viral meningitis


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Related to viral meningitis: Bacterial Meningitis, Viral encephalitis

meningitis

 [men″in-ji´tis] (pl. meningi´tides)
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 inflammatory 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.
Bacterial Meningitis. This form occurs when pathogenic bacteria enter the subarachnoid space and cause a pyogenic inflammatory response. The most common causes are Streptococcus pneumoniae (pneumococcus), Neisseria meningitidis (meningococcus), and Haemophilus influenzae, which are responsible for approximately 70 per cent of all cases. The incidence is age-related. In adults, S. pneumoniae and N. meningitidis cause most of the cases; in children aged 1 month to 15 years, N. meningitidis and H. influenzae predominate; in neonates less than 1 month old, the disease is usually a nosocomial infection with gram-negative enteric bacilli.

Almost all bacterial infections of the meninges enter the nervous system after having invaded and infected another region of the body and then are spread by local extension, as from the sinuses, or through the blood, as in septicemia. The organisms gain access to the ventriculosubarachnoid spaces and the cerebrospinal fluid where they cause irritation of the tissues bathed by the fluid.

Bacterial meningitis typically begins with headache, nausea and vomiting, stiff neck (nuchal rigidity), and chills and fever. Irritability and confusion occur early in the course of the disease, and convulsive seizures occur in about 25 per cent of patients. As the disease progresses the patient becomes less rational, has decreasing levels of consciousness, and lapses into coma. Inability to straighten the knee when the hip is flexed (a positive kernig's sign) and involuntary flexing of the hip and knee when the neck is flexed forward (a positive brudzinski's sign) are indicative of meningeal irritation.

A diagnosis of bacterial meningitis is verified by isolation of the organism from a specimen of cerebrospinal fluid obtained by lumbar puncture. Treatment with the appropriate antibacterial agent is begun at once to reduce the numbers of proliferating bacteria attacking the central nervous system. Supportive measures include rest, maintenance of fluid and electrolyte balance, and prevention or control of convulsions with anticonvulsant drugs.

The prognosis is generally good, especially for meningococcal meningitis in which residual neurologic deficits and persistent convulsive seizures are rare. Pneumococcal meningitis and meningitis due to Haemophilus influenzae are more likely to be complicated by these sequelae as well as by septic shock and hydrocephalus.
Benign Viral Meningitis. This term encompasses a group of disorders in which there is some meningeal irritation but no pyogenic organism can be found in the cerebrospinal fluid. It is, therefore, called also aseptic meningitis complex, which is somewhat misleading because the meningeal irritation often follows infection with the mumps virus or with one of the picornaviruses.

The patient with this disorder typically complains of headache and signs characteristic of meningeal irritation, intolerance to light, and pain when the eyes are moved from side to side. Most of the symptoms are mild, and treatment is largely supportive and symptomatic; the disease is self-limiting.
Patient Care. Assessment of the patient with meningitis includes monitoring vital signs, neurologic status, and fluid and electrolyte status. The plan of care should include provisions for rest and relief from discomfort, a quiet and nonstimulating environment, protection from injury during convulsions, control of elevated body temperature, and isolation precautions as indicated by the specific causative organism. In general, enteric precautions are indicated for patients with aseptic meningitis caused by an enterovirus. Fungal and meningococcal meningitis require respiratory precautions. Antibiotics must be given precisely as ordered so as to avoid further damage to the central nervous system. Early signs of increased intracranial pressure from brain edema are reported promptly so that measures to reduce pressure can be taken as soon as possible. During the acute phase and convalescence the patient is watched for signs of complications such as septic shock, vascular collapse, and hydrocephalus. Nutritional status must be maintained throughout the course of illness to reinforce the patient's natural resources for combating infection and recovering from its deleterious effects.
Portals of entry resulting in meningitis, meningoencephalitis, and intracranial mass lesions. From Mahon and Manuselis, 2000.
aseptic meningitis any of several mild types of meningitis, most of which are caused by viruses; see viral meningitis.
bacterial meningitis meningitis caused by bacteria; common pathogens are Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, and Mycobacterium tuberculosis. Some types may be serious, acute, or even fulminating. See also viral meningitis.
cerebrospinal meningitis an inflammation of the brain and spinal cord; it may be caused by any of numerous different organisms.
epidemic cerebrospinal meningitis an acute infectious disease with seropurulent inflammation of the membranes of the brain and spinal cord, due to infection by Neisseria meningitidis (meningococcus). It usually occurs in epidemics, and symptoms are those of acute cerebral and spinal meningitis. There is also usually an eruption of erythematous, herpetic, or hemorrhagic spots on the skin. The fulminating or malignant form is known as Waterhouse-Friderichsen syndrome.
spinal meningitis inflammation of the meninges of the spinal cord.
viral meningitis meningitis due to any of various viruses, such as a coxsackievirus or the mumps virus, with lymphocytes in the cerebrospinal fluid. It usually has a short uncomplicated course characterized by malaise, fever, headache, stiffness of neck and back, and nausea. See also aseptic meningitis.

viral meningitis

A form of aseptic meningitis due to infection with adenovirus, coxsackievirus, echovirus, HIV, mumps virus, lymphocytic choriomeningitis virus, polio viruses, and others. Patients report fever, headache, and stiff neck. Lumbar puncture reveals an excessive number of lymphocytes, typically without a decrease in cerebrospinal fluid glucose levels.
See also: meningitis
References in periodicals archive ?
The mean CSF LDH are 280.94 [+ or -] 74.488 mg/dl (95% CI: 261.60-300.48) for pyogenic meningitis, 171.24 [+ or -] 211.58 mg/ dl (95% CI: 171.24-211.58) for tubercular meningitis, and 35.60 [+ or -] 10.394 mg/dl (95% CI: 32.58-38.36) for viral meningitis. This difference between CSF LDH is statistically significant between all groups.
Dr Mike Griffiths, senior investigator of the study, said, "Diagnosing a specific cause of meningitis quickly is key to getting patients on the right antibiotics if needed, or avoiding unnecessary antibiotics in those with viral meningitis."
'Viral meningitis' was diagnosed when CSF showed elevated WCC (>5 lymphocytes, or any polymorphonucleocytes), with CSF chemistry (protein and glucose) within the normal range.
Tanya Altmann, a pediatrician at Calabasas Pediatrics in California, said that "viral meningitis is transmitted through close casual contact.
The CDC estimates that viral meningitis affects about 10 of every 100,000 individuals, and bacterial meningitis affects 1.4 of every 100,000 each year (about 4,000 individuals).
A retrospective chart review looking for cases of viral meningitis with associated elevation of intracranial pressure was performed.
Viral meningitis causes milder, flu-like symptoms and doesn't usually result in septicaemia.
He revealed: "For the last four weeks, I have been in and out of the hospital and have been diagnosed with viral meningitis.
So, in developing countries like India, we cannot institute empirical antiviral therapy to all patients of suspected viral meningitis. Therefore, several different techniques to discriminate rapidly between viral meningitis and bacterial meningitis have been evaluated.
A BIRMINGHAM woman is backing a charity campaign to get people talking about viral meningitis.
I WAS touched to read in Gabrielle Fagan's recent article "Family is what defines me, not illness" (Post, May 20), that Liberty X star Michelle Heaton's baby Aaron Jay bravely battled viral meningitis.
Gloucestershire HOT on the heels of our awareness week - Vocal About A Viral - showing the impact viral meningitis can have, come three other weeks, all of which help to demonstrate the devastating after-effects of meningitis.