Meningitis

Description

• Meningitis, or spinal meningitis, is an inflammation of the meninges, the membranes surrounding the brain and spinal cord.
• Meningitis can be caused by either bacterial or viral infection.
• Bacterial meningitis is an uncommon but life-threatening condition; viral meningitis, although more common, is generally less serious.
• Anyone can contract meningitis, but those most at risk are children under five, teenagers and young adults, older people and people with certain chronic illnesses.
• The classic symptoms of meningitis are fever, headache and neck stiffness.
• Prompt diagnosis and treatment of bacterial meningitis and the associated condition of meningococcal septicaemia are vital for a good outcome and recovery.

What is meningitis?

Meningitis is an inflammation of the meninges, the membranes surrounding the brain and spinal cord. It can be caused by either bacterial or viral infection.

Bacterial meningitis is a life-threatening condition that requires immediate medical treatment. Viral meningitis is more common than the bacterial form, but generally less serious.

Meningococcal septicaemia is a type of blood poisoning associated with meningitis, and is a very serious condition.

What causes meningitis?

Bacterial meningitis

Bacterial meningitis is caused when blood from an infected area in another part of the body carries bacteria to the brain and spinal cord. Bacteria can also reach the brain when you have an ear or sinus infection, or after a skull fracture in which the meninges are torn or damaged.

The most important causes of bacterial meningitis are meningococcal meningitis (caused by the bacterium Neisseria meningitides), pneumococcal meningitis, (caused by the bacterium Streptococcus pneumoniae) and Haemophilus influenza type b (Hib) meningitis, but there are many other types.

The bacteria which cause meningococcal and pneumococcal meningitis are very common and live naturally in the back of the nose or throat. They can be spread by prolonged close contact and by coughing, sneezing and intimate kissing. The bacteria survive for only a short period of time outside the body, so they do not live long in the air and are not carried on household objects. They also cannot be picked up from water supplies, swimming pools or food processing plants.

Most people have natural resistance to the bacteria. Only rarely do the bacteria overcome the body’s immune defences and pass through the lining of the nose and throat into the bloodstream from where they may cause meningitis or septicaemia. People can carry the bacteria for long periods without becoming ill, and being a carrier actually helps boost natural immunity. At any one time, about 10 to 25 per cent of the population are carriers.

Meningococcal Septicaemia

Some bacteria that cause meningitis can also cause septicaemia. This is particularly true of the meningococcal form.

Septicaemia occurs when bacteria enter the bloodstream and release toxins, which break down the walls of the blood vessels.

In some cases, the bacteria multiply in the blood and cause septicaemia before the bacteria infect the meninges. In other cases, infection in the blood and the meninges develops simultaneously, resulting in both meningitis and septicaemia. In a few cases, the body seems able to prevent the bacteria multiplying in the blood but not in the meninges, so only meningitis develops.

Viral meningitis

Viral meningitis can be caused by many different viruses, the commonest being Coxsackie and echoviruses (often known as enteroviruses). Coxsackie viruses can be found in the intestines, and therefore in faeces and sewage-polluted water. Meningitis can also develop as a result of infection with herpes simplex, influenza, measles, polio or chickenpox. Meningitis used to be a complication of mumps, but has virtually been eliminated following the introduction of the MMR (Measles, Mumps and Rubella) vaccine.

Who gets meningitis and who is at risk?

Anyone can contract meningitis, but those most at risk are children under five, teenagers and young adults (the 14-25 age group), older people (over 55), and people with certain chronic illnesses, such as chronic heart, lung, kidney or liver disease; diabetes; coeliac syndrome; deficient immune systems due to disease or treatment, such as cancer, organ transplantation, or HIV; nephrotic syndrome; thalassemia; a non-functioning spleen; and sickle cell disease.

Bacterial meningitis affects more men than women.

Viral meningitis and some forms of bacterial meningitis are contagious, although none of the bacteria that cause meningitis are as contagious as flu, for example, and are not spread by casual contact.

