Tuberculous Meningitis Causes And Symptoms

Introduction

Tuberculous Meningitis (TBM) is an infectious disease, that quietly infiltrates our central nervous system and poses a serious health threat. This condition, caused by the Mycobacterium tuberculosis bacterium, leads to inflammation in the protective layers that envelop the brain and spinal cord.¹ Unlike other types of meningitis, TBM creeps in gradually, wearing a mask of vague symptoms that can persist for weeks before it reveals its true colours with more severe effects.² This stealthy approach makes it a challenge to detect the disease in its early stages, often resulting in advanced stages by the time treatment begins.

In this article, we'll embark on a journey to uncover the causes and symptoms of Tuberculous Meningitis, shedding light on a condition that often lurks in the shadows of our health concerns. It's vital for everyone to familiarise themselves with the early indicators of this disease. since TBM doesn't discriminate by age. Diagnosing TBM in its early stages makes it a manageable condition rather than a life-threatening one. 

Transmission of tuberculosis 

To gain a thorough understanding of TBM, it's essential to begin with an understanding of tuberculosis (TB) itself. TB is caused by a bacterium known as Mycobacterium tuberculosis. Although it primarily targets the lungs, it can also travel into other parts of the body.³ The bacterium's transmission is airborne. In simpler terms, when an individual infected with TB coughs or sneezes, they release tiny droplets into the air. Inhaling these minuscule airborne droplets is the most common means by which TB infection is transmitted⁴ from one person to another.

Understanding this primary mode of transmission is a crucial step in comprehending how TB, and consequently TBM, is spread and what preventive measures can be taken to reduce the risk of infection.

Meningitis: what you need to know

Meningitis is inflammation of the protective layers covering the brain and spinal cord (meninges). This condition can be triggered by various factors, including infections, injuries, cancer, and specific medications.⁵

Tuberculous Meningitis (TBM) refers to meningitis which has been caused by tuberculosis infection, a rare form of this condition. TB Meningitis is caused by the bacilli Mycobacterium tuberculosis which has infected the central nervous system.⁵

Understanding the root cause of meningitis is pivotal, as treatment paths vary depending on the initial trigger. So, let's delve deeper into these distinctions, empowering ourselves with knowledge to tackle this condition effectively.

Unravelling the causes of tuberculous meningitis

TBM is a unique form of tuberculosis (TB) that can be traced back to the Mycobacterium tuberculosis bacterium, and it usually takes a specific route to reach the central nervous system.

Here's how it unfolds:

Airborne transmission

TBM originates from the same source as TB, primarily the Mycobacterium tuberculosis bacterium. When an individual infected with TB coughs or sneezes, tiny respiratory droplets containing the bacteria are released into the air. Inhaling these minuscule droplets is the most common way of contracting tuberculosis.⁴

The path of infection

Once these bacteria are inhaled, the bacteria enter the respiratory system organs such as the lungs. From there, the bacteria embark on a journey through the body via the bloodstream or lymphatic system.¹ Their ultimate destination? The central nervous system.

The nervous system

Once the Mycobacterium tuberculosis bacterium reaches the central nervous system, it starts multiplying. This multiplication leads to the formation of small abscesses within the nervous system which are essentially pockets of infection.⁶

The critical breakthrough

When one of these abscesses’ ruptures, the bacteria within it are released, and they flood into the protective layers surrounding the brain known as meninges which leads to the development of Tuberculous Meningitis.⁶ 

What are the risk factors for TBM? 

Tuberculous Meningitis is an extrapulmonary manifestation of tuberculosis and not every case of TB will develop into TBM. Certain risk factors will increase the likelihood and severity of TBM such as:

1. Age: Young children, particularly those aged 2 to 4 years, are at a heightened risk of progressing from a tuberculosis infection to TBM. Their developing immune systems are less effective at combating the disease⁷
2. The impact of HIV: Individuals living with HIV face an elevated risk of developing TBM. This is primarily because the HIV virus can compromise the immune system, which makes them more susceptible to TB and its neurological manifestation⁷
3. The role of nutrition: Poor nutrition can weaken the immune system, making it less capable of defending against TB and preventing its spread to the central nervous system. In particular, deficiencies in nutrients like vitamin D can play a significant role in this vulnerability to developing TBM⁷
4. Close contact: Being in close contact with individuals already infected with TB can increase the risk of contracting TB, which, if not managed, can eventually lead to the development of TBM⁴
5. Immunosuppressive medications: People with autoimmune diseases like Crohn's Disease or rheumatoid arthritis often require immunosuppressive medications which can lead to an increased the risk of TB Meningitis⁷

