Pulmonary tuberculosis

Pulmonary Tuberculosis
Tuberculosis (abbreviated as TB for tubercle bacillus or Tuberculosis) is a common and often deadly infectious diseaseerculosis) is a common and often deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs (as pulmonary TB).

Pulmonary Tuberculosis
Scanning electron micrograph of Mycobacterium tuberculosis

Epidemiology
According to the World Health Organization (WHO), nearly 2 billion people—one third of the world's population—have been exposed to the tuberculosis pathogen.
Annually, 8 million people become ill with tuberculosis, and 2 million people die from the disease worldwide.
In 2004, around 14.6 million people had active TB disease with 9 million new cases.
The annual incidenceThe annual incidence rate varies from 356 per 100,000 in AfricaThe annual incidence rate varies from 356 per 100,000 in Africa to 41 per 100,000 in the Americas.
Tuberculosis is the world's greatest infectious killer of women of reproductive age and the leading cause of death among people with HIVTuberculosis is the world's greatest infectious killer of women of reproductive age and the leading cause of death among people with HIV/AIDS.

Epidemiology
Most common infectious cause of death worldwide
Latent phase of TB enabled it to spread to one third of the world population
8,000,000 new cases each year
3,000,000 infected patients die

Epidemiology

Epidemiology
Major changes in trends secondary to HIV
- 1953-1985 cases decreased from 84,304 to 22,201
- during this period cases were reactivation of old infection and elderly
- TB and AIDS registries suggests that HIV-infected pts account for 30-50% increase in cases of TB

Epidemiology
World TB incidence. Cases per 100,000; Red => 300, orange = 200–300, yellow = 100–200, green = 50–100, blue =< 50 and grey = n/a. Data from WHO, 2006

Incidence
1985-1990 TB cases increased 55% in Hispanics and 27% in African Americans
Populations at risk
- Foreign-born individuals
- Low socioeconomic status
- Cancer pts
- Celiac disease
- Cigarette smokers
- TNF-a antagonists
- Corticosteroids
- HIV

Transmission
When people suffering from active pulmonary TB cough, sneeze, speak, or spit, they expel infectious aerosolWhen people suffering from active pulmonary TB cough, sneeze, speak, or spit, they expel infectious aerosol droplets 0.5 to 5 µm in diameter.
A single sneeze can release up to 40,000 droplets.
People with prolonged, frequent, or intense contact are at particularly high risk of becoming infected, with an estimated 22% infection rate.
A person with active but untreated tuberculosis can infect 10–15 other people per year.
Others at risk include people in areas where TB is common,

Transmission

Transmission
people who inject drugs using unsanitary needles,
residents and employees of high-risk congregate settings,
medically under-served and low-income populations,
high-risk racial or ethnic minority populations,
children exposed to adults in high-risk categories,
patients immunocompromised patients immunocompromised by conditions such as HIV patients immunocompromised by conditions such as HIV/AIDS, people who take immunosuppressant drugs,
and health care workers serving these high-risk clients.

Pathogenesis

Pathogenesis
Hyperlink to Microsoft Word
Pathophysiology of Pulmonary Tuberculosis.doc
Pathogenesis of TB infection and disease.doc

Diagnostics
Inject intradermally 0.1 ml of 5TU PPD tuberculin
Produce wheal 6 mm to 10 mm in diameter
Represent DTH (delayed type hypersensitivity)

Reading of Mantoux test
Read reaction 48-72 hours after injection
Measure only induration
Record reaction in mm

Classifying the Tuberculin Reaction
>5 mm is classified as positive in
HIV-positive persons
Recent contacts of TB case
Persons with fibrotic changes on CXR consistent with old healed TB
Patients with organ transplants and other immunosuppressed patients

Classifying the tuberculin reaction
>10 mm is classified as positive in
Recent arrivals from high-prevalence countries
Injection drug users
Residents and employees of high-risk settings
Mycobacteriology laboratory personnel
Persons with clinical conditions that place them at high risk
Children <4 years, or children and adolescents exposed to adults in high-risk categories

Classifying the tuberculin reaction
>15 mm is classified as positive in
Persons with no known risk factors for TB

Factors may affect TST
False negative
Faulty application
Anergy
Acute TB (2-10 wks to convert)
Very young age (< 6 months old)
Live-virus vaccination
Overwhelming TB disease
False positive
BCG vaccination (usually <10mm by adulthood)
Nontuberculous mycobacteria infection

Chest Radiography
Abnormalities often seen in apical or posterior segments of upper lobe or superior segments of lower lobe
May have unusual appearance in HIV-positive persons
Cannot confirm diagnosis of TB!!

Chest radiography
No chest X-ray pattern is absolutely typical of TB
10-15% of culture-positive TB patients not diagnosed by X-ray
40% of patients diagnosed as having TB on the basis of x-ray alone do not have active TB

Specimen Collection
Obtain 3 sputum specimens for smear examination and culture
Persons unable to cough up sputum
induce sputum
bronchoscopy
gastric aspiration
Follow infection control precautions during specimen collection

Number of sputum samples required
overall diagnostic yield for sputum examination related to
the quantity of sputum (at least 5 mL)
the quality of sputum
multiple samples obtained at different times to the laboratory for processing
3 samples obtained at least eight hours apart with at least one sample obtained in the early morning

Smear Examination
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
Not specific for M. tuberculosis

AFB smear
Mycobacterium tuberculosis (stained red) in sputum

Cultures

Signs and Symptoms

Signs and Symptoms
Hemoptysis
Also known as coughing up blood, it is a symptom of bleeding somewhere in the respiratory tract. Frothy and bright red blood may come from the nose, mouth, or throat (upper respiratory tract), the lower respiratory tract, or the lungs. The seriousness of the disorder depends on the cause of the bleeding.

