Infection in the Immunocompromised Host

The Immunocompromised Host

Infections in Cancer

Host Defense Defect

Microorganisms Commonly Causing Infection

Common Underlying Conditions

Impaired antibody function

Streptococcus pneumoniae, Hemophilus influenzae type B, Neisseria meningitidis, Enteroviruses

Congenital and acquired hypoglobulinemia, B-cell malignancies, AIDS

Defects in complement

(CLL, multiple myeloma, chemotherapy)

Streptococcus pneumoniae, Haemophilus influenzae type B, Neisseria spp (encapsulated bugs)

Congenital and acquired hypocomplementemic states, hypocomplementemic vasculitis

Depressed cell-mediated immunity (Hodgkin’s, CLL, Steroids, Malnutrition)

Mycobacteria, Listeria monocytogenes, Nocardia
asteroids
, Salmonella, fungi (including Pneumocystis carinii), Toxoplasma gondii, Strongyloides stercoralis, herpes group viruses, measles (intracellular pathogens)

AIDS, transplant recipients, lymphoma, prolonged corticosteroid therapy, congenital defects

Decrease in the number of fully functional granulocytes (neutropenia)

Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus, oral bacterial flora, Aspergillus spp, Candida spp (extracellular pathogens)

Myeloproliferative disorders, cytotoxic chemotherapy, congenital disorders

CHEST X-RAY FINDINGS AND RATES OF PROGRESSION OF DISEASE AS CLUES TO DIAGNOSIS

RATE OF PROGRESSION

Chest X-ray abnormality

Acute

Subacute-Chronic

Consolidation:

Bacterial, hemorrhage Thromboembolic

Fungal, TB, Tumor, Nocardia

Diffuse Interstitial:

Pulmonary edema, ARDS, Bacterial

Viral, Pneumocystis, Drug

Nodular:

(Bacterial, fungal); pulmonary edema

Tumor, Fungal, Nocardia, TB

Foundations of Emprical Therapy in the Neutropenic Host