Meningitis

Welcome to this video tutorial looking at an overview of meningitis. Meningitis is an inflammation of the meninges (the layers of tissue that cover the brain and spinal cord) and of the subarachnoid space (the fluid-filled space between the meninges).

Meningitis has several different causes, the most common being bacterial and viral infections. Other causes include fungi, parasites, and sometimes non-infectious causes like cancer, lupus, drugs, brain surgery or head injury. The different types of meningitis may cause different symptoms and different types of treatment are needed. However, all types of meningitis cause a painful, stiff neck, headache, and fever. It becomes difficult or impossible for the patient to lower the chin to the chest due to pain and stiffness. These symptoms are more difficult to identify or may be absent in infants, the elderly, or people taking immunosuppressants.

Common Types

Bacterial meningitis is a bacterial infection of the meninges and subarachnoid space that can appear suddenly and progress very quickly. It is a medical emergency and can cause death in just a few hours. Bacterial meningitis can be caused by bacteria spreading through the bloodstream from an infection in another part of the body, a penetrating head wound, an infection in or around the head (such as sinusitis, otitis, or mastoiditis), damaged skin (such as skin infections, abscesses, pressure ulcers, or large burns), an infected shunt, or a neurosurgical procedure. In addition to painful stiff neck, headache, and fever; symptoms also seen in bacterial meningitis include altered mental status (such as irritability or lethargy), sensitivity to light, nausea/vomiting, chills, tachycardia, heart murmurs, purple areas of skin that resemble bruises, and Kernig’s sign, where the patient is unable to extend the leg when lying flat.

Diagnosis is confirmed with a lumbar puncture; however, treatment is started as soon as possible, even before the diagnosis is confirmed. Antibiotics are usually effective if given promptly, and dexamethasone (a corticosteroid) is used to reduce swelling in the brain. Patients that have a weakened immune system are at a higher risk of developing bacterial meningitis. Babies and elderly are also at an increased risk, as well as people gathered in large groups, such as college campuses. How the bacteria is spread depends on the type of bacteria – some types are airborne and spread by coughing or sneezing, by sharing respiratory or throat secretions (such as saliva from coughing or kissing), and some are spread by eating contaminated food. When the immune system is weakened and cannot effectively attack the bacteria that has invaded the meninges and subarachnoid space, the result is inflammation (meningitis), which can also cause complications such as blood clots, cerebral edema, intracranial pressure, excess CSF in the brain, inflammation of cranial nerves resulting in deafness, vision problems, and other nerve problems. Septic shock and DIC are systemic complications that can be fatal. Most patients with meningitis recover well if treated early; however, if treatment is delayed, permanent nerve or brain damage or death is more likely. Some patients that have had bacterial meningitis may have lifelong problems, such as mental impairment, paralysis, vision and/or hearing impairment. Vaccination can help prevent some types of bacterial meningitis – pneumococcal vaccine, meningococcal vaccine, and haemophilus influenzae type b (Hib) vaccine. Patients with bacterial meningitis should be kept on droplet isolation for the first 24 hours of therapy to help prevent it from spreading.

Viral meningitis is the most common type of meningitis and is usually less severe than acute bacterial meningitis. Common causes of viral meningitis include non-polio enteroviruses (which reside in the digestive tract and are very contagious), herpes simplex type 2, varicella-zoster, HIV, and various viruses spread by mosquitoes (such as West Nile virus). Other viruses that can cause meningitis include measles, mumps, influenza, and lymphocytic choriomeningitis. These viruses are spread in various ways, depending on the virus, some more common in certain seasons. Close contact with a person with viral meningitis may cause the virus to spread, but only a small number of people actually develop viral meningitis.

