Mariano Marcos State University
COLLEGE OF HEALTH SCIENCES
Department of Physical Therapy
City of Batac, Ilocos Norte
TUBERCULOSIS
MEDICAL BACKGROUND
Submitted by:
Abainza, Nicole Andrie
Domingo, Elaine Jean
Ligot, Kylie
Tabunan, Trisha
Zacarias, Allen Neithan
Submitted to:
Jeffreel M. Conception, PTRP
PT167 Instructor
FEBRUARY 2023
TUBERCULOSIS
INTRODUCTION
Tuberculosis (TB) is a disease caused by germs that are spread from person
to person through air. TB usually affects the lungs, but it can also affect other parts of
the body, such as the brain, kidney, or spine. A person with TB can die if they do not
get treatment. This chapter will discuss the medical background of Tuberculosis, with
it’s etiology, epidemiology, risk factors, anatomy and physiology, pathophysiology,
clinical signs and symptoms, differential diagnosis, medical management, and physical
therapy management.
LEARNING OUTCOMES
Upon the completion of this lesson, the student will be able to:
1.
Describe the underlying causes and occurrence of tuberculosis.
2.
Explain the pathophysiology of tuberculosis.
3.
Differentiate the diagnosis related to tuberculosis.
4.
Practice the various physical therapy assessment and intervention that are use for
patient with tuberculosis.
LEARNING INPUTS AND CENTRAL ACTIVITIES
DEFINITION
An acute or chronic infection caused by Mycobacterium tuberculosis generally
transmitted by the inhalation or ingestion of infected droplets and usually affects the
lungs. Although the primary infection site is the lung, mycobacteria commonly exist in
other parts of the body and this is referred to as extrapulmonary tuberculosis. The
extrapulmonary sites may include the renal system, skeletal system, GI tract,
meninges, and genitals. Extrapulmonary tuberculosis occurs with increased frequency
in people with HIV infection. Latent infection is defined as harboring M. tuberculosis
without evidence of active infection. Active infection, on the other hand, is based on
the presence of clinical and laboratory findings.
EPIDEMIOLOGY
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Tuberculosis (TB), a highly infectious bacterial disease, was prominent in the first
half of the 1900s.
With improved sanitation and medical care, TB was largely controlled.
A recent resurgence of the disease probably resulted from the migration patterns
of people globally and the poor becoming poorer in high-income countries.
TB affects many organ systems, including the lungs, and is more prevalent in
people living in poor sanitary conditions with poor health.
Mycobacterium tuberculosis is highly contagious but responds well to
medication.
TB remains a global health problem with the highest rates in Southeast Asia,
sub-Saharan Africa, and Eastern Europe.
Before the development of anti-TB drugs in the late 1940s, TB was the leading
cause of death in the United States.
Drug therapy, along with improvements in public health and general living
standards, resulted in a marked decline in incidence.
Between 1985 and 1992 there was a 20 % increase in new TB cases in the
United States.
Now, after years of rising TB infection rates, the United States has started to see
a decrease in the annual number of cases.
Cases of multidrug-resistant TB have continued to rise annually, and there
remains a huge reservoir of individuals who are infected.
Multidrug-resistant TB has emerged as a major infectious disease problem
throughout the world.
The AIDS pandemic, the increased incidence of TB in populations without easy
access to anti-TB medications (homeless people and economically
disadvantaged people), the deterioration of the public health infrastructure,
interruptions in the drug supply, and inadequate training of health care providers
in the epidemiology of TB are some factors contributing to the increased
incidence of multidrug-resistant TB.
RISK FACTORS
Some of the main risk factors for tuberculosis include:
1. Poverty. People living in poverty often lack access to quality healthcare.
2. HIV Infection. Because HIV attacks the immune system, it puts people at
greater risk of getting sick from other bacteria and viruses. The combination of
HIV and TB can be especially deadly because the two diseases feed off each
other. In 2021, about 187,000 people with HIV died of TB worldwide.
3. Homelessness. People who are homeless often live in crowded conditions
with little or no access to healthcare
4. Substance Abuse. Intravenous (IV) drug use and alcoholism weaken the
immune system.
5. Kidney Disease and Diabetes. Chronic conditions, such as kidney disease
and diabetes, weaken your immune system, making it harder for the body to
fight off TB.
