On presentation, laboratory abnormalities found in some but not all patients include
elevated liver enzymes (uncommon to 80%), prolonged APTT, lymphopenia, hyponatremia
(20–60%), hypokalemia, thrombocytopenia (33–50%), and hypoxia (104).
From 23% to 34% of patients were admitted to intensive care units. Predictors of
mortality were age over 60 years and elevated neutrophil count on presentation. Two
institutions reported mortality rates of 12% and 15.7% (105). Mortality rates for SARS patients
admitted to an intensive care unit are 34% to 53% at 28 days (112). In the United States, eight
cases were identified in 2003, two were admitted to intensive care units, one required
mechanical ventilation, and there were no deaths (110).
Diagnosis: Immunoswab (monoclonal antibody-based) assay; ELISA, Western Blot,
immunodot, immunofluorescent antibody, viral culture and viral neutralization—for confir-
mation of serology (biosafety level III laboratory required), and reverse transcriptase
polymerase chain reaction. Electron microscopy and viral culture are low-sensitivity tests (113).
Differential diagnosis: Other bacterial and viral pneumonias, tickborne relapsing fever
with ARDS, antiphospholipid syndrome (114,115). SARS should be suspected in patients with
no response to therapy in the first 72 hours, especially in the presence of lymphopenia or an
absolute low neutrophil count.
Treatment: Supportive. It has been recommended that those patients requiring mechan-
ical ventilation should receive lung protective, low tidal volume therapy (116).
There is a higher incidence of pneumothorax in mechanically ventilated SARS patients
(20–34%), but the study by Kao et al. found no statistical difference in pneumothorax risk in
respirator settings (117).
Steroids may be detrimental and available antivirals have not proven of benefit (107).
Viral Hemorrhagic Fevers (6)
The viral hemorrhagic fever agents principally fall into four families of RNA viruses: the
Arenaviridae (Argentine, Bolivian, Brazilian, and Venezuelan hemorrhagic fevers and Lassa
fever); the Bunyaviridae (Hantavirus genus, Crimean-Congohemorrhagic fever from the
Nairovirusgenus, and Rift Valley fever virus from the Phlebovirus genus); the Filoviridae
(Ebola and Marburg viruses); and the Flaviviridae (dengue and yellow fever viruses).
Incubation period: Incubation periods for most pathogens are from 7 to 14 days, with
variousranges(Lassafever:5–21days;RiftValleyfever:2–6days;Crimean-Congo
hemorrhagic fever after tick bite: 1–3 days; contact with contaminated blood: 5–6 days);
Hantavirus hemorrhagic fever with renal syndrome: 2 to 3 weeks (range: 2 days–2 months);
Hantavirus pulmonary syndrome (Sin Nombre virus): 1 to 2 weeks (range: 1–4 weeks); Ebola
virus: 4 to 10 days (range 2–21 days); Marburg virus: 3 to 10 days; dengue hemorrhagic fever:
2 to 5 days; yellow fever: 3 to 6 days; Kyasanur forest hemorrhagic fever: 3 to 8 days; Omsk
hemorrhagic fever: 3 to 8 days; Alkhumra hemorrhagic fever: not determined. These
incubation periods are documented for the pathogens’ traditional modes of transmission
(mosquito tick bite, direct contact with infected animals or contaminated blood, or aerosolized
rodent excreta).
Contagious period: Patients should be considered contagious throughout the illness.
Clinical disease: Most diseases present with several days of nonspecific illness followed by
hypotension, petechiae in the soft palate, axilla, and gingiva. Some patients develop neurologic
complications. Patients withLassa feverdevelop conjunctival injection, pharyngitis (with white
and yellow exudates), nausea, vomiting, and abdominal pain. Severely ill patients have facial
and laryngeal edema, cyanosis, bleeding, and shock.
Livestock affected byRift Valley fever viruscommonly abort and have 10% to 30%
mortality. There is 1% mortality in humans with 10% of patients developing retinal disease one
to three weeks after their febrile illness.
Patients withCrimean-Congo hemorrhagic feverpresent with sudden onset of fever, chills,
headache, dizziness, neck pain, and myalgia. Lymphadenopathy and tender hepatomegaly is
present. Some patients develop nausea, vomiting, diarrhea, flushing, hemorrhage, and
gastrointestinal bleeding.
Patients withHantavirus hemorrhagic fever with renal syndromego through five phases of
illness: (i) febrile (flu-like illness, back pain, retroperitoneal edema, flushing, conjunctival, and
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