pulmonary tuberculosis Pulmonary tuberculosis, also known as "lung consumption," is a respiratory infectious disease caused by infection with Mycobacterium tuberculosis. The lesions mainly occur in the lung tissue, trachea, bronchi, and pleura.

Pulmonary tuberculosis, also known as "pulmonary consumption," is a respiratory infectious disease caused by infection with Mycobacterium tuberculosis. The disease primarily affects the lung tissue, trachea, bronchi, and pleura. In our country, pulmonary tuberculosis is classified as a notifiable infectious disease of Class B.

The basic cause of pulmonary tuberculosis is the infection of the human body with Mycobacterium tuberculosis. Healthy individuals can become infected by inhaling droplets containing Mycobacterium tuberculosis, leading to the development of pulmonary tuberculosis. Whether an infection leads to the disease depends on factors such as the individual's immune system, the quantity and virulence of Mycobacterium tuberculosis, among others.

In general, after being infected with Mycobacterium tuberculosis, most individuals will have their immune systems eliminate the majority of the bacteria. However, a small number of Mycobacterium tuberculosis may remain in the body in a dormant state for an extended period. During this time, the infected person does not display symptoms and is in a state of latent tuberculosis infection.

A small percentage of people (including those susceptible to pulmonary tuberculosis) infected with Mycobacterium tuberculosis may have their immune systems unable to effectively clear or suppress the bacteria, leading to significant bacterial proliferation within the body, causing inflammation and other pathological changes. This can result in clinical symptoms such as coughing, sputum production, blood-tinged sputum, or hemoptysis, and the condition may progress to active pulmonary tuberculosis.

Pulmonary tuberculosis generally has contagious characteristics (except for tuberculous pleurisy), with pulmonary tuberculosis patients (those who are sputum smear-positive) being the main source of transmission within the population.

It is important to note that individuals infected with Mycobacterium tuberculosis do not necessarily transmit the infection to others. Those with latent tuberculosis infection generally do not have contagiousness; however, when their immune function is compromised, it may progress to active pulmonary tuberculosis, becoming contagious.

Patients with active pulmonary tuberculosis typically have strong contagiousness. After receiving appropriate drug treatment for at least two weeks, the majority of patients become non-infectious.

Known risk factors associated with pulmonary tuberculosis include:

Age: Elderly individuals and infants have an increased risk of pulmonary tuberculosis.

Weakened immune system: Individuals with conditions such as HIV infection, undergoing chemotherapy, and diabetes are at higher risk of developing pulmonary tuberculosis.

Close contact with individuals infected with tuberculosis bacteria.

Poor nutritional status.

Living in crowded environments.

Poor hygiene conditions.

Occupation in the medical field: Doctors, nurses, social workers, or healthcare providers are at a higher risk of pulmonary tuberculosis.

Substance abuse and alcoholism.

Travel to geographical areas where untreated pulmonary tuberculosis is common, such as parts of Latin America, Africa, Asia, and some parts of Europe.

Chronic lung diseases.

Smoking.

Use of certain immunosuppressive drugs, such as steroids and infliximab.

Coughing, sputum production for more than two weeks, and blood-tinged sputum or hemoptysis are suspicious symptoms of pulmonary tuberculosis.

Latent tuberculosis infection:

There are no clinical symptoms of pulmonary tuberculosis, and there is no contagiousness. Among the 2.5 billion people globally infected with Mycobacterium tuberculosis, the majority are latent tuberculosis infection carriers. However, individuals with latent tuberculosis infection may develop active pulmonary tuberculosis, with a lifetime risk of developing tuberculosis as high as 15%.

Non-active pulmonary tuberculosis:

Patients may have no obvious symptoms and are only detected during chest imaging examinations.

Active pulmonary tuberculosis:

The onset of pulmonary tuberculosis is often slow. As the disease progresses, patients may experience symptoms such as coughing, sputum production, blood-tinged sputum, or hemoptysis, and some patients may experience recurrent upper respiratory tract infection symptoms.

For lesions occurring in the pleura, symptoms may include irritative cough, chest pain, and difficulty breathing.

For lesions occurring in the trachea and bronchi, patients often have a persistent, irritating cough, and in cases of bronchial lymphatic fistula formation and entry into the bronchi or bronchial stenosis, wheezing or breathing difficulties may occur.