6. Working in Healthcare. Doctors, nurses, and other healthcare workers get
exposed to lots of patients on a regular basis, which means they’re also more
likely to be close to someone with tuberculosis.
7. Smoking Tobacco. Smoking can increase your risk of getting TB and dying
from it. The WHO estimates 8 percent of TB cases worldwide can be linked to
smoking
8. Babies, Young Children, and Elderly People. The immune system can be
more vulnerable when someone is very young or very old.
ETIOLOGY
Tuberculosis (TB) is caused by a type of bacterium called Mycobacterium tuberculosis.
It's spread when a person with active TB disease in their lungs coughs or sneezes and
someone else inhales the expelled droplets, which contain TB bacteria. Although TB
is infectious, it doesn’t spread easily. You usually have to spend a lot of time in contact
with someone who is contagious in order to catch it. Children with TB or people with a
TB infection that occurs outside the lungs do not spread the infection.
ANATOMY & PHYSIOLOGY
Lungs
● cone shaped and are described as having
an apex, a base, three borders (anterior,
inferior, and posterior), and three
surfaces
(costal,
medial,
and
diaphragmatic)
● highest point of the apex of each lung
approximately 1 inch above the middle
third of each clavicle.
● Upper
Respiratory
Tract:
nose,
pharynx, and larynx
● Lower Respiratory Tract: extends from
the level of the true vocal cords in the
larynx to the alveoli within the lungs.
Generally, the lower respiratory tract may
be divided into two parts: the tracheobronchial tree, or conducting airways, and
the acinar or terminal respiratory units.
● Tracheobronchial tree (conducting airways): are not directly involved in the
exchange of gases in the lungs. They simply conduct air to and from the
respiratory units. Airway diameter progressively decreases with each
succeeding generation of branching.
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Terminal respiratory (acinar) units: made up of respiratory bronchioles,
alveolar ducts, and alveoli. These structures together are termed the acinus
and participate in gas exchange.
Alveoli
● where gas exchange occurs
● Two major types of epithelial cells exist
along the alveolar wall: the Squamous
pneumocytes (type I) cells and the Granular
pneumocytes (type II) cells.
● Squamous pneumocytes (type I) cells are
flat and thin and cover approximately 93% of
the alveolar surface.
● Granular pneumocytes (type II) cells are
thick, cuboidal shaped, cover 7% of the
alveolar wall, and are involved in the
production of surfactant. Surfactant is a
lipoprotein that lowers alveolar surface
tension at end-expiration and thereby
prevents the lung from collapsing.
● The alveoli, like the bronchi, contain cellular components of inflammation and
immunity. The alveolar macrophage engulfs and ingests foreign material in the
alveoli and provides a protective function against disease.
Capillaries
● composed of a single layer of endothelial cells deliver blood in close proximity
to the alveoli.
● Capillaries can distend and accommodate the volume of blood being delivered
to the lung.
● The alveolar-capillary interface is where the exchange of gases occurs. The
thickness of the alveolar-capillary membrane is between 0.5 and 1.0 µm.
PATHOPHYSIOLOGY
Tuberculosis may occur in 3 stages:
1. Primary infection
Infection requires inhalation of particles small enough to traverse the upper
respiratory defenses and deposit deep in the lungs, usually in the subpleural airspaces
of the middle or lower lobes. Larger droplets tend to lodge in the more proximal airways
and typically do not result in infection. Infection usually begins from a single droplet
nucleus, which typically carries few organisms. Perhaps only a single organism may
suffice to cause infection in susceptible people, but less susceptible people may
require repeated exposure to develop an infection. To initiate infection, M. tuberculosis
bacilli must be ingested by alveolar macrophages. Bacilli that are not killed by the
macrophages actually replicate inside them, ultimately killing the host macrophage
(with the help of CD8 lymphocytes); inflammatory cells are attracted to the area,
causing a focal pneumonitis that coalesces into the characteristic tubercles seen
histologically.
In the early weeks of infection, some infected macrophages migrate to regional
lymph nodes (eg, hilar, mediastinal), where they access the bloodstream. Organisms
may then spread hematogenously to any part of the body, particularly the apicalposterior portion of the lungs, epiphyses of the long bones, kidneys, vertebral bodies,
and meninges. Hematogenous dissemination is less likely in patients with partial
immunity due to vaccination or to prior natural infection with M. tuberculosis or
environmental mycobacteria.
