6.CLINICAL FEATURES

Meningococcal disease presentation may be non-specific in the early stages and a high index of suspicion should be maintained. Disease presentation may also be acute and rapidly progressive. Key symptoms such as fever, headache and neck stiffness may be absent or slow to develop, particularly in young infants with meningococcal meningitis. Only 50% of patients present with meningococcaemia, and a rash is usually but not always present.

6.1 Clinical features of meningococcal meningitis

Although sudden onset of illness with rapid progression to shock does occur, more commonly meningococcal disease is of a less dramatic nature and therapy is often effective. The disease may present initially as a flu-like illness with fever, malaise, headache, muscle pain, nausea or vomiting. Features of disease may include the following:

• Neck stiffness
• Photophobia
• Prostration
• Vomiting
• Impaired consciousness
• Hypotension
• Raised intracranial pressure

In infants particularly (less than 1 year old), the onset may be insidious and classical signs absent. The diagnosis should be suspected in young children in the presence of vomiting and fever, irritability, and, if still patent, raised anterior fontanel tension. With early diagnosis and appropriate management, the mortality rate of meningococcal meningitis is between 5% and 10%, however persistent neurological damage occurs in about 10 to 20% of survivors.

6.2 Clinical features of meningococcal septicaemia

disease may present initially as a non-specific upper respiratory illness e.g. pharyngitis, followed by fever, headache, joint pain, vomiting, neck stiffness and photophobia. The haemorrhagic rash is a distinctive feature of meningococcal septicaemia and is indicative of severe disease, where the mortality rate may be as high as 50%. Although the rash is typically haemorrhagic or petechial in nature, it can also resemble the maculopapular rash of viral infections. In many cases the petechial rash will start on the buttocks, back of the legs and conjunctivae. The rash typically does not blanch on pressure and the petechiae may be difficult to see in the early stages, particularly in dark skin (checking the conjunctivae, soles and palms may in such cases reveal the petechiae). Remember the rash may be absent.

The onset of illness can be very rapid and, in 5-10% of cases, the disease may be fulminant within a few hours of onset. Cases may present with hypotension, shock, confusion, coma and death. Disseminated intravascular coagulation (DIC) may also occur. Such patients often respond poorly to antimicrobials, steroids, or vasopressor agents and usually require admission to an intensive care unit.

6.3 Clinical Differentiation

The clinical differential diagnosis of bleeding and fever with or without neurological signs includes:

• Viral haemorrhagic fevers (notably Crimean Congo Haemorrhagic Fever for South Africa)
• Severe tick bite fever
• Rift Valley fever
• Severe sepsis – caused by Gram-negative or Gram-positive bacteria
• Fulminant malaria
• Fulminant hepatitis
• Advanced HIV infection with AIDS related complications
• Leukaemia and other malignancies.