Tuberculosis , MTB or TB (short for tubercles bacillus) is a common and in some cases deadly infectious disease caused by various
strains of mycobacteria, usually Mycobacterium tuberculosis in humans.[1] Tuberculosis usually attacks the lungs but can also affect other
parts of the body. It is spread through the air when people who have active MTB infection cough, sneeze, or spit.[2] Most infections in
humans result in an asymptomatic, latent infection, and about one in ten latent infections eventually progresses to active disease, which, if
left untreated, kills more than 50% of its victims.
The classic symptoms are a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss (the last giving rise to the
formerly prevalent colloquial term "consumption"). Infection of other organs causes a wide range of symptoms. Diagnosis relies on
radiology (commonly chest X-rays), a tuberculin skin test, blood tests, as well as microscopic examination and microbiological culture of
bodily fluids. Treatment is difficult and requires long courses of multiple antibiotics. Contacts are also screened and treated if necessary.
Antibiotic resistance is a growing problem in (extensively) multi-drug-resistant tuberculosis. Prevention relies on screening programs and
vaccination, usually with Bacillus Calmette-Guérin vaccine.
One third of the world's population is thought to be infected with M. tuberculosis,[3][4] and new infections occur at a rate of about one per
second.[5] The proportion of people who become sick with tuberculosis each year is stable or falling worldwide but, because of population
growth, the absolute number of new cases is still increasing.[5] In 2007 there were an estimated 13.7 million chronic active cases, 9.3
million new cases, and 1.8 million deaths, mostly in developing countries.[6] In addition, more people in the developed world contract
tuberculosis because their immune systems are more likely to be compromised due to higher exposure to immunosuppressive drugs,
substance abuse, or AIDS. The distribution of tuberculosis is not uniform across the globe; about 80% of the population in many Asian and
African countries test positive in tuberculin tests, while only 5–10% of the US population test positive.[1]
Signs and symptoms
When the disease becomes active, 75% of the cases are pulmonary TB, that is, TB in the lungs. Symptoms include chest pain, coughing up
blood, and a productive, prolonged cough for more than three weeks. Systemic symptoms include fever, chills, night sweats, appetite loss,
weight loss, pallor, and fatigue.[5] Tuberculosis also has a specific odour attached to it, this has led to trained animals being used to vet
samples as a method of early detection.[9]
In the other 25% of active cases, the infection moves from the lungs, causing other kinds of TB, collectively denoted extrapulmonary
tuberculosis.[10] This occurs more commonly in immunosuppressed persons and young children. Extrapulmonary infection sites include the
pleura in tuberculosis pleurisy, the central nervous system in meningitis, the lymphatic system in scrofula of the neck, the genitourinary
system in urogenital tuberculosis, and bones and joints in Pott's disease of the spine. An especially serious form is disseminated TB, more
commonly known as miliary tuberculosis. Extrapulmonary TB may co-exist with pulmonary TB as well.[11
pathogenesis
About 90% of those infected with Mycobacterium tuberculosis have asymptomatic, latent TB infection (sometimes called LTBI), with only
a 10% lifetime chance that a latent infection will progress to TB disease.[1] However, if untreated, the death rate for these active TB cases is
more than 50%.[45]
TB infection begins when the mycobacteria reach the pulmonary alveoli, where they invade and replicate within the endosomes of alveolar
macrophages.[1][46] The primary site of infection in the lungs is called the Ghon focus, and is generally located in either the upper part of the
lower lobe, or the lower part of the upper lobe.[1] Bacteria are picked up by dendritic cells, which do not allow replication, although these
cells can transport the bacilli to local (mediastinal) lymph nodes. Further spread is through the bloodstream to other tissues and organs
where secondary TB lesions can develop in other parts of the lung (particularly the apex of the upper lobes), peripheral lymph nodes,
kidneys, brain, and bone.[1][47] All parts of the body can be affected by the disease, though it rarely affects the heart, skeletal muscles,
pancreas and thyroid.[48]
Tuberculosis is classified as one of the granulomatous inflammatory conditions. Macrophages, T lymphocytes, B lymphocytes and
fibroblasts are among the cells that aggregate to form a granuloma, with lymphocytes surrounding the infected macrophages. The
granuloma functions not only to prevent dissemination of the mycobacteria, but also provides a local environment for communication of
cells of the immune system. Within the granuloma, T lymphocytes secrete cytokines such as interferon gamma, which activates
macrophages to destroy the bacteria with which they are infected.[49] Cytotoxic T cells can also directly kill infected cells, by secreting
perforin and granulysin.[46]
Importantly, bacteria are not always eliminated within the granuloma, but can become dormant, resulting in a latent infection.[1] Another
feature of the granulomas of human tuberculosis is the development of abnormal cell death, also called necrosis, in the center of tubercles.
To the naked eye this has the texture of soft white cheese and was termed caseous necrosis.[50]
If TB bacteria gain entry to the bloodstream from an area of damaged tissue they spread through the body and set up many foci of
infection, all appearing as tiny white tubercles in the tissues. This severe form of TB disease is most common in infants and the elderly and
is called miliary tuberculosis. Patients with this disseminated TB have a fatality rate near 100% if untreated. However, If treated early, the
fatality rate is reduced to near 10%.[51]
In many patients the infection waxes and wanes. Tissue destruction and necrosis are balanced by healing and fibrosis.[50] Affected tissue is
replaced by scarring and cavities filled with cheese-like white necrotic material. During active disease, some of these cavities are joined to
the air passages bronchi and this material can be coughed up. It contains living bacteria and can therefore pass on infection. Treatment with
appropriate antibiotics kills bacteria and allows healing to take place. Upon cure, affected areas are eventually replaced by scar tissue.[50]
If untreated, infection with Mycobacterium tuberculosis can become lobar pneumonia.[52]
Assessment Diagnosis Planning Intervention Evaluation
Subjective: Ineffective airway Short term goal: 1. Assess At the end of the shift
clearance related to respiratory the client was able to
Difficulty of breathing poor cough effort rate. display patency of
possibly evidence by During my 6 hours 2. Note chest airway as manifested
abnormal breath intervention the client movement use by:
Objective: sounds and dyspnea. will be able to : of accessory
muscles during
Abnormal breathe respiration.
sounds: Wet crackels. 1. Clients
1. Sustain 3. Auscultate respiratory rate
respiratory rate breathe sounds: is within normal
Dyspnea: use of within normal note areas with range : RR: 19
accessory muscle for range: RR: 12- adventitious bpm
respiration: elevated 20 CPM. sounds. 2. Secretions
shoulders. 2. Display 4. Document decreased
decreasing respiratory 3. Clients
amount of secretions: restlessness
Restlessness secretion. character and was alleviated
3. Allay amount of and remain
restlessness. sputum. calm.
5. Maintain the
Vital Signs:
patient on
Long term goal: moderate high
BP: 80/60 hhmg
back rest.
RR: 26CPM 6. Check for
During the clients stay obstructions:
PR:75BPM
at the hospital he will accumulation of
be able to maintain secretion.
patent airway as 7. Take
evidence by: medication as
ordered by the
physician.
1. Normal
respiration as
evidence by
absence of
dyspnea and
adventitious
breathe sounds
(wet crackles)
2. Normal
breathing
pattern: RR: 12-
20 CPM
3. Absence of
bronchial
secretions.
4. Ally
restlessness.
