What Are the Main Causes and Symptoms of Meningitis?
Meninges are the protective sheath or covering over the neurons of the body. The brain and spinal cord have the highest number of neurons, which form our central nervous system. This central nervous system in turn controls our body’s metabolism and response. The primary function of meninges is to act as a protective barrier for neurons. Meningitis is a disease that causes inflammation in the meningeal sheath. Inflammation is a localized physical condition that occurs as the body’s natural immune response, it has five main symptoms which are, redness, swelling, pain, heat, and loss of function. There are various causative agents of the disease which include, bacteria, viruses, and protozoans. Among all these meningitis caused by bacteria the most common has the highest death rates.
Bacterial Meningitis
Bacterial meningitis is the most common type of meningeal disease. It is caused by bacteria named Neisseria meningitidis, it is commonly known as meningococcus. Thus the more common name of bacterial meningitis is meningococcal meningitis. It affects all age groups but is primarily found in children below the age of ten. Before the development of antibiotics for its treatment, it has a death rate of nearly 40-50% and certain parts of Africa are still widely affected by this pandemic, and is known as the meningitis belt. There are various types of serogroups responsible for causing meningococcal meningitis, serogroup A is widely responsible for the meningitis epidemic in Africa. Other serotypes are, B, C, Y, and W-135.
There are also some other bacteria that cause meningitis these include strains of staphylococci, pneumococci, streptococci, and viruses like H. influenzae. H influenzae causes meningitis mostly in infants and has symptoms common to meningococcal meningitis. Sometimes nasal infection or infection in the mid-ear can carry the pathogen to the meninges, where they multiply and cause disease. Blood can also carry various pathogens to the meninges.
Route of Pathogen Entry
Meningitis bacteria usually enter the body through the nasal cavity, it is transmitted via nasal droplets. Sometimes infected blood transfusion also causes this. Blood carries pathogens to the associated organs where they reach the meninges, and pathogens multiply there increasing their population. This leads to inflammation of the region and pus formation. Pus formation usually results in the thickening of the cerebrospinal fluid which can result in a seizure.
Meningitis Symptoms
Meningococcal meningitis includes symptoms are as follows
Fever
Vomiting
Headache
Stiffness in the neck
Anorexia
Irritability
Some less common symptoms include-
Deafness
Seizure
Blindness
Paralysis
Stages of Meningitis
There are three mainstages of meningitis, in the first stage, pathogens multiply in the throat and nasal cavity, in the second stage pathogens enter the bloodstream and they then reach into the cerebrospinal nerves meninges. During the first stage of infection vomiting and severe pain develops, in the second stage fever and hemorrhagic patches appear in severe cases. During the last stage of disease, inflammation in nerve and pus formation in cerebrospinal fluid, which leads to paralysis and seizure.
Meningococcal Vaccine
Meningitis vaccines against specific serogroups of N. meningitidis are available, they are carbohydrate vaccines, developed by purifying complex carbohydrates associated with the bacterial cell membrane. Carbohydrate vaccines are not very impactful among children and infants.
Another class of vaccine known as the conjugate vaccine is used for meningitis, these are polysaccharides conjugated with proteins to provide an effective immune response. The conjugate vaccine has been successfully developed for the serogroup C and tetravalent serogroup specific vaccine (A, C, W-135, and Y)
Vaccine development for serotype B is primarily difficult due to its complex nature of genetic makeup.
Other treatments include the administration of antibiotics such as penicillin in case of meningococcal meningitis. Ampicillin and chloramphenicol are the antibiotics that are administered in case of meningitis caused by H. influenzae. Rifampin is also an antibiotic derivative that is being used to control the spread of meningitis.
Viral Meningitis
Viral meningitis is caused by viruses such as H. influenza, these are the pathogens mainly responsible for causing meningitis in infants. Some other pathogens include the west nile virus, mumps, measles, herpes simplex types I and II, varicella, and lymphocytic choriomeningitis (LCM) virus. The most common family to cause viral meningitis is an enterovirus. Viral meningitis is commonly called aseptic meningitis. They have symptoms common with meningococcal meningitis, which includes fever, headache, and vomiting. It is not a fatal form, it generally occurs to an immunocompromised patient, they are generally treated with the body’s immune system.
