UNIT III PULMONARY TUBERCULOSIS - PowerPoint Presentation

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UNIT IIIPULMONARY TUBERCULOSIS

Mrs.Indumathi

Lecturer

YNC

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OBJECTIVE

By the end of the session the student will be able to:

define tuberculosis

explain the epidemiological triad of tuberculosisidentify the mode of transmission and incubation perioddiscuss the clinical manifestations of tuberculosis

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OBJECTIVE

explain the diagnostic measures used in early detection of TB

discuss the treatment modalities used in curative aspect of TB

enumerate the control and preventive measures discuss the different Tuberculosis Control Program

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Definition

Tuberculosis is a specific infectious disease caused by

M.tuberculosis

that primarily affects the lung parenchyma.

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It may also be transmitted to other parts of the body including the meninges, kidney, bones and lymph nodes.

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Epidemiology

:

India accounts for nearly one third of global burden of tuberculosis.

Every year approximately 1.8 million persons develop tuberculosis

of

which about 0.8 million are new smear positive highly infectious

cases.

A

bout

4.17 lakh people die of TB every

year

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Prevalence of infection increased with the age, up to the age of 45-54 years in males. In females the peak of TB prevalence is below 35 years.

Tuberculosis infection as well as disease is more or less uniformly distributed in urban, semi-urban and rural areas.

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EPIDEMIOLOGICAL TRIAD

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M. tuberculosis is a rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 µm by 3 µm.

1. Agent factors : Agent

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Source

of infection

:

There

are 2 sources of infection:

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2. Host

factors

:

Age

SexHeredity

Nutrition

Immunity

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3. Environmental factors:

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Mode of transmission

:

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TB is not transmitted by fomites, such as dishes and other particles used by the patient.

Patients with extra pulmonary TB or smear negative TB constitutes a minimal hazard for transmission of infection

.

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Incubation period

:

It

ranges from 3 to 6 weeks and thereafter the development of disease depends upon the closeness of contact, extent of the disease and sputum positivity of the source case

and

host-parasite relationship.

Thus

the incubation period may be weeks, months or years.

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Pathophysiology

:

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Primary

infection…..

The

first time a client is infected with TB, the disease is said to be a primary infection.

Primary

TB infections are usually located in the apices of the lungs or near the pleura of the lower lobes.

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Stage

1

A susceptible person inhales

droplet nuclei and

becomes infected.

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organism.

Once nuclei are inhaled, the bacteria are non-specifically taken up by alveolar macrophages.

The macrophages will not be activated, therefore unable to destroy the intracellular organism

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Stage

2

Begins 7-21

days after initial infection.

MTB multiplies within the inactivated macrophages until macrophages burst.

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Stage 3

:

T cell recognition and release of cytokines and interferon

Activation

of macrophages and release of lytic enzymes and reactive

intermediates

Granulomas

, new tissue masses of live and dead bacilli, are surrounded by macrophages, which form a protective wall around the Granulomas.

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The 1

0

infection

site may or may not undergo a process of necrotic degeneration (caseation), which produces cavities filled with a cheese-like mass of tubercle bacilli, dead white blood cells (WBC’s) and necrotic lung tissue

.This is called as “Ghon tubercle”.

These

lesions may contain living bacilli that can be reactivated, even after many years and cause secondary infection.

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Stage 4

:

Many macrophages

are inactivated or poorly activated.

MTB uses these macrophages to replicate causing the tubercle to grow.The growing tubercle may invade a bronchus, causing an infection which may spread to other parts of the lungs. Spreading of TB may cause miliary tuberculosis, which can cause secondary lesions.

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Stage 5

:

The caseous centers of the tubercles liquefy, may drain into the tracheobronchial tree and may be coughed up

.

The air filled cavities remain, and may be detected on X-ray study.This liquid is very crucial for the growth of TB, and therefore it multiplies rapidly (extracellularly).

This later becomes a large antigen load, causing the walls of nearby bronchi to become necrotic and rupture.

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Secondary

infection….

After initial exposure and infection, the person may develop active disease because of compromised or inadequate immune system

response.

Active disease also occurs with reinfection and activation of dormant bacteria. It most commonly occurs within the lungs, usually in the apical or posterior segments of the upper lobes or the superior segments of the lower lobes.

