Pulmonary Tuberculosis

References:

1. Brunner & Suddarth’s Textbook of Medical-Surgical Nursing, 15th Edition, ISBN 978-197-51-6103-3, by Janice L. Hinkle, Kerry H. Cheever, and Kristen J. Overbaugh (Ch. 19, pp. [ebook] 1576–1588)
2. About GeneXpert (CDC, 2024)
3. Shi, J., Dong, W., Ma, Y., Liang, Q., Shang, Y., Wang, F., Huang, H., & Pang, Y. (2018). GeneXpert MTB/RIF Outperforms Mycobacterial Culture in Detecting Mycobacterium tuberculosis from Salivary Sputum. BioMed research international, 2018, 1514381. https://doi.org/10.1155/2018/1514381
4. About Streptomycin (Waters, Tadi, 2023)

Also Read

1. Tuberculosis

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Tuberculosis (TB) is an infectious disease that primarily affects the lung parenchyma. It may also be transmitted to other parts of the body (extrapulmonary tuberculosis), including the meninges, kidneys, bones, and lymph nodes. The primary infectious agent, M. tuberculosis, is an acid-fast aerobic rod that grows slowly and is sensitive to heat and ultraviolet light. Mycobacterium bovis and Mycobacterium avium have rarely been associated with the development of a TB infection.

Incidence Rates

TB is a worldwide public health problem that is closely associated with poverty, malnutrition, overcrowding, substandard housing, and inadequate health care. Mortality and morbidity rates continue to rise; M. tuberculosis infects an estimated one-third of the world’s population and remains the leading cause of death from infectious disease in the world. In 2023, an estimated 10.8 million people fell ill with and a total of 1.25 million people died from TB (WHO, 2024).

Transmission and Risk Factors

TB spreads from person to person by airborne transmission. An infected person releases droplet nuclei (usually particles 1 to 5 mcm in diameter) through talking, coughing, sneezing, laughing, or singing. Larger droplets settle; smaller droplets remain suspended in the air and are inhaled by a susceptible person.

Risk Factors for Tuberculosis ( CBC, 2018b)

1. Close contact with someone who has active TB; inhaled airborne nuclei is proportional to the amount of time spent in the same air space, proximity, and degree of ventilation.
2. Immunocompromised status, e.g., those with HIV infection, cancer, transplanted organs, and prolonged high-dose corticosteroid therapy.
3. Substance use disorder—individuals who use IV/injection drug or abuse alcohol.
4. Any person without adequate health care; homelessness, those who are impoverished, and racial-ethnic minorities.
5. Preexisting medical conditions or special treatment, e.g., diabetes, chronic kidney disease, malnourishment, select malignancies, hemodialysis, transplanted organ, gastrectomy, and jejunoileal bypass.
6. Immigration from or recent travel to countries with a high prevalence of TB—southeastern Asia, African, Latin America, Caribbean.
7. Institutionalization in long-term care facilities, psychiatric institutions, and prisons.
8. Living in overcrowded, substandard housing.
9. Being a health care worker performing high-risk activities: administering aerosolized medications, sputum induction procedures, bronchoscopy, suctioning, coughing procedures, caring for patients who are immune suppressed, home care with the high-risk population, and administering anesthesia and related procedures (e.g., intubation, suctioning).