Viral meningitis follows three main stages during the infection cycle, they enter generally through the nasal cavity via inhalation of contaminated nasal droplets, pathogens then replicate and move to the bloodstream, which then carries to the brain.
Rifampin is administered to control viral meningitis. Treatment for viral meningitis is supportive, that is rest, hydration, and anti-inflammatory drugs are only administered. Paitents generally recover within 7-10 days.
Difference Between Viral Meningitis and Bacterial Meningitis
FAQs on Meningitis: Key Facts, Stages, and Prevention
1. What exactly is meningitis and which part of the body does it affect?
Meningitis is a serious medical condition characterised by the inflammation of the meninges. The meninges are the three protective membranes that surround and cushion the brain and spinal cord. This inflammation is most often caused by an infection, which can lead to severe complications affecting the central nervous system.
2. What are the different types of meningitis?
Meningitis is primarily classified based on its cause. The main types are:
- Bacterial Meningitis: A severe form caused by bacteria like Neisseria meningitidis and Streptococcus pneumoniae. It is a medical emergency.
- Viral Meningitis: The most common and generally less severe type, caused by viruses such as enteroviruses.
- Fungal Meningitis: A rare type that typically affects individuals with weakened immune systems.
- Parasitic Meningitis: Caused by parasites and is less common.
- Non-Infectious Meningitis: Caused by other medical conditions, injuries, or certain drugs, rather than an infection.
3. What are the most common signs and symptoms of meningitis?
The early symptoms of meningitis can appear suddenly and are often mistaken for the flu. The classic signs include a sudden high fever, a severe headache, and a stiff neck. Other common symptoms are nausea, vomiting, confusion, sensitivity to light (photophobia), and a lack of appetite. In cases of meningococcal meningitis, a distinctive dark purple or red rash that doesn't fade under pressure (the 'glass test') can be a key indicator.
4. How is meningitis diagnosed and treated?
Diagnosing meningitis promptly is crucial. Doctors typically perform a physical exam and may order blood tests. However, the definitive diagnostic test is a lumbar puncture (spinal tap), where a sample of cerebrospinal fluid (CSF) is collected and analysed to identify the specific cause. Treatment varies by type: bacterial meningitis requires immediate hospitalisation and intravenous antibiotics, while viral meningitis is often managed with rest, fluids, and pain relievers as it usually resolves on its own.
5. Is meningitis contagious, and how does it spread?
Yes, the infectious forms of meningitis are contagious. The method of transmission depends on the causative agent. Bacterial meningitis can spread from person to person through respiratory droplets from coughing, sneezing, or close contact like kissing. Viral meningitis often spreads through respiratory secretions or contact with faecal matter from an infected person. It is important to note that you catch the germ, not the disease itself; not everyone exposed to the germs will develop meningitis.
6. How does bacterial meningitis differ from viral meningitis in terms of severity and outcome?
The primary difference lies in their severity. Bacterial meningitis is a medical emergency and can be fatal or cause permanent disabilities, such as hearing loss, brain damage, or learning difficulties, if not treated immediately with antibiotics. In contrast, viral meningitis is generally much less severe and most people recover completely within 7 to 10 days with only supportive care. While uncomfortable, it rarely leads to long-term complications.
7. Why is early diagnosis so critical for a positive outcome in meningitis patients?
Early diagnosis is critical because bacterial meningitis can progress with extreme speed. The bacteria multiply in the cerebrospinal fluid, leading to inflammation and increased pressure on the brain and spinal cord. This can cause irreversible neurological damage or death within hours. Starting antibiotic treatment at the earliest suspicion of bacterial meningitis is the most important factor in preventing severe complications and improving the chances of a full recovery.
8. What are the key preventive measures against meningitis?
Prevention is key to controlling meningitis. The most effective method is vaccination. Several vaccines protect against the most common types of bacterial meningitis, including:
- The Meningococcal vaccine (protects against Neisseria meningitidis)
- The Pneumococcal conjugate vaccine (protects against Streptococcus pneumoniae)
- The Haemophilus influenzae type b (Hib) vaccine
Practising good hygiene, such as frequent handwashing and not sharing personal items like utensils or drinks, also helps reduce the risk of transmission.
