FEBRILE NEUTROPENIA (FN) — DEFINITIONS AND RISK STRATIFICATION
Febrile neutropenia is defined as a single oral temperature ≥ 38.3°C (101°F) OR ≥ 38.0°C (100.4°F) sustained for ≥ 1 hour, with an absolute neutrophil count (ANC) < 500 cells/mm³ (or < 1,000 cells/mm³ with expected decline to < 500).
Risk Stratification:
HIGH-RISK (requires hospitalization and IV therapy): MASCC score < 21, CISNE score ≥ 3, anticipated prolonged neutropenia (> 7 days), ANC < 100, clinically unstable (hypotension, organ dysfunction), inpatient at time of fever, acute leukemia not in remission, uncontrolled or progressive cancer, significant comorbidities.
LOW-RISK (oral outpatient therapy may be appropriate): MASCC score ≥ 21, CISNE score 0–2, anticipated short duration of neutropenia (< 7 days), clinically stable, solid tumor patients with outpatient-managed cancer.
EMPIRIC TREATMENT OF HIGH-RISK FEBRILE NEUTROPENIA
First-line: ANTIPSEUDOMONAL BETA-LACTAM MONOTHERAPY — cefepime, piperacillin-tazobactam, or meropenem. Carbapenem (meropenem) is preferred when: prior ESBL-producing organism, high risk of resistant gram-negative bacteria, sepsis/septic shock warranting the broadest coverage.
Add VANCOMYCIN empirically ONLY when: hemodynamic instability/septic shock, pneumonia (chest X-ray infiltrate), skin or soft tissue infection, blood cultures positive for gram-positive organism, concern for central venous access device infection, colonization with MRSA or beta-lactam-resistant pneumococci. Vancomycin is NOT routinely added to initial febrile neutropenia treatment without one of these indications.
DAPTOMYCIN is NOT appropriate for pneumonia — it lacks lung penetration (inactivated by surfactant).
AZTREONAM + vancomycin: reserve for patients with SEVERE penicillin allergy (IgE-mediated, anaphylaxis history) — not preferred routinely.
Aminoglycosides (tobramycin) + beta-lactam: combination not recommended as standard first-line (increased toxicity without proven benefit); AVOID as empiric routine therapy.
LOW-RISK FEBRILE NEUTROPENIA
Oral outpatient therapy: ciprofloxacin + amoxicillin/clavulanate (if no penicillin allergy). In patients with penicillin allergy: levofloxacin ± clindamycin (ASCO/IDSA recommends adding clindamycin or amoxicillin-clavulanate to fluoroquinolone; NCCN allows levofloxacin as single agent for low-risk). IV vancomycin or meropenem are NOT indicated for low-risk FN.
ANTIBIOTIC DISCONTINUATION IN FEBRILE NEUTROPENIA
If neutropenia resolves and patient has been afebrile ≥ 48 hours but has an identified infection (e.g., pneumonia): do NOT simply stop antibiotics — the infection requires a full course. If patient can be discharged: DE-ESCALATE to oral step-down therapy to complete the pneumonia course at home. Key principle: neutrophil recovery allows treating the underlying infection like a standard immunocompetent patient. Continuing IV antibiotics solely for febrile neutropenia criteria (once neutropenia resolves) is NOT necessary if the patient is afebrile.
ANTIMICROBIAL PROPHYLAXIS IN HEMATOLOGIC MALIGNANCY
For patients receiving induction chemotherapy for ACUTE LEUKEMIA with anticipated prolonged profound neutropenia: Antibacterial prophylaxis: fluoroquinolone preferred (levofloxacin, ciprofloxacin). In patients with fluoroquinolone intolerance/allergy: oral 3rd-generation cephalosporin (cefdinir, cefpodoxime).
Antifungal prophylaxis for ALL: fluconazole, micafungin, or amphotericin are appropriate. Posaconazole is preferred for AML/MDS.
PJP prophylaxis: TMP-SMX is preferred. In sulfa allergy: dapsone, atovaquone, or inhaled pentamidine are alternatives.