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Pathophysiology

1. Initial infection and Ghon tubercule formation
   1. TB begins with inhalation of mycobacteria. They deposit onto the alveoli and begin to multiply. Through the lymph system and blood stream, these can be transported to other parts of the body (kidneys, bones, cerebral cortex) and other areas of the lungs (upper lobes).
   2. The body’s immune response by initiating an inflammatory reaction. Phagocytes (neutrophils and macrophages) engulf many of the bacteria, and TB-specific lymphocytes lyse the bacilli and normal tissue.
   3. This tissue reaction results in the accumulation of exudate in the alveoli, causing bronchopneumonia. The initial infection usually occurs 2 to 10 weeks after exposure.
   4. Granulomas, new tissue masses of live and dead bacilli, are surrounded by macrophages, which form a protective wall. This transforms into a fibrous tissue mass, the central portion of which is called a Ghon tubercle.
   5. The material (bacteria and macrophages) becomes necrotic, forming a cheesy mass. This mass may become calcified and form a collagenous scar. At this point, the bacteria become dormant, and there is no further progression of active disease.
2. Ulceration and progression of tuberculosis
   1. After initial exposure and infection, active disease may develop because of a compromised or inadequate immune system response. Active disease may also occur with reinfection and activation of dormant bacteria. In this case, the Ghon tubercle ulcerates, releasing the cheesy material into the bronchi. This allows the bacteria to go airborne and further spread the disease.
   2. Once the ulcerated tubercle heals and forms scar tissue, the infected lung becomes more inflamed, resulting in the further development of bronchopneumonia and tubercle formation.
3. Dormancy and prognosis
   1. Unless this cycle is arrested, it spreads slowly downward to the hilum of the lungs and later extends to adjacent lobes. The process may be prolonged and is characterized by long remissions when the disease is arrested, followed by periods of renewed activity.
   2. Approximately 10% of people who are initially infected develop active disease. Some people develop reactivation TB (also called adult-type progressive TB). The reactivation of a dormant focus occurring during the primary infection is the cause.

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Prevention Recommendations

Centers for Disease Control and Prevention Recommendations for Preventing Transmission of Tuberculosis in Health Care Settings

1. Early identification and treatment of people with active TB
   • Maintain a high index of suspicion for TB to identify cases rapidly.
   • Promptly initiate effective multidrug anti-TB therapy based on clinical and drug-resistance surveillance data.
2. Prevention of spread of infectious droplet nuclei by source control methods and by reduction of microbial contamination of indoor air
   • Initiate AFB (acid-fast bacilli) isolation precautions immediately for all patients who are suspected or confirmed to have active TB and who may be infectious. AFB isolation precautions include the use of a private room with negative pressure in relation to surrounding areas and a minimum of six air exchanges per hour. Air from the room should be exhausted directly to the outside. The use of ultraviolet lamps or high-efficiency particulate air filters to supplement ventilation may be considered.
   • People entering the AFB isolation room should use disposable particulate respirators that fit snugly around the face.
   • Continue AFB isolation precautions until there is clinical evidence of reduced infectiousness (i.e., cough has substantially decreased and the number of organisms on sequential sputum smears is decreasing). If drug resistance is suspected or confirmed, continue AFB precautions until the sputum smear is negative for AFB.
   • Use special precautions during cough-inducing procedures.
3. Surveillance for TB transmission
   • Maintain surveillance for TB infection among health care workers (HCWs) by routine, periodic tuberculin skin testing. Recommend appropriate preventive therapy for HCWs when indicated.
   • Maintain surveillance for TB cases among patients and HCWs.
   • Promptly initiate contact investigation procedures among HCWs, patients, and visitors exposed to a patient with infectious TB who is untreated, or ineffectively treated, and for whom appropriate AFB procedures are not in place. Recommend appropriate therapy or preventive therapy for contacts with disease or TB infection without current disease. Therapeutic regimens should be chosen based on the clinical history and local drug-resistance surveillance data.

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Clinical Manifestations

As detailed under its pathophysiology, TB is normally insidious. Most patients have a low-grade fever, cough, night sweats, fatigue, and weight loss. These symptoms can be attributed to continued immune activation and release of cytokines as a result of infection. The cough may be nonproductive, or mucopurulent sputum may be expectorated. Hemoptysis may also occur. Both the systemic and pulmonary symptoms are chronic and may have been present for weeks to months.

• Older adult patients usually present with less pronounced symptoms than younger patients, likely due to immune senescence.
• Extrapulmonary tuberculosis occurs in up to 20% of cases in the United States. This occurs more frequently in patients with HIV.

