Approach to the Immunocompromised Host with Infection in the Intensive Care Unit
Section snippets
Altered Clinical Expression
Because of diminished or absent inflammatory responses, the expected local clinical and radiographic signs of infection may not be present. In patients who are critically ill there are other confounders which may camouflage symptom and sign detection, such as iatrogenic sedation, and multiple processes (fluid overload, atelectasis), which produce pulmonary radiographic changes unrelated to infection. Detectable but atypical presentations caused by opportunistic pathogens are also more prevalent
Initial assessment of the immunocompromised patient
A pathogen-based discussion does not accurately emulate real clinical practice where the clinician initially only has knowledge of the type of immune defects and the patient's signs and symptoms suggestive of infection. There is a common ethic to the diagnostic assessment of the diverse population who meet the definition of immunocompromised host. The specific types of natural or acquired immune compromise predisposes such hosts to infection with a spectrum of pathogens which can be further
Common clinical presentations
Although there is a diverse number of opportunistic pathogens which may cause invasive disease in the immunocompromised host, there are a finite number of stereotypical presentations or syndromes (Box 3). Systemic signs of infection coupled with respiratory insufficiency/failure and radiographic infiltrates, altered sensorium with or without focal neurologic signs and fever/sepsis of unknown origin are two characteristic presentations which usually culminate in ICU admission and merit
Management of iatrogenic immunosuppression
Withdrawal or rapid tapering of iatrogenic immunosuppression, particularly corticosteroids, is a well-described option particularly in organ transplant recipients with rapid deterioration caused by life-threatening infection or posttransplant lymphoproliferative disease.56, 57 However there are several mitigating factors which need to be considered on a case-by-case basis:
Is allograft rejection already occurring? Unexplained allograft dysfunction should be investigated with a biopsy to rule out
Protective isolation and special precautions
Despite the higher prevalence of multidrug resistant bacteria in the ICU, more severe illness of the immunocompromised host requiring ICU care, the vast majority of immunocompromised hosts requiring intensive care do not routinely require protective or reverse isolation. The intent of protective isolation is to prevent the acquisition of exogenous organisms by maintaining them in a single room, with a closed door to limit entry, coupled with ambient positive pressure. Such practices have
Emerging trends among immunocompromised hosts relevant to ICU practice
Multidrug-resistant bacteria, particularly from the nosocomial setting, have become more prevalent among immunocompromised hosts because of their greater time exposure to the health-care environment and selective pressure from prophylactic and therapeutic anti-infective exposure. Since the 1990s, VRE has become a prominent pathogen in oncologic and liver-transplant recipients although its clinical impact has diminished somewhat with the use of linezolid therapy. Early reports of
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