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Clinical manifestations

:

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Physical findings…

.

Occasionally, rhonchi due to partial bronchial obstruction

Systemic features include fever (often low-grade and intermittent) and wasting.

In some cases, pallor and finger clubbing develop.Common hematologic findings are mild anemia and leukocytosis.

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Diagnosis:

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1.

Tuberculin skin testing…

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Induration

Test results

0-4 mm

Not significant

More than 5mmKnown or suspected HIV infection, IV drug users, people in close contact with a known TB case>10mmPositive for clients in all other high risk groups.

15mm and more

Positive for clients in low risk groups.

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2. Mycobacterial culture:

Isolation and identification of M. tuberculosis from a sputum specimen obtained from a patient with a productive cough.

4 to 8 weeks may be required before growth is detected

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3. AFB microscopy:

Microscopic examination of a diagnostic specimen such as a smear of expectorated sputum or of tissue

3 sputum specimens, preferably collected early in the morning

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4. Radiographic studies:

Classic picture is upper lobe disease with infiltrates and cavities

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Classification of TB

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CLS

Type

Description

0

-No exposure Not infected

Negative reaction to tuberculin skin test.

1

-TB exposure

- No evidence of

Infection

Negative reaction to tuberculin test skin test.

2

-TB infection

- No disease

Positive reaction to tuberculin skin test. Negative bacteriologic studies (if done). No clinical or radiographic evidence of TB.

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CLS.

Type

Description

3

Current TB disease M. tuberculosis cultured (if done) or both a positive reaction to tuberculin skin test and clinical and/or radiographic evidence of current disease.

4

Previous TB

disease

History of episode(s) of TB, abnormal stable radiographic findings in a person with a positive reaction to the tuberculin skin test, negative bacteriologic studies (if done) and no clinical or radiographic evidence of current disease.

5

TB suspect

Diagnosis pending

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Medical management:

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The two aims of tuberculosis treatment are

to interrupt tuberculosis transmission

to prevent morbidity and mortality

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Antituberculosis drugs:

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An antitubercular drug should satisfy the following criteria:

Highly effective

Free from side effects

Easy to administer

Reasonably cheap

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ATT

Bactericidal

Bacteriostatic

Rifampicin, Isoniazid, streptomycin and Pyrazinamide

Ethambutol and thioacetazone

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TREATMENT REGIMEN

Bacteriocidal agents:

Drug

Dose

Side effects

Rifampicin

10 -12 mg/ kg taken 1hr. Before or 2hr. After food

450-600mg

Gastritis

Thrombocytopenia

Nephrotoxicity

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TREATMENT REGIMEN

Bacteriocidal agents:

Drug

Dose

Side effects

INH (ISONIAZID)

4 – 5 mg/kg (max. 300 mg)

Gastric

Irritation

Neuropathy

Liver damage

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TREATMENT REGIMEN

Drug

Dose

Side effects

streptomycin

.75-1gm in single injection

Vestibular damage

Nystagmus

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TREATMENT REGIMEN

Drug

Dose

Side effects

Pyrazinamide

30 mg/kg divided into three doses per day

Liver damage

Hyperuricemia

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Bacteriostatic drugs:

They inhibit the multiplication of the bacilli and lead to their destruction by the immune mechanism of the host.

It includes

Ethambutol- dosage is 15mg/kg body weight given in 2 to 3 doses

Thioacetazone- usual dose is 2 mg/kg body weight

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TREATMENT REGIMEN

Bacteriostatic agents:

Drug

Dose

Side effects

Ethambutol

15mg/kg given in 3 doses

Retro-bulbar neuritis

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TREATMENT REGIMEN

Drug

Dose

Side effects

Thioacetazone

(combination with INH is used)

2mg/kg

Nausea

Vomiting

Blurring of

vision

Urticaria

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Phases of anti-TB treatment:

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The US centers for Disease Control and Prevention recommends a two-phase approach for treatment consisting of:

Induction phase

Continuation phase

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Induction phase:

It is a short aggressive or intense phase, early in the course of treatment, lasting 1-3 months.

During this phase, there is rapid killing of tubercle bacilli.

Infectious patients become non-infectious within about two weeks.

They mainly use 4 drugs.

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Continuation phase:

Usually use 2 drugs.

The drugs eliminate the remaining tubercle bacilli.

