Introduction

Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, remains one of the most potent public health challenges worldwide. According to a recent report by the World Health Organization, approximately 10.6 million people suffered from tuberculosis in 2022, with about 1.3 million deaths. This annual data from the WHO underscores the significant burden of this disease and the urgent need for action.¹

Neonatal tuberculosis, on the other hand, is a relatively rare form of tuberculosis that is challenging to diagnose and often misunderstood. Although extensive research has been conducted in the past and continues to be ongoing to address perinatal or neonatal tuberculosis, mitigation remains difficult due to the nature of the condition. Therefore, understanding the transmission dynamics of the condition is crucial.^2,3

Understanding neonatal tuberculosis

Tuberculosis (TB) is a serious illness caused by bacteria called Mycobacterium tuberculosis. These bacteria can spread through the air when someone with TB coughs, talks, or sings, putting others nearby at risk of getting infected. While adults with TB can easily spread the bacteria, children are less likely to do so because the types of TB they usually get are less contagious.

Signs and symptoms

TB can make people really sick, but not everyone who gets infected becomes ill. Signs and symptoms of TB disease in children include coughing, feeling tired or weak, losing weight, having a fever, or sweating a lot at night. The most common type of TB affects the lungs, but it can also affect other parts of the body. When TB spreads beyond the lungs, it can cause different symptoms depending on where it goes.^3,4

Babies, young children, and kids with weak immune systems, like those with HIV, are at the highest risk of getting very sick from TB. They might develop severe forms of TB like TB meningitis, which affects the brain, or disseminated TB disease, where the bacteria spreads throughout the body. TB is a serious disease that needs to be diagnosed and treated early to prevent it from getting worse.⁴

Epidemiology

According to the World Health Organisation every year, around 217,000 pregnant women contract tuberculosis. If these women don't get diagnosed and treated for TB while they're pregnant, their babies are at a high risk of having health problems when they're born and getting sick with TB later on.¹

Modes of transmission

Vertical transmission from mother to child

Vertical transmission is nothing but passing something from mother to baby. Here in this case a mother might transmit the disease from her to the fetus. 

When a mother is infected with tuberculosis during pregnancy, there always remains a risk of passing it on from her to the baby she is carrying. Tuberculosis in the mother might have different kinds of representation, such as tuberculous pleuritis, meningitis, genital tract infection, or disseminated disease. However, in some cases, tuberculosis might not be diagnosed in the mother until after the baby is born.^5,6

In the mother's womb, the baby is surrounded by a protective environment that is generally considered to help in the defense of the baby, but tuberculosis bacteria can still find their way to reach the baby. If the infection spreads through the mother's bloodstream, the bacteria can reach the baby through the umbilical vein. Once inside the baby's body, the bacteria can spread widely, potentially causing harm. Additionally, if the placenta becomes infected, the bacteria can be transmitted to the fetus through the blood or through the baby's ingestion or aspiration of infected amniotic fluid.^5,6

In cases of hematogenous congenital tuberculosis, the bacteria generally establish a primary focus, with often involvement of nearby lymph nodes. This primary focus in the fetus might remain dormant until after birth when changes in the circulatory system in the baby's body trigger its activation. Symptoms of congenital tuberculosis can manifest at birth or within the first few weeks of life, presenting as respiratory distress, fever, enlarged liver and spleen, poor feeding, lethargy or irritability, swollen lymph nodes, abdominal distension, ear drainage, or skin lesions. These symptoms can vary depending on the location and size of the bacterial lesions.^3,5,6

Clinically, congenital tuberculosis in infants can mimic other congenital infections or conditions like septicemia. Diagnosis can be challenging, especially since symptoms may not respond to typical antibiotic treatments. Suspicion of congenital tuberculosis should be heightened if the mother has a history of tuberculosis or is at risk for the infection.^5,6

Postnatal transmission

In a comfortable setting like a home where a child is growing up, the presence of tuberculosis (TB) in a family member or caregiver can endanger the child's health. When the infected person coughs, sneezes, or talks, tiny droplets carrying TB bacteria hover in the air, seeking someone to infect. If the child breathes in these bacteria, they can lodge in their lungs or other body parts, leading to illness.³

