Question

A 23-year old female college student entered the emergency room with a headache and fever that she has had for the past three days. The student’s roommate found her in the dorm room confused and highly agitated. When she arrived in the emergency room, the patient was comatose. The physician performed a lumbar puncture. The following laboratory results were obtained:

Laboratory Results of CSF:

            Color/Clarity: Colorless and Slightly cloudy

            WBC:              380 cells/mm^3

                                    94% are polymorphonuclear cells

            Protein:                        220 mg/dL

            Glucose:          32 mg/dL

Gram stain results of CSF:

            Moderate WBC seen

            Many Gram negative diplococcic

The organism was isolated from a blood culture and the CSF culture. The patient was put on penicillin therapy, but was too late. The patient expired later that day.

Question:

a. What is the most probable organism responsible for the infection based on the Gram stain and clinical presentation?

Question:

b. What manual tests would confirm the identification of the organism?

Question:

c. How do the clinical presentation and the laboratory findings correlate?

Question:

d. How did the college student come into contact with the organism? What should be done with those in close contact with the student?

Answer 1

A Streptococcus pneumoniae and Neisseria meningitidis are the leading cause of bacterial meningitis.Meningitis is an acute inflammation of the meningeal tissues surrounding the brain and spinal cord

b Diagnosis is usually verified by doing a lumbar puncture with analysis of the CSF.Variations in the CSF depend on the causative organism ..Protein levels in the CSF are usually elevated and are higher in bacterial than in viral meningitis.Specimens of CSF ,sputum and nasopharyngeal secretions are taken for the culture before the start of antibiotic therapy to identify the causative organism.A gram stain is done to detect bacteria.X-RAYS may demonstrate infected sinuses.CT scans and MRI are normal in uncomplicated meningitis.CT scans may reveal evidence of increased ICP or hydrocephalus.

c The predominant white blood cell type in the CSF during bacterial meningitis is polymorphonuclear cells.Rapid diagnosis based on history and physical examination is crucial because the patient is usually in a critical state when health care is sought.When meningitis is suspected ,antibiotic therapy is instituted after the collection of specimens for cultures,even before the diagnosis is confirmed.

d Meningitis usually occur in the fall,winter,or early spring and is often secondary to viral respiratory disease.The organisms usually gain entry to the CNS through the upper respiratory tract or the blood stream but they may enter by direct extension from penetrating wounds of the skull or through fractured sinuses in basal skull fractures.