Symptoms and early signs 

Symptoms develop gradually and vary from person to person; they often start quietly and subtly. Recognising the early signs and symptoms can help in early detection. These are some of the symptoms according to the Meningitis Now Organisation:⁸

1. Initial non-specific symptoms: Onset of TBM is typically gradual, and often goes unnoticed in the initial stages. Within the first two weeks, you might experience non-specific symptoms such as general aches, fatigue, loss of appetite, and a persistent mild fever
2. Specific symptoms: neck stiffness, sensitivity to light, and bouts of vomiting. These are indicative signs of a more serious infection
3. Neurological symptoms: The later stages of TBM can bring forth neurological symptoms. These are clear indicators of nerve damage, often accompanied by a severe headache, seizures, and confusion. In severe cases, these neurological symptoms may escalate and lead to a coma
4. Unique signs in infants and children: Children and infants are more vulnerable and may display different symptoms. Look out for irritability, poor feeding, and a bulging fontanelle, which is the soft spot on their head

Often, by the time the condition becomes unmistakable, it has already progressed significantly, underscoring the urgency of early detection and intervention. If someone is experiencing any of these symptoms, it is critical to seek immediate medical attention.

Diagnosis and treatment of tuberculous meningitis

To diagnose TBM, a lumbar puncture is required. This procedure involves inserting a fine needle into the spinal canal, positioned between two vertebrae, and drawing out a sample of cerebrospinal fluid (CSF) for analysis.¹

Medical professionals might employ imaging studies, such as CT scans and MRIs. These advanced tools help to identify abnormalities within the brain and spinal cord. The images produced provide valuable insights into the extent and location of any potential damage, aiding in the diagnostic process.⁶

Once TBM is diagnosed, the treatment protocol closely mirrors that of other forms of meningitis - an intensive course of three to four antibiotics. These antibiotics are specifically selected to combat the Mycobacterium tuberculosis bacterium responsible for the infection. Additionally, medicines to reduce inflammation of the meninges, the protective layers around the brain and spinal cord, are prescribed.⁶

Preventing tuberculous meningitis

While Tuberculous Meningitis (TBM) doesn't have a specific vaccine to ward it off, there are several measures you can take to minimize the risk of developing tuberculosis (TB) and, consequently, its severe neurological manifestation, TBM.

Boosting your immune system

The first line of defence against TBM and TB, in general, is maintaining a strong immune system. A healthy lifestyle, balanced nutrition, and regular exercise all contribute to a robust immune system. Overall, good health enables your body to defend itself from TB infections more effectively.

For individuals with existing medical conditions that cause a weakener immune systems, adhering to the recommendations provided by their healthcare provider is crucial. These guidelines help to manage these conditions and, in turn, reduce the risk of TB.

The BCG vaccine

The Bacille Calmette-Guérin (BCG) vaccine plays a pivotal role in the fight against TB. The vaccine contains a weakened form of the bacterium responsible for TB. When administered to children, it provides immunity against the disease, particularly its severe forms like TB Meningitis.⁴

In the UK, the BCG vaccination program targets babies, children, and young people who are at higher risk of contracting TB. This vaccine offers a valuable layer of protection and a fortified defence in place against potential TB infections.

Summary

• TBM is a serious infectious disease affecting the central nervous system, caused by the bacterium Mycobacterium tuberculosis
• Unlike other types of meningitis, TBM's symptoms often develop gradually, making early diagnosis challenging
• Understanding the causes of TBM includes knowing the transmission routes of Mycobacterium tuberculosis and how it travels to the central nervous system via the respiratory system
• Recognizing the symptoms of TBM, which can vary from person to person, is vital for early and effective intervention
• Specific causes and risk factors for TBM include: age, existing HIV infection, malnutrition, close contact with TB patients, and immunosuppressive medications
• Preventing TBM starts with maintaining a strong immune system through a healthy lifestyle and proper nutrition
• The Bacille Calmette-Guérin (BCG) vaccine, administered to high-risk individuals, provides immunity against severe forms of TB, including TB Meningitis

Understanding these factors can help individuals and healthcare professionals in the early detection, management, and prevention of TBM and related conditions.