HSV prophylaxis: valacyclovir or acyclovir for patients with acute leukemia receiving intensive chemotherapy.
HEPATITIS B PROPHYLAXIS WITH ANTI-CD20 THERAPY (RITUXIMAB)
Screen ALL patients with hepatitis B panel before rituximab or other anti-CD20 monoclonal antibodies. If HBsAg POSITIVE or HBcAb POSITIVE (with or without HBsAg): prophylactic antiviral therapy is REQUIRED. Entecavir is PREFERRED over lamivudine (lower resistance rates). Rituximab therapy can PROCEED as planned — prophylaxis is given concurrently. Do NOT eliminate/delay rituximab. HBV DNA monitoring is obtained for baseline/monitoring but does not require rituximab delay.
ASPERGILLOSIS DIAGNOSIS AND TREATMENT
Invasive Aspergillosis (IA) diagnostic criteria: CT chest showing characteristic findings (nodules with halo sign, air crescent sign) + galactomannan antigen positive from BAL or serum + appropriate host factors (prolonged profound neutropenia).
First-line treatment: VORICONAZOLE — gold standard for invasive aspergillosis.
Liposomal amphotericin B: alternative when voriconazole cannot be used.
Echinocandins (micafungin, caspofungin): NOT recommended as INITIAL treatment for IA per IDSA guidelines; role is in salvage/combination therapy.
Fluconazole has NO activity against Aspergillus — do NOT continue or increase fluconazole dose.
VORICONAZOLE AND VINCRISTINE DRUG INTERACTION:
Voriconazole is a STRONG CYP3A4 INHIBITOR. Vincristine is a MAJOR CYP3A4 substrate. Co-administration significantly increases vincristine exposure → severe neurotoxicity. When a patient requires aspergillosis treatment AND is receiving vincristine: voriconazole is CONTRAINDICATED. Use liposomal amphotericin B as the alternative.
BREAKTHROUGH INVASIVE ASPERGILLOSIS ON POSACONAZOLE PROPHYLAXIS
When IA occurs despite adequate posaconazole levels (trough ≥ 700 ng/mL): posaconazole failure or resistant organism is suspected. Switch to liposomal amphotericin B (some experts also consider adding an echinocandin in areas with low resistance). Continuing or switching posaconazole to IV is generally not recommended in proven breakthrough infection.
CLOSTRIDIOIDES DIFFICILE INFECTION (CDI) TREATMENT
Risk factors: recent antibiotic use (especially fluoroquinolones, clindamycin, broad-spectrum beta-lactams), immunosuppression.
NON-FULMINANT initial CDI: fidaxomicin 200 mg PO BID (preferred for first episode — higher sustained cure rate, lower recurrence risk) OR vancomycin 125 mg PO QID. Metronidazole PO is NO LONGER first-line for initial CDI episodes per IDSA/SHEA guidelines.
FULMINANT CDI (hypotension/shock, ileus, or megacolon): vancomycin 500 mg PO + rectally Q6H + metronidazole 500 mg IV Q8H. Key: rectal vancomycin is given ONLY when ILEUS is present (oral drug cannot reach colon). IV metronidazole is used because oral absorption is impaired in fulminant disease. Ileus finding = higher vancomycin dose (500 mg) + rectal route.
VACCINATIONS IN CANCER PATIENTS
LIVE vaccines (MMR, varicella, yellow fever, live influenza): administer ≥ 4 weeks BEFORE immunosuppressive chemotherapy. NOT safe during or soon after immunosuppressive therapy. After anti-B-cell therapy (rituximab, obinutuzumab, ofatumumab): live vaccines ≥ 6 months after completing anti-CD20 therapy (B cells need to recover).
INACTIVATED vaccines (flu shot, pneumococcal, hepatitis B, inactivated polio): administer ≥ 2 weeks BEFORE chemotherapy ideally. If given during chemotherapy: administer BETWEEN chemotherapy cycles (not immediately before or with chemo) to maximize humoral response. NOT immediately before or concurrent with chemotherapy administration (poor immune response).