2. Latent infection
Occurs after most primary infections. In about 95% of cases, after about 3
weeks of uninhibited growth, the immune system suppresses bacillary replication,
usually before symptoms or signs develop. Persons with LTBI have M. tuberculosis in
their bodies, but do not have TB disease and cannot spread the infection to other
people. A person with LTBI is not regarded as having a case of TB. The process of
LTBI begins when extracellular bacilli are ingested by macrophages and presented to
other white blood cells. This triggers the immune response in which white blood cells
kill or encapsulate most of the bacilli, leading to the formation of a granuloma.
Tubercle bacilli (mycobacterium tuberculosis) can survive in this material for
years; the balance between the host’s resistance and microbial virulence determines
whether the infection ultimately resolves without treatment, remains dormant, or
becomes active. Infectious foci may leave fibronodular scars in the apices of one or
both lungs (Simon foci, which usually result from hematogenous seeding from another
site of infection) or small areas of consolidation (Ghon foci). A Ghon focus with lymph
node involvement is a Ghon complex, which, if calcified, is called a Ranke complex
LTBI may be detected by using the tuberculin skin test (TST) or an interferongamma release assay (IGRA). It can take 2 to 8 weeks after the initial TB infection for
the body’s immune system to be able to react to tuberculin and for the infection to be
detected by the TST or IGRA. Within weeks after infection, the immune system is
usually able to halt the multiplication of the tubercle bacilli, preventing further
progression.
3. Active infection
Healthy people who are infected with tuberculosis have about a 5 to 10%
lifetime risk of developing active disease, although the percentage varies significantly
by age and other risk factors. In 50 to 80% of those who develop active disease, TB
reactivates within the first 2 years, but it can also reactivate decades later.
Any organ initially seeded may become a site of reactivation, but
reactivation occurs most often in the lung apices, presumably because of favorable
local conditions such as high oxygen tension. Ghon foci and affected hilar lymph nodes
are much less likely to be sites of reactivation. Conditions that impair cellular immunity
(which is essential for defense against TB) significantly facilitate reactivation. Thus,
patients coinfected with HIV and not receiving appropriate antiretroviral therapy (ART)
have about a 10% annual risk of developing active disease.
PATHOGENESIS OF TB
Droplet nuclei containing tubercle bacilli
are inhaled, enter the lungs, and travel to
the alveoli.
Tubercle bacilli multiply in the alveoli.
A small number of tubercle bacilli enter
the bloodstream and spread throughout
the body. The tubercle bacilli may reach
any part of the body, including areas
where TB disease is more likely to
develop (such as the brain, larynx, lymph
node, lung, spine, bone, or kidney).
Within 2 to 8 weeks, special immune cells
called macrophages to ingest and
surround the tubercle bacilli. The cells
form a barrier shell, called a granuloma,
that keeps the bacilli contained and
under control (LTBI).
If the immune system cannot keep the
tubercle bacilli under control, the bacilli
begin to multiply rapidly (TB disease).
This process can occur in different areas
in the body, such as the lungs, kidneys,
brain, or bone (see diagram in box 3).
LTBI vs TB Disease
SITES OF TB DISEASE
TB disease can occur in pulmonary and extrapulmonary sites.
Pulmonary
TB disease most commonly affects the lungs; this is referred to as pulmonary
TB. In 2011, 67% of TB cases in the United States were exclusively pulmonary.
Patients with pulmonary TB usually have a cough and an abnormal chest radiograph
and may be infectious. Although the majority of TB cases are pulmonary, TB can occur
in almost any anatomical site or as a disseminated disease.
Extrapulmonary
TB disease occurs in places other than the lungs, including the larynx, the
lymph nodes, the pleura, the brain, the kidneys, or the bones and joints. In HIV-infected
persons, extrapulmonary TB disease is often accompanied by pulmonary TB. Persons
with extrapulmonary TB disease usually are not infectious unless they have
1) pulmonary disease in addition to extrapulmonary disease;
2) extrapulmonary disease located in the oral cavity or the larynx; or
3) extrapulmonary disease that includes an open abscess or lesion in which the
concentration of organisms is high, especially if drainage from the abscess or
lesion is extensive, or if drainage fluid is aerosolized.
Persons with TB pleural effusions may have underlying pulmonary TB that is
masked on a chest radiograph because the effusion fluid compresses the lung. These
patients should be considered infectious until pulmonary TB disease is excluded.
