Case Studies -- Johns

Question 1

Bacterial Meningitis

Definition

Answer 1

Inflammatory response to bacterial infection of the pia-arachnoid and the CSF of the subarachnoid space

Question 2

Clinical Manifestations of

Acute Bacterial Meningitis

Answer 2

Short prodromal respiratory illness or sore throat

Fever, headache, stiff neck, vomiting, change in consciousness, seizures, dehydration and vascular collapse

Question 3

Treatment for acute bacterial meningitis

Answer 3

IV fluids

Immediate antibiotics
Ages 2-50 ** vancomycin** plus ceftiaxone
Age > 50 ** ampicillin** (for lesteria) plus vancomycin
plus **ceftriaxone **

Question 4

Meningitis vs. Encephalitis

Answer 4

Meningitis – normal brain function. May have headache, fever and feel uncomfortable but cerebral function remains normal.

Encephalitis – abnormal brain function. Altered mental status, motor or sensory deficits, seizures, altered behavior and personality changes.

Why distinguish? Likely cause is different. Meningitis – consider bacteria, Encephalitis - viral

Meningoencephalitis – “the grey area”

Question 5

Viral vs. Post-infectious Encephalitis

Answer 5

Viral – primary infection by viral invasion of CNS and causes damage to neurons. Virus can be seen by EM and cultured from brain biopsy

Post Infectious – immune mediated disease from prior viral infection, neurons are spared but perivascular inflammation and demyelination. (more perminant damage)

Measles, polio, rubella can cause both

Difficult to differentiate

Question 6

Herpes Simplex Type 1

Encephalitis

Answer 6

Most common cause of fatal sporadic encephalitis in the US.

Question 7

Lab Abnormalities in Encephalitis in HSV-I

Answer 7

CSF – Increased WBC’s with lymphocytes, increased RBC’s and protein. Low glucose is uncommon.

PCR (polymerase chain reaction) of CSF fluid for herpes simplex DNA is the gold standard.

Question 8

Treatment for HSV-I encephalitis

Answer 8

Empiric treatment with acylovir ASAP!!

Devastating infection of CNS with 70% of survivors having deficits.

Reduces mortality from 50% to 19%

Question 9

Acyclovir

Answer 9

Prodrug – administered in an inactive form and metabolized into active form.

Poorly water soluble – IV most effective

Incorporates into viral DNA, chain terminator

Give for 14-21 days for herpes encephalitis

Only active in lytic infection of virus… in latency, can’t block. Only works were thymidine kinase is expressed!