapulmonary tuberculosis (other than
laryngeal) is generally not communicable.
 Incubation period

From infection to demonstrable primary lesion

or significant tuberculin reaction, about 2–10
weeks.

latent infection may persist for a lifetime

 Period of communicability
Theoretically, as long as viable tubercle bacilli are
discharged in the sputum.
The degree of communicability depends on:
• Number of bacilli discharged
• Virulence of the bacilli
• Adequacy of ventilation
• Exposure of bacilli to sun or UV light
 Period of communicability

Effective antimicrobial chemotherapy

usually eliminates communicability within 2–4

weeks

Children with primary tuberculosis are

generally not infectious.
 TUBERCULOSIS

The risk of developing disease is highest in

children under 3, lowest in later childhood,
and high again among young adults, the very
old and the immunosuppressed.
 TUBERCULOSIS
For adults with latent TB infection also infected
with HIV, This has resulted in a parallel
pandemic of TB disease
In some urban sub-Saharan African areas, where
10–15% of the adult population are co-infected
with both HIV and TB, annual TB disease rates
have increased
Under such conditions, the risk of multi-drug-
resistant (MDR) TB is high.
 Methods of control

A. Preventive measures:
1) Promptly identify, diagnose and treat
potentially infectious patients with TB disease.
Establish case-finding and treatment
facilities for infectious cases to reduce
transmission.
 Methods of control
2) Ensure medical, laboratory and X-ray
facilities, ensure provision of drugs and
facilities for early and complete treatment of
cases and people at high risk of infection, and
of beds for those needing hospitalization.
 Methods of control

3) Educate the public in mode of spread and

methods of control

4) Reduce or eliminate those social conditions

that increase the risk of infection.
 Methods of control

5) Preventive chemotherapy with isoniazid for

6–12 months has been effective in preventing
the progression of latent TB infection to TB
disease.
 Methods of control
It is important to rule out active TB disease
before starting treatment for latent TB
infection, especially in immunocompromised

persons such as HIV-infected individuals, in

order to avoid the development of drug
resistance.
 Methods of control

Directly Observed Treatment Supervised (DOTS

strategy) should be used when possible and can
be administered twice weekly.

Not more than 1 month’s supply of medication

should be given at any one time.
 Methods of control

Persons with HIV infection and a positive PPD

who do not have active TB disease should
receive treatment for latent TB infection.
 Methods of control

All people with evidence of TB disease should

be considered for counselling and tested for
HIV infection if appropriate counselling is
available.
 Methods of control

6) BCG immunization is considered for persons

from areas of high tuberculosis prevalence.

BCG immunization protect against TB

meningitis and disseminated disease in children
under 5.
 Methods of control
protection from BCG vaccine may persist for as
long as 20 years in high incidence situations,
others have shown no protection at all.
Efforts to develop a vaccine more effective than
BCG have identified candidate vaccines that are
currently undergoing testing in humans for
safety and immunogenicity
 Methods of control

7) Take measures to prevent silicosis among

those working in industrial plants and mines.
 Methods of control
B. Control of patient, contacts and the
immediate environment
control of infectivity is best achieved through
prompt specific drug treatment, usually
leading to sputum conversion within 2-4 weeks.
Hospitalization is necessary only for patients
with severe illness
B. Control of patient, contacts and the
immediate environment
Patients should be taught to cover both mouth
and nose when coughing or sneezing.
Patients whose sputum is bacteriologically
negative, who do not cough do not require
isolation, nor do children with active TB
disease.
B. Control of patient, contacts and the
immediate environment

Proper patient support ensuring that drugs are

taken as prescribed, including DOTS (the
internationally recommended strategy for TB
control), is essential, especially for persons
with suspected drug resistance
B. Control of patient, contacts and the
immediate environment
Decontamination of air may be achieved by
ventilation & by ultraviolet light.
B. Control of patient, contacts and the
immediate environment
Management of contacts:

Chemoprophylaxis or treatment of latent TB

infection—TLTBI) is usually recommended for
persons who are in contact with TB infection
and in whom TB disease has been ruled out.
 Control of patient, contacts and the
immediate environment
PPD testing of all members of the household
and other close contacts is recommended. If

negative, a repeat skin test should be

performed 2–3 months after exposure has
ended.
 Control of patient, contacts and the
immediate environment
Specific treatment:

For drug-susceptible disease, a 6-month regimen

is recommended, including isoniazid (INH),
rifampicin (RIF), pyrazinamide

(PZA) and ethambutol (EMB) for the first 2

months, followed by INH and RIF for 4 months.
 Control of patient, contacts and the
immediate environment
HIV-associated TB, Rifampicin lowers serum
levels of many protease inhibitors and some
nucleoside reverse transcriptase inhibitors and
its replacement by rifabutin can be considered
 Control of patient, contacts and the
immediate environment
Treatment for 9 to 12 months for:

1- Children with meningitis

2- Miliary disease

3- Bone/Joint disease

4- HIV infection
 Treatment failure
Sputum smear positivity at 5 months from start of
treatment
can be due to irregular drug-taking or
the presence of drug-resistant bacilli.
If INH or RIF cannot be included, treatment
should continue for at least 18 months after
cultures have become negative.
Thank You