Meningitis – Inflammation of the Meninges

Overview

Our brain has sheet-like protective coverings called meningesInflammation (swelling), due to some reason, in these protective membranes is termed meningitis. The incidence of meningitis around the world varies according to age group, region, and immunity of the people. According to World Health Organization (WHO), around 1.2 million people contract meningitis across the globe. Any age group can be affected by this disease, however, neonates (newly born) and old or immunocompromised (who have weak immunity) are more susceptible. 

In Australia, the incidence of invasive meningococcal disease is low. In 2018 there were 1.1 cases per 100,000 people nationally. 

In the following article, we will highlight the types, presentation, causes, and some common treatments for meningitis. 

Signs and Symptoms

The signs and symptoms of meningitis vary according to the age group. It presents differently in neonates i.e., age 0-2 and above age 2. 

Newborns

  • High fever
  • Excessive sleepiness or irritability 
  • Sluggishness or lethargy 
  • Constant crying 
  • Vomiting 
  • Difficult to comfort even when held or fondled 
  • Poor feeding 

Older than 2

  • Sudden high fever 
  • Neck stiffness 
  • Persistent severe headache
  • Flu-like symptom in the early period of the disease
  • Confusion or concentration deficit 
  • Seizures or unconsciousness 
  • Lack of appetite 
  • Skin rash (meningococcal meningitis) 

Causes and Risk Factors

Causes

Meningitis can be caused by various pathogens (bacteria, viruses, etc.). The most notorious pathogens belong to bacteria, and, rarely, they can be caused by viruses, fungi, and some parasites. According to the causative agents, meningitis can be divided into different types that will be covered in detail in the following paragraphs.

Bacterial Meningitis

It is often the most serious form of meningitis and you might need medical aid right away. Several types of bacteria causing bacterial meningitis are:

 – Streptococcus pneumonia (most common)

 – Neisseria meningitidis or meningococcus 

 – Haemophilus influenza (type b)

– Listeria monocytogenes (especially in neonates, pregnant women, and older folks)

Picture of acute pneumococcal meningitis. Image by Yale Rosen

Viral Meningitis

Viral meningitis is considered more common but less severe than the bacterial form. It is also known as aseptic meningitis i.e., not involving bacteria. It usually heals on its own. Some causative viruses are:
– Enteroviruses (most common in summer months)
– HIV (Human immunodeficiency virus)
– Herpes simplex virus (especially HSV-1)
– Mumps virus 

Chronic Meningitis

This term refers to meningitis growing slowly over 2 weeks or more. It is mostly caused by slow-growing organisms e.g., mycobacterium tuberculosis and some fungi. Signs and symptoms are similar to the acute form.

Fungal Meningitis

This is a much less common form of meningitis in developed countries. Immunocompromised people (people with weak immune systems e.g., AIDS or CGD). 

Parasitic Meningitis

This is also a rare form. You can get this disease by eating undercooked foods e.g., fish and poultry. Parasitic meningitis usually affects animals. 

Other Causes of Meningitis

Other causes include non-infectious chemical reactions, drug allergies, or some types of cancers. 

Risk Factors

Risk factors for meningitis include:

  • Age – neonates, and children under age 10. People over 60 years. 
  • Immunity – immunocompetent (healthy) people rarely get this, while people with weaker immune systems are susceptible to this disease
  • Skipping vaccination – vaccinations are available for several forms of meningitis causing agents. Skipping doses can make you vulnerable to meningitis
  • Living in a congested community setting – people living in close spaces i.e., dormitories in colleges
  • Pregnancy – certain pathogens i.e., listeria can infect pregnant women

Diagnosis

Your health care provider can diagnose meningitis according to the history of complaints you have, your physical exam, and some diagnostic test (lab tests). The following test can be done to confirm a meningitis diagnosis:

