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hantavirus pulmonary syndrome
Identified in the southwest USA in 1993, but retrospectively identified serologically as far back as 1959.
Etiology:
- Hantaviruses associated with rodent subfamily Sigmodontinae
a) Sin Nombre virus which infects Peromyscus manniculatus in the southwest & Peromyscus leucopus in southern states is the most important virus causing Hantavirus pulmonary syndrome in the USA
b) Black Creek Canal virus which infects the cotton rat Sigmodon hispidus
c) bayou virus which infects the rice rat Oryzomys palustris
d) Andes virus
Epidemiology:
1) infection acquired via inhalation of rodent excreta
2) human to human transmission may occur [1]
3) more common in southwest US
4) median age of patients is 32 years (range: 12-69 years)
5) 52% of patients are male; 55% are Native American
6) eight people in summer of 2012 infected at Yosemite National Park, Curry Village (3 of them died) [5,4]
Clinical manifestations:
1) rapidly progessive syndrome
2) prodrome of about 3-4 days (range 1-11 days)
- fever, myalgia, malaise, nausea/vomiting, abdominal pain dizziness (common), vertigo (occasional)
3) pulmonary phase (acute respiratory distress syndrome)
a) mild hypotension, tachycardia, tachypnea, hypoxemia, pulmonary edema
b) physical findings in chest unremarkable
c) conjunctival & cutaneous signs of vascular involvement are absent
d) respiratory failure within a few hours in immunocompetent individuals
Laboratory:
1) complete blood count (CBC)
a) leukocytosis with left shift
b) atypical lymphocytes
c) thrombocytopenia (70%)
d) hemoconcentration (70%)
2) urinalysis: albuminuria
3) evidence of disseminated intravascular coagulation (DIC) only in a minority of patients
4) mildly increased serum creatinine & serum urea nitrogen
5) lactic acidosis in severely ill patients
6) Hantavirus antigen
- immunofluorescent antibody staining of sputum or lung tissue
7) Hantavirus serology
- IgM testing of acute-phase serum, positive even in prodrome
- Hantavirus sin nombre IgM in serum
8) Hantavirus RNA
9) see ARUP consult [4]
Radiology: Chest X-ray:
a) early evidence of pulmonary interstitial edema
b) pleural effusion common
Differential diagnosis:
1) abdominal surgical conditions
2) pyelonephritis
3) rickettsial diseases (Rocky Mountain spotted fever)
4) sepsis
5) meningiococcemia
6) plague
7) tularemia
8) influenza
9) Borreliosis (relapsing fever)
Management:
1) prognosis
- 40-50% mortality
- most patients surviving the 1st 48 hours are extubated & discharged from hospital without residua
2) supportive therapy
- goal is to prevent hypoxemia
- supplemental oxygen
- endotracheal intubation if indicated
- Swan-Ganz catheterization
- cautious fluid administration guided by pulmonary capillary wedge pressure
- vasopressors to maintain blood pressure
3) pharmaceutical agents
- ribavirin has been used on an experimental basis
Related
hantavirus
General
lung disease
viral hemorrhagic fever syndrome; hemorrhagic nephroso-nephritis
References
- Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 18.
American College of Physicians, Philadelphia 1998, 2012, 2018.
- Harrison's Principles of Internal Medicine, 14th ed.
Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 1144
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed)
Lippincott-Raven, Philadelphia, 1998, pg 518, 795
- ARUP Consult: Hantavirus
The Physician's Guide to Laboratory Test Selection & Interpretation
https://www.arupconsult.com/content/hantavirus
- Physician's First Watch, Aug 29 2012
Massachusetts Medical Society
http://www.jwatch.org
- National Park Service
Hantavirus Pulmonary Syndrome Response Continues at Yosemite National Park
http://www.nps.gov/yose/parknews/hanta_8-27-12.htm
- National Park Service
Hantavirus Frequently Asked Questions
http://www.nps.gov/yose/planyourvisit/hantafaq.htm