Even simple interactions, like being held or cuddled by the infected person, can transfer TB bacteria from their skin or clothes to the child's mouth or eyes. It's like passing on a secret handshake, but this time, it's the bacteria finding a way into the child's body. Touching objects or surfaces around the house can also spread TB bacteria. If the child touches these contaminated surfaces and then their face, the bacteria can sneak into their body like a stealthy intruder.³

In homes with poor ventilation or crowded living conditions, the risk of TB transmission rises. Imagine a room filled with people chatting, laughing, and sharing the air. If one person has TB, the bacteria can easily spread to others, including children, like passing around a bag of snacks at a party, but instead of snacks, it's TB bacteria being shared.³

Outside the home, children may encounter individuals infected with TB. If the infected person coughs or sneezes, the child can unknowingly inhale the TB bacteria, like an unexpected ambush.³

In settings like schools or daycare centres, where children spend much time together, the risk of TB transmission increases. Imagine a bustling classroom filled with kids chatting and playing. If one child has TB, they can easily spread the bacteria to classmates through close contact, like a chain reaction, with one infection leading to another.³

Even in healthcare settings, where children seek medical attention, there's a risk of TB transmission if they come into contact with infected individuals. Whether during a routine doctor's visit or a hospital stay, without proper infection control measures, TB bacteria can spread.³

Diagnosis

Diagnosing tuberculosis (TB) in children can be a real challenge sometimes. Firstly, the symptoms of TB in children can be non-specific, with normal symptoms like cough, fever, and fatigue making it hard to distinguish from other common childhood illnesses like a regular cold or flu.⁷

Getting samples for testing can be really difficult as children are least expected to collaborate with a professional. This is really significant, especially for young children who may not be able to produce enough sputum for analysis or the child has hysterical behaviour. This can delay diagnosis and treatment, allowing the disease to progress further.⁷

To overcome these challenges, healthcare providers use a variety of diagnostic tests. The tuberculin skin test involves injecting a small amount of TB protein under the skin and checking for a reaction, indicating exposure to TB bacteria. Interferon assays, on the other hand, measure the immune response to TB bacteria in a blood sample, providing more accurate results than the skin test but can be a really cost-sensitive method.⁷

Chest X-rays are also used to look for signs of TB infection in the lungs, such as abnormal shadows or lesions. If the child is more than a certain age limit, tests like polymerase chain reaction (PCR) can be employed, which can detect TB DNA in sputum or other bodily fluids, providing a rapid and accurate diagnosis, especially in cases where traditional methods fail to provide a timely solution.⁷

Prevention and treatment

Preventing and treating neonatal TB is crucial for the health and well-being of newborns. To prevent transmission, it's important for pregnant women to get screened for TB and receive treatment if necessary. Additionally, maintaining good hygiene practices, such as covering the mouth and nose when coughing or sneezing, can help reduce the risk of spreading TB to newborns.^1,7

For treatment, newborns diagnosed with TB often receive a combination of antibiotics for several months under the guidance of healthcare professionals. It's essential for caregivers to follow the treatment plan diligently to ensure the infection is fully treated and to prevent the development of drug-resistant TB. Regular monitoring and follow-up appointments with healthcare providers are also essential to track progress and ensure the baby's health. Furthermore, the World Health Organization suggests BCG vaccination, which can provide comprehensive immunity from TB. The BCG vaccine is given as per the universal vaccination program in several nations and is optional in most others.^1,7

Summary 

In conclusion, tuberculosis remains a significant global health challenge, with neonatal tuberculosis posing rare yet unique complexities in diagnosis and management. From the challenges in identifying symptoms to the modes of transmission and diagnostic challenges, addressing this issue requires a focused approach. Through early detection, effective treatment, and preventive measures, we can safeguard the health and well-being of newborns and reduce the spread of this highly potent infectious disease.