Phys · infectious
Infections in the Immunocompromised Host
Also known as febrile neutropenia · neutropenic sepsis · neutropenic fever protocol · opportunistic infection · immunocompromised host · infection in the cancer patient · transplant infection timeline · post-transplant lymphoproliferative disorder · overwhelming post-splenectomy infection · OPSI · invasive aspergillosis · CMV disease · hepatitis B reactivation · anti-TNF tuberculosis
Consultant-physician-depth guide to the febrile immunocompromised patient — the central principle that the TYPE of immune defect predicts the organism, empiric therapy, and prophylaxis. Covers neutropenic fever (post-chemotherapy, AML induction) with the door-to-antibiotic protocol and piperacillin-tazobactam, the IDSA threshold of temperature above 38.3 single or above 38 sustained with neutrophils below 0.5, and G-CSF prophylaxis. Cellular immunodeficiency (HIV CD4-based; transplant 0 to 1 month nosocomial, 1 to 6 months opportunistic, above 6 months community) with PCP, Toxoplasma, Cryptococcus, HSV, VZV, CMV, MAC. Humoral immunodeficiency (myeloma, CLL, splenectomy) with encapsulated bacteria and vaccination. The solid organ transplant infection timeline, biologic therapy infections (anti-TNF and TB, rituximab and HBV, alemtuzumab and CMV), prophylaxis strategies (co-trimoxazole for PCP, valganciclovir for CMV D+/R-, fluconazole in high-risk neutropenia), and vaccination including avoidance of live vaccines — structured for FRACP DWE and DCE preparation.
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- A single temperature above 38.3 degrees (or sustained above 38 for over one hour) in a patient with neutrophils below 0.5 is febrile neutropenia — a medical emergency requiring empiric antipseudomonal antibiotics within one hour; do not wait for cultures or a rising count
- Pseudomonas aeruginosa bacteraemia in neutropenia can kill within hours — the empiric regimen MUST cover it from the first dose; ecthyma gangrenosum is its cutaneous signature
- Any patient starting rituximab, chemotherapy, or a biologic must be screened for hepatitis B with HBsAg AND anti-HBc — resolved HBV can reactivate and cause fulminant hepatic failure; prophylactic entecavir or tenofovir prevents it
- Any patient starting anti-TNF therapy must be screened for latent tuberculosis with an IGRA and chest X-ray before the first dose — TB reactivation occurs at a median of 12 weeks, often extrapulmonary or disseminated
- Persistent fever in neutropenia beyond 3 to 5 days mandates a chest CT, galactomannan, and empiric antifungal therapy — invasive aspergillosis carries 50 to 60 per cent mortality despite treatment
- An asplenic patient with fever has overwhelming post-splenectomy infection (OPSI) until proven otherwise — give ceftriaxone within one hour; mortality is 50 to 70 per cent despite treatment, and a delayed first antibiotic is the single greatest predictor of death
- CMV disease in a transplant recipient at 1 to 6 months suppresses host immunity and predisposes to bacterial sepsis, invasive fungal infection, and EBV-driven post-transplant lymphoproliferative disorder — preventing CMV prevents these secondary complications
- Do NOT give live vaccines (MMR, varicella, yellow fever, live attenuated influenza, oral polio, oral typhoid Ty21a, BCG) to severely immunosuppressed patients, transplant recipients on immunosuppression, or those with HIV and CD4 below 200
Infections in the Immunocompromised Host
[1]The one-minute consultant answer
A fever in an immunocompromised patient is a different disease from a fever in a normal host, because the type of immune defect predicts the organism, the empiric therapy, and the prophylaxis. The single most important question at the bedside is therefore what is the type of immunodeficiency? — and the answer divides every patient into one of five buckets that drive the rest of the encounter. [1]
Neutropenia (most often post-chemotherapy, classically AML induction, when neutrophils fall below 0.5) is a medical emergency: febrile neutropenia is defined as a single temperature above 38.3 degrees or a sustained temperature above 38 for over one hour in a patient with a neutrophil count below 0.5, and the door-to-antibiotic time must be within one hour [1]. The empiric regimen is an antipseudomonal beta-lactam — piperacillin-tazobactam 4.5 g IV in the ANZ setting — given immediately after blood cultures, because Pseudomonas aeruginosa bacteraemia can kill within hours and the empiric cover must include it from the first dose. A Cochrane review of 71 trials confirmed that beta-lactam monotherapy is as effective as beta-lactam plus aminoglycoside combination with less toxicity [2], and another Cochrane review established that routine G-CSF does not reduce mortality in established febrile neutropenia [3].
