Tuberculosis: Symptoms, Stages, and When to Seek Medical Attention

Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis, with symptoms that may vary depending on the site of infection and the immune status of the patient. Pulmonary tuberculosis is the most common form, but the bacteria can also affect other organs such as the lymphatic system, meninges, or bones. Early symptoms may be mild and easily overlooked, but if not treated promptly, the condition can worsen and lead to serious complications.

The manifestation of symptoms is closely related to the extent of infection and the body's immune response. Some patients may present with non-specific symptoms in the early stages of infection, while those who remain untreated for a long time may gradually develop significant respiratory abnormalities. Understanding the characteristic symptoms of tuberculosis aids in early diagnosis, and timely medical intervention is key to controlling disease transmission and preventing complications.

Early Symptoms and Signs

The early symptoms of tuberculosis are usually mild and non-specific, often mistaken for a common cold or excessive fatigue. Patients may begin to exhibit the following signs weeks to months after infection:

• Mild fever: Especially a slight increase in temperature in the evening or at night, usually not exceeding 38°C
• Night sweats: Profuse sweating during sleep, leading to severely soaked pajamas and bed linens
• Unexplained weight loss: A weight drop of more than 5% in a short period without intentional dieting
• Persistent fatigue: A generalized sense of weakness that cannot be relieved even with adequate rest

These early symptoms may persist for weeks to months, and some patients may experience a recurrence of symptoms after initial relief. Individuals with weakened immune systems (such as HIV-infected or diabetic patients) may experience a more rapid progression of symptoms.

Common Symptoms

Respiratory Symptoms

The most typical symptom in patients with pulmonary tuberculosis is a persistent dry cough or productive cough, which may initially occur only in the morning and then gradually develop into a continuous cough. Sputum may appear yellow or green, and in severe cases, may contain blood or blood clots, known as hemoptysis. The cough symptoms typically last for more than three weeks, which is distinctly different from the self-limiting cough of a common respiratory infection.

Systemic Symptoms

Tuberculosis can trigger a systemic immune response, with common symptoms including:

• Prolonged low-grade fever: Most pronounced in the evening to early morning hours
• Decreased appetite and rapid weight loss: Due to metabolic abnormalities caused by chronic inflammatory responses
• Muscle and joint pain: Especially back pain may occur in cases of thoracic vertebra infection
• Lymphadenopathy: Painless lumps may be felt in the neck or supraclavicular lymph nodes

These symptoms may be accompanied by mild fever and night sweats, forming a chronic wasting state, which in severe cases may lead to malnutrition and further decline in immune function.

Disease Progression and Symptom Changes

Untreated tuberculosis goes through three stages of symptom changes:

Latent Infection Stage

About 90% of infected individuals show no symptoms during this stage, but active tuberculosis bacteria are present in the body. Patients in this stage are not infectious but require preventive treatment to avoid future disease onset.

Active Tuberculosis Stage

When the immune system fails to suppress the tuberculosis bacteria, symptoms begin to manifest. Pulmonary infection leads to a gradual worsening of the cough, sputum may show blood streaks, and wheezing may be heard during breathing. Patients in this stage are highly infectious, releasing hundreds of tuberculosis bacteria with each cough.

Complication Stage

If left untreated, tuberculosis bacteria may invade other organs, causing severe symptoms:

• Extrapulmonary tuberculosis: Such as meningitis causing headaches and seizures, or bone tuberculosis leading to localized severe pain
• Pneumothorax: Cavitation in the lungs may lead to lung rupture
• Sepsis: An excessive immune response may trigger a systemic inflammatory response

The severity of symptoms is directly proportional to the delay in treatment, and some patients may exhibit metabolic abnormalities such as dry skin and brittle hair due to prolonged malnutrition.

When to Seek Medical Attention

Immediate medical attention should be sought if any of the following symptoms occur:

• A persistent dry cough or hemoptysis lasting more than three weeks
• Unexplained weight loss exceeding 5 kilograms
• Night sweats that completely soak bedding
• Persistent low-grade fever accompanied by lymphadenopathy

High-risk groups (such as those who have been in contact with diagnosed patients, HIV-infected individuals, or immunocompromised patients) should undergo specialized examinations even with mild symptoms. Physicians may recommend diagnostic procedures such as sputum culture, chest X-ray, or gamma-interferon release assays (IGRA).

Early diagnosis can significantly increase the success rate of treatment, while delayed treatment may lead to drug resistance, developing into multidrug-resistant tuberculosis (MDR-TB). If symptoms include difficulty breathing, confusion, or fever exceeding 38.5°C, it should be treated as an emergency and immediate medical attention should be sought.

 

Frequently Asked Questions

If tuberculosis symptoms persist for more than three weeks but test results are negative, should further testing be done?

Yes. Early tuberculosis may present with atypical symptoms such as mild cough or fatigue, and a single test may not provide an immediate diagnosis. If symptoms persist for more than three weeks, it is recommended to undergo multiple sputum cultures, imaging studies, or blood tests, and inform the physician of exposure history to rule out latent infection or testing errors.

Can I reduce the dosage of medication on my own during tuberculosis treatment to lessen side effects?

No, you must not adjust the medication dosage on your own. Tuberculosis treatment must strictly follow a standard regimen of 6-9 months; interrupting treatment can lead to drug resistance, making treatment more difficult. If side effects such as liver discomfort or severe rash occur, you should immediately contact your physician to adjust the treatment plan rather than stopping the medication on your own.

Does receiving the BCG vaccine completely prevent tuberculosis?

The BCG vaccine can reduce the risk of severe forms of tuberculosis (such as tuberculous meningitis), but its protective effect against adult pulmonary tuberculosis is limited. After vaccination, it is still necessary to avoid exposure to sources of infection and to undergo regular health check-ups. The vaccine does not provide lifelong immunity, and high-risk groups (such as healthcare workers) should implement other protective measures.

How can I distinguish between a long-term cough caused by tuberculosis and a common cold or allergies?

A cough due to tuberculosis typically lasts more than three weeks and gradually worsens, possibly accompanied by low fever, night sweats, and weight loss. Colds or allergies are usually associated with runny nose and sneezing, and coughs typically resolve within two weeks. If symptoms persist beyond three weeks or if there is fever, sputum acid-fast staining and chest X-ray examinations should be conducted to confirm the diagnosis.

After completing tuberculosis treatment, is it still possible to have pulmonary sequelae?

Some patients may have mild sequelae due to lung tissue damage, such as mild asthma or pulmonary fibrosis, but most patients can gradually restore function. Regular medication adherence and follow-up during treatment can significantly reduce the risk of sequelae. After recovery, it is advisable to avoid tobacco and air pollution and to undergo regular pulmonary function tests to monitor health status.