Cerebrospinal meningitis

    Cerebrospinal Meningitis

Cerebrospinal meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space).
The brain and spinal cord are covered by three layers of tissue called meninges .These layers are the dura mater (outermost), arachnoid membrane (middle), and pia mater (innermost). Between the arachnoid membrane and pia mater is the subarachnoid space. This space contains cerebrospinal fluid, which flows through the meninges, fills the spaces within the brain, and helps cushion the brain and spinal cord.
Meningitis is most often caused by infection with microorganisms such as bacteria, viruses, or fungi. However, certain drugs and disorders that are not infections occasionally cause meningitis (called noninfectious meningitis). These disorders include sarcoidosis, Behçet syndrome, brain cancer, and cancers that have spread to the meninges, including leukemia and lymphoma.
Meningitis often appears suddenly (called acute meningitis). Sometimes it develops over a period of several days to a few weeks (called subacute meningitis). If it lasts 4 weeks or longer, it is considered chronic. It can recur after it has seemed to disappear (called recurrent meningitis).
Meningitis can be classified by what causes it (bacteria, viruses, or something else) or by how quickly it develops (acute, subacute, or chronic). But it is usually classified as one of the following:
Acute bacterial meningitis (the most serious type)
Viral meningitis
Noninfectious meningitis
Recurrent meningitis
Chronic meningitis
Aseptic meningitis, often used to refer to viral meningitis, actually refers to meningitis caused by anything other than the bacteria that usually cause acute bacterial meningitis. Thus, aseptic meningitis can include meningitis caused by viruses, disorders that are not infections, drugs, or other organisms (such as the bacteria that cause Lyme disease or syphilis). Inflammation of the MENINGES, usually by either a bacterium (bacterial m.) or a virus (viral m.). When it affects the dura mater it is termed; PACHYMENINGITIS when the arachnoid and pia mater are involved, it is called .LEPTOMENINGITIS .The term meningitis does not refer to a specific disease entity but rather to the pathologic condition of inflammation of the tissues of the meninges. The etiologic agent can be anything that activates an INFLAMMATION RESPONSE, including both pathogenic and nonpathogenic organisms, such as bacteria, viruses, and fungi; chemical toxins such as lead and arsenic; contrast media used in myelography; and metastatic malignant cells. Enteroviruses are the most common causes of aseptic meningitis.

STRUCTURE 0F THE MENINGES

History of the organisms causing meningitis
Meningitis outbreak was first recorded in Geneva in 1805. Gaspard Vieusseux (1746-1814) and Andre Matthey (1778-1842) in Geneva, and Elisa North (1771-1843) in Massachusetts, described epidemic (meningococcal) meningitis. Several other epidemics in Europe and the United States were described shortly afterward.
In Africa the first outbreak was described in 1840. African epidemics became much more common in the 20th century. The first major one was reported in Nigeria and Ghana in 1905–1908. In early reports large number of people died of the disease.
The first evidence that linked bacterial infection as a cause of meningitis was written by Austrian bacteriology Anton Vaykselbaum who described meningococcal bacteria in 1887.
Heinrich Quincke (1842-1922) utilized his new technique of lumbar puncture (1891) to provide an early analysis of cerebrospinal fluid (CSF). William Mestrezat (1883-1929), and H. Houston Merritt (1902-1979) compiled large series of CSF profiles in meningitis.
Organisms causing meningitis were identified in the late 19th century including
 
 Symptoms
Early meningitis symptoms may mimic the flu (influenza). Symptoms may develop over several hours or over a few days.
Possible signs and symptoms in anyone older than the age of 2 include:
Sudden high fever
Stiff neck
Severe headache that seems different than normal
Headache with nausea or vomiting
Confusion or difficulty concentrating
Seizures
Sleepiness or difficulty waking
Sensitivity to light
No appetite or thirst
Skin rash (sometimes, such as in meningococcal meningitis)

Signs in newborns
Newborns and infants may show these signs:
High fever
Constant crying
Excessive sleepiness or irritability
Inactivity or sluggishness
Poor feeding
A bulge in the soft spot on top of a baby's head (fontanel)
Stiffness in a baby's body and neck
Infants with meningitis may be difficult to comfort, and may even cry harder when held.
When to see a doctor
Seek immediate medical care if you or someone in your family has meningitis symptoms, such as:
Fever
Severe, unrelenting headache
Confusion
Vomiting
Stiff neck
Bacterial meningitis is serious, and can be fatal within days without prompt antibiotic treatment. Delayed treatment increases the risk of permanent brain damage or death.
It's also important to talk to your doctor if a family member or someone you work with has meningitis. .You may need to take medications to prevent getting the infection.