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Assessment and Diagnostic Findings

Once a patient presents with a positive skin test, blood test, or sputum culture for acid-fast bacilli, additional assessments (e.g., complete history, physical examination, tuberculin skin test, chest x-ray, and drug susceptibility testing) must be done.

1. Clinical manifestations of fever, anorexia, weight loss, night sweats, fatigue, cough, and sputum production prompt a thorough respiratory assessment: consolidation (by evaluating breath sounds), fremitus, and egophony.
2. Chest x-ray usually reveals lesions in the upper lobes.
3. For all patients, the initial M. tuberculosis isolate should be tested for drug resistance. Drug susceptibility patterns should be repeated at 3 months for patients who do not respond to therapy.

Tuberculin Skin Test

The Mantoux method is used to determine whether a person has been infected with the TB bacillus and is used widely in screening for latent M. tuberculosis infection. The Mantoux method is a standardized, intracutaneous injection procedure and should be performed only by those trained in its administration and reading.

1. Tubercle bacillus extract (tuberculin), purified protein derivative (PPD) is injected into the intradermal layer of the inner aspect of the forearm, approximately 4 inches below the elbow.
2. Intermediate-strength PPDF, in a tuberculin syringe with a half-inch 26- or 27-gauge needle, is used. The needle, with the bevel facing up, is inserted beneath the skin. Then, 0.1 mL of PPD is injected, creating an elevation in the skin, a well-demarcated wheal 6 to 10 mm in diameter. The site, antigen name, strength, lot number, date, and time of the test are recorded.
3. The test result is read 48 to 72 hours after injection. Tests read after 72 hours tend to underestimate the true size of induration (raised hard area or swelling). A delayed localized reaction indicates that the person is sensitive to tuberculin.
4. A reaction occurs when both induration and erythema (just erythema is not significant) are present. After the area is inspected for induration, it is lightly palpated across the injection site, from the area of normal skin to the margins of the induration. The diameter of the induration (not erythema) is measured in millimeters at its widest part, and the size of the induration is documented.
5. The size of the induration determines the significant of the reaction. A significant reaction indicates past exposure to M. tuberculosis or vaccination with bacille Calmette-Guérin (BCG) vaccine. The BCG vaccine is used in Europe and Latin America but not routinely in the United States. Individuals who have been vaccinated with BCG will return an induration of 5 to 9 mm. Over five to ten years, most people will show minimal to no reaction due to BCG alone.
   • A reaction of 0 to 4 mm is not considered significant.
   • A reaction of 5 mm or greater may be significant in people who are considered to be at risk. It is defined as positive in patients who are HIV positive or have HIV risk factors and are of unknown HIV status, in those who are close contacts of someone with active TB, and in those who have chest x-ray results consistent with TB.
   • A reaction of 10 mm or greater is usually considered significant in people who have normal or mildly impaired immunity.

A significant (positive) result does not necessarily mean that active disease is present in the body. More than 90% of people who are tuberculin-significant reactors do not develop clinical TB. However, all significant reactors are candidates for active TB. In general, the more intense the reaction, the greater the likelihood of an active infection. Additional testing is required to determine if the patient has latent or active TB.

Moreover, an insignificant (negative) result does not exclude TB infection or disease, because patients who are immunocompromised cannot develop an immune response that is adequate to produce a positive skin test. This is referred to as anergy.

QuantiFERON-TB Gold® Plus and T-SPOT®

Interferon-gamma release assays (IGRAs) are TB blood tests and are preferred diagnostic tests for patients who have received the BCG vaccine and patients who are not likely to return for a second appointment to look for a reaction to the tuberculin skin test. The results of both of these tests are available within 24 to 36 hours. A positive IGRA signifies that the patient has been infected with TB bacteria and additional tests are needed. A negative IGRA means that the patient’s blood did not react to the test and a latent or active TB infection is not likely.

