pneumococcal meningitis

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Pneumococcal meningitis is a serious bacterial infection that affects the meninges, the protective membranes surrounding the brain and spinal cord. This type of meningitis is caused by the bacterium *Streptococcus pneumoniae*, also known as pneumococcus.

Causes and transmission:

Pneumococcal meningitis occurs when *Streptococcus pneumoniae* bacteria enter the bloodstream and travel to the central nervous system (CNS). The bacteria can be transmitted through respiratory droplets, such as when an infected person coughs or sneezes. Close contact with an infected individual or touching contaminated surfaces can also spread the bacteria.

Symptoms:

Symptoms of pneumococcal meningitis can develop suddenly and may include:

1. High fever
2. Severe headache
3. Stiff neck
4. Nausea and vomiting
5. Sensitivity to light (photophobia)
6. Confusion or altered mental state
7. Seizures
8. Sleepiness or difficulty waking up

In infants, signs may include:

1. Irritability
2. Poor feeding or vomiting
3. High-pitched crying
4. Bulging fontanelle (soft spot on the head)
5. Stiffness in the body and neck

Diagnosis and treatment:

Early diagnosis and prompt treatment are crucial to improve the chances of recovery and reduce the risk of complications. Pneumococcal meningitis is typically diagnosed through a lumbar puncture (spinal tap) to obtain a sample of cerebrospinal fluid (CSF) for laboratory analysis.
Treatment for pneumococcal meningitis usually involves:

1. Intravenous antibiotics to target the *Streptococcus pneumoniae* bacteria
2. Corticosteroids to reduce inflammation in the CNS
3. Supportive care, such as fluids, pain relief, and fever control
4. Monitoring and managing potential complications, including seizures and increased intracranial pressure

Prevention:

Pneumococcal meningitis can be prevented through vaccination. The pneumococcal conjugate vaccine (PCV) and the pneumococcal polysaccharide vaccine (PPV) are available to protect against various strains of *Streptococcus pneumoniae*. These vaccines are recommended for specific age groups and individuals at increased risk for pneumococcal disease, including young children, adults over 65, and people with certain medical conditions.

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Topic Highlights:-

1. Meninges are the protective membranes enclosing the brain and spinal cord.
2. Meningitis is the inflammation of the meninges.
3. This visual presentation describes the structure and function of meninges, the inflammatory disease meningitis, its causes, symptoms, diagnosis, and treatment, mainly vaccination.

Transcript:-
The meninges are a part of the central nervous system. Meninges are very fine membranes that provide a covering to the brain and the spinal cord. Meninges consist of three layers. The outermost layer is the dura mater. It is a tough and durable membrane that lines the skull and bones of vertebral canal that holds the spinal cord within. The dura mater surrounds and supports the dural sinuses carrying blood from the brain toward the heart. The arachnoid mater, the second layer is a thin transparent membrane that appears like a loosely fitting sac attached to the dura mater. It provides a cushioning effect for the brain and the spinal cord.

The pia mater is a very delicate membrane that firmly adheres to the brain and the spinal cord and follows all the folds and contours of the brain. The larger blood vessels found in the dura mater branch into tiny capillaries in the pia mater and nourish the brain and spinal cord. Together, the arachnoid and pia mater are known as leptomeninges.

The space between the arachnoid mater and the pia mater is filled with a fluid called the cerebrospinal fluid or the CSF. The CSF cushions the brain and spinal cord and prevents it from impact during head and neck injuries. The primary function of the meninges and the cerebrospinal fluid is to protect the central nervous system which consists of the brain and the spinal cord.

Meningitis is the inflammation of the meninges. Meningitis is generally caused by microorganisms such as bacteria or viruses that spread into the CSF through the blood. Viruses are the most common cause of meningitis, but bacterial meningitis can be much more severe. Meningitis can also be caused by non-infectious causes such as drugs or tumors.

Bacterial meningitis usually occurs secondary to other bacterial infections in the body. The bacteria present at another infection site enter the blood and travel to the meninges where they cause infection. The bacteria may gain entry into the meninges directly, in the case of a skull fracture or via a sinus or ear infection. There are several bacteria that can cause meningitis. Some of them are Pneumococcus or Streptococcus pneumoniae, Haemophilus influenzae or Neisseria meningitidis.

Pneumococcus is the most common bacterium that causes meningitis in infants, young children and elderly adults. Haemophilus influenzae type B used to be the leading cause of meningitis in developed countries and is currently the main cause of meningitis in developing countries. Neisseria meningitidis is the leading bacterial cause of meningitis in young adults and tends to occur in clusters in villages and towns and as epidemics in larger territories. Listeria monocytogenes is a lesser-known cause of bacterial meningitis and it mainly affects pregnant women, newborn babies and seniors.

Pneumococcus is a fragile bacterium with a protective capsule. It is usually seen in pairs. From the primary site of infection, pneumococcus may gain entry into the bloodstream. Through the blood they overcome the immune system to reach the brain and the spinal cord. They are likely to survive due to limited defenses here. They disrupt and disintegrate the cells resulting in meningeal inflammation. The infection may lead to cerebral edema and intracranial hypertension leading to a decrease in cerebral blood flow. Eventually, if this uncontrolled process is not effectively treated, it may result in permanent neuronal injury.

