A 54-year-old woman is hospitalized for induction chemotherapy to treat acute myeloid leuk… — USMLE Step 2 CK

A 54-year-old woman is hospitalized for induction chemotherapy to treat acute myeloid leukemia. On day $10$ of her hospital stay, she develops a new-onset fever. She reports no cough, dyspnea, dysuria, or abdominal pain. Temperature is $38.8^\circ\text{C}$ ( $101.8^\circ\text{F}$ ), blood pressure is $112/74$ mm Hg, pulse is $98$ /min, and respirations are $16$ /min. Physical examination reveals a clean and intact right internal jugular central venous catheter site with no surrounding erythema, induration, or tenderness. Lungs are clear to auscultation. Cardiovascular and abdominal examinations are unremarkable. Skin examination shows no rashes or lesions.

Laboratory studies:
Leukocytes: $400/\text{mm}^3$
Absolute neutrophil count: $80/\text{mm}^3$
Hemoglobin: $9.2$ g/dL
Platelets: $45,000/\text{mm}^3$
Serum creatinine: $0.9$ mg/dL

Blood and urine cultures are obtained. Which of the following is the most appropriate empiric pharmacotherapy for this patient?

CefepimeCevap
B
Cefepime and vancomycin
C
Ceftriaxone
D
Ciprofloxacin and fluconazole
E
Meropenem and micafungin

Cevap

The most appropriate empiric pharmacotherapy is an antipseudomonal beta-lactam such as cefepime.

The correct answer is cefepime. This patient has febrile neutropenia (temperature

\geq 38.3^\circ\text{C}

and absolute neutrophil count

< 500/\text{mm}^3

), which is a life-threatening complication of cytotoxic chemotherapy. Because these patients lack an adequate immune response, infections can disseminate rapidly without classic inflammatory signs. High-risk patients (e.g., inpatient status, prolonged neutropenia expected for

> 7

days, profound neutropenia

\leq 100/\text{mm}^3

) require immediate broad-spectrum intravenous antibiotics. Initial empiric therapy must cover both gram-negative (particularly *Pseudomonas aeruginosa*) and gram-positive organisms. Monotherapy with an antipseudomonal beta-lactam, such as cefepime, meropenem, or piperacillin-tazobactam, is the standard of care.

Adım Adım Çözüm

Calculate the absolute neutrophil count and identify the clinical syndrome.

The patient has an absolute neutrophil count of

80/\text{mm}^3

and a temperature of

38.8^\circ\text{C}

, confirming a diagnosis of neutropenic fever.

Neutropenic fever is an oncologic emergency defined by a single oral temperature

\geq 38.3^\circ\text{C}

(

101^\circ\text{F}

) and an absolute neutrophil count

< 500/\text{mm}^3

Risk-stratify the patient to determine the required treatment intensity and setting.

The patient is high-risk because she is undergoing inpatient induction chemotherapy, and her neutropenia is expected to last

> 7

days.

High-risk patients require hospital admission (or continued inpatient management) and intravenous empiric antibiotics.

Select the appropriate empiric antimicrobial coverage.

Monotherapy with an antipseudomonal beta-lactam (e.g., cefepime, meropenem, or piperacillin-tazobactam) is indicated. Vancomycin is not added.

Empiric coverage must include Pseudomonas aeruginosa. Gram-