What Is Bacterial Meningitis?

Bacterial meningitis is an infection that occurs in the meninges, which are the protective membranes that cover the brain and spinal cord. It is caused by various bacteria, such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae.

Bacterial meningitis can cause a severe headache, fever, nausea, vomiting, and a stiff neck. Seizures, confusion, and even death have been reported in extreme cases of the illness. As the disease can advance rapidly and result in serious complications, early diagnosis and treatment are essential for a successful outcome.

The causes, symptoms, and available treatments of bacterial meningitis are all covered in detail in this article. For disease prevention, the importance of early detection and treatment, as well as the accessibility of vaccines, are emphasised.


The dura mater, pia mater, and arachnoid mater are the three membranes that line the vertebral canal and the skull, which surround the brain and spinal cord and are generally known as the meninges. This inflammation of the meninges is known as meningitis.1

Meningitis affects mostly people in low-income to middle-income regions, and it can be caused by bacterial, viral, or fungal infections and, less frequently, by parasites. 

  • Viral meningitis is caused by non-polio enteroviruses (group b coxsackievirus and echovirus). Other viral causes: mumps, Parechovirus, Herpes viruses; including Epstein Barr virus, Herpes simplex virus, and Varicella-zoster virus, measles, and influenza1
  • Fungal meningitis mostly affects people in an immunocompromised state, ranging from people with HIV/AIDS to cancer. Meningitis-causing fungi include Cryptococcus neoformans, Aspergillus, Coccidioides immitis, Candida, and Mucormycosis; which is more common in diabetes mellitus and transplant recipients1

The following are risk factors for meningitis:1,2

  • Age: Children below 5 and adults above 65 are more susceptible to the meningitis infection
  • Close and prolonged contact, which includes sneezing, kissing, coughing, or living in close quarters with an infected person, increases spread of meningitis
  • Incomplete vaccination can cause meningitis in children. Pneumococcus, Haemophilus influenzae type B, Meningococcus, Measles, and Varicella-virus are all vaccine-preventable causes of meningitis
  • The presence of chronic medical conditions, including diabetes, cystic fibrosis, and renal failure
  • People with a compromised immune system or those taking drugs to suppress their immune system, as seen in transplant recipients, congenital immunodeficiencies, or AIDS

Meningitis can also be brought on by an inflammatory response to a particular kind of chemotherapy, bleeding into the meninges, or other chemical agents. Other risk factors include:

  • Exposure to vectors — organisms that transmit diseases from one host to another, such as ticks and mosquitoes
  • Travelling to endemic regions where meningitis occurs frequently
  • Bacterial endocarditis — when bacteria gets into the bloodstream and goes into the heart and causes inflammation in the lining of the heart valves and heart chambers (endocardium)
  • Sickle cell anaemia increases the risk of bacterial meningitis. Research shows that the risk of pneumococcal meningitis was predicted to be 10 times higher in children with sickle cell disease than in normal children. In contrast, the risk of bacterial meningitis was 5 times higher3
  • Alcohol use disorder increases the risk of meningococcal infection, as seen in a case report of adults with community-acquired bacterial meningitis4
  • Ventriculoperitoneal (VP) shunt inserted into the brain to help drain extra cerebrospinal fluid in people with hydrocephalus5
  • The existence of a malignant tumour or cancer. Lung, melanoma, and breast cancer are the most prevalent solid organ tumours resulting in carcinomatous meningitis, with various incidents reported in various studies. Gliomas, ependymomas, and medulloblastomas are parenchymal brain tumours that can result in carcinomatous meningitis6
  • Dural defects are a hole or tear in the dura mater, a thick, protective membrane covering the brain and spinal cord. A dural defect can cause a number of problems, including spinal fluid leakage, which can be a breeding ground for bacteria
  • People who have had a splenectomy, a surgery to remove the spleen due to damage or other issues. The spleen is also a part of the immune system and helps the body fight diseases

Causes of bacterial meningitis

Bacterial meningitis is caused by various types of bacteria, including:

  • Streptococcus pneumoniae
  • Listeria monocytogenes
  • Group B Streptococcus
  • Haemophilus influenzae
  • Neisseria meningitidis

Meningitis may also be seen in the following groups:

  • Patients with recent surgery, central lines, and trauma may have Staphylococcus aureus
  • Immunocompromised hosts who may have Mycobacterium tuberculosis  
  • People who have visited places where Lyme disease is prevalent may have meningitis caused by Borrelia burgdorferi 
  • Treponema pallidum in people with HIV/AIDS and those with numerous sexual partners
  • Newborns infected with Escherichia coli 

Signs and symptoms of bacterial meningitis

Once infected, the incubation phase for the bacteria lasts 4 days on average; however, it can last anywhere between 2 and 10 days. The bacteria can sometimes overcome the body's natural defences, allowing infection to travel through the circulatory system to the brain. The bacteria can be harboured in the throat. At any time, a sizable part of the population (between 5 and 10%) has Neisseria meningitidis in their throat.

Meningitis may cause little to no signs in infants, but in adults, the symptoms of bacterial meningitis can vary depending on the type of bacteria causing the infection. 