BLINATUMOMAB AND CAR-T VACCINATION CONSIDERATIONS
Blinatumomab (anti-CD19/CD3 bispecific): causes prolonged B-cell depletion and hypogammaglobulinemia for approximately 1 YEAR or more after therapy. Immunoglobulins remain suppressed — if inactivated vaccines are administered, MONITOR ANTIBODY LEVELS to confirm immune response. Live influenza vaccine is NOT safe post-blinatumomab until B-cell recovery.
CAR-T therapy (CD19-directed): COVID-19 mRNA vaccines: administer ≥ 3 months after CAR-T. mRNA vaccines ONLY (not other vaccine types) per NCCN COVID-19 Vaccination Advisory Committee recommendations. Live vaccines are contraindicated during and after CAR-T.
BB is a 55-year-old male with AML after CLAG salvage chemotherapy. He develops febrile neutropenia (ANC 0.1 × 109/L) with fever 39.5°C, BP 82/54, HR 124, RR 26, and new right lower lung opacification on chest X-ray. Prior AML induction was complicated by ESBL-producing E. coli bacteremia. CrCl ≈ 80 mL/min. No allergies. Which treatment is most appropriate for BB at this time?
A. Cefepime + daptomycin
B. Levofloxacin + linezolid
C. Aztreonam + vancomycin
D. Meropenem + vancomycin
[expand] Answer: D. Meropenem + vancomycin
Explanation: BB has HIGH-RISK febrile neutropenia with multiple indicators: hospitalized at time of fever, hemodynamically unstable (hypotension), new pneumonia on chest X-ray, acute leukemia, and profound neutropenia. An antipseudomonal beta-lactam is the backbone of treatment. Meropenem (carbapenem) is preferred over cefepime here because BB has a prior ESBL-producing E. coli infection — ESBL organisms are resistant to cephalosporins but susceptible to carbapenems. Vancomycin is added because BB has BOTH hemodynamic instability AND pneumonia — two separate indications for empiric vancomycin addition. Daptomycin (option A) is inappropriate because it lacks lung penetration — pulmonary surfactant inactivates it. Levofloxacin + linezolid (option B) — oral fluoroquinolones + oxazolidinones is not an appropriate regimen for high-risk septic FN. Aztreonam + vancomycin (option C) — reserved for severe penicillin allergy; BB has no allergies.
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BL is a 49-year-old female with breast cancer (day 10 post dose-dense AC) with high-risk culture-negative febrile neutropenia and pneumonia on chest X-ray. She received cefepime for 3 days, has been afebrile for 48 hours, and has now recovered her neutrophil count. Which is the most appropriate response regarding antibacterial discontinuation?
A. Discontinue cefepime since neutropenia has resolved
B. Continue cefepime since BL has not received an adequate course for FN
C. Continue cefepime since BL has not received an adequate course for pneumonia
D. De-escalate to oral step-down therapy since BL has not received an adequate course for pneumonia
[expand] Answer: D. De-escalate to oral step-down therapy since BL has not received an adequate course for pneumonia
Explanation: BL has neutrophil recovery — once ANC normalizes, she can be managed like a standard immunocompetent patient with pneumonia. However, she has only received 3 days of antibiotics for her pneumonia — this is an inadequate course (community-acquired pneumonia typically requires 5 days minimum; hospital-acquired pneumonia may require longer). The appropriate action is to DE-ESCALATE from IV cefepime to oral antibiotics and discharge her to complete the pneumonia course at home. Simply stopping antibiotics (option A) would leave the pneumonia undertreated. Continuing IV cefepime in the hospital (option C) is not necessary once she has ANC recovery and is afebrile — she can transition to oral therapy.
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KP is a 58-year-old female preparing to start R-HyperCVAD for Ph-negative B-cell ALL. Hepatitis B panel: HBsAb positive, HBsAg negative, HBcAb positive. LFTs normal. Allergies: fluoroquinolones AND sulfa drugs. Which prophylactic antimicrobial regimen is most appropriate?
