ACUTE BACTERIAL MENINGITIS

The mode of transmission is probably person-to-person contact  through respiratory tract secretions or droplets.

Etiology:  Acute bacterial meningitis beyond the neonatal period is mainly  caused by 3 organisms; Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitides. Other organisms are less common.

? Streptococcus pneumonia

? Haemophilus influenzae type b;

? Neisseria meningitides;

Clinical Manifestation: The onset is either sudden or insidious.

? Sudden onset is less common manifestation & associated with rapidly progressive manifestations of shock, purpura, DIC, and ↓ conciousness which often progress to coma or death within 24 hr.

? Insidious onset is more common & manifested as nonspecific findings e.g. fever, headache, anorexia, photophobia, poor feeding, myalgias, arthralgias, tachycardia, hypotension, & skin rash e.g. petechiae, purpura & tache cérébrale (which elicited by stroking skin with a blunt object and observing raised red streak within 1 min). Focal neurologic signs may occur due to vascular occlusion or cerebral infarction.

? Sometimes meningitis is preceded by several days of fever associated with URT or GIT symptoms, followed by nonspecific signs of CNS infection e.g. increasing lethargy and irritability.

v Signs of Meningeal Irritation include: nuchal rigidity, back pain, Kernig sign, & Brudzinski sign, although the last 2 signs are not consistently present in infants < 1-1.5 yr.

v Signs of Increased ICP include: headache, nausea, vomiting, cranial nerve palsy (especially the abducet & oculomotor); severe cases causing Cushing triad which include hypertension, bradycardia, & irregular respiration (apnea or hyperventilation). In infants, there is bulging fontanel & diastasis (widening) of sutures.