The risk of getting the dangerous forms of bacterial meningitis and septicaemia is very small. However, sometimes the bacteria can spread to other people who have had close or prolonged contact with a person with meningitis.

People in the same household, or anyone with direct contact with a patient's oral secretions (such as a partner) would be considered at increased risk of acquiring the infection.

Symptoms and signs of meningitis

The following symptoms of meningitis (and septicaemia) may occur in adults and older children over the age of two years

Common symptoms

• High fever and chills
• Severe headache
• Stiff neck (unable to touch chin to chest)

These symptoms can develop over several hours, or they may take one to two days. Meningitis can resemble a bad case of the flu.

Other symptoms may include

• Nausea
• Vomiting
• Diarrhoea
• Discomfort looking into bright lights
• Drowsiness
• Pain in arms, legs and abdomen
• Confusion or disorientation, delirium (delusions or hallucinations)
• Reddish-purple, patchy rash which turns white if pressure is applied to the area

In newborns and infants

• Fever with cool hands and feet
• Feeding poorly or refusing feeds
• Vomiting
• High-pitched moaning cry
• Dislike of being handled, irritable
• Neck retraction with arching of back
• Blank staring expression
• Difficult to wake, lethargic, slow reactions
• Pale blotchy complexion
• Rash

Not everyone gets all of the above symptoms, and the classic symptoms of fever, headache, and neck stiffness may be absent or difficult to detect in infants, children and the elderly. As the disease progresses, patients of any age may have seizures, and coma may occur in severe cases.

The rash is usually a late symptom, and indicates septicaemia. It starts as tiny red or brownish blood spots, which look like pin-pricks, and develops into purple bruises or blood blisters. This rash is caused by bleeding under the skin, as a result of breakdown of the blood vessel walls.

How is meningitis diagnosed?

The doctor will review your symptoms and medical history, and examine you. Knowing whether meningitis is viral or bacterial is important because the severity of illness and treatment differ. To determine this, a sample of spinal fluid is taken by performing a spinal tap or lumbar puncture, in which a needle is inserted into the spinal canal in the lower back to withdraw a small amount of spinal fluid. This procedure is very safe. If bacterial meningitis is diagnosed, identification of the type of causative bacteria is important for selection of correct antibiotics.

Other tests may also be done, including

• Blood tests
• CT scan or MRI scan of the brain
• X-rays of skull, sinuses or chest

How is meningitis treated?

Urgent treatment is essential for bacterial meningitis and septicaemia. If your doctor suspects you have bacterial meningitis, he or she will hospitalise you for treatment with antibiotics, and other supportive care. You will probably receive antibiotics intravenously for at least seven to 10 days (or longer for children). These are effective, but need to be started early in the course of the disease. The sooner you are diagnosed and treated, the greater your chances of full recovery. Appropriate antibiotic treatment of most common types of bacterial meningitis should reduce the risk of death to below 15%, although risk is higher among the elderly.

Antibiotics are not helpful in cases of viral meningitis, and treatment is based on appropriate nursing care. If you have a severe case of viral meningitis, you will be admitted to hospital for tests to determine which form is making you ill, but most cases can be treated at home.

During recovery, follow the treatment plan prescribed by your doctor, drink plenty of fluids, eat nutritious foods, and get sufficient rest in a quiet, dimly lit room. Ask your doctor which pain reliever for headache and discomfort is best for you. Acetaminophen or ibuprofen for headache and body ache is often prescribed. (Anyone under age 21 who has a possible viral infection should not take aspirin because of the risk of Reye's syndrome.)

What is the outcome of meningitis?

If bacterial meningitis is treated immediately, chances of recovery are good. The majority of people who contract bacterial meningitis and develop meningococcal septicaemia make a full recovery. However, in some cases, and even with appropriate treatment, after-effects, disability and death can occur. Bacterial meningitis is fatal in one in 10 cases and one in seven survivors is left with a serious disability, such as deafness or brain injury. Fatality rates for septicaemia are even higher - about 20 per cent.