Causes of Meningitis
Viral infections are the most common cause of meningitis, followed by bacterial infections and, rarely, fungal infections. Because bacterial infections can be life-threatening, identifying the cause is essential.
Bacterial meningitis
Bacteria that enter the bloodstream and travel to the brain and spinal cord cause acute bacterial meningitis. But it can also occur when bacteria directly invade the meninges. This may be caused by an ear or sinus infection, a skull fracture, or, rarely, after some surgeries.
Several strains of bacteria can cause acute bacterial meningitis, most commonly:
Streptococcus pneumoniae (pneumococcus). This bacterium is the most common cause of bacterial meningitis in infants, young children and adults in the United States. It more commonly causes pneumonia or ear or sinus infections. A vaccine can help prevent this infection.
Neisseria meningitidis (meningococcus). This bacterium is another leading cause of bacterial meningitis. These bacteria commonly cause an upper respiratory infection but can cause meningococcal meningitis when they enter the bloodstream. This is a highly contagious infection that affects mainly teenagers and young adults. It may cause local epidemics in college dormitories, boarding schools and military bases. A vaccine can help prevent infection.
Haemophilus influenzae (haemophilus). Haemophilus influenzae type b (Hib) bacterium was once the leading cause of bacterial meningitis in children. But new Hib vaccines have greatly reduced the number of cases of this type of meningitis.

Viral meningitis
Viral meningitis is usually mild and often clears on its own. Most cases in the United States are caused by a group of viruses known as enteroviruses, which are most common in late summer and early fall. Viruses such as herpes simplex virus, HIV, mumps, West Nile virus and others also can cause viral meningitis.
Chronic meningitis
Slow-growing organisms (such as fungi and Mycobacterium tuberculosis) that invade the membranes and fluid surrounding your brain cause chronic meningitis. Chronic meningitis develops over two weeks or more. The symptoms of chronic meningitis — headaches, fever, vomiting and mental cloudiness — are similar to those of acute meningitis.
Fungal meningitis
Fungal meningitis is relatively uncommon and causes chronic meningitis. It may mimic acute bacterial meningitis. Fungal meningitis isn't contagious from person to person. Cryptococcal meningitis is a common fungal form of the disease that affects people with immune deficiencies, such as AIDS. It's life-threatening if not treated with an antifungal medication.
Other meningitis causes
Meningitis can also result from noninfectious causes, such as chemical reactions, drug allergies, some types of cancer and inflammatory diseases such as sarcoidosis.

Risk factors vaccinations

Skipping . Risk rises for anyone who hasn't completed the recommended childhood or adult vaccination schedule.
Age. Most cases of viral meningitis occur in children younger than age 5. Bacterial meningitis is common in those under age 20.
Living in a community setting. College students living in dormitories, personnel on military bases, and children in boarding schools and child care facilities are at greater risk of meningococcal meningitis. This is probably because the bacterium is spread by the respiratory route, and spreads quickly through large groups
Pregnancy. Pregnancy increases the risk of listeriosis — an infection caused by listeria bacteria, which also may cause meningitis. Listeriosis increases the risk of miscarriage, stillbirth and premature delivery.
Compromised immune system. AIDS, alcoholism, diabetes, use of immunosuppressant drugs and other factors that affect your immune system also make you more susceptible to meningitis. Having your spleen removed also increases your risk, and patients without a spleen should get vaccinated to minimize that risk.

Complications

Meningitis complications can be severe. The longer you or your child has the disease without treatment, the greater the risk of seizures and permanent neurological damage, including:
Hearing loss
Memory difficulty
Learning disabilities
Brain damage
Gait problems
Seizures
Kidney failure
Shock
Death
With prompt treatment, even patients with severe meningitis can have good recovery.