Cellular immunodeficiency (HIV by CD4 count; transplant by time since engraftment) opens the door to the opportunistic organisms: PCP, Toxoplasma, Cryptococcus, CMV, HSV, VZV, MAC, and the endemic fungi. Humoral immunodeficiency (multiple myeloma, CLL, splenectomy) is the home of the encapsulated bacteria — S. pneumoniae, H. influenzae, N. meningitidis — and overwhelming post-splenectomy infection (OPSI), which is prevented by vaccination, prophylactic penicillin, and a standby-antibiotic plan. Solid organ transplant follows a timeline — month 0 to 1: donor-derived, nosocomial, wound; months 1 to 6: opportunistic (CMV, BK, PCP, Aspergillus, EBV); beyond 6 months: community-acquired. And biologic therapy has its own signature: anti-TNF reactivates TB (median 12 weeks, often extrapulmonary) [7]; rituximab reactivates HBV even from resolved infection (which is why every patient must be screened with HBsAg and anti-HBc and given prophylactic entecavir or tenofovir) [5].
The non-negotiable principles: screen before you suppress (TB before anti-TNF; HBV before rituximab or chemotherapy; strongyloides before steroids in anyone from a tropical area; vaccinations before immunosuppression begins); give prophylaxis that works (co-trimoxazole for PCP; valganciclovir for CMV D+/R-; fluconazole or posaconazole in high-risk neutropenia); and never give a live vaccine to a severely immunosuppressed patient [6].
References9ShowHide
- [1]Freifeld AG, Bow EJ, Sepkowitz KA, et al. Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america Clin Infect Dis, 2011.PMID 21258094
- [2]Paul M, Dickstein Y, Schlesinger A, et al. Beta-lactam versus beta-lactam-aminoglycoside combination therapy in cancer patients with neutropenia Cochrane Database Syst Rev, 2013.PMID 23813455
- [3]Mhaskar R, Clark OAC, Lyman G, et al. Colony-stimulating factors for chemotherapy-induced febrile neutropenia Cochrane Database Syst Rev, 2014.PMID 25356786
- [4]Tomblyn M, Chiller T, Einsele H, et al. Guidelines for preventing infectious complications among hematopoietic cell transplantation recipients: a global perspective Biol Blood Marrow Transplant, 2009.PMID 19747629
- [5]Loomba R, Rowley A, Wesley R, et al. Systematic review: the effect of preventive lamivudine on hepatitis B reactivation during chemotherapy Ann Intern Med, 2008.PMID 18378948
- [6]Rubin LG, Levin MJ, Ljungman P, et al. 2013 IDSA clinical practice guideline for vaccination of the immunocompromised host Clin Infect Dis, 2014.PMID 24421306
- [7]Keane J, Gershon S, Wise RP, et al. Tuberculosis associated with infliximab, a tumor necrosis factor alpha-neutralizing agent N Engl J Med, 2001.PMID 11596589
- [8]Perfect JR, Dismukes WE, Dromer F, et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the infectious diseases society of america Clin Infect Dis, 2010.PMID 20047480
- [9]Paul M, Dickstein Y, Borok S, Vidal L, Leibovici L Empirical antibiotics targeting gram-positive bacteria for the treatment of febrile neutropenic patients with cancer Cochrane Database Syst Rev, 2017.PMID 28577308