The exact number of people who experience after-effects or disabilities is not known: it is thought to be about one person in every eight who survives the disease. Not everyone suffers after-effects, and those that do often find they improve with time. Many after-effects will resolve by six to twelve months after your illness.

Physical disabilities and after-effects of meningitis may include

• Hearing impairment or deafness, which may be temporary. A hearing test should be conducted within six weeks after the date of infection.
• Changes in eyesight or loss of eyesight, which may not necessarily be permanent.
• Brain damage
• Residual headaches
• Joint stiffness
• Loss of balance or lack of co-ordination
• Seizures
• Tissue damage. (In the case of severe septicaemia, skin grafts may be needed)
• Amputation of digits (fingers or toes) or limbs due to septicaemia which can cause blood clots in the small blood vessels supplying these parts of the body
• Arthritis
• Weakness, paralysis or muscle spasms

Emotional/behavioural after-effects

• Temper tantrums or excessive dependency in small children
• Fatigue
• Moodiness or aggression
• Depression
• Memory difficulties or lack of concentration
• Learning difficulties
• Changes in character or behavioural problems (in extreme cases)

It can take months to recover from bacterial meningitis or septicaemia. Many people find they have times when they feel good, and other times when they feel very bad and fear they are becoming ill again. This up-and-down pattern is normal, and with time, the "bad days" become fewer.

Your doctor should also be able to advise you as to whether any additional treatments such as physiotherapy or occupational or speech therapy would be helpful.

Recovery from viral meningitis is usually complete, but headaches, tiredness and depression may persist for days, weeks or even months. Since different viruses can cause the illness, the length of time it takes to recover can vary. You should notice a gradual improvement.

Can meningitis be prevented?

There are vaccines that provide excellent protection against some forms of meningitis, but all strains of the disease cannot yet be prevented.

Meningococcus has three main strains - A, B and C. There is a vaccine against the A and C strains, effective in about 80% of cases. There is no vaccine against meningococcus group B, which is still the most common group causing meningitis and meningococcal septicaemia. If someone becomes ill with A or C strain, their close contacts should be offered the vaccine. It is not very effective in young children and protection for adults only lasts for three years.

A safe and highly effective vaccine against Haemophilus influenza type b meningitis has become part of the immunisation programme in many countries including South Africa, and has dramatically reduced the number of Hib meningitis cases in many parts of the world.

The existing vaccine against pneumococcal infection is only partially effective and does not work in children under two years of age. However, this vaccine is recommended for people at high risk of pneumococcal infection and aged two years or older. Those at high risk include persons over 65 years of age and younger persons with certain chronic medical problems. (See Who gets meningitis and who is at risk?).

If you have been exposed to meningococcal meningitis, (for example if you are a family member or close contact of someone with the disease) the doctor will give you antibiotics to help prevent you from getting the disease. The antibiotics used in South Africa are usually co-trimoxazole or rifampicin.

If you do have a contagious form of meningitis, your doctor will let you know when you are no longer contagious and can return to normal activities. Until then, you can help prevent spreading the disease by

• Washing your hands frequently and making sure anyone who has contact with your child does the same.
• Not letting family members share cups or utensils.
• Avoiding contact with saliva, such as by kissing.

Awareness of the signs and symptoms of meningitis and meningococcal septicaemia, and being prepared to take immediate action is very important in preventing the serious complications of these diseases.

When to call the doctor

Early diagnosis and treatment of meningitis is vital. Bacterial meningitis and septicaemia are emergency conditions, which can kill in hours if not treated. If any symptoms that suggest meningitis or meningococcal septicaemia occur, you should see a doctor immediately. Do not wait for the rash to appear - it may be the last symptom to appear, and in cases of meningitis without septicaemia may not occur at all.

- Reviewed by Dr Andrew Rose-Innes, Neurology Division, The Oregon Clinic, Portland Oregon.