Presentation Transcript
The Case of the Big Bad Bug#16: The Case of the Big Bad Bug #16 Jim Pointer, MD
Alameda County EMS
Medical Director
The Call: The Call A south county resident calls 9-1-1 complaining of a 2 day history of fever (103˚), headache, maliaise, nausea, weakness, stiff neck, and a rash.
History: History The patient is a 74 year old male with a past history of CABG x 3 and prostate cancer.
Current medications include:
Nitroglycerine
Aspirin
Proscar
No history of foreign travel
Field Assessment: Field Assessment Primary survey: WNL
Vital signs:
B/P – 152/97, PR – 138, RR – 22
Temp – 102.6 p.o.
Secondary survey (pertinent findings)
HEENT – dry mucous membranes
Lungs – clear
Skin – warm/dry; erythematous maculopapular rash on neck & trunk
Neuro – confused, GCS: 13 - 14
Treatment: Treatment IV – normal saline 500cc’s
Glucose check – 102 mg/dl
Transport to Culex Memorial Hospital
Hospital Course: Hospital Course The patient tells the physician that he saw several dead Stellar’s Jays on his property 5-7 days ago. When he picked them up he received several insect bites
Hospital Exam: Hospital Exam Vital signs:
B/P – 142/98, PR – 126, RR – 20
Temp - 102.7 p.o.
Pulse Ox - 98% RA
Additional physical findings
Mild nuchal rigidity
Laboratory Findings: Laboratory Findings CBC – 11.1 K
86 lymphocytes, 10 PMNs, 2 Basophils, 2 Eosinophils
Na+, K+, HCO3, Cl-, BUN, creatinine, glucose – WNL
Cerebrospinal fluid:
Color – clear, WBC – 120 cells/mm3
Protein – 82 mg/dL (n = 20 – 45)
Glucose – 78 mg/dL (n = 50 – 80)
West Nile Virus: West Nile Virus Ecology:
Enzootic cycle – culcine mosquitoes and birds
Corrids (crows, ravens, jays) are particularly susceptible
“Bridge vector” mosquitoes in late summer
Over 30 mosquito species responsible
Mammals (humans, horses, ? deer) “dead-end hosts”
Surveillance systems – dead birds, “sentinel chickens”, ill horses
West Nile Virus (cont.): West Nile Virus (cont.) First isolated in 1937
First occurred in western hemisphere in New York in 1999
About 400 deaths reported in the US to date – about 9,000 cases reported for 2003
Vaccine available for horses (1/3 of infected horses die)
Transmission Cycle: Transmission Cycle
Virology: Virology Single stranded RNA virus
Family: Flaviviridae
Genus: Flavivirus
Member of Japanese encephalitis virus serocomplex including:
Japanese encephalitis
St. Louis encephalitis
Murray Valley encephalitis
Kunjin viris
Geographic Distribution 2004: Geographic Distribution 2004
Geographic Distribution Calif.: Geographic Distribution Calif.
Geographic Distribution horses: Geographic Distribution horses
Clinical Features: Clinical Features Incubation period: 3 – 14 days
Probably < 20% of those infected will develop clinical infection
Febrille illness of sudden onset
malaise, myalgias, anorexia
nausea, vomiting
Eye pain, headache
Rash, lymphadenopathy
Clinical Features (cont.): Clinical Features (cont.) 1/150 infections result in meningitis/ encephalitis
Encephalitis is more common
Advancing age most significant risk factor for neurologic disease
Age 50 to 59 - 10x higher
Age > 80 - 43x higher
Severe weakness in 50% of hospitalized patients in U.S.
Table of Symptoms: Table of Symptoms
Outcome: Outcome Death rates: 4 – 14 %
Much higher in older patients or those with diabetes or immunocompromised
Morbidity
Fatigue
Memory loss
Depression
Difficulty walking
Treatment: Treatment Supportive
Ribavirin and interferon effective in vitro
No clinical trials
Lab Findings: Lab Findings WBC – normal or elevated
Occasional anemia
Low sodium
CSF:
WBC - 0 to 1782 cells/mm3
Protein - elevated
Glucose - normal
Lab Findings (cont.): Lab Findings (cont.) MRI – meningeal or periventricular enhancement
IgM –
most efficient diagnostic method (serum or CSF)
Persistent for > 6 months
Present in other Flavivirus infections and in vaccinated persons
Reporting: Reporting Reportable disease
Serum and CSF specimens must be submitted
Prevention: Prevention Reduce # of mosquitoes
Eliminate breeding sites
Apply larvacides or approved pesticides
Prevent mosquito bites
Use DEET (not > 50% adults/10% kids)
Employ barrier methods
Slide27: Pull out Betty…pull out! I think you hit an artery
Reference: Reference Petersen LR, Marfin AA: West Nile Virus: A primer for the clinician, American Journal of Internal Medicine. 2002; 137 : E 173 - 179