A. Cefpodoxime, posaconazole, pentamidine, valacyclovir, lamivudine
B. Cefdinir, fluconazole, dapsone, valacyclovir, entecavir
C. Cefpodoxime, micafungin, atovaquone, tenofovir
D. Cefdinir, isavuconazole, valacyclovir, entecavir
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Answer: B. Cefdinir, fluconazole, dapsone, valacyclovir, entecavir
Explanation: KP needs comprehensive prophylaxis for ALL induction:
Antibacterial: fluoroquinolone preferred but CONTRAINDICATED (allergy) → oral 3rd-generation cephalosporin (cefdinir or cefpodoxime). Both cefdinir and cefpodoxime appear in the options — either is acceptable antibacterially.
Antifungal: for ALL, fluconazole, micafungin, or amphotericin are appropriate (posaconazole is specifically recommended for AML/MDS, not ALL). Fluconazole is appropriate here.
PJP prophylaxis: TMP-SMX preferred BUT KP has SULFA ALLERGY → alternatives: dapsone (option B), atovaquone (option C), or pentamidine (option A).
HSV prophylaxis: valacyclovir — appropriate for acute leukemia with intensive chemotherapy.
Hepatitis B prophylaxis: HBcAb positive + rituximab → antiviral required; ENTECAVIR preferred over lamivudine (lower resistance).
Option B correctly includes all components.
Option A has lamivudine (less preferred) and pentamidine (an alternative but less commonly chosen).
Option C lacks HSV prophylaxis.
Option D uses isavuconazole — not specifically indicated for ALL and is a stronger choice for mold coverage.
KP is preparing to start rituximab for DLBCL. Hepatitis B panel: HBsAb positive, HBsAg negative, HBcAb positive. LFTs normal. Which is the most appropriate course of action?
A. Initiate entecavir and proceed with rituximab
B. Initiate lamivudine and proceed with rituximab
C. Eliminate rituximab and initiate entecavir
D. Eliminate rituximab and obtain HBV DNA
[expand] Answer: A. Initiate entecavir and proceed with rituximab
Explanation: KP has HBcAb positive status — this indicates prior hepatitis B exposure with risk of HBV reactivation during immunosuppressive anti-CD20 therapy (rituximab). Prophylactic antiviral therapy is REQUIRED for HBcAb positive patients receiving rituximab. Entecavir is the PREFERRED antiviral (superior resistance profile vs. lamivudine). Rituximab SHOULD NOT be delayed or eliminated — it is the cornerstone of her lymphoma treatment and can be given concurrently with entecavir prophylaxis. Lamivudine (option B) is acceptable but less preferred due to higher resistance rates. Eliminating rituximab (options C and D) is inappropriate — no indication to withhold the essential oncologic therapy.
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AP is a 68-year-old female with multiple myeloma on RVD who presents with 12 bowel movements/24 hours, temperature 39.1°C, BP 80/43, SCr 1.65 (baseline 0.5), and an ILEUS on CT abdomen/pelvis. C. difficile toxin and antigen positive. History of levofloxacin use two weeks ago. Which treatment is most appropriate for AP at this time?
A. Vancomycin 500 mg PO and rectally Q6H + metronidazole 500 mg IV Q8H
B. Vancomycin 125 mg PO and rectally Q6H + metronidazole 500 mg PO Q8H
C. Metronidazole 500 mg PO Q8H
D.Fidaxomicin 200 mg PO BID
[expand] Answer: A. Vancomycin 500 mg PO and rectally Q6H + metronidazole 500 mg IV Q8H
Explanation: AP has FULMINANT CDI — defined by hypotension (BP 80/43), ileus on CT, and severe clinical presentation. Management of fulminant CDI per IDSA/SHEA guidelines: vancomycin 500 mg PO (higher dose due to severity) + vancomycin 500 mg RECTALLY Q6H (rectal route is ONLY used when ILEUS is present, because ileus prevents oral drug from reaching the colon) + metronidazole 500 mg IV Q8H (IV route because oral absorption is unreliable in fulminant disease). Fidaxomicin (option D) — appropriate for non-fulminant CDI but NOT sufficient for fulminant disease. Vancomycin 125 mg PO + oral metronidazole (option B) — wrong doses and wrong routes for fulminant CDI with ileus. Metronidazole PO alone (option C) — no longer first-line and entirely insufficient for fulminant CDI.
