VIRAL MENINGITIS Flashcards
Common Causes in Acute Meningitis
- Enteroviruses (coxsackieviruses, echoviruses, and human enteroviruses 68-71) - Varicella-zoster virus - Herpes simplex virus 2 - Epstein-Barr virus - Arthropod-borne viruses - HIV
- most common cause of viral meningitis >85% of cases
- most likely in the summer and fall months (children <15 years)
- PE: careful search for stigmata of enterovirus infection including exanthems, hand-foot-mouth disease, herpangina, pleurodynia, myopericarditis, and hemorrhagic conjunctivitis.
- CSF profile: lymphocytic pleocytosis (100-1000 cells/pL), normal glucose and normal or mildly elevated protein concentration.
- CSF reverse transcriptase PCR (RT-PCR) is the diagnostic procedure of choice
Enteroviruses
- increasingly recognized as a major cause of viral meningitis in adults
- second most important cause of viral meningitis 5% of total cases
- uncomplicated meningitis: ____-2 Herpes simplex virus} - - HSV encephalitis: ____-1 (90%)
- occurs in ~25-35% of women and ~10-15% of men at the time of an initial (primary) episode of genital herpes.
- Diagnosis is usually by CSF PCR
Herpes simplex virus}
- Should be suspected in the presence of concurrent chickenpox or shingles
- The frequency as a cause of meningitis is extremely variable, ranging from as low as 3% to as high as 20% in different series
- Diagnosis is usually based on CSF PCR
- Serologic studies complement PCR testing
Varicella-zooster virus
- May also produce aseptic meningitis, with or without associated infectious mononucleosis.
- Presence of atypical lymphocytes in the CSF or Peripheral blood
- Serum and CSF serology - IgM viral capsid antibodies (VCAs), antibodies to early antigens (Eas), and the absence of antibodies to EBV-associated nuclear antigen (EBNA)
Epstein-Barr virus
- should be suspected in any patient presenting with a viral meningitis with known or suspected risk factors for HIV infection
- may occur following primary infection with HIV in 5-10% of cases and less commonly at later stages of illness.
- Cranial nerve palsies (CN: V, Vil, or VIII) are more common in HIV meningitis than in other viral infections
- Diagnosis can be confirmed by detection of HIV genome in blood or CSF
HIV
- should be considered when meningitis occurs in the late winter or early spring, especially in males. (M:F of 3:1)
- presence of parotitis, orchitis, oophoritis, pancreatitis, or elevations in serum lipase and amylase is suggestive
- Diagnosis is typically made by culture of virus from CSF or by detecting IgM antibodies or seroconversion
Mumps
- be considered when aseptic meningitis occurs in the late fall or winter
- individuals with a history of exposure to house mice (Mus musculus), pet or Lymphocytic choriomeningitis virus laboratory rodents or their excreta.
- Lab clues: Presence of leukopenia, thrombocytopenia, or abnormal liver function tests.
- Diagnosis is based on serology and/or culture of virus from CSF.
Lymphocytic choriomeningitis virus
CLINICAL MANIFESTATION OF VIRAL MENINGITIS
- Immunocompetent adult patients:
+ Headache
+ Fever
+ signs of meningeal irritation coupled with an inflammatory CSF profile - Headache characterized as frontal or retroorbital and frequently associated with photophobia and pain on moving the eyes.
- Nuchal rigidity is present in most cases
Constitutional signs: malaise, myalgia, anorexia, nausea and vomiting, abdominal pain, and/or diarrhea. - Mild lethargy or drowsiness
- Profound alterations in consciousness, do not occur, and suggest the presence of encephalitis or other alternative diagnoses.
- most important laboratory test
- Pleocytosis
- normal or slightly elevated protein conc. (0.2- 0.8 g/L [20-80 mg/dt])
- normal glucose conc.
- Normal or mildly elevated opening pressure (100-350 mmH20)
CSF Examination
has become the single most important method for diagnosing CNS viral infections
Polymerase Chain Reaction Amplification of Viral Nucleic Acid
- Sensitivity is generally poor.
- Specific viruses may also be isolated from throat swabs, stool, blood, and urine.
Viral Culture
diagnosis of arboviruses such as WNV
Serologic Studies
Treatment of almost all cases is primarily symptomatic and includes use of
- analgesic
- antipyretics
- antiemetics
Tx for Seriously ill HSV patients:
- IV acyclovir
- Acyclovir
- Famciclover
- Valacyclovir
Patients with HIV meningitis should receive highly active
- antiretroviral therapy
is an effective method of preventing the development of meningitis and other neurologic complications associated with poliovirus, mumps, measles, rubella, and varicella infection.
