Difference Between Sarcoidosis and Tuberculosis

The key difference between sarcoidosis and tuberculosis is that sarcoidosis is a non-infectious immune-mediated disease with non-caseating granuloma formation, whereas tuberculosis is an infectious disease caused by Mycobacterium tuberculosis accompanied by caseation necrosis.

Sarcoidosis and tuberculosis are two distinct medical conditions that affect the lungs and can have similar symptoms.

CONTENTS

1. Overview and Key Difference
2. What is Sarcoidosis 
3. What is Tuberculosis
4. Sarcoidosis vs Tuberculosis in Tabular Form
5. Summary – Sarcoidosis vs Tuberculosis

What is Sarcoidosis?

Sarcoidosis is an immune-mediated disease. It is characterized by granuloma formation in various tissues. Granuloma secretes various chemicals such as 25(OH)2vitamin D3, which causes increased calcium levels in the blood. Patients will get a variety of clinical manifestations, such as lymph node enlargement, lung fibrosis, arthritis, skin manifestation, etc. Sometimes, nervous system involvement can also occur, which is called neuro-sarcoidosis. This is a long-standing progressive illness with multisystem involvement.

Diagnosis is based on the symptoms and signs supported by elevated angiotensin-converting enzyme (ACE) levels and calcium levels in the blood. A CT scan will show features such as lymphadenopathy and lung involvement. If detected early can be controlled effectively with steroids that can control the overactive immune response. Alternatively, drugs that are most commonly used to treat cancer and suppress the immune system, such as methotrexate, azathioprine, and leflunomide, may be used.

What is Tuberculosis?

Tuberculosis is caused by a mycobacterium called Mycobacterium tuberculosis. Tuberculosis has two forms pulmonary and extrapulmonary. Pulmonary tuberculosis is characterized by cavitation of the lungs and destruction of lung parenchyma. Tuberculosis is common among immunocompromised people such as drug addicts and diabetic patients.  Typical symptoms are a chronic cough, hemoptysis or passing blood with sputum, evening pyrexia, night sweats, loss of appetite and significant loss of weight. Any system can get involved in tuberculosis, and examples are TB meningitis, TB arthritis, etc.

Diagnosis is by the microbiological confirmation of the TB bacilli in affected tissues. Different methods are used to diagnose TB, including acid-fast stain, culture, and polymerase chain reaction. X-ray and CT scans may be helpful in the diagnosis. Treatment is by anti-tuberculous therapy that includes isoniazid, rifampicin, pyrazinamide, and ethambutol.

There are different treatment regimens, and long-standing compliance is essential during the treatment period. TB can be effectively treated with currently available medicines. There are other different medicines available to treat resistant TB. BCG vaccine is used for the prevention of disseminated tuberculosis in children. It is given at birth to all children as an intradermal injection. The Mantoux test is used to detect previous exposure to tuberculosis. It will be positive even with BCG vaccination. However, the Mantoux test will be strongly positive in a TB patient, and it’s an important supportive investigation.

What is the Difference Between Sarcoidosis and Tuberculosis?

The key difference between sarcoidosis and tuberculosis is that tuberculosis is caused by Mycobacterium tuberculosis, and it’s an infectious disease, whereas sarcoidosis is an immune-medicated disease where no infective agent is involved. Moreover, tuberculosis causes caseating granulomas, while sarcoidosis causes non-caseating granulomas. In addition, chronic cough and hemoptysis are prominent in pulmonary tuberculosis due to cavitation of the lungs, while difficulty in breathing is prominent in pulmonary sarcoidosis due to lung fibrosis and infiltrations.

The following table summarizes the difference between sarcoidosis and tuberculosis.