Killing the remaining bacilli prevents relapse after completion of treatment.

the duration of treatment was not less than 18 months to achieve complete sterilization of the bacilli.

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I

nitial intensive phase with 4 drugs (INH, rifampicin and pyrazinamide, supplemented by either streptomycin or ethambutol) for a period of 2 months,

followed by 2 drugs in the continuation phase, (INH plus rifampicin or thioacetazone) given daily or intermittently

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Directly observed treatment, short course chemotherapy (DOTS)

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Dots is a strategy to ensure cure by providing the most effective medicine and confirming that it is taken.

The strategy assures a compulsory and free availability of good quality drugs to all TB cases and

It necessitates drug administration under direct supervision, thereby ensuring the requisite regimen-compliance.

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How DOTS is carried out…??

Intensive phase - a health worker or other trained person watches as the patient swallows the drug in his presence.

Continuation phase - the patient is issued medicine for one week in a multiblister combipack

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The drugs are provided in patient-wise boxes with sufficient shelf-life.

In the programme alternate day treatment is used.

The cases are divided into three types of categories- category I, category II and category III.

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Prevention:

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By far the best way to prevent tuberculosis is to diagnose infectious cases rapidly and administer appropriate treatment until cure.

Additional strategies include :

BCG vaccination

Treatment of persons with latent tuberculosis infection

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1. BCG vaccination:

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BCG was derived from an attenuated strain of M. bovis, bacille Calmette Guerin, which was avirulent for man while retaining its capacity to induce an immune response.

There are 2 types of BCG vaccine-

the liquid (fresh)

vaccine and the

freeze dried vaccine. Freeze-dried vaccine is a more stable preparation than liquid vaccine. For vaccination, the usual strength is 0.1mg in 0.1ml volume intradermally. The dose to newborn aged below 4 weeks is 0.05ml.

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Multidrug resistant TB (MDR-TB

):

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A case of TB caused by a strain of M. tuberculosis that is resistant to two or more antituberculosis drugs.

Some define MDR-TB as a case of TB caused by a strain of M. tuberculosis that is resistant to Isoniazid and rifampin.

XDR-TB (extensively resistant tuberculosis) refers to cases of TB that are resistant to Isoniazid, rifampin, the second line drugs, the fluoroquinolones, and at least one of three injectable drugs i.e. Amikacin.

It arise by spontaneous point mutations in the mycobacterial genome.

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Drug-resistant tuberculosis may be either primary or acquired.

Primary drug resistance is that in a strain infecting a patient who has not previously been treated.

Acquired resistance develops during treatment with an inappropriate regimen.

Reasons for secondary resistance are numerous and complex: Wrong drugs used in an improper way, failure to assess drug susceptibility patterns of the organism, large bacterial load especially in the case of cavitation, poor adherence to the treatment regimen

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Treatment

For strains resistant to Isoniazid and rifampin, combinations of a fluoroquinolone, ethambutol, pyrazinamide, and streptomycin given for 18 to 24 months and for at least 9 months after sputum culture conversion, may be effective.

For patients with bacilli resistant to all of the first-line agents, cure may be attained with a combination of four second-line drugs, including one injectable agent. A duration of 24 months is recommended

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Nursing management:

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Nursing diagnoses:

Ineffective airway clearance related to copious trachea-bronchial secretions

Imbalanced nutrition less than body requirement related to increased metabolic needs associated with infection

Activity intolerance related to fatigue, decreased intake of adequate nutrition and fever

Deficient knowledge about treatment regimen and preventive health measures Ineffective health maintenance related to lack of understanding of resources

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Patient education:

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References…

Fauci, Braunwald, Kasper. Harrison’s principles of internal medicine.17

th

edition. New Jersey: McGraw Hill Kumar P. Clark. M. Kumar and Clark’s clinical medicine.7

th edition. New Delhi: Saunders publication. Black JM, Hawks JH. Medical-surgical nursing for positive outcomes.8th edition. Missouri: Elsevier publication. Lewis, Heitkemper, Derksen.Medical surgical nursing: assessment and management of clinical problems.6th edition .Missouri: Mosby publication. Manohan, Sands, Neighbors, Marek, Greek. Phipps medical surgical nursing: health and illness perspectives.8

th

edition. Missouri: Mosby publication

.