Vaccination
Common causative organisms: SUBACUTE MENINGITIS
- M Tuberculosis
- C. neoformans
- H.capsvlatum-
- Cimmitis-
- T. pallidum
endemic to the Ohio and Mississippi River valleys of the central United States and to parts of Central and South America
H.capsvlatum-
endemic to the desert areas of the southwest United States, northern Mexico, and Argentina.
Cimmitis-
invades the CNS early in the course of syphilis. (CN VII &VIII most frequently involved)
T. pallidum-
CLINICAL MANIFESTATION SUBACUTE MENINGITIS
- unrelenting headache
- stiff neck
- low-grade fever
- lethargy for days to several weeks
- Cranial nerve abnormalities and night sweats may be present.
- This syndrome overlaps that of chronic meningitis
Classic CSF abnormalities:
- elevated opening pressure
- lymphocytic pleocytosis (10-SOO cells/pL)
- elevated protein concentration in the range of 1-S 9/L
- decreased glucose concentration in the range of 1.1-2.2 mmol/L (20-40 mg/dL)
Tuberculous Meningitis
Combination of unrelenting headache, stiff neck, fatigue, night sweats, and fever witha CSF lymphocytic pleocytosis and a mildly decreased glucose concentration is ___ for tuberculous meningitis.
highly suspicious
gold standard to make the diagnosis of tuberculous meningitis
Culture
- Classic CSF abnormalities:
1. mononuclear or lymphocytic pleocytosis
2. increased protein concentration
3. decreased glucose concentration - Eosinophils in the CSF in C immitis meningitis
Cryptococcal polysaccharide antigen test -highly sensitive and specific - CSF complement fixation antibody test - specificity of 100% and a sensitivity of 75% for coccidioidal meningitis.
Fungal Meningitis
- Reactive serum treponemal test (fluorescent treponemal antibody absorption test [FTA-ABS] or microhemagglutination assay- T. pallidum[MHA-TP]) with a CSF lymphocytic or mononuclear pleocytosis and an elevated protein concentration
- CSF Venereal Disease Research Laboratory (VORL) test is positive
Syphilitic Meningitis
Tx for Tuberculous Meningitis
Initial therapy is a combination of:
- Isoniazid (300 mg/d)
- Rifampin (10 mg/kg per day)
- Pyrazinamide (30 mg/kg per day in divided doses)
- Ethambutol (15-25 mg/kg per day in divided doses) - Pyridoxine (SO mg/d).
Tx for Meningitis due to C. neoformans in Non-HIV
Non-Transplant Px
- Induction tx: Amphotericin B IV (0.7 mg/kg/day) + flucytosine for at least 4 wks if CSF culture results are negative after 2 wks of treatment.
- Extended for a total of 6 weeks in the patient with neurologic complications.
- Followed by consolidation therapy with fluconazole 400 mg/d for 8 weeks.
Tx for Meningitis due to C. neoformans in Non-HIV
Organ Transplant Px
- liposomal AmB or AmB lipid complex (ABLC) + flucytosine for at least 2 wks or until CSF culture is sterile.
- Follow CSF yeast cultures for sterilization
- Followed by an 8- to 10-wk course of fluconazole
- Dose of fluconazole is decreased to 200 mg/d for 6 months toa year If the CSF culture is sterile after 10 weeks of acute therapy.
Tx for Meningitis in HIV
- AmB or alipid formulation + flucytosine for at least 2 weeks
- Followed by fluconazole for a minimum of 8 weeks
- HIV-infected patients may require indefinite maintenance therapy with fluconazole 200 mg/d.
Tx for Meningitis due to H. capsulatum
- AmB (0.7-1.0 mg/kg/day) for 4-12 weeks. Total dose of 30 mg/kg.
- Maintenance therapy with Itraconazole 200 mg 2-3X daily is initiated and continued for at least 9 mons to a year
Tx for Meningitis due to C. immitis
- High-dose fluconazole (1000 mg daily) as monotherapy or IV AmB for >4 weeks.
- Intrathecal AmB (0.25-0.75 mg/d 3X weekly) may be required to eradicate the infection.
- Lifelong therapy with fluconazole (200-400 mg daily): prevent relapse
- AmBisome (S mg/kg per day) or AmB lipid complex (S mg/kg per day) substituted for AmB in patients who have or who develop significant renal dysfunction.
Tx for Syphilitic Meningitis
- Aqueous penicillin G in a dose of 3-4 million units IV q4h for 10-14 days.
- Alternative regimen : 2.4 million units of Procaine Pen G (IM) daily with SOO mg of oral Probenecid 4x daily for 10-14 days.
- Followed with 2.4 million units of benzathine penicillin G (IM) once a week for 3 weeks.
Treatment success criterion
- Reexamination of the CSF
- CSF should be reexamined at 6-month intervals for 2 years
- Cell count is expected to normalize within 12 months and VORL titer to decrease by two dilutions or revert to nonreactive within 2 years of completion of therapy