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AP (same patient, different scenario) has 12 bowel movements/24 hours, temperature 38.3°C, BP 120/75, SCr 0.65 (normal), NO ileus on imaging. C. difficile toxin and antigen positive. Which treatment is most appropriate?
A. Vancomycin 500 mg PO and rectally Q6H + metronidazole 500 mg IV Q8H
B. Vancomycin 125 mg PO and rectally Q6H + metronidazole 500 mg PO Q8H
C. Metronidazole 500 mg PO Q8H
D. Fidaxomicin 200 mg PO BID
[expand] Answer: D. Fidaxomicin 200 mg PO BID
Explanation: AP now has NON-FULMINANT CDI — hemodynamically stable (BP 120/75), normal renal function, no ileus. For non-fulminant initial CDI, IDSA/SHEA guidelines recommend: fidaxomicin 200 mg PO BID × 10 days (preferred — higher sustained cure rate and lower recurrence) OR vancomycin 125 mg PO QID × 10 days. Fidaxomicin is the preferred agent among the options for non-fulminant first-episode CDI. Oral metronidazole (option C) is no longer recommended as first-line for CDI. Rectal vancomycin (option B) is only needed when ileus is present — AP has NO ileus here.
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JD is a 33-year-old male with relapsed ALL receiving blinatumomab. On antifungal prophylaxis with fluconazole 400 mg PO daily. He develops febrile neutropenia with CT showing large nodules with halo sign and positive galactomannan on bronchoscopy BAL. Which treatment is most appropriate for JD?
A. Increase fluconazole to 800 mg PO daily
B. Switch fluconazole from PO to IV
C. Switch fluconazole to micafungin
D. Switch fluconazole to voriconazole
[expand] Answer: D. Switch fluconazole to voriconazole
Explanation: JD has PROBABLE INVASIVE ASPERGILLOSIS based on: characteristic CT findings (halo sign with large nodules), positive galactomannan antigen from BAL, and appropriate host factors (prolonged profound neutropenia in acute leukemia). Voriconazole is the GOLD STANDARD first-line treatment for invasive Aspergillus infections per IDSA guidelines. Fluconazole (options A and B) has NO antifungal activity against Aspergillus species — increasing the dose or switching to IV is completely ineffective. Micafungin (option C) — echinocandins are NOT recommended as initial monotherapy for invasive aspergillosis per IDSA guidelines; they may be used as salvage/combination therapy.
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BA is a 22-year-old with B-cell ALL receiving CALGB 10403 (contains vincristine). On fluconazole prophylaxis. CT chest shows nodules with halo sign; BAL galactomannan positive. He has been neutropenic for 14 days. Which treatment is most appropriate for BA?
A. Continue fluconazole
B. Switch fluconazole to voriconazole
C. Switch fluconazole to micafungin
D. Switch fluconazole to liposomal amphotericin B
[expand] Answer: D. Switch fluconazole to liposomal amphotericin B
Explanation: BA has probable invasive aspergillosis — voriconazole is the gold standard treatment. HOWEVER, BA is receiving VINCRISTINE — a major CYP3A4 substrate. Voriconazole is a STRONG CYP3A4 INHIBITOR — co-administration with vincristine is CONTRAINDICATED because it dramatically increases vincristine plasma levels, causing severe neurotoxicity. Therefore, voriconazole (option B) cannot be used. Liposomal amphotericin B is the appropriate ALTERNATIVE for IA when voriconazole is contraindicated — it has broad antifungal coverage including Aspergillus and does not have the same CYP3A4 interaction concern with vincristine. Continuing fluconazole (option A) is futile — no Aspergillus activity. Micafungin (option C) — echinocandins are not recommended as initial monotherapy for IA.