In children with pulmonary tuberculosis, delayed development may be observed. Primary pulmonary tuberculosis in children may lead to symptoms such as wheezing due to enlargement of lymph nodes near the trachea or bronchi, or the formation of lymph node-bronchial fistulas.

Patients with pulmonary tuberculosis may also experience systemic symptoms such as night sweats, fatigue, intermittent or sustained low-grade fever, loss of appetite, weight loss, and in female patients, menstrual irregularities or amenorrhea. A small number of patients may experience a sudden onset of high fever, sometimes accompanied by varying degrees of respiratory distress.

A minority of patients may exhibit tuberculous hypersensitivity syndrome, including:

Nodular erythema

Herpetic conjunctivitis/keratitis, etc.

When combined with extrapulmonary tuberculosis, corresponding symptoms affecting the involved organs may occur, such as:

Deformities and functional impairments in skeletal tuberculosis

Headaches and meningeal irritation in neurological tuberculosis

Intermittent diarrhea and local tenderness in digestive system tuberculosis

Painless hematuria and infertility in genitourinary tuberculosis, etc.

Pulmonary tuberculosis needs to be differentiated from diseases such as pneumonia and lung cancer.

Pneumonia

Mainly differentiates from secondary pulmonary tuberculosis.

Various pneumonias exhibit diverse clinical characteristics due to different pathogens, but typically present with sudden onset, fever, prominent cough, and elevated white blood cell and neutrophil counts. Chest X-rays show relatively light and uniform patchy or nodular shadows, and these shadows significantly resolve after antibiotic treatment within approximately 1-2 weeks.

Chronic obstructive pulmonary disease

Often presents with chronic cough and sputum production, with occasional hemoptysis. More common in winter, with acute exacerbations possibly accompanied by fever. Pulmonary function tests reveal obstructive ventilatory dysfunction. Chest imaging aids in differential diagnosis.

Bronchiectasis

Manifests as chronic, recurrent cough and abundant purulent sputum, often accompanied by recurrent hemoptysis. Mild cases show no abnormalities on chest X-rays or only exhibit thickening of lung markings, while typical cases may show cylindrical changes. CT scans, especially high-resolution CT, can reveal dilated bronchial lumens, aiding in diagnosis.

Lung cancer

Patients often have a long history of smoking and present with an irritating cough, blood-tinged sputum, chest pain, and weight loss. Chest X-rays or CT scans show lung cancer masses typically with lobulated margins, spicules, and notches. Eccentric thick-walled cavities may form after cancer tissue necrosis and liquefaction.

Repeated sputum cytology and tuberculosis bacilli tests, as well as live tissue examination of lesions, are important for differential diagnosis.

Symptomatic treatment

General symptoms of pulmonary tuberculosis usually disappear rapidly under rational chemotherapy and do not require special treatment.

Hemoptysis is a common symptom of pulmonary tuberculosis. For mild hemoptysis, comforting the patient, alleviating tension, and bed rest are the main approaches. Hemostatic agents such as aminocaproic acid, aminomethylbenzoic acid, phenylsulfonamide, and carbachol can be used.

For severe hemoptysis, vasopressin should be used cautiously, and it is contraindicated in patients with hypertension, coronary atherosclerotic heart disease, heart failure, and pregnant women. Bronchial artery embolization can be used for hemoptysis caused by bronchial artery damage.

Corticosteroid therapy

Only used for severe tuberculous toxic symptoms. It must be ensured that effective anti-tuberculosis drug treatment is in place.

The dosage depends on the condition, generally using oral prednisone at 20 mg per day, once daily, for 1-2 weeks, followed by a weekly reduction of 5 mg. The duration of treatment is 4-8 weeks.

As latent tuberculosis infection is non-infectious, there are no special precautions in daily life.

For active pulmonary tuberculosis patients, close contact with others should be avoided. Once they are no longer infectious after treatment, they can resume normal activities.

Pulmonary tuberculosis patients should take medication as prescribed by their doctor and pay attention to the following daily matters:

When coughing or sneezing, patients should avoid close contact with others and cover their mouth and nose.

They should not spit phlegm everywhere and should spit into a covered sputum basin with disinfectant.

If spitting phlegm is inconvenient, it can be spat into a disinfectant wet tissue or a sealed sputum bag.

They should try to avoid crowded public places, and if necessary, wear a mask.