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MENINGITIS - ACUTE, BACTERIAL

Acute meningitis is the infection of the subarachnoid space and cerebrospinal fluid by bacteria that may cause local and systemic inflammatory response.
There is the classic triad of symptoms of fever, neck stiffness and altered level of consciousness.
Other symptoms include chills, myalgia, photophobia, severe headache, focal neurologic symptoms, nausea, vomiting, seizures and some patients may present with rash.

 

Definition

  • Meningitis is the infection of the meninges and subarachnoid space that is usually caused by bacteria results in high mortality and morbidity throughout the world

Etiology

  • The introduction of conjugated vaccines against H influenzae type B, N meningitidis and S pneumoniae caused decline in the incidence of bacterial meningitis in children thus majority of cases are now present in the adult population
  • Causative agents depend on the age of the patient and predisposing factors

Other causes of acute meningitis include the following:

  • Spirochetes eg Treponema pallidum
  • Mycobacteria eg Mycobacterium tuberculosis
  • Fungi eg Cryptococcus, Coccidioides, Sporothrix
  • Viruses eg herpes simplex virus (HSV), varicella zoster, cytomegalovirus (CMV), enterovirus
  • Protozoa and helminths

Signs and Symptoms

  • Classic triad: Fever, neck stiffness and an altered level of consciousness is present in <50% of cases as some may have severe headache (especially in children) or any of the other symptoms:
    • Chills
    • Myalgia
    • Photophobia
    • Focal neurologic symptoms [eg cranial nerve palsies, ataxia, dilated/unequal and poorly reacting pupils (late sign)]
    • Nausea/vomiting
    • Seizures (late sign)
    • Some patients may present with petechial rash

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