Meningococcal Infections Clinical Presentation

The clinical pattern of meningococcemia varies. After a few days of upper respiratory symptoms, the temperature rises abruptly, often after a chill. Malaise, weakness, myalgias, headache, nausea, vomiting, and arthralgias are common presenting symptoms. A skin rash, which is essential for recognizing meningococcemia, is the characteristic manifestation. The skin rash may advance from a few ill-defined lesions to a widespread petechial eruption within a few hours.

Fulminant meningococcemia is the most serious form of meningococcal disease. This form occurs in approximately 5-15% of cases of meningococcal disease. It begins abruptly with a high fever, chills, myalgias, weakness, nausea, vomiting, and headache. Apprehension, restlessness, and, frequently, delirium occur within the next few hours. The rash appears suddenly and is widespread, purpuric, and ecchymotic.

In adults, bacterial meningitis has a characteristic clinical pattern, although the progression of symptoms varies somewhat. Symptoms of meningitis may accompany the petechial rash of meningococcemia and may produce the predominant features on presentation.

Bacterial meningitis is a febrile illness of short duration; the major symptoms include headache and a stiff neck. Lethargy or drowsiness is common. Confusion, agitated delirium, and stupor are rarer; however, coma is an ominous prognostic sign.

The clinical pattern of bacterial meningitis is often atypical in young children because headache and nuchal rigidity are frequently absent. Irritability, especially upon movement, is a common presenting manifestation of meningitis in a young child. Convulsions may signal the onset of meningitis at this age. Progression of the illness results in the development of lassitude and a more constant fever, often accompanied by abdominal discomfort. Projectile vomiting may occur.

Chronic meningococcemia is a rare form of meningococcal disease. This is an intermittent bacteremic illness that lasts from at least one week to as long as several months. The fever tends to be intermittent, with afebrile periods ranging from 2-10 days, during which the patient seems completely healthy. As the disease progresses, the febrile periods become more common, and the fever may become continuous.

Eventually, a skin eruption or some other manifestation of meningococcal disease appears during a febrile episode.

Petechiae are the most common skin lesions of meningococcemia, and they may be distributed sparsely over the body, as depicted in the image below.

Critically ill patients with sepsis may develop rapidly progressing petechiae, ecchymoses, and extensive palpable purpura or retiform purpura, accompanied by DIC and vascular collapse.

Ill-defined pink macules are noted in some cases. Maculopapular lesions also occur and are sometimes large and plaquelike with a central petechia. Rash may be missed early in an individual with dark skin.

The skin lesions tend to occur in crops on any part of the body, occasionally presenting on the conjunctivae and the mucous membranes. The face is usually spared, and involvement of the palms and the soles is less common.

Patients with acute meningococcemia usually present with moderate fever (average, 39.5°C) and no signs of shock.

Fulminant meningococcemia is associated with a purpuric eruption, as shown in the images below. Lesions are generally characterized by maplike purpuric or necrotic areas. Amputation may be required in severe cases.

Hemorrhages may appear on the buccal mucosa and the conjunctivae.

Less frequently, fulminant meningococcemia presents as purpura fulminans. In rare cases, no skin lesions develop.

Symmetric peripheral gangrene has been described in this form.

Signs of meningitis are typically absent. However, cyanosis, hypotension, and profound shock eventually appear.

Patients with fulminant meningococcemia usually present with a high fever (average temperature, 40.6°C). The blood pressure is lowered, and pulmonary insufficiency develops within a few hours.

Many patients with fulminant meningococcemia die despite appropriate antibiotic therapy and intensive care. Patients with fatal forms of fulminant meningococcemia are likely to die within 24-48 hours of presentation.

The characteristic physical examination findings of meningitis include pain and resistance to neck flexion. Other signs of meningeal irritation can also be elicited. Children with meningitis may have none of these findings.

The Kernig sign is positive when the leg cannot be extended more than 135° on the thigh when flexed 90° at the hip.

The Brudzinski sign is positive when neck flexion causes involuntary flexion of the thighs and the legs.

Focal neurologic signs are uncommon presenting findings of bacterial meningitis. However, nuchal rigidity may not be elicited in patients who are comatose and who may have signs of focal or diffuse neurologic deficits.

Papilledema is not a presenting feature of bacterial meningitis and suggests the presence of an accompanying process.

A common presenting sign of meningococcal meningitis is a petechial rash.

Most patients with meningitis are febrile, although the height of fever varies.

N meningitidis is a gram-negative diplococcus that grows well on solid media supplemented with blood and incubated in a moist atmosphere enriched with carbon dioxide.

Oxidase and catalase are biochemical markers for preliminary identification of N meningitidis. Sugar fermentations are required for final identification of the species. N meningitidis ferments glucose and maltose, not sucrose or lactose.

Agglutination reactions with immune serum subdivide N meningitidis into serogroups A, B, C, W135, X, Y, and Z, depending on a group-specific capsular polysaccharide antigen. Most strains that cause meningococcal disease have the polysaccharide antigen of groups A, B, or C. Group Y and group W135 meningococci cause disease more commonly than groups X and Z. Meningococcal strains that lack these group-specific antigens are believed to be nonpathogenic. The cell wall of pathogenic meningococci contains a toxic lipopolysaccharide or endotoxin. Meningococcal endotoxin appears to be chemically identical to enteric bacilli endotoxin.

Susceptibility to meningococcal disease has been linked with the absence of bactericidal antibody against pathogenic meningococci. Immunoglobulin G (IgG) antibodies that have specificity for the meningococcal polysaccharides mediate bactericidal activity. Complement is needed for expression of this activity. Asymptomatic nasopharyngeal carriage of meningococci induces a humoral antibody response, and most individuals acquire immunity to meningococcal disease by age 20 years. Passively transferred maternal antibody provides temporary protection to infants for the first 3-6 months of life. Colonization with nonpathogenic meningococci seems to induce cross-reacting protective antibodies. An episode of meningococcal disease confers group-specific immunity, but a second episode may be caused by another meningococcal serogroup.

Recurrent meningococcal disease has been linked to congenital complement deficiencies, which usually affect the terminal components of the complement cascade.

Hereditary properdin deficiency may also predispose to meningococcal disease.