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The lymphoma group asks you to present an in-service on vaccinations in cancer patients. Which statement is most appropriate to include in your presentation?
Patients receiving R-CHOP should receive live vaccines ≥ 3 weeks prior to chemotherapy
Patients receiving R-EPOCH should receive inactivated vaccines ≥ 1 week after chemotherapy
Patients receiving ABVD should receive inactivated vaccines immediately prior to chemotherapy
Patients receiving R-ICE should receive live vaccines ≥ 6 months after chemotherapy
Explanation:
R-ICE contains rituximab (anti-CD20 monoclonal antibody). Anti-CD20 agents cause profound B-cell depletion — live vaccines must be withheld until at least 6 MONTHS after completing anti-B-cell antibody therapy to allow B-cell recovery and adequate immune response.
Option A — live vaccines should be given ≥ 4 WEEKS (not 3 weeks) before immunosuppressive chemotherapy.
Option B — inactivated vaccines should be given ≥ 2 WEEKS (not 1 week) before chemotherapy; if given during chemotherapy, give BETWEEN cycles — not immediately after.
Option C — inactivated vaccines should NOT be given immediately prior to ABVD; the timing is critical because administration around the same time as chemotherapy reduces immunogenicity. Vaccines given between chemotherapy cycles produce better humoral responses.
LB is a 35-year-old male with AML (post-HiDAC consolidation) presenting with febrile neutropenia (ANC 0.1, BP 82/54, HR 124, RR 26, chest X-ray with right lower lung opacification). Prior AML induction complicated by MRSA bacteremia. CrCl > 60 mL/min. MASCC score 19. No allergies. Which treatment is most appropriate?
A. Ciprofloxacin + amoxicillin/clavulanate
B. Levofloxacin + vancomycin
C. Cefepime + vancomycin
D. Meropenem + tobramycin
[expand] Answer: C. Cefepime + vancomycin
Explanation: LB has HIGH-RISK febrile neutropenia (MASCC < 21) with hemodynamic instability, pneumonia, and prior MRSA bacteremia — all are independent indications for empiric vancomycin addition. Antipseudomonal beta-lactam + vancomycin is the appropriate regimen. Cefepime is appropriate as the antipseudomonal backbone (unlike BB who had prior ESBL, LB does not have a documented resistant gram-negative history requiring carbapenem). Vancomycin covers MRSA — particularly important given LB's prior MRSA bacteremia history. Oral fluoroquinolones (option A, B) — not appropriate for high-risk septic FN requiring hospitalization and IV therapy. Meropenem + tobramycin (option D) — aminoglycoside combination is not standard empiric therapy; tobramycin adds nephrotoxicity without proven benefit as routine empiric addition.
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TS is a 19-year-old female with relapsed ALL who completed blinatumomab and is in complete molecular remission. Which vaccination recommendation is most appropriate for TS?
Inactivated influenza vaccine can be administered starting ≥ 3 months post-blinatumomab
Live influenza vaccine can be administered starting ≥ 6 months post-blinatumomab
Inactivated polio vaccine can be given now since blinatumomab is not myelosuppressive
Immunoglobulins will be suppressed for approximately 1 year following blinatumomab; consider monitoring antibody levels if inactivated vaccines are administered
Explanation: Blinatumomab (anti-CD19/CD3 bispecific T-cell engager) causes profound and prolonged B-cell depletion and hypogammaglobulinemia that typically persists for approximately 1 YEAR or more after therapy. Because immunoglobulin levels remain suppressed, the patient's ability to mount a humoral response to vaccines is significantly impaired. If inactivated vaccines are administered during this period, antibody levels should be MONITORED to confirm an adequate immune response has been generated. Live influenza vaccine (option B) — live vaccines are contraindicated during B-cell depletion; and the timing is not simply ≥ 6 months (this applies to anti-CD20 agents, not specifically blinatumomab's hypogammaglobulinemia context). Options A and C incorrectly suggest vaccines can be given at defined timepoints without acknowledging the prolonged immunoglobulin suppression specific to blinatumomab.