Miliary TB
Miliary TB occurs when tubercle bacilli enter the bloodstream and disseminate
to all parts of the body, where they grow and cause disease in multiple sites. It results
in the formation of millet seed-sized (1 to 2 mm) tuberculous foci. Miliary disease has
been classified as both an extrapulmonary and a pulmonary form of TB. This condition
is rare but serious. “Miliary” refers to the radiograph appearance of millet seeds
scattered throughout the lung. It is most common in infants and children younger than
5 years of age, and in severely immunocompromised persons. Miliary TB may be
detected in an individual organ, including the brain; in several organs; or throughout
the whole body. The condition is characterized by a large amount of TB bacilli, although
it may easily be missed, and is fatal if untreated. Up to 25% of patients with miliary TB
may have meningeal involvement.
Central Nervous System
When TB occurs in the tissue surrounding the brain or spinal cord, it is called
tuberculous meningitis. Tuberculous meningitis is often seen at the base of the brain
in imaging studies. Symptoms include headache, decreased level of consciousness,
and neck stiffness. The duration of illness before a diagnosis is variable and relates in
part to the presence or absence of other sites of involvement. In many cases, patients
with meningitis have abnormalities on a chest radiograph consistent with old or current
TB and often have miliary TB.
CLINICAL SIGNS & SYMPTOMS
Clinical signs and symptoms are absent in the early stages of TB. Many cases are
found incidentally when routine chest radiographs are made for other reasons. When
systemic manifestations of active disease initially appear, the clinical signs and
symptoms listed here may appear.
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Fatigue
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Malaise
Anorexia
Weight loss
Low-grade fevers (especially in late afternoon)
Night sweats
Frequent productive cough
Dull chest pain, tightness, or discomfort
Dyspnea
Dyspnea
Hemoptysis
Fever
DIFFERENTIAL DIAGNOSIS
CAUSES
Prolonged
Pulmonary
Eosinophilia
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Parasites
Medications
Radiation effects
Malignancies
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It is a granulomatous disorder
of unknown origin that can
affect multiple body systems.
It affects blacks 10 to 20 times
more often than whites and
women twice as often as men.
It usually occurs in the third or
fourth decade of life.
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Leading cause of morbidity
and mortality among cigarette
smokers
Air pollution
Occupational exposure to
irritating dusts or gases
Hereditary factors
Infection
Allergies
Aging
Harmful drugs and chemicals
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Pulmonary
Sarcoidosis
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Chronic
Obstructive
Pulmonary
Disease (COPD)
MANIFESTATIONS
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Acute respiratory illness
with fever
Night sweats
Weight loss
Dyspnea
It can be confused with
tuberculosis, but these
patients
deteriorate
when
treated
with
antituberculosis drugs.
Shortness of breath
which often gets worse
with activity
Dry cough that will not go
away
Chest pain
Wheezing
Intermittent episodes of
wheezing or cough
With a variable degree of
chronic bronchitis and
emphysema
Excess
phlegm
or
sputum
Shortness of breath
Trouble taking a deep
breath.
ASSESSMENT
A. Physical Examination
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Dullness to chest percussion
Auscultation revealed vocal fremitus sound
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Appearance of the Patient
● Cachexia- is loss of weight, muscle atrophy, fatigue, weakness, and
significant loss of appetite in someone who is not actively trying to lose
weight.
● Pallor- a pale color that can be caused by illness, emotional shock, or
stress, avoiding excessive exposure to sunlight, anemia, or genetics.
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Vitals
● Tachypnea- is characterized by rapid breathing, a sufficient gas-exchange
of the body, for example after exercise, in which case it is not
hyperventilation
● Tachycardia- a form of cardiac arrhythmia which refers to a rapid beating
of the heart.
● Fever- increase in internal body temperature to levels that are above
normal
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Lungs
● Decreased breath sounds- refer to the specific sounds identified through
auscultation of the respiratory system with a stethoscope.
● Rales- are the clicking, rattling, or crackling noises heard on auscultation
of (listening to) the lung with a stethoscope during inhalation.
● Rhonchi- is the "coarse rattling sound somewhat like snoring, usually
caused by secretion in bronchial airways".
● Bronchial breath sounds- are loud, harsh breathing sounds with a midrange pitch.
B. Ancillary Procedures
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Blood tests- Blood tests can confirm or rule out latent or active tuberculosis.