Symptoms usually begin with those of a viral infection, such as fever, respiratory symptoms or muscle aches. Symptoms of meningitis then follow, including headache and a painful, stiff neck. Common symptoms to watch for in babies also include irritability, poor eating, or lethargy. Diagnosis is based on analysis of CSF from a lumbar puncture. Culture samples may also be taken from other areas, such as a throat swab, nasal secretions, blood, or stool; to help identify the virus. Usually if patients appear to be seriously ill, they are treated for acute bacterial meningitis until diagnosis is confirmed. Treatment for viral meningitis is primarily supportive as it takes its course and usually resolves within a week or two, or occasionally a few months. If the infection is caused by HIV, then antiretroviral drugs are given; if herpes simplex or herpes zoster is detected, then acyclovir can be given. Patients with normal immune systems usually recover without complications. Infants and patients with weakened immune systems tend to have more severe illness from viral meningitis. Some vaccines that protect against measles, mumps, chickenpox, and influenza can help prevent those viruses that can lead to viral meningitis. However, there are no vaccines to protect against non-polio enteroviruses, which are the most common cause of viral meningitis. Prevention of viral meningitis is best accomplished by preventing the spread of viruses, such as good hand hygiene, avoid sharing drinks, eating utensils, or kissing people who are sick, covering coughs and sneezes, staying home when sick, etc.

We’ve talked about the two most common types of meningitis – bacterial and viral. Now we’ll look briefly at the not so common types. Fungal meningitis is caused by a fungus spreading through the blood to the spinal cord; it is not spread from person to person. Those with a weakened immune system are at increased risk, with the most common cause being Cryptococcus. Cryptococcus and other fungi, such as Histoplasma, are mainly transmitted via soil contaminated with bird droppings or decaying organic matter. When the soil is disturbed, the fungal spores can be inhaled, and spread from the lungs to the spinal cord. There is one type of fungus, Candida, which is usually acquired in a hospital setting. Signs and symptoms include headache, stiff neck, fever, nausea/vomiting, light sensitivity, and altered mental status. Lumbar puncture will confirm diagnosis, and treatment involves long courses of high dose antifungal medications.

Rare Types

Another type of rare meningitis is parasitic meningitis. These parasites are not spread from one person to another, but rather by a person ingesting something that has the infectious form or stage of the parasite, such as eating contaminated produce, raw or undercooked freshwater fish, frogs, or poultry, or perhaps when a child puts dirt in their mouth that has been contaminated with raccoon feces. Signs and symptoms as well as diagnosis are the same as with meningitis caused by other infections. Treatment is based on the symptoms. A very rare form of parasitic meningitis is primary amebic meningoencephalitis (PAM) that causes a brain infection that is usually fatal. PAM is caused by a microscopic amoeba that enters the body through the nose when swimming in warm freshwater that contains Naegleria fowleri. This amoeba travels from the nose to the brain where it destroys the brain tissue. It cannot be spread from one person to another. Almost all infections are fatal, even when treated.

Meningitis is occasionally caused by noninfectious conditions, such as cancers, lupus, head injury, brain surgery, or certain drugs or vaccines. This type of meningitis is not spread from person to person, but rather by disorders that cause inflammation in the body, such as autoimmune disorders. Symptoms are similar to those seen with all types of meningitis – stiff neck, headache, and fever. Diagnosis is based on CSF from lumbar puncture, and treatment involves treating the cause and the symptoms.

Review Questions

Now let’s look at some questions for review:
The nurse is assessing a patient diagnosed with bacterial meningitis. Which of the following signs would support the diagnosis of bacterial meningitis?

1. Numbness around the lips and peripheral paralysis
2. Irritability and positive Kernig’s sign
3. Fast breathing and shortness of breath
4. Nystagmus and positive Babinski’s sign

Here’s another question

For the patient diagnosed with bacterial meningitis, which type of precautions should the nurse implement?

1. Standard precautions
2. Contact precautions
3. Airborne precautions
4. Droplet precautions

And one more

Viruses that can cause viral meningitis include which of the following:

1. HIV and varicella zoster
2. Influenza and herpes simplex type 2
3. Measles and mumps
4. All of the above

Thank you for watching and happy studying!