Does hemoptysis mean tuberculosis? What tests are needed?

Author: Shi Huanzhong, Chief Physician, Beijing Chaoyang Hospital, Capital Medical University

Reviewer: Wang Qian, Chief Physician, Third Medical Center, PLA General Hospital

Hemoptysis is one of the five major symptoms of respiratory disease. Although it is not as common as cough, sputum, shortness of breath and chest pain, it is the most serious symptom.

Once hemoptysis occurs, all respiratory doctors will not easily miss the cause of hemoptysis.

1. What are the common causes of hemoptysis?

There are several most common causes of hemoptysis: first, bronchiectasis, also known as bronchiectasis; second, pulmonary tuberculosis; third, lung tumor, also known as lung cancer.

Figure 1 Original copyright image, no permission to reprint

There are many other causes of hemoptysis, but the incidence rate is not very high.

For example, bronchial vascular malformations, arteriovenous aneurysms, and coughing up pink foamy sputum caused by left heart failure are actually caused by hemoptysis.

Some pneumonia patients have mild damage to the bronchial mucosa, and a small amount of bleeding may occur when blood vessels rupture. Hemoptysis may also occur when the upper respiratory tract, such as the nasopharynx or pharynx, is damaged or inflamed.

In short, once the symptoms of hemoptysis occur, it must be taken seriously. Generally, a chest X-ray or even a lung CT scan is required to find the cause of the hemoptysis, so as to avoid missing certain serious diseases and causing serious consequences.

2. What is going on with coughing, sputum, and hemoptysis?

When this symptom occurs, the first thing that comes to mind is pulmonary tuberculosis, because our country has about 1 million new cases of tuberculosis every year, and it is a common and frequently occurring disease.

The symptoms of pulmonary tuberculosis are mainly chronic cough, sputum, and hemoptysis. On this basis, symptoms of tuberculosis poisoning may appear, such as weight loss, fatigue, and night sweats.

If the patient has related symptoms, a chest X-ray or CT scan is generally required. Tuberculosis lesions can be seen in areas where tuberculosis is common, such as flake-like shadows, cavity formation, and cord-like changes.

Typical tuberculosis symptoms, combined with imaging examinations, can make a basic diagnosis, but to truly confirm the diagnosis, acid-fast bacilli must be found in the patient's sputum or the tuberculosis bacilli must be cultured.

There are many types of acid-fast bacilli, the most important of which is tuberculosis. These bacilli can be identified using acid-fast staining under a microscope, and finding acid-fast bacilli almost certainly indicates tuberculosis. If the pathogen cannot be found directly, typical pathological changes found through biopsy can also assist in diagnosis.

Of course, in addition to tuberculosis, diseases such as bronchiectasis and lung cancer can also cause repeated coughing, sputum, and hemoptysis, so pay attention to examination and differentiation.

3. If tuberculosis is suspected, what tests should be done?

Generally, when there are no clues, a chest X-ray can be taken first to find the basic lesions. If the chest X-ray is normal, there is no need to do a CT scan. After all, the price of a chest X-ray is relatively cheap, almost all patients can accept it, and the radiation dose is relatively small.

If a lesion is found on a chest X-ray, a CT scan is still routinely performed. CT can detect relatively subtle lesions in the lungs. As an imaging examination, CT has become the most basic means of diagnosing pulmonary tuberculosis. However, it is not enough to directly confirm the diagnosis. Even if CT highly suspects tuberculosis, the pathogen must still be found.

Acid-fast staining can be performed on sputum samples, alveolar lavage fluid collected during bronchoscopy, or even bronchial lining tissue obtained by biopsy to look for the presence of acid-fast bacilli. At the same time, the same specimen is retained for tuberculosis culture. If tuberculosis bacilli can be successfully cultured, it is the traditional method for diagnosing tuberculosis.

Of course, not every patient's sputum smear test is positive and the pathogen can be found; a negative sputum smear does not mean that there are no Mycobacterium tuberculosis, it may just not be found.

Figure 2 Original copyright image, no permission to reprint

At this time, we have some modern methods, such as some biological indicators and some molecular biology. The better indicator now is T-Spot. Tuberculosis experts and respiratory experts believe that this test is still relatively reliable. In the case of negative pathogens, if the T-Spot result is positive, tuberculosis should also be highly suspected.

There is also another test called PPD skin test, which is extracted from tuberculosis bacterial protein. The results of the PPD skin test are usually available in 48-72 hours. If a rash appears on the skin and is larger than 20 mm, it is called a strong positive. Blisters are also a strong positive, which highly indicates that tuberculosis is active in the body. Therefore, these tests can also help us determine whether the patient has tuberculosis.

For tuberculosis, the country now has a standard anti-tuberculosis treatment plan, but all anti-tuberculosis drugs have side effects, especially rifampicin and some more traditional anti-tuberculosis drugs. The main toxicity is liver damage and kidney damage. This is why doctors must give anti-tuberculosis drugs only after a clear diagnosis.

However, in some cases, if the pathogen cannot be found and the patient's lesions are very typical, the patient will be given anti-tuberculosis drugs, which is called experimental anti-tuberculosis treatment. After a period of anti-tuberculosis treatment, such as one month, two months, or three months, the follow-up examination will show that the lesions have been significantly absorbed compared to before, which in turn can support the clinical diagnosis of tuberculosis.