  • Spinal tap – spinal tap is a procedure in which a sample of your cerebrospinal fluid (CSF) is taken from your spinal cord. The CSF is then used for the definitive diagnosis of meningitis and the type of meningitis. 
    In bacterial meningitis, your CSF has less glucose than normal, increased protein and WBC levels. In the case of viral meningitis, glucose levels are normal and protein levels are found to be lower than normal. 
    Also, a sample of the CSF can be cultured on different media (used for pathogen growth in labs) to identify the type of bacteria or virus that has caused your meningitis. 
  • Radiological imaging – CT scan (computerised tomographic scan) is an advanced type of X-ray used to assess the swelling or inflammation caused by meningitis. 
  • Blood Cultures – your doctor may take your blood samples to see if microorganisms grow in them. In the presence of certain bacteria, your blood will show a positive culture of that bacteria or virus. In routine cases, bacterial growths are seen because viruses grow much slower and need a very strict environment to grow in. 

If the pathologist confirms the presence of some microorganism in your CSF or blood, your healthcare provider will confirm the diagnosis and start your treatment immediately.

Illustration of the spinal tap procedure performed to collect a biological sample of cerebrospinal fluid (CSF) from the spinal cord. Image by Medical gallery of Blausen Medical 2014

Treatment

Meningitis is treated differently based on the microorganism that caused it. 

  • Bacterial Meningitis – acute bacterial meningitis can be very severe and should be treated immediately. Intravenous antibiotics and even corticosteroids are used sometimes for effective treatment. Ceftriaxone and Vancomycin are drugs of choice for most types of bacterial meningitis. 
  • Viral meningitis – most of the cases of viral meningitis heal on their own. You might need to:
     – take bed rest 
    – drink plenty of fluids 
    – symptomatic medications like over-the-counter pain killers and antipyretic (fever-reducing) medication can be used

For the treatment of meningitis caused by the Herpes simplex virus, antivirals like Valacyclovir or Acyclovir can be prescribed by your doctor.

Prevention

The common routes of spreading of these microorganisms are:

  • Coughing 
  • Sneezing 
  • Kissing 
  • Inhaling droplets containing bacteria or viruses 
  • Sharing utensils
  • Touching infected surfaces

You can prevent getting affected by meningitis by implementing the following in your lifestyle:

  • Wash or sanitize your hands regularly – as we all know, careful hand-washing eliminates most of the dangerous, disease-causing microorganisms
  • Practice good hygiene – do not eat or share meals with people who are sick i.e., having flu or cough. Do not eat at places where there are hygiene issues. 
  • Maintain your immune system – the stronger your immune system is, the better it is at repelling diseases. You can increase the strength of your immune system by eating healthy whole foods, sleeping on time, and exercise regularly.
  • Cook your food well – heating your food to a temperature over 75 C is enough to kill meningitis-causing organisms especially Listeria. Pregnant women should always cook their food (especially deli meats and milk) well to avoid listeriosis (meningitis caused by Listeria monocytogenes).

Vaccinations

You can prevent meningitis by getting vaccinated against some meningitis-causing bacteria. The readily available vaccines are: 

 – Haemophilus influenza type b (Hib) vaccine – given to children starting about the age of 2 months

 – Pneumococcal conjugate vaccine (PCV13) – should be given to children under 2 years of age along with additional doses in the following years. This prevents you from getting pneumococcal meningitis 

 – Pneumococcal polysaccharide vaccine (PPSV23) – for people older than 65

Meningococcal conjugate vaccine – for children of age 12-13 with a booster shot in the following years

In case of the above-explained symptoms contact your doctor immediately and get yourself checked. 