Sputum Culture

A sputum specimen may be used to screen for TB. A culture takes 2 to 6 weeks for M. tuberculosis complex to grow.

1. The presence of AFB on a sputum smear may indicate disease but does not confirm the diagnosis of TB because some AFB are not M. tuberculosis.
2. A culture is done to confirm the diagnosis. For all patients, the initial M. tuberculosis isolate should be tested for drug resistance.

GeneXpert®

GeneXpert® is an automated diagnostic test that can identify Mycobacterium tuberculosis (MTB) DNA and resistance to rifampicin (RIF) via machine analysis of a sputum sample. In the Philippines, it is considered a gold standard. It offers faster results (within 2 hours) and can be more sensitive in detecting TB, especially for smear-negative cases.

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Gerontologic Considerations

TB may have atypical manifestations in older adult patients, whose symptoms may include unusual behavior and altered mental status, fever, anorexia, and weight loss. In many older adult patients, the tuberculin skin test produces no reaction due to a loss of immunologic memory or delayed reactivity for up to 1 week (recall phenomenon). A second skin test is performed in 1 to 2 weeks. Older adults who live in long-term care facilities (i.e., are institutionalized) are at increased risk for primary and reactivated TB as compared to those in the community.

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Medical Management

Pulmonary TB is treated primarily with anti-TB agents for 6 to 12 months. A prolonged treatment duration is necessary to ensure eradication of the organisms and to prevent relapse.

Drug Resistance

Drug resistance, continuing and increasing worldwide concern, must be considered when planning effective therapy.

1. Multidrug resistance (MDR TB): Resistance to two agents, isoniazid and rifampin. The populations at greatest risk for multidrug resistance are those who are HIV positive, institutionalized, or homeless.
2. Extensively drug resistance (XDR TB): Resistance to isoniazid and rifampin, in addition to any fluoroquinolone, and at least one of the three injectable second-line agents (i.e., amikacin, kanamycin, or capreomycin). The populations at greatest risk are those with HIV infection or other immunocompromised conditions.

The increasing prevalence of drug resistance points out the need to begin TB treatment with four or more medications, to ensure completion of therapy, and to develop and evaluate new anti-TB medications. MDR TB is difficult to treat. Treatment is guided by sputum specimen culture and sensitivity testing as the patient typically is resistant to isoniazid and rifampin.

Commonly Used Agents	Most Common Side Effects	Nursing Considerations
Isoniazid	Peripheral neuritis, hepatic enzyme elevation, hepatitis, hypersensitivity	Bactericidal Pyridoxine (Vitamin B₆) is used as prophylaxis for neuritis.
Rifampin, Rifampicin	Hepatitis, febrile reaction, purpura (rare), nausea, vomiting	Bactericidal Orange urine and other body secretions Discoloring of contact lenses Monitor AST and ALT
Rifabutin		Avoid protease inhibitors
Rifapentine	Hepatotoxicity, thrombocytopenia	Orange-red coloration of body secretions, contact lenses, dentures Use with caution in adults or those with renal disease
Pyrazinamide	Hyperuricemia, hepatotoxicity, skin rash, arthralgia, GI distress	Bactericidal Monitor uric acid, AST, and ALT
Ethambutol	Optic neuritis (which may lead to blindness but is rare at 15 mg/kg), skin rash	Bacteriostatic Use with caution with renal disease or when eye testing is not feasible. Monitor visual acuity, color, and discrimination.

In current TB therapy, four first-line medications (“RIPE therapy”) are used:

1. Isoniazid
2. Rifampin/Rifampicin (same drug, different spelling)
3. Pyrazinamide
4. Ethambutol

Combination medications, such as isoniazid and rifampin or isoniazid, pyrazinamide, and rifampin and medications given twice a week (e.g., rifapentine) are available to help improve patient adherence. However, these medications are more costly.

