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Meningococcal Infections - Causes, Symptoms and Treatment
Definition:
Two major meningococcal infections (meningitis and mcningioma) are caused by a gram-negative bacteria Neisseria meningitidis. which ,also causes primary pneumonia,purulent conjunctivitis, endocarditis, sinusitis, and genital infection. Meningococcemia occurs as simple bacteremia, fulminant meningococcemia and, rarely, chronic meningococcemia. It often accompanies meningitis. (For more information on meningitis, see "Meningitis.") Mcningococcal infections may occur sporadically or in epidemics; virulent infections may be fatal within a matter of hours.
Causes of Meningococcal Infections
Meningococcal infections occur most often among children (ages 6 months to 1 year) and men, usually military recruits, because of overcrowding. N. meningitidis has at least seven serogroups (A, B, C, D, X, Y, Z); group A causes most epidemics.
These bacteria are often present in upper respiratory flora. Transmission takes place through inhalation of an infected droplet from carriers (an estimated 2% to 38% of the population). The bacteria then localize in the nasopharynx. Following an incubation period of approximately 3 or 4 days, the bacteria spread through the bloodstream to the joints, skin, adrenal glands, lungs, and central nervous system. The tissue damage that results (possibly due to the effects of bacterial endotoxins) produces symptoms and, in fulminant meningococcemia and meningococcal bacteremia, progresses to hemorrhage, thrombosis, and necrosis.
Signs and Symptoms of Meningococcal Infections
Clinical features of meningococcal infection vary. Symptoms of meningococcal bacteremia include a sudden, spiking fever; headache; sore throat; cough; chills; myalgia (in the back and legs); arthralgia; tachycardia; tachypnea; mild hypotension; and a petechial, nodular, or maculopapular rash. In 10% to 20% of patients, this progresses to fulminant meningococcemia, with extreme prostration, enlargement of skin lesions, disseminated intravascular coagulation (DIC), and shock.
Characteristics of chronic meningococcemia include intermittent fever, maculopapular rash, joint pain, and enlarged spleen.
Diagnosis for Meningococcal Infections
Isolation of N. meningitidis through a positive blood culture, cerebrospinal fluid (CSF) culture, or lesion scraping confirms the diagnosis, except in nasopharyngeal infections, because N. meningitidis exists as part of the normal nasopharyngeal flora. Tests that support the diagnosis include counterimmunoelectrophoresis of the CSF or blood, a low white blood cell count and, in patients with skin or adrenal hemorrhages, decreased platelet and clotting levels. Diagnostic evaluation must rule out Rocky Mountain spotted fever and vascular purpuras.
Treatment for Meningococcal Infections
As soon as meningococcal infection is suspected, treatment begins with large doses of aqueous penicillin G, ampicillin, or a cephalosporin, such as cefoxitin, and moxalactam. For the patient who is allergic to penicillin, chloramphenicol I.V is used. Therapy may also include mannitol for cerebral edema, I.V. heparin for disseminated intravascular coagulation (DIC), dopamine for shock, and digoxin and a diuretic if heart failure develops. Supportive measures include fluid and electrolyte maintenance, proper ventilation (patent airway and oxygen if necessary), insertion of an arterial or central venous pressure (CVP) line to monitor cardiovascular status, and bed rest. Chemoprophylaxis with rifampin or minocycline is useful for facility workers who come in contact with the patient; minocycline can also temporarily eradicate the infection in carriers.
Special Considerations and Prevention Tips for Meningococcal Infections
- To prevent the spread of meningococcal infection, impose respiratory isolation until the patient has received antibiotic therapy for 24 hours.
- The dosages of I.V. antibiotics should be adjusted as necessary to maintain blood and CSF drug levels.
- Enforce bed rest in early stages. Provide a dark, quiet, restful environment.
- Maintain adequate ventilation with oxygen or a ventilator if necessary. Suction and turn the patient frequently.
- Keep accurate intake and output records to maintain proper fluid and electrolyte levels. Monitor blood pressure, pulse, arterial blood gas levels, and CVP.
- Watch for complications, such as DIC, arthritis, endocarditis, and pneumonia.
- If the patient is receiving chloramphenicol, monitor his complete blood count.
- Check the patient's drug history for allergies before giving antibiotics.
- Label all meningococcal specimens. Deliver them to the laboratory quickly because meningococci are very sensitive to changes in humidity and temperature.
- Report all meningococcal infections to public health department officials.
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