2. The biggest cause of death among infectious
disease
1/3 of people worldwide are infected
1.5 to 2 million people die every year
resistence
Importance
7. M. tuberculosis is most commonly transmitted from
a person with infectious pulmonary TB by droplet
nuclei.
Those with culture-negative pulmonary TB and
extrapulmonary TB are essentially noninfectious.
Source of infection
8.
9. the risk of developing disease after being infected
depends largely on endogenous factors.
Disease
10.
11. About one-third of patients died within 1 year after
diagnosis.
More than 50% died within 5 years.
The 5-year mortality rate among sputum smear–
positive cases was 65%.
Of the survivors at 5 years, ~60% had undergone
spontaneous remission.
NATURAL HISTORY OF DISEASE
13. In fact, cases of active TB are often accompanied
by strongly positive skin-test reactions. There is also
evidence of reinfection with a new strain of M.
tuberculosis in patients previously treated for active
disease. This evidence underscores the fact that
previous latent or active TB may not confer fully
protective immunity.
16. Soon after the initial infection with tubercle bacilli
May be asymptomatic
Fever
pleuritic chest pain
often seen in children
middle and lower lung zones
hilar or paratracheal lymphadenopathy
erythema nodosum on the legs
Primary Disease
17. In the majority of cases, the lesion heals
Spontaneously
In young children and persons with impaired
immunitymay progress rapidly to clinical illness
Pleural effusion
Necrosis and cavitation in primary site
Enlarged lymph nodes may compress bronchi
obstruction
22. Apical and posterior segments of the upper lobes
Superior segments of the lower lobes
Infiltrates to extensive cavitary disease
Pneumonia
Symptoms and signs are often nonspecific and,
consisting mainly of diurnal fever and night sweats
due to defervescence, weight loss, anorexia,
general malaise, and weakness.
Postprimary (Adult-Type) Disease
23. In up to 90% of cases cough eventually develops
often initially nonproductive and limited to the
morning and subsequently accompanied by the
production of purulent sputum.
Hemoptysis (in 20–30%)
Pleuritic chest pain
Dyspnea
24. Physical findings are of limited use in pulmonary
TB.
Rales
Rhonchi
mild anemia leukocytosis, and thrombocytosis with
a slightly elevated erythrocyte sedimentation rate
and/or C-reactive protein level.
26. painless swelling of the lymph nodes
commonly at posterior cervical and supraclavicular
sites
Associated pulmonary disease is present in fewer
than 50% of cases
The diagnosis is established by fine-needle
aspiration biopsy (with a yield of up to 80%) or
surgical excision biopsy.
Lymph Node TB (Tuberculous
Lymphadenitis)
27. ~20% of extrapulmonary cases
The effusion may be small, remain unnoticed, and
resolve spontaneously or may be sufficiently large
to cause symptoms such as fever, pleuritic chest
pain, and dyspnea.
dullness to percussion and absence of breath
sounds.
Pleural TB
28. Determination of the pleural concentration of
adenosine deaminase (ADA) may be a useful
screening test, and TB may be excluded if the
value is very low.
30. ~10–15% of all extrapulmonary cases
Urinary frequency
Dysuria
Nocturia
Hematuria
Flank or abdominal pain
Culture of three morning urine specimens yields a
definitive diagnosis in nearly 90% of cases.
Genitourinary TB
31. ~10% of extrapulmonary cases
Weight-bearing joints
Aspiration of the abscess or bone biopsy confirms
the tuberculous etiology
Skeletal TB
32. The key to the diagnosis of TB remains a high
index of suspicion.
AFB MICROSCOPY
low sensitivity (40–60%)
inexpensive
two or three sputum specimens, preferably
collected early in the morning, should be
submitted to the laboratory.
DIAGNOSIS
35. Tuberculin Skin Testing
lack of mycobacterial species specificity
False-positive reactions may be caused by
infections with nontuberculous mycobacteria and
by BCG vaccination.
limited value in the diagnosis of active TB
DIAGNOSIS OF LATENT M.
TUBERCULOSIS INFECTION
36. to prevent morbidity and death by curing TB while
preventing the emergence of drug resistance
to interrupt transmission by rendering patients
noninfectious.
TREATMENT
37. Four major drugs are considered first-line agents
for the treatment of TB: isoniazid, rifampin,
pyrazinamide, and ethambutol
DRUGS
38. (1) the fluoroquinolone antibiotics;
(2) the injectable aminoglycosides kanamycin,
amikacin, and streptomycin;
(3) the injectable polypeptide capreomycin and the
oral agents
(4) Ethionamide and prothionamide
(5) cycloserine and terizidone (therizidone),
(6) PAS (para-aminosalicylic acid)
SECONED LINE
39. Standard short-course regimens are divided into an
initial, or bactericidal, phase and a continuation, or
sterilizing, phase.
The treatment regimen of choice for virtually all
forms of drug-susceptible TB in adults consists of a
2-month initial (or intensive) phase of isoniazid,
rifampin, pyrazinamide, and ethambutol followed
by a 4-month continuation phase of isoniazid and
rifampin
REGIMS