Streptomycin

Streptomycin was historically a first-line treatment, even considered the most effective treatment for TB at one point, but is now reserved for multidrug-resistant TB and as a second-line treatment regimen in combination with other drugs. This is because of rising resistance and the availability of more effective and less toxic alternatives. it is known to have ototoxic, nephrotoxic, and teratogenic effects. It has also been linked to leukopenia, neutropenia, and pancytopenia.

Recommended treatment guidelines for newly diagnosed cases (by WHO, 2019) consists of two phases:

1. Initial Phase: multiple-medication regimen of isoniazid, rifampin, pyrazinamide, and ethambutol plus vitamin V₆ 50 mg. All are taken once a day and are oral medications. This intensive-treatment regimen is given daily for 8 weeks.
2. Continuation Phase: after the initial phase, options for the continuation phase of treatment include isoniazid and rifampin or isoniazid and rifapentine. This continued for 4 months in most patients.
   • Therapy is indicated to continue for up to 7 months in patients with:
     • Cavitary pulmonary TB whose sputum culture whose sputum culture is positive at the end of the initial phase of treatment.
     • Those whose initial phase of treatment did not include pyrazinamide.
     • Those being treated once weekly with isoniazid and rifapentine whose sputum culture is positive at the end of the initial phase of treatment.

People are considered noninfectious after 2 to 3 weeks of continuous medication therapy. The total number of doses taken, not simply the duration of treatment, more accurately determines whether a course of therapy has been completed.

Isoniazid as Prophylaxis

Isoniazid may also be used as a prophylactic (preventive) measure for people who are at risk for significant disease, including:

• Household family members of patients with active disease
• Patients with HIV infection who have a PPD test reaction with 5 mm of induration or more
• Patients with fibrotic lesions suggestive of old TB detected on a chest x-ray and a PPD reaction with 5 mm of induration or more
• Patients whose current PPD test results show a change from former test results, suggesting recent exposure to TB and possible infection (skin test converters)
• Patients who use IV/injection drugs who have PPD test results with 10 mm of induration or more
• Patients who high-risk comorbid conditions and a PPD result with 10 mm of induration or more
• 35 years or younger who have PPD test results with 10 mm of induration or more and one of the following criteria: - Foreign-born form countries with a high prevalence of TB - Populations that are high-risk and medically underserved - Patients living in institutions

Prophylactic isoniazid treatment involves taking daily doses for 6 to 12 months. Liver enzymes, blood urea nitrogen (BUN), and creatinine levels are monitored monthly. Sputum culture results are monitored for AFB to evaluate the effectiveness of treatment and the patient’s adherence to the treatment regimen.

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Nursing Management

Nursing management includes promoting airway clearance, advocating adherence to the treatment regimen, promoting activity and nutrition, and preventing transmission.

Collecting Sputum Cultures

The best time to obtain sputum cultures is in the morning. Three samples are obtained to be tested via direct sputum smear microscopy. Each sample should be at least 5 mL.

• The patient should stop any antibiotics for at least one day. On the morning of collection, oral care is only done after collection.
• The patient is instructed to expectorate via deep breathing and coughing exercises.

Promoting Airway Clearance

Copious secretions obstruct the airways in many patients with TB and interfere with adequate gas exchange.

1. Increasing fluid intake promotes systemic hydration and serves as an effective expectorant.
2. Correct positioning to facilitate airway drainage (postural drainage) is taught to the patient. This utilizes gravity to assist in the removal of bronchial secretions.

Promoting Adherence to Treatment Regimen

The major reason treatment fails is that patients do not take their medications regularly and for the prescribed duration, potentially due to side effects or complexity of the treatment regimen. Risk factors for nonadherence include previous failure to complete therapy; patients who are physically, emotionally, mentally, or financially challenged; patients with substance use problems; and patients who do not understand the importance of treatment.