These tests measure your immune system's reaction to TB bacteria. These
tests require only one office visit. A blood test might be useful if you're at high
risk of TB infection but have a negative response to the skin test, or if you've
recently received the BCG vaccine.
Imaging tests- If you've had a positive skin test, your doctor is likely to order a
chest X-ray or a CT scan. This might show white spots in your lungs where
your immune system has walled off TB bacteria, or it might reveal changes in
your lungs caused by active tuberculosis.
Sputum tests- If your chest X-ray shows signs of tuberculosis, your doctor
might take samples of your sputum — the mucus that comes up when you
cough. The samples are tested for TB bacteria. Sputum samples can also be
used to test for drug-resistant strains of TB. This helps your doctor choose the
medications that are most likely to work. Getting results of these tests can take
four to eight weeks.
MEDICAL MANAGEMENT
Surgical Management
Surgery may be indicated to resect lung segments that are chronically involved.
The extent and severity of the disease determines the course of recovery.
Pharmacologic Management
1. Antibiotics
It can be effective in managing the disease well enough to avoid
hospitalization. If detected early, the prognosis is favorable, provided the
patient adheres to the medication schedule and the bacilli do not become
resistant to the medications. The first-line drugs isoniazid (INH), rifampin (RIF),
pyrazinamide (PZA), and ethambutol (EMB) are used together in initial
treatment. There are a several different TB treatment regimens, chosen based
on numerous factors. Dosing of first-line drugs can be done at different
intervals.
● Isoniazid (INH): given orally once/day, has good tissue penetration, and is
highly bactericidal.
● Rifampine (RIF): given orally, is bactericidal, is well-absorbed, penetrates will
into cells and cerebrospinal fluid, and acts rapidly. It also eliminates dorman
organisms in macrophages or causeous lesions that can cause late relapse.
Thus, RIF should be used throughout the course of therapy.
● Pyrazinamide (PZA) is essential first-line drug and may also be used as part
of treatment for multi-drug resistant disease (MDR TB). It is not generally
recommended for the treatment of latent tuberculosis.
● Ethambutol (EMB) a bacteriostatic drug that inhibits cell wall synthesis
preventing multiplying of bacilli.
2. Corticosteroids
These are sometimes used to treat TB when inflammation is a major
cause of morbidity and are indicated for patients with acute respiratory distress
syndrome or closed-spaced infections, such as meningitis and pericarditis.
Corticosteroids that are needed for other indications pose no danger to patients
who have active TB and who are receiving an effective TB regimen.
● Dexamethasone. 2 mg orally or q 6 hrs for adults and children >25kg; children
< 25kg are given 8 mg.
PHYSICAL THERAPY MANAGEMENT
1. Tuberculosis is particularly infectious, thus special precautions should be taken
by the physical therapist to prevent its spread during its infectious stage.
2. Patients are prone to excessive fatigue; treatments should be selected to
promote improved oxygen transport without exceeding the patient’s capacity to
deliver oxygen and without contributing to excessive fatigue.
3. Stimulation of the oxygen transport system with exercise is necessary to avoid
the deconditioning and further compromise of oxygen transport. The patient
therefore warrants being monitored closely.
REFERENCES:
Book:
Goodman, C. C., & Snyder, T. E. K. (2007). Differential Diagnosis for Physical
Therapists: Screening for Referral. W B Saunders Company.
Frownfelter, D. L., Dean, E., & Dean, E. W. (2006). Cardiovascular and
Pulmonary Physical Therapy: Evidence and Practice. Mosby.
Website:
Goldman, R. (2023). Tuberculosis: Risk Factors, Causes, and Prevention. Everyday
Health.
https://www.everydayhealth.com/tuberculosis/guide/risk-factors-causesprevention/
Mangamoori, J. (n.d.). Tuberculosis with a case presentation.
https://www.slideshare.net/MangamooriJagadesh/tuberculosis-with-acase-presentation
Nardell, E. A. (2023). Tuberculosis (TB). MSD Manual Professional Edition.
https://www.msdmanuals.com/professional/infectiousdiseases/mycobacteria/tuberculosis-tb
Transmission and Pathogenesis of Tuberculosis.
https://www.cdc.gov/tb/education/corecurr/pdf/chapter2.pdf
Tuberculosis physical examination - wikidoc. (n.d.).
https://www.wikidoc.org/index.php/Tuberculosis_physical_examination