Tuberculosis (TB) is a contagious disease primarily caused by the bacterium Mycobacterium tuberculosis. This infection typically affects the lungs, but it can also spread to various other parts of the body, leading to a wide range of health issues. While many people may carry the bacteria without showing symptoms, some develop active disease which, if left untreated, can have severe and lasting consequences on overall health.
Impact on the Respiratory System
Tuberculosis most commonly targets the lungs, leading to a condition known as pulmonary TB. The bacteria are inhaled and can settle in the lung tissue, initiating an infection. Common symptoms associated with pulmonary tuberculosis include a persistent cough, which may produce mucus or even blood, chest pain, and shortness of breath. These symptoms often develop gradually, sometimes appearing mild at first and worsening over time.
Within the lungs, the Mycobacterium tuberculosis bacteria trigger an immune response. This response often results in the formation of granulomas, which are collections of immune cells that wall off the bacteria. While these granulomas initially limit the infection, they can also cause tissue damage and inflammation. Over time, these granulomas may break down, leading to the formation of cavities within the lung tissue.
The development of cavities is a characteristic change in advanced pulmonary TB. These hollow spaces can impair the lung’s ability to exchange gases, reducing overall lung function. Scarring, or fibrosis, also occurs as the body attempts to repair damaged lung tissue. This scarring can stiffen the lungs and diminish their capacity, contributing to chronic respiratory problems even after treatment.
Without effective treatment, progressive destruction of lung tissue can severely compromise respiratory function, making breathing difficult. The infection can also lead to complications like pleural effusion, where fluid accumulates around the lungs, compressing them and causing pain.
Impact Beyond the Lungs
While the lungs are the most frequent site of infection, Mycobacterium tuberculosis can spread through the bloodstream and lymphatic system to other organs, causing extrapulmonary TB. This can result in a wide array of symptoms depending on the affected body system.
Nervous System
When TB reaches the nervous system, it can lead to tuberculous meningitis, an inflammation of the membranes surrounding the brain and spinal cord. Symptoms often include persistent headaches, confusion, and a stiff neck. Intracranial tuberculomas, which are masses of tissue, can also form within the brain.
Skeletal System
The skeletal system is also vulnerable to TB, commonly manifesting as bone and joint tuberculosis. Pott’s disease, a form of spinal tuberculosis, affects the vertebrae and can cause back pain, deformities, and paralysis if the spinal cord is compressed. Other joints, such as the hips and knees, can also become infected, leading to pain and reduced mobility.
Lymphatic System
In the lymphatic system, TB can cause lymphadenitis, resulting in swollen lymph nodes, particularly in the neck. These nodes may become tender and can sometimes form abscesses that drain to the skin. This condition is often referred to as scrofula.
Genitourinary System
Tuberculosis can also affect the genitourinary system, involving the kidneys, bladder, and reproductive organs. Renal TB may cause symptoms such as painful urination, blood in the urine, and flank pain. Bladder infection can lead to frequent urination and urgency, while genital involvement can result in menstrual irregularities or scrotal abnormalities.
Gastrointestinal Tract
The gastrointestinal tract can be impacted by tuberculosis, leading to symptoms like abdominal pain, weight loss, and malabsorption. This can result in strictures, obstructions, or fistulas within the digestive tract, impairing nutrient absorption and overall digestive function.
Broader Body Effects and Lasting Implications
Tuberculosis can exert systemic effects, leading to generalized symptoms. Common manifestations include unexplained fever, night sweats, and significant unintentional weight loss. Patients often experience fatigue and a general feeling of malaise. These non-specific symptoms can sometimes delay diagnosis.
Even after successful treatment, tuberculosis can leave lasting consequences. Chronic lung disease is a frequent long-term complication of pulmonary TB due to scarring and damage. This can lead to persistent respiratory symptoms such as shortness of breath and a chronic cough, resembling conditions like chronic obstructive pulmonary disease (COPD). Lung impairment can persist for many years.
Organ damage from extrapulmonary TB can also have lasting implications. Tuberculous meningitis can result in neurological deficits, including cognitive impairment or seizures. Bone and joint TB may leave permanent deformities or chronic pain, limiting mobility. Drug-resistant forms of TB present a serious challenge, requiring longer, more complex, and often more toxic treatment regimens.
The quality of life for TB survivors can be affected by chronic physical impairments, psychological distress, and social stigma. Many individuals experience ongoing fatigue, reduced exercise capacity, and mental health challenges like depression and anxiety.