Signs and Symptoms
Anorexia
The sysmptom of poor appetite whatever the cause

Treatment

Tuberculosis treatment
The standard "short" course treatment for tuberculosis (TB), is isoniazid (TB), is isoniazid, rifampicin (TB), is isoniazid, rifampicin, pyrazinamide (TB), is isoniazid, rifampicin, pyrazinamide, and ethambutol (TB), is isoniazid, rifampicin, pyrazinamide, and ethambutol for two months, then isoniazid and rifampicin alone for a further four months. The patient is considered cured at six months (although there is still a relapse rate of 2 to 3%). For latent tuberculosis (TB), is isoniazid, rifampicin, pyrazinamide, and ethambutol for two months, then isoniazid and rifampicin alone for a further four months. The patient is considered cured at six months (although there is still a relapse rate of 2 to 3%). For latent tuberculosis, the standard treatment is six to nine months of isoniazid alone.
If the organism is known to be fully sensitive, then treatment is with isoniazid, rifampicin, and pyrazinamide for two months, followed by isoniazid and rifampicin for four months. Ethambutol need not be used.

Drugs
All first-line anti-tuberculous drug names have a standard three-letter and a single-letter abbreviation:
ethambutol is EMB or E,
isoniazid is INH or H,
pyrazinamide is PZA or Z,
rifampicin is RMP or R,
Streptomycin is STM or S.

Drugs
There are six classes of second-line drugs (SLDs) used for the treatment of TB. A drug may be classed as second-line instead of first-line for one of two possible reasons: it may be less effective than the first-line drugs.
aminoglycosidesaminoglycosides: e.g., amikacinaminoglycosides: e.g., amikacin (AMK), kanamycin (KM);
polypeptidespolypeptides: e.g., capreomycinpolypeptides: e.g., capreomycin, viomycinpolypeptides: e.g., capreomycin, viomycin, enviomycin;
fluoroquinolonesfluoroquinolones: e.g., ciprofloxacinfluoroquinolones: e.g., ciprofloxacin (CIP), levofloxacinfluoroquinolones: e.g., ciprofloxacin (CIP), levofloxacin, moxifloxacin (MXF);
thioamidesthioamides: e.g. ethionamidethioamides: e.g. ethionamide, prothionamide
cycloserine (the only antibiotic in its class);
p-aminosalicylic acid (PAS or P).

Drugs
considered "third-line drugs"
not very effective or because their efficacy has not been proven .
Rifabutin is effective, but is not included on the WHO list because for most developing countries, it is impractically expensive.
rifabutin
macrolidesmacrolides: e.g., clarithromycin (CLR);
linezolid (LZD);
thioacetazone (T);
thioridazinea;
arginine;
vitamin D;
R207910.

Drugs
Daily Dose of TB Drugs

Drugs
Multi-drug resistant TB (MDR-TB) is defined as resistance to the two most effective first-line TB drugs: rifampicin) is defined as resistance to the two most effective first-line TB drugs: rifampicin and isoniazid.
Extensively drug-resistant TB (XDR-TB) is also resistant to three or more of the six classes of second-line drugs.

Monitoring and DOTS
DOTSDOTS stands for "Directly Observed Therapy, Short-course" and is a major plan in the WHO global TB eradication programme.
The DOTS strategy focuses on five main points of action.
These include government commitment to control TB,
diagnosis based on sputum-smear microscopy tests done on patients who actively report TB symptoms,
direct observation short-course chemotherapy treatments,
a definite supply of drugs, and
standardized reporting and recording of cases and treatment outcomes.

Prevention
TB prevention and control takes two parallel approaches.
In the first, people with TB and their contacts are identified and then treated.
Identification of infections often involves testing high-risk groups for TB.
In the second approach, children are vaccinated to protect them from TB.

Vaccines
Many countries use Bacillus Calmette-Guérin (BCG) vaccine as part of their TB control programs, especially for infants. According to the W.H.O., this is the most often used vaccine worldwide, with 85% of infants in 172 countries immunized in 1993.
BCG provides some protection against severe forms of pediatric TB
unreliable against adult pulmonary TB,
Currently, there are more cases of TB on the planet than at any other time in history
urgent need for a newer, more effective vaccine that would prevent all forms of TB—including drug resistant strains—in all age groups and among people with HIV.

Current Surgical Intervention
Patients with hemoptysis first received Bronchial Artery Embolization because of the recurrent hemoptysis.
Current indication of Lung Resection for pulmonary tuberculosis includes MDR-TB with a poor response to medical therapy, hemoptysis due to bronchiectasis or Aspergillus superinfection, and destroyed lung as previously reported, which are consistent with our indications.
Surgery remains a crucial adjunct to medical therapy for the treatment of MDR-TB and medical failure lesions.