Uncertain Terrain

A 70-year-old man with mantle cell lymphoma presented to the hospital with a 10-day history of fever, myalgia, and exertional shortness of breath.His other medical history was notable for hypertension, hyperlipidemia, and depression.He was receiving rituximab and bendamustine for treatment of his lymphoma, and his last doses were 3 weeks prior to this presentation.When presented with a new consultation, our early goals are to gather information about the patient and create a problem representation (PR) that can help direct recommendations for diagnostics or interventions.A PR is a summary statement that highlights the important and defining features of a case in order to generate a focused differential diagnosis.An effective PR is comprised of 3 components: the "who" (patient demographic characteristics and epidemiologic risk factors), the "when" (duration and tempo of illness), and the "what" (diagnostically high-yield elements of the presenting syndrome).First, "who" is our patient?As infectious diseases (ID) clinicians, we are known for our ability to recognize relevant epidemiologic exposures and characterize a patient's immune status.For those with different forms of immune dysfunction, an important skill is estimating a patient's "net state of immunosuppression."This conceptual framework consists of a comprehensive assessment of all factors that contribute to susceptibility to infection, such as the type, dose, and duration of immunosuppressive therapy; neutropenia or lymphopenia; solid organ or hematopoietic cell transplantation; and other conditions.For this patient, I would highlight his underlying mantle cell lymphoma as well as receipt of a B cell-depleting agent (ie, rituximab).