Meningitis refers to a clinical syndrome that is characterized by an inflammation of the 3 layers of tissue that line the spinal cord. This tissue is called the meninges. The inflammation affects the underlying cerebrospinal fluid. Bacterial meningitis is a dangerous disease process that attacks the central nervous system. It is critical to diagnose this process quickly, because any delay in treatment may result in brain damage or death. Meningitis may result in hearing loss, mental deficits, paralysis, peripheral gangrene, or seizures.
Bacterial meningitis was usually fatal before the advent of antibiotics. Currently, there is still a 25% fatality rate even with antibiotic therapy. Resistant bacterial strains have also developed throughout the world. In the United States, there are approximately 4100 cases of bacterial meningitis per year, with 500 annual deaths. All college students should be vaccinated against Neisseria meningitides. The Hib vaccine has dramatically diminished the incidence of meningitis in infants due to Haemophilus influenza type B.
Most cases of meningitis result from bacterial or viral infections that enter the meninges through the blood from another part of the body. Some infections that may cause meningitis include skin infections, infections of the respiratory or gastrointestinal tract and infections of the nasopharynx and sinuses.
There is a classic triad of signs and symptoms that characterize bacterial meningitis. The triad consists of fever, neck stiffness and a headache. This presentation is fairly common, but meningitis may be subacute, which may result in delayed diagnosis. Other symptoms include photophobia (light sensitivity), sleepiness, nausea and vomiting, irritability, confusion, and other mental status changes that may include coma. Patients suffering from less severe viral meningitis may demonstrate symptoms of fatigue, diminished appetite and muscle pain.
Infants with meningitis may demonstrate a bulging fontanelle, unless the infant is dehydrated. Some infants may remain quiet but begin to cry when they are held. This is known as “paradoxical irritability.” A high-pitched cry or a loss of muscle tone (floppiness) may occur in infants with meningitis.
It is critical for a physician to obtain a thorough history when evaluating patients with signs or symptoms that may result from meningitis. Often, a history provides important clues to diagnosis. Exposure to patients or even animals with similar symptoms, a travel history, consideration of epidemiological factors, seasonal factors and risk factors are all critical pieces of information that should be acquired during the patient interview. Some risk factors for meningitis include ages under five years of greater than 60 years, systemic diseases that include diabetes and renal insufficiency, immunosuppression (as in HIV or in patients on immunosuppressant drugs), contiguous infections that include sinusitis and otitis, splenectomy and crowded conditions that increase the risk of meningitis outbreaks. 25% of patients with acute bacterial meningitis have sinusitis or otitis upon presentation. Up to 40% of patients with acute or subacute bacterial meningitis have been treated prior to presentation with oral antibiotics due to an incorrect diagnosis of their symptoms.
Physical findings that should be assessed and noted by the clinician include the presence or absence of prominent lymph nodes, any swelling in the optic disc of the retina (this must be documented after a thorough examination with an otoscope), neck stiffness (known as meningismus) and any nerve palsies in the face.
When a diagnosis of meningitis is suspected, the clinician should obtain a complete blood count, and lab work should also assess blood glucose, electrolytes, renal function, and liver function.
Because bacterial meningitis is so deadly, it is critical for the clinician to begin prompt antibiotic therapy when the patient presents with the suspected diagnosis. However, it is also very important to obtain a sample of spinal fluid to send to the laboratory for evaluation of the type of bacteria causing the infection. Empiric therapy refers to prompt treatment with antibiotics that are tailored to cover the most likely organism. In order to make this type of judgment, the physician should be aware of the most probable organisms by age group and geographic location.
When a lumbar puncture is completed, several lab tests that include a bacterial culture and sensitivity should be ordered, but antibiotic therapy for presumed organisms should be initiated immediately after lumbar puncture. Steroids are also administered to patients with meningitis in order to decrease morbidity. Steroids have a protective effect on the nerve cells.
When patients develop meningitis as a result of a hospital-acquired infection, antibiotics are often directly administered into the spinal fluid. Other complications of acute bacterial meningitis include low blood pressure, or shock; poor tissue oxygenation, low blood sodium levels that may lead to seizures, cardiac arrhythmia and even strokes.
A partial list of immediate and delayed complications of meningitis include septic shock and coma, seizures, septic arthritis, hemolytic anemia, and pericardial effusions; deafness, cranial nerve paralysis, focal paralysis, hydrocephalus, cognitive deficits, ataxia, blindness and peripheral gangrene. Cerebral edema, or swelling of the brain, is common to bacterial meningitis in different degrees. Cortical blindness, learning disabilities, cerebral palsy and mental retardation may occur with damage to the tissues of the brain as a result of meningitis.
If you or a family member has experienced any complications, morbidity or death as a result of undiagnosed or improperly treated meningitis, or as a result in a delay in treatment, then you should contact Passen & Powell at 312-527-4500 for a Free Consultation.