Tuberculosis Flashcards
The causative organism of TB is ?
Mycobacterium tuberculosis
How to measure the magnitude of Tb problem?
The most important and sensitive measurment is (the incidence of infection) or ((tuberculin conversion rate))-the percentage of those newly infected on one year based on tuberculin testing-
Tb cases can be classified into:
1.New case
2.relapse case
3.treatment failure case
4.treatment after interruption
5.chronic case
Mycobacterium tuberculosis is classified into
1.human type
2.bovine type
3 atypical type
All are acide fast bacillus
What is the most imoprtant investigation obtained in early morning in case of TB
Sputum study
Sputum study in tb can be done by
By stainig using
1.Ziehl-neelsen methode
2.fluorescent microscopy
3.serology , DNA testing
Relationship of bacilli to sunlight and dark ?
*Bacilli can live in dark humid area for months or years
But direct sunlight can killthem within a minut
Relationship of bacilli to heat
Heat can rapidly destroy them within 20 minutes at 60c°
Who is the reservoir in Human type Tubericulosus ?
The man is the reservoir
Mode of transmission of Tb is
1Inhalation (droplet infection)
2.ingestion ( bovin type in unpasterized milk) may initiate intestinal Tb
Incupation period of TB?
Could be weeks or months depend on
1.host-agent relation ship
2.dose of infection
Peroid of infectivity of Tb is
As long as the bacilli excereted by the (infected sick host) which may be moths or few years
The progression and development of Tuberculosis disease depend on ?
1.Genetic ( have weak association with HLA )
2.phsiological ( old age , gender , pregnancy)
3.immunological (effect of primary infection on childhood , BCG vaccination , malnutrition , DM)
4.enviromental factor (living vondition , overcrowding ,occupation)
5.miscellaneous(alchol, smoking)
Special tests important to investigate TB
1.sputum examination of smears for Tb bacilli (AFB): zn stain
2.Nucleic acid amplification assay
3.photoflurography or mass miniature Radiography
4. Tubriculin test
What is the tubriculin test
Is a delayed immune response
Tubriculin test ((monteux test)) how it can be done ?
Performed by injecting 0.1ml of (OT) old tubriculin or (PPD) purified protien derivative , intradermal , can be read after 72 hour ,
((an induration of 10mm diameter or more considered to be positive))
Tubriculin test importance
Is the choice in areas with low infection rate and in communities in which BCG vaccines not used extensively
Treatment and control of TB
1.case finding(investigation)
2.isolation , effective treatment of tb
((Directly observed treatment short course))(DOTs)》most important for pulnonary TB
3.BCG vaccination
4.chemoprophylaxis by INH- isonizide
5.Healty education
BCG vaccine is
1.Live attenuated vaccine from Bovine strine of mycobacterium
2.injected intradermally in (Lower deltoid area
3.BCG vaccine prevent the most serious forms of TB in Children but Helpless to prevent the most contageous form in adult
National Tubericulosis program
1.DoTs strategy (directly observed treatment)
2.BCG vaccination of all children at birth in additin to school children entry , leaving age
3.prohibiting the sale of anti TB drugs
3.provide anti TB therapy for free to all detected paithent
4.screening all forign labor forces entering the county for work by
A.chest x ray
B.3.sputum smears for acid fast bacilli
Why TB would continue as public healt problem world wide in future
Due to
1.chronic nature of the disease
2.ability of the bacilli to remain alive (Dortmant)
3.concentration of the disease in old age group
4.High prevalence rate in under developed countries
5.Emergence of MDR strain (multi drug resistance)
6.association of Tb with other infections as HIV
Historically where we found Tb lesions
We found it in the vertebrae of Neolithic man in europ , in the Egyptian mummies
Tb is Endemic , pandamic or epidemic ?
Tb is an Endemic caused by mucobacterium tubericulosus
Wh tb is considered the most prevalent infectious disease in the world
B/c
1.it has been neglected in the training program of medical staff
2.minimized by those responsible for controling infectious diseases
3.coepidemic of Tb/hiv
1959
Prevalence of Pulmonary Tb in libya
2.3%
1959
Prevalence of tb in libyan childrens in past 5 years
6%