References
  1. Meningitis and encephalitis fact sheet. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Meningitis-and-Encephalitis-Fact-Sheet. Accessed Sept. 3, 2020.
  2.  Bacterial meningitis. Centers for Disease Control and Prevention. https://www.cdc.gov/meningitis/bacterial.html. Accessed Sept. 3, 2020.
  3.  Bartt R. Acute bacterial and viral meningitis. Continuum Lifelong Learning in Neurology. 2012; doi: 10.1212/01.CON.0000423846.40147.4f.
  4.  Viral meningitis. Centers for Disease Control and Prevention. https://www.cdc.gov/meningitis/viral.html. Accessed Sept. 3, 2020.
  5.  Fungal meningitis. Centers for Disease Control and Prevention. https://www.cdc.gov/meningitis/fungal.html. Accessed Sept. 3, 2020.
  6.  Derber CJ, et al. Head and neck emergencies: Bacterial meningitis, encephalitis, brain abscess, upper airway obstruction, and jugular septic thrombophlebitis. Medical Clinics of North America. 2012; doi: 10.1016/j.mcna.2012.08.002.
  7.  Longo DL, et al., eds. Acute meningitis. In: Harrison’s Principals of Internal Medicine. 20th ed. McGraw Hill; 2018. https://accessmedicine.mhmedical.com. Accessed Sept. 3, 2020.
  8.  Acute bacterial meningitis. Merck Manual Professional Version. https://www.merckmanuals.com/professional/neurologic-disorders/meningitis/acute-bacterial-meningitis. Accessed Sept. 3, 2020.
  9.  Prevention — Listeriosis. Centers for Disease Control and Prevention. https://www.cdc.gov/listeria/prevention.html. Accessed Sept. 3, 2020.
  10.  Subacute and chronic meningitis. Merck Manual Professional Version. https://www.merckmanuals.com/professional/neurologic-disorders/meningitis/subacute-and-chronic-meningitis. Accessed Sept. 3, 2020.
  11. Van de Beek D, et al. Advances in treatment of bacterial meningitis. The Lancet. 2012; doi: 10.1016/S0140-6736(12)61186-6.
  12.  Recommended immunization schedules for children and adolescents aged 18 years or younger, United States, 2020. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html. Accessed Sept. 3, 2020.
  13.  Recommended adult immunization schedule for adults aged 19 or older, United States, 2020. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/schedules/hcp/imz/adult.html. Accessed Sept. 3, 2020.
  14.  Meningococcal vaccination: What everyone should know. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/vpd/mening/public/index.html. Accessed Sept. 4, 2020.
  15.  Sexton D. Approach to the patient with chronic meningitis. https://www.uptodate.com/contents/search. Accessed Sept. 4, 2020.
  16.  Tunkel A. Aseptic meningitis in adults. https://www.uptodate.com/contents/search. Accessed Sept. 4, 2020.
  17.  Di Pentima C. Viral meningitis: Management, prognosis, and prevention in children. https://www.uptodate.com/contents/search. Accessed Sept. 4, 2020.
  18.  Parasitic meningitis. Centers for Disease Control and Prevention. https://www.cdc.gov/meningitis/parasitic.html. Accessed Sept. 4, 2020.
  19.  Rabinstein AA (expert opinion). Mayo Clinic. Sept. 4, 2020.
  20.  Summary of WHO position papers — Recommendations for routine immunization. World Health Organization. https://www.who.int/immunization/policy/immunization_tables/en/. Accessed Sept. 4, 2020.
  21.  Summary of WHO position papers — Recommendations for routine immunizations for children. World Health Organization. https://www.who.int/immunization/policy/immunization_tables/en/. Accessed Sept. 4, 2020.
  22.  https://www1.health.gov.au/internet/main/publishing.nsf/Content/ohp-meningococcal-W.htm
  23. https://www.mayoclinic.org/diseases-conditions/meningitis/diagnosis-treatment/drc-20350514
  24. https://www.webmd.com/children/understanding-meningitis-basics#3-9

The content shared in the Health Literacy Hub website is provided for informational purposes only and it is not intended to replace advice, diagnosis, or treatment offered by qualified medical professionals in your State or Country. Readers are encouraged to confirm the information provided with other sources, and to seek the advice of a qualified medical practitioner with any question they may have regarding their health. The Health Literacy Hub is not liable for any direct or indirect consequence arising from the application of the material provided.

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