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TS is a 19-year-old female with relapsed ALL who was just discharged after receiving CD19-directed CAR-T therapy. She asks about COVID-19 vaccination. Which statement is correct regarding COVID-19 vaccination for TS?
A. TS may receive any COVID-19 vaccine at any time after CAR-T
B. TS may receive any COVID-19 vaccine ≥ 3 months after CAR-T
C. TS may receive any of the mRNA COVID-19 vaccines ≥ 3 months after CAR-T
D. COVID-19 vaccines are contraindicated in patients who have received CAR-T
[expand] Answer: C. TS may receive any of the mRNA COVID-19 vaccines ≥ 3 months after CAR-T
Explanation: Per the NCCN COVID-19 Vaccination Advisory Committee: mRNA COVID-19 vaccines are recommended ≥ 3 months after CAR-T cell therapy. The specification is MRNA vaccines ONLY — not all COVID-19 vaccine types. Option A is incorrect — timing restrictions apply. Option B is incorrect — not ALL vaccine types are appropriate post-CAR-T; only mRNA vaccines are specifically recommended. Option D is incorrect — vaccines are not categorically contraindicated; they are encouraged at the appropriate time with the appropriate vaccine type.
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BL is a 25-year-old female with breast cancer (day 8 post dose-dense AC). Temperature 39.2°C, hemodynamically stable. ANC = 0.2 × 10⁹/L (note: 0.2 × 100 cells/L = 200 cells/µL). No other medical history. SEVERE penicillin allergy. MASCC score 26, CISNE score 1. Which treatment is most appropriate?
A. Ciprofloxacin + amoxicillin/clavulanate
B. Aztreonam + vancomycin
C. Levofloxacin ± clindamycin
D. Meropenem + tobramycin
[expand] Answer: C. Levofloxacin ± clindamycin
Explanation: BL has LOW-RISK febrile neutropenia — MASCC score 26 (≥ 21 = low risk), CISNE score 1 (low risk), hemodynamically stable, no complications, anticipated short neutropenia duration (dose-dense AC). Low-risk FN can be managed OUTPATIENT with ORAL antibiotics. Standard low-risk outpatient regimen: ciprofloxacin + amoxicillin/clavulanate — but BL has SEVERE penicillin allergy (amoxicillin/clavulanate is a penicillin → contraindicated). Alternative: levofloxacin ± clindamycin. NCCN allows levofloxacin as single agent for low-risk FN; ASCO/IDSA recommends adding clindamycin (gram-positive coverage without penicillin) to the fluoroquinolone. Aztreonam + vancomycin (option B) — IV therapy not indicated for low-risk FN; reserved for severe penicillin allergy requiring IV therapy in high-risk patients. Meropenem + tobramycin (option D) — IV carbapenem + aminoglycoside combination is not appropriate for low-risk outpatient-eligible FN.
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LB is a 25-year-old female with AML (day 24 post 7+3 induction) with culture-negative febrile neutropenia and pneumonia on chest X-ray (day 20). She received cefepime since day 20. Afebrile × 72 hours with neutrophil count recovered. Which is the most appropriate response?
A. Discontinue cefepime since neutropenia has resolved and she has been afebrile ≥ 48 hours
B. Discontinue cefepime since LB has received an adequate course for pneumonia
C. Continue cefepime since LB has not received an adequate course for FN
D. De-escalate to oral step-down therapy since LB has not received an adequate course for pneumonia
[expand] Answer: D. De-escalate to oral step-down therapy since LB has not received an adequate course for pneumonia
Explanation: LB has recovered ANC — once neutropenia resolves, she can be managed as a standard immunocompetent patient. She has pneumonia and has received cefepime for 4 days (day 20 to day 24) — this is NOT yet an adequate course for pneumonia (typically 5–7+ days minimum). De-escalating to oral antibiotics for discharge is appropriate — she does not need to continue IV therapy in the hospital once neutropenia resolves. Simply discontinuing (options A and B) would leave the pneumonia undertreated. Continuing IV cefepime for FN criteria alone (option C) is not necessary once neutropenia has resolved.