Heavy smokers, people with impaired respiratory drainage, those with recent respiratory viral infection or toxic damage to the respiratory cilia are most susceptible for primary infection. Meningitis occurs in people of all age groups, but infants, very young children and the elderly individuals are more predisposed to the infection. These infections are more common in the winter months.

The symptoms of meningitis generally take one or two days to develop and can be mistaken for flu. High fever, severe headache, vomiting, nausea, stiff neck, sensitivity to light, excessive sleepiness, difficulty in concentrating, seizures, confusion, lack of appetite, ice cold hands and feet, leg pain and pale skin tone are some of the symptoms of meningitis.

In newborn babies these symptoms of meningitis may not be recognizable. Sometimes, the soft patches on the infant’s head may bulge. The infant may cry continuously and may become more irritable when picked up or consoled. The other signs are excessive sleepiness and poor feeding.

Meningitis is diagnosed on the basis of a medical history, a physical exam and diagnostic tests. During the physical exam, the doctor may look for signs of infection in the ear, sinuses, throat, and skin along the spinal cord. Throat culture is a test in which a cotton swab is used to scrape the walls of the throat. This sample is sent to a laboratory to identify the causative bacteria. CT scans or X-rays of the chest, skull or sinuses can reveal the presence of inflammation or swelling in these areas.

The diagnosis of meningitis can be confirmed by performing a Lumbar Puncture or a Spinal Tap Test. In this procedure, a fine needle is inserted into the space between the bones of the spine and a sample of the cerebrospinal fluid is drawn out for analysis. The analysis can reveal the type of bacteria causing meningitis and indicate low glucose levels and high white blood cell count and increased proteins in the fluid.

Taking precautions to minimize pneumococcal infection can help prevent the spread of meningitis. The bacteria are transmitted from one person to another through prolonged contact as the bacteria cannot live long outside the body. The most important method of preventing the spread of infection is to wash hands frequently and thoroughly after using the toilet or after having sneezed or coughed or after blowing the nose. Children should be taught the correct method of hand washing too. When sick, avoid kissing others, using utensils that others might use or sharing toothbrushes or cigarettes. Advise adults not to kiss infants on the mouth in order to prevent spread of infection. If pregnant, insure that meat is thoroughly cooked and avoid eating cheeses made from non-pasteurized milk.

Early treatment of pneumonia and ear infections caused by the pneumococcus may decrease the risk of meningitis. However, the most effective way to prevent meningitis is vaccination. All effective vaccines are made using purified polysaccharide derived from the protective capsule of the bacterium, and do not contain any whole bacteria. Pneumococcal conjugate vaccine is a special vaccine that was invented for use in infants and toddlers. Here the polysaccharide is conjugated with the carrier protein which enhances immunity. The vaccine’s protection lasts at least 3 years. Since most serious pneumococcal infections happen during the first 2 years of life, the vaccine protects children when they are at greatest risk. Pneumococcal infections can be hard to treat since the bacteria can become resistant to some medications. This makes preventing the disease even more important.

Another vaccine, the pneumococcal polysaccharide vaccine, is for older children and adults. These vaccines can boost immunity against various strains of pneumococcus that cause meningitis. The vaccine contains inactivated bacteria so that the immune system can recognize and fight active bacteria.

If bacterial meningitis is suspected, the patient will be prescribed a course of broad-spectrum antibiotics. Broad-spectrum antibiotics are powerful antibiotics that can kill a large variety of bacteria. Once the laboratory test results are obtained, and the doctor is able to identify the bacterium pneumococcus, the treatment can be changed to a narrower spectrum antibiotic that works particularly well against it. Pneumococcal meningitis is a serious disease and is treated with intravenous antibiotics such as ceftriaxone, which kill bacteria by interfering with its ability to form cell walls. Ceftriaxone is generally used for severe infections.

Intravenous corticosteroids are usually given early in the course of treatment to control brain pressure and swelling, and reduce the body’s production of inflammatory substances that can cause further damage.

Pain medications and sedatives may be used to reduce pain and fever. In addition, anticonvulsants may be prescribed to prevent seizures. In cases where lots of fluid has accumulated in the meninges a surgical procedure may be performed to drain out this fluid.

Other important treatment measures are taken depending on the condition of the patient. Treatment will usually be given for 10-14 days. Severe cases will need careful monitoring in an intensive care unit and may need artificial ventilation to provide breathing support.

Meningitis is a serious disease and its complications can be severe or even fatal. If treatment for bacterial meningitis is delayed, the patient is likely to suffer from complications like deafness, blindness, loss of ability to speak, learning disabilities, behavioral problems, paralysis of various muscles, mental retardation and even permanent brain damage. Other complications include kidney failure and adrenal gland failure.

If the bacteria find their way into the blood stream, they can result in a life threatening condition called septicemia. Septicemia requires emergency medical treatment. Some of these complications are mild and will slowly improve after several weeks or months. Many people however are left permanently disabled.