Hantavirus Pulmonary Syndrome
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Contents |
Introduction
- Identified in the southwest USA in 1993, but retrospectively identified serologically as far back as 1959.
Etiology
- Hantaviruses associated with the rodent subfamily Sigmodontinae
- 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
- Black Creek Canal virus which infects the cotton rat Sigmodon hispidus
- bayou virus which infects the rice rat Oryzomys palustris
- Andes virus
Epidemiology
- infection acquired via inhalation of rodent excreta
- human to human transmission may occur [4]
- more common in southwest US
- median age of patients is 32 years (range: 12-69 years)
- 52% of patients are male; 55% are Native American
Clinical-manifestations
- rapidly progessive syndrome
- prodrome of about 3-4 days (range 1-11 days)
- fever, myalgia, malaise, nausea/vomiting, abdominal pain dizziness (common), vertigo (occasional)
- pulmonary phase
- mild hypotension, tachycardia, tachypnea, hypoxemia, pulmonary edema
- physical findings in chest unremarkable
- conjunctival & cutaneous signs of vascular involvement are absent
- respiratory failure within a few hours in immunocompetent individuals
Laboratory
-
- marked leukocytosis
- atypical lymphocytes
- thrombocytopenia (70%)
- hemoconcentration (70%)
- urinalysis: albuminuria
- evidence of disseminated intravascular coagulation ( DIC) only in a minority of patients
- mildly increased serum creatinine & serum urea nitrogen
- lactic acidosis in severely ill patients
- immunofluorescent antibody staining of sputum or lung tissue
- IgM testing of acute-phase serum, positive even in prodrome
- reverse-transcriptase polymerase chain reaction ( RT-PCR)
Radiology
-
- early evidence of pulmonary interstitial edema
- pleural effusion common
Differential-diagnosis
- abdominal surgical conditions
- pyelonephritis
- rickettsial diseases ( Rocky Mountain spotted fever)
- sepsis
- meningiococcemia
- plague
- tularemia
- influenza
- Borreliosis ( relapsing fever)
Management
- prognosis
- 40-50% mortality
- most patients surviving the 1st 48 hours are extubated & discharged from hospital without residua
- 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
- pharmaceutical agents
- ribavirin has been used on an experimental basis
More General Terms
Additional Terms
References
- Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
- 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
- Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