Diagnosis
Blood cultures. Blood samples are placed in a special dish to see if it grows microorganisms, particularly bacteria. A sample may also be placed on a slide and stained (Gram's stain), then studied under a microscope for bacteria.
Imaging. Computerized tomography (CT) or magnetic resonance (MR) scans of the head may show swelling or inflammation. X-rays or CT scans of the chest or sinuses may also show infection in other areas that may be associated with meningitis.
Examination: The doctor performs an early examination to determine if help is needed with breathing or blood pressure. The doctor then checks your blood pressure, pulse, and temperature.
Testing: Once the doctor examines you and learns of your symptoms, further evaluation depends on the doctor's assessment of the likelihood of meningitis. If the doctor suspects bacterial meningitis, he or she may order the following:
Antibiotics may be given early in the evaluation.
A CT scan may be performed. This can sometimes determine if the brain is infected or has an abscess.
Blood is drawn to check the white and red blood cell counts.
A chest X-ray film may be obtained to look for signs of pneumonia or fluid in the lungs.
Other tests may be performed to look for other sources of infection.
Spinal tap: A spinal tap, or lumbar puncture, is necessary to diagnose meningitis. The results of the spinal tap are essential to help the doctor determine both the presence and then the type of meningitis. Correctly diagnosing meningitis is absolutely essential to guide treatment decisions. If you are too sick for a spinal tap, you will be treated with antibiotics on the assumption that you have meningitis. The spinal tap will be done when your condition improves.
Cerebrospinal fluid is obtained through a spinal tap. This fluid surrounds and cushions the brain and the spinal cord. The fluid is analyzed in the lab for things like the presence of white and red blood cells and protein and glucose (sugar) levels. The doctor then interprets the test results to determine if meningitis is present. The test results can also indicate if the meningitis is due to a bacterial infection, fungal infection, or a virus.
To obtain the fluid, you are given an injection of lidocaine (Anestacaine, UAD Caine, Xylocaine HCl, Xylocaine-MPF), a local anesthetic similar to Novocaine used by dentists. A small needle is placed in the lower back, around the small of the back, to obtain the fluid.
Although the spinal tap can sometimes be uncomfortable, it is generally not very painful. The main complications of the procedure are headache, which occasionally occurs, and infection, which is extremely rare.
Because the results of the spinal tap can take up to several hours to return, the treatment often begins before the results are available. The doctor focuses early treatment on a medical opinion of the most likely cause based on your symptoms and physical examination findings.

TREATMENTS

The treatment depends on the type of meningitis you or your child has.
Bacterial meningitis
Acute bacterial meningitis must be treated immediately with intravenous antibiotics and, more recently, corticosteroids. This helps to ensure recovery and reduce the risk of complications, such as brain swelling and seizures.
The antibiotic or combination of antibiotics depends on the type of bacteria causing the infection. Your doctor may recommend a broad-spectrum antibiotic until he or she can determine the exact cause of the meningitis.
Your doctor may drain any infected sinuses or mastoids — the bones behind the outer ear that connect to the middle ear.

Viral meningitis

Antibiotics can't cure viral meningitis, and most cases improve on their own in several weeks. Treatment of mild cases of viral meningitis usually includes:
Bed rest
Plenty of fluids
Over-the-counter pain medications to help reduce fever and relieve body aches
Your doctor may prescribe corticosteroids to reduce swelling in the brain, and an anticonvulsant medication to control seizures. If a herpes virus caused your meningitis, an antiviral medication is available.
Other types of meningitis
If the cause of your meningitis is unclear, your doctor may start antiviral and antibiotic treatment while the cause is determined.
Chronic meningitis is treated based on the underlying cause. Antifungal medications treat fungal meningitis and a combination of specific antibiotics can treat tuberculous meningitis. However, these medications can have serious side effects, so treatment may be deferred until a laboratory can confirm that the cause is fungal. Chronic meningitis is treated based on the underlying cause.
Noninfectious meningitis due to allergic reaction or autoimmune disease may be treated with corticosteroids. In some cases no treatment may be required, because the condition can resolve on its own. Cancer-related meningitis requires therapy for the individual cancer.