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PA is a 58-year-old female with multiple myeloma on RVD. She presents with 12 bowel movements/24 hours, temperature 38.8°C, BP 80/40, SCr 2.1 (baseline 0.5), and ILEUS on CT abdomen. C. difficile toxin and antigen positive. Recent levofloxacin use.
Which treatment is most appropriate?
A. Vancomycin 500 mg PO and rectally Q6H + metronidazole 500 mg IV Q8H
B. Vancomycin 125 mg PO and rectally Q6H + metronidazole 500 mg PO Q8H
C. Metronidazole 500 mg PO and rectally Q8H
D. Fidaxomicin 200 mg PO BID
[expand] Answer: A. Vancomycin 500 mg PO and rectally Q6H + metronidazole 500 mg IV Q8H
Explanation: PA has FULMINANT CDI — defined by hypotension (BP 80/40) AND ileus (seen on CT). Per IDSA/SHEA guidelines: fulminant CDI treatment = vancomycin 500 mg PO Q6H (higher dose for severity) + vancomycin 500 mg RECTALLY Q6H (because ileus is present — oral drug cannot transit to the colon, rectal instillation is required) + metronidazole 500 mg IV Q8H (IV route because oral absorption is unreliable in ileus/fulminant disease). Option B uses wrong dose (125 mg vs. 500 mg for fulminant) and oral metronidazole (wrong route for ileus). Metronidazole alone (option C) is no longer first-line and is entirely insufficient for fulminant CDI. Fidaxomicin (option D) is for non-fulminant CDI only.
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JB is a 63-year-old male with refractory AML on gemtuzumab ozogamicin salvage therapy. On posaconazole DR 300 mg PO daily prophylaxis (trough level 1300 ng/mL — adequate). He develops febrile neutropenia with CT showing large nodules with halo sign and positive galactomannan on BAL bronchoscopy. Which treatment is most appropriate?
A. Continue posaconazole
B. Switch posaconazole to liposomal amphotericin B
C. Switch posaconazole from oral to IV
D. Switch posaconazole to micafungin
[expand] Answer: B. Switch posaconazole to liposomal amphotericin B
Explanation: JB has BREAKTHROUGH invasive aspergillosis despite adequate posaconazole prophylaxis (trough 1300 ng/mL is well within therapeutic range). This represents either posaconazole failure or a resistant organism — continuing posaconazole is not appropriate. In breakthrough IFI on anti-mold prophylaxis: experts recommend switching to a different drug class (amphotericin-based products) with or without adding an echinocandin. Liposomal amphotericin B has broad antifungal coverage and is the most appropriate choice among the options. Continuing posaconazole (option A) is not appropriate in a confirmed breakthrough infection. Switching to IV posaconazole (option C) — still the same drug with the same potential resistance issue. Switching to micafungin (option D) — echinocandins are not recommended as INITIAL monotherapy for invasive aspergillosis per IDSA guidelines.
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2. A 50-year-old woman undergoes a matched sibling allogeneic hematopoietic stem cell transplant for a relapsed acute myelogenous leukemia. She received busulfan and cyclophosphamide preparative regimen followed later on by methotrexate and tacrolimus for graft versus host disease prophylaxis. The patient also needs to begin her prophylactic antimicrobials; however, which one will interact with tacrolimus?
A. Levofoxacin (Levaquin) (15%)
B. Valacyclovir (Valtrex) (7%)
C. Posaconazole (Noxafil) (68%)
D. Dapsone (6%)
Levofloxacin and valacyclovir do not utilize these pathways, while dapoxetine is a substrate of several cytochrome P450 isoenzymes, including 3A4, but does not significantly inhibit or induce it.
Posaconazole is a strong inhibitor of the 3A4 isoenzyme and would be expected to increase the tacrolimus blood levels.