Common signs and symptoms include:

  • Fever
  • Headache
  • Reduced oral intake
  • Stiff neck
  • Nausea and vomiting
  • Sensitivity to light
  • Confusion 

According to the World Health Organization, 10% to 20% of survivors of bacterial meningitis may experience hearing loss, brain damage, or a learning disability. Less common but far more serious symptoms, hemorrhagic rash and sudden cardiac arrest, are associated with the more serious form of meningitis, meningococcal septicaemia.

Management and treatment for bacterial meningitis

Bacterial meningitis is a medical emergency requiring immediate treatment with antibiotics once your healthcare provider suspects a meningitis infection. Meningitis can mimic the symptoms of a viral infection, such as influenza, making diagnosing and treating the patient challenging.2  Showing two or more of the symptoms listed above does not automatically mean an ongoing meningitis infection; hence, you must not self-medicate.

Once a proper diagnosis is made, hospitalisation is usually necessary to provide supportive care, such as fluids, pain management, and monitoring of vital signs. Sometimes, a person may need to be placed on a ventilator to help them breathe.

Neurological problems in children with bacterial meningitis might include hydrocephalus, seizure disorder, hearing loss, cognitive impairment, and excess fluid in the brain. Antibiotic treatment must be started immediately for kids with bacterial meningitis to improve their symptoms and lower their risk of neurological damage.7

Measures for disease control can help to reduce the risk of transmission. Additionally transmission is reduced by promptly administering antibiotics to people in close contact with someone with meningococcal meningitis.


How is bacterial meningitis diagnosed?

A combination of a physical exam, blood tests, and a lumbar puncture is used to diagnose bacterial meningitis. A lumbar puncture is a procedure done by inserting a needle into the spinal cord to collect cerebrospinal fluid. The fluid is then tested for bacteria or other signs of infection. Regardless of continual improvements in diagnostic techniques and therapeutic approaches, fatality rates for meningococcal meningitis and pneumococcal meningitis are still as high as 30% and 5%–10%, respectively.

How can I prevent bacterial meningitis?

The most effective way to prevent bacterial meningitis is by getting vaccinated. The Centres for Disease Control and Prevention (CDC) recommend that all people over 11 years old get a meningococcal vaccine. Licensed meningococcal disease vaccinations have been accessible for more than 40 years. Although the availability of vaccines and the coverage of strains have significantly improved over time, there is still no one-size-fits-all vaccine against meningococcal illness. Vaccines are serogroup-specific, and depending on the type administered, the length of the protection they provide can vary.

Who is at risk of bacterial meningitis?

Anyone can contract bacterial meningitis, but some people are more vulnerable than others. These include those with weakened immune systems, people who have recently had an upper respiratory infection, and those who have had close contact with meningitis patients.

When should I see a doctor?

If you experience symptoms of bacterial meningitis, such as fever, headache, stiff neck, nausea and vomiting, sensitivity to light, and confusion, seek medical attention immediately. Bacterial meningitis must be treated immediately to avoid serious complications or death. 


Bacterial meningitis is a serious infection that affects the lining of the brain and spinal cord. Neisseria meningitidis (meningococcus), Streptococcus pneumoniae (pneumococcus), and Haemophilus influenzae type B are among the bacteria that cause it. Symptoms include fever, headache, stiffness in the neck, and a rash. Bacterial meningitis can cause serious side effects like brain damage, deafness, or even death if it is not treated immediately. Some bacterial meningitis vaccines are available, and prompt antibiotic treatment is necessary to avoid serious complications. It is crucial to understand the warning signs and symptoms of bacterial meningitis and seek medical help immediately if you think you might have an infection.


  1. Hersi K, Gonzalez FJ, Kondamudi NP. Meningitis. [Updated 2022 Aug 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459360/ 
  1. Young, Nicholas, and Mark Thomas. “Meningitis in Adults: Diagnosis and Management.” Internal Medicine Journal, vol. 48, no. 11, Nov. 2018, pp. 1294–307. DOI.org (Crossref), Available from:  https://doi.org/10.1111/imj.14102 
  1. Pelkonen, Tuula, et al. “Bacterial Meningitis in Children With Sickle Cell Disease in Angola.” Pediatric Infectious Disease Journal, vol. 41, no. 8, Aug. 2022, pp. e335–38. DOI.org (Crossref). Available from:  https://doi.org/10.1097/INF.0000000000003581 
  1. Ryu, Seo Hee, et al. “A Case of Community-Acquired Acinetobacter Meningitis.” Infection & Chemotherapy, vol. 44, no. 6, 2012, p. 473. DOI.org (Crossref), https://doi.org/10.3947/ic.2012.44.6.473.
  1. Fowler JB, De Jesus O, Mesfin FB. Ventriculoperitoneal Shunt. [Updated 2022 Apr 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459351/ 
  1. Anwar A, Gudlavalleti A, Ramadas P. Carcinomatous Meningitis. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560816/ 
  2. Zainel, Abdulwahed, et al. “Bacterial Meningitis in Children: Neurological Complications, Associated Risk Factors, and Prevention.” Microorganisms, vol. 9, no. 3, Mar. 2021, p. 535. DOI.org (Crossref). Available from: https://doi.org/10.3390/microorganisms9030535
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Chimezirim Ozonyiri

Bachelor of Science - BS, Microbiology, General, Tansian University, Nigeria

Chimezirim has several years of experience in the healthcare, non-profit, and education sectors. She is passionate about health promotion and began her journey into health and lifestyle writing over two years ago.

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