Crit Care Clin

Laboratory tests in critical care.

Midha NK. Stratton CW.
Clinical Microbiology Laboratory, Vanderbilt University School of Medicine Nashville, Tennessee, USA.
A simple clinical index can be utilized to identify occult bacterial infections in the critical care unit. Use of this index enables the critical care physician to estimate the likelihood of occult infection, thus reducing and directing the diagnostic effort. This article reviews nonspecific screening tests used in the index.

Fulminant hepatic failure.

Year 1998
Bernstein D. Tripodi J.
State University of New York School of Medicine, Stony Brook, USA.
Fulminant hepatic failure is a devastating illness that carries considerable mortality and affects patients with previously healthy livers. Although the etiology of FHF remains unclear in a significant number of cases, viral hepatitis and drug-induced liver injury account for the majority of identifiable causes. The clinical presentation varies widely, but is always characterized by the presence of encephalopathy. Markedly elevated transaminases are seen, but do not correlate with extent of liver injury. Prothrombin time, bilirubin, creatinine, and arterial pH are prognostic indicators of survival in FHF. FHF and its consequences must be readily recognized so that appropriate triage and treatment can be administered. All patients should be managed in an intensive care setting pending transfer to a liver transplantation center. Supportive care remains the mainstay of treatment, with liver transplantation reserved for select patients.

Infections in nonleukopenic compromised hosts (diabetes mellitus, SLE, steroids, and asplenia) in critical care.

Year 1998
Cunha BA.
Infectious Disease Division, Winthrop-University Hospital, Mineola, New York, USA.
Acutely ill patients who are immunocompromised but not neutropenic most commonly are: (1) diabetic; (2) on chronic high-dose steroid therapy; (3) have lupus; or (4) have impaired or absent splenic function. These patients often present in the CCU because of the severity of their infection. Differential diagnosis may be approached by first considering the patient's underlying disease, i.e., SLE. The next step in the diagnostic process is to appreciate the immune defect associated with these disorders. The nature of the immune defect determines which clinical pathogens are related to the immune defect. Pathogens are associated with a sterotyped pattern of organ involvement. The object of the diagnostic analysis is to determine the most likely organism affecting a particular organ system, given the defect in host defenses associated with the patient's underlying illness. In this way, a useful clinical diagnosis can be made rapidly, and appropriate clinical specimens obtained for diagnostic testing. Often empiric therapy must be started pending the results of diagnostic testing. In such situations, empiric therapy ordinarily is directed against the bacterial pathogens most likely to cause disease relevant to the patient's impaired defenses. Specific therapy for unusual or exotic pathogens should not be empiric and should be based on demonstration of a pathogenic role by the microorganism. In the case of miliary tuberculosis or invasive fungal disease, a case may be made for early empiric therapy to cover these organisms if there is sufficient clinical suspicion based on the presenting signs and symptoms as well as the pattern of organ involvement. As with all infections, but particularly in immunocompromised patients, the early initiation of appropriate antimicrobial therapy is essential and often life-saving.

Nosocomial diarrhea.

Year 1998
Cunha BA.
Infectious Disease Division, Winthrop-University Hospital, Mineola, New York, USA.
Nosocomial diarrheas are an important problem in hospitals, and in critical care units in particular. Hospital-acquired diarrhea may be on an infectious or noninfectious basis. Common noninfectious causes of nosocomial diarrhea include medication-induced changes in the fecal flora or changes secondary to enteral hyperalimenation. Infectious causes of nosocomial diarrhea are due to enteric pathogens in outbreak situations and virtually all of the causes are due to Clostridium difficile. C. difficile is a resident of the human colon and does not cause disease if its toxins are not elaborated. Chemotherapeutic agents, and more commonly, antibiotics, induce the elaboration of toxin A and B from C. difficile in the distal gastrointestinal tract. The spectrum of disease of C. difficile in hospitalized patients includes asymptomatic carriage to mild watery diarrhea, fulminant and severe diarrhea, and pseudomembranous enterocolitis. The treatment of C. difficile diarrhea is usually with oral metronidazole or vancomycin, and C. difficile colitis is treated with intravenous metronidazole. Infection control measures are necessary to prevent the spread of this sporforming organism within the institution since it is capable of surviving in the hospital environment for prolonged periods.