160 likes | 498 Views
Central Nervous System Infections. Dr. Sudheer Kher Prof & Head Dept of Microbiology Gulf Medical College, Ajman, UAE. CNS Infections. Classification Bacterial meningitis Pyogenic Mycobacterial Viral meningitis (aseptic meningitis). Pyogenic meningitis. Clinical Features
E N D
Central Nervous System Infections Dr. Sudheer Kher Prof & Head Dept of Microbiology Gulf Medical College, Ajman, UAE
CNS Infections Classification • Bacterial meningitis • Pyogenic • Mycobacterial • Viral meningitis (aseptic meningitis)
Pyogenic meningitis • Clinical Features • Symptoms – Severe headache, Malaise, Fever. Abrupt onset. Vomiting, photophobia, Convulsions, Irritability, Lethargy, Drowsiness, Unconsciousness • Signs – Signs of meningeal irritation like neck & spinal stiffness, Kernig’s sign.
Pyogenic meningitis • Clinical Features • Age –Largely a disease of infancy & childhood but can be seen throughout the life. • Neonatal meningitis – Characteristic signs of meningitis may be absent. Features like obviously unwell, Failure to feed & vomiting may be present. More common in premature than full term. • Elderly & immunocompromised - Characteristic signs of meningitis may be absent. Mental confusion may be the predominant feature.
Meningitis • Clinical Features • Sequelae – Extensive pathological changes. Deafness, encephalopathy, cranial nerve palsies, obstructive hydrocephalus are the sequelae. • Causal organisms – Common • Neisseria meningitidis – infants, children and young adults • Haemophilus influenzae – infants & pre-school children • Streptococcus pneumoniae – middle age & elderly • E. coli - Neonatal • Group B Streptococci - Neonatal • Klebsiella - Neonatal • Proteus species – Neonatal • Tuberculosis – All ages but predominantly children
Pyogenic meningitis • Causal organisms – Uncommon • Listeria monocytogenes • Cryptococcus neoformans (fungus) • Leptospira species
Laboratory Diagnosis • Isolation specimens – • CSF • Counting chamber for WBC count • Gram film on deposit for bacteria & cells • Leishman film if required for WBCs • Ziehl – Neelsen film if required • Blood – Culture as often there is precedent or concomitant bacterimia
Laboratory Diagnosis • Culture of CSF – • Centrifuged deposit on Blood agar, Chocolate agar, Glucose broth & cooked meat broth. Incubated at 37C under 5-10% CO2. • Lowenstein – Jensen Medium for MTB culture if indicated. • Culture of Blood –Positive in 40% patients of Pyogenic meningitis
Laboratory Diagnosis • Demonstration of bacterial antigens or DNA – • Of value when meningitis has been partially treated and no bacteria can be seen or cultured • Tests – • Latex agglutination or Phadebact coagglutination test for N. meningiitidis • PCR for H. influenzae type b & S. pneumoniae