CDC malaria branch clinician. Once approved, four equal doses of artesuante will be provided
over a three-day period, with the remainder of the seven-day therapy to be completed with a
supplemental antimalaria drug such as doxycycline, clindamycin, mefloquine, or atovaquone-
proquanil (35).
Although there is no randomized controlled trial demonstrating efficacy or survival
benefit over chemotherapy alone, exchange transfusion is occasionally used for severe malaria
when parasitemia levels exceed 10% or if the patient has altered mental status, non-volume
overload pulmonary edema or renal complications (36,37). It is usually continued until the
parasite load is<1% (usually 8 to 10 units). IV quinidine or artesuante should not be delayed
for an exchange transfusion and can be given concurrently. Controlled trials of adjunctive
corticosteroid use has shown not only a lack of efficacy, but deleterious effects in patients with
severe malaria (38). Renal failure and/or lactic acidosis can contribute to life-threatening
metabolic acidosis in patients with severe malaria, and hemofiltration is associated with lower
mortality than peritoneal dialysis in these patients (39).
Early recognition and prompt therapy of patients with complicated malaria is critical to
successful outcome. All patients with severe or complicated malaria should be managed in an
intensive care setting. Proposed criteria for ICU admission include: base excess<8, high-level
parasitemia (non-endemic area>10% and endemic area>20%), Glascow Coma Score<8,
blood glucose<2.2 mmol/L, urine output<0.5 mL/kg/h, or pulmonary edema (29). Close
clinical monitoring with special attention to the following is recommended: (1) clinical
improvement within 48 to 72 hours; (2) thick and thin smears prepared every 12 hours;
(3) parasitemia reduced by 75% within 48 hours. Failure to show clinical or microscopic
resolution suggests one or more of the following: (1) secondary complications such as bacterial
superinfection [observed in 14% of returning travelers with severe malaria (40)]; (2) problems
with medication administration; and (3) antimalarial resistance.
CRITICAL CARE INFECTIOUS DISEASE SYNDROMES
Severe pneumonia or ARDS
Among travelers, respiratory tract infections comprised only 8% of all infections reported to
GeoSentinel from 1997–2001 (41). For severe pneumonia or infection-related ARDS acquired
within the United States, the most common etiologies are community-acquired respiratory
pathogens such asStreptococcus pneumoniaeandLegionella pneumophilaor as a complication of
bacterial sepsis with other pathogens (42,43). However, the differential diagnosis of potential
pathogens is broader if the patient is a returned traveler.
The WHO estimates that one-third of the world’s population is currently infected with
TB, and that prevalence increases by greater than 85,000 new infections each day (44). It is not
clear how many travelers acquire this infection abroad. One Dutch study that evaluated
travelers to countries where the population faces at least a 1% risk of TB infection annually,
found the overall incidence of new TB infection was 3.5 per 1000 person-months of travel
(approaching that of the local populations in endemic areas) (45).
It is helpful for the critical care physician to recall not only the high prevalence of TB
world-wide, but the variable presentation of this infection, which may include pulmonary
infiltrate with hypoxia and hemoptysis, exudative pleural effusion, miliary, even disseminated
disease (46–48). A fulminant presentation of miliary TB may occur in both adults and in
children, with as many as two-thirds of the latter cases complicated by meningeal involvement
(46,47). The clinical presentation of severe tuberculous pneumonia may be indistinguishable
from other causes of bacterial pneumonia. Miliary TB has a nonspecific presentation, including
fever, tachypnea, rales, and altered mental status and, less commonly, ARDS and DIC.
With mortality rates of miliary TB as high as 21%, airborne precautions, aggressive
diagnostic evaluation (acid-fast staining of sputum, bronchial washings, etc.), and early
initiation of an empiric multidrug antituberculous regimen (e.g., isoniazid, rifampin,
pyrazinamide, and ethambutol/streptomycin) (49,50) should be considered whenever miliary
TB is suspected. However, with drug-resistant TB increasingly prevalant (44), choosing the
most tolerable empiric drug regimen with the highest likelihood of success can be challenging.
Multidrug-resistant (MDR) TB has been defined as an isolate resistant to isoniazid and
rifampin; while extensive drug-resistant (XDR) TB defines an isolate resistant to isoniazid,
326 Wood-Morris et al.