1. Education on the medications, schedule, and side effects is important. Emphasize that TB is a communicable disease and that taking medications is the most effective means of preventing transmission.
2. Taking medications:
   • Medications are taken either on an empty stomach or at least 1 hour before meals, because food interferes with medication absorption. However, this may result in gastrointestinal upset.
   • People taking isoniazid should avoid foods that contain tyramine and histamine—tuna, aged cheese, red wine, soy sauce, yeast extracts—because eating them while taking isoniazid may result in headache, flushing, hypotension, lightheadedness, palpitations, and diaphoresis. People should also avoid alcohol because of the high potential for hepatotoxic effects.
   • Rifampin can alter the metabolism of certain other medications, making them less effective. These medications include beta-blockers, oral anticoagulants (e.g., warfarin), digoxin, quinidine, corticosteroids, oral hypoglycemic agents, oral contraceptives, theophylline, and verapamil.
   • Rifampin can also discolor contact lenses as secretions (urine, saliva, sputum, sweat, teeth, and tears) become reddish-orange or reddish-brown. The patient may be advised to wear eyeglasses while taking this medication.
3. Side effects: the nurse should monitor for other side effects of anti-TB medications, including hepatitis, neurologic changes (hearing loss, neuritis), and rash. Liver enzymes, BUN, and serum creatinine levels are monitored to detect changes in liver and kidney function. Sputum culture results are monitored for AFB to evaluate the effectiveness of treatment regimen and adherence to therapy.
4. Drug resistance: the nurse educates the patient about the risk of drug resistance if the medication regimen is not strictly and continuously followed.
5. Monitoring: the nurse carefully monitors vital signs and observes for spikes in temperature or changes in clinical status. Monitoring of temperature and respiratory status should also be taught to non-hospitalized patients with active TB. Any alteration is reported to the primary provider.
6. DOT: directly observed therapy is used in the community setting to enhance adherence. A health care provider or other responsible person directly observes that the patient ingests the prescribed medications. Although highly successful, this is a resource intensive program.
7. Case management: each patient with TB is assigned a case manager who coordinates all aspects of the patient’s care to ensure completion of therapy.

Promoting Activity and Adequate Nutrition

The prolonged chronic illness combined with impaired nutritional status often result in debilitation of patients with TB. Anorexia, weight loss, and malnutrition are common in patients with TB. The patient’s willingness to eat may be altered by fatigue from excessive coughing; sputum production; chest pain; generalized debilitated state; or cost, if the patient has few resources.

1. A progressive activity schedule planned to focus on increasing activity tolerance and muscle strength is made by the nurse.
2. Identifying facilities (e.g., shelters, soup kitchens, Meals on Wheels) that provide meals in the patient’s neighborhood may increase the likelihood that the patient with limited resources and energy will have access to a more nutritious intake.
3. A nutritional plan that allows for small, frequent meals may be required.
4. Liquid nutritional supplements may assist in meeting basic caloric requirements.

Preventing Transmission of Tuberculosis Infection

1. Education about hygiene measures, including mouth care, covering the mouth and nose when coughing and sneezing, proper disposal of tissues, and hand hygiene.
2. Contact tracing to determine who have been in contact with the affected patient during the infectious stage so they can undergo screening and possible treatment if indicated.
3. Monitoring for the occurrence of military TB. Military TB, TB migrating to other parts of the body, is a result of invasion of the bloodstream by the tubercle bacillus. It is a very serious form of TB. These disseminate throughout all tissues, with tiny military tubercules developing in the lungs, spleen, liver, kidneys, meninges, and other organs.
   • Clinically, manifestations can vary from an acute, rapid progression with high fever to a slowly developing process with low-grade fever, anemia, and debilitation. There may be no localizing signs except an enlarged spleen and a reduced number of leukocytes.
   • Within a few weeks, the chest x-ray reveals small densities scattered diffusely throughout both lung fields; these are the military tubercules, which gradually grow.
   • The nurse monitors vital signs and observes for spikes in temperature as well as changes in renal and cognitive function. Few physical signs may be elicited on a physical examination of the chest, but at this stage, the patient has a severe cough and dyspnea.
   • Treatment of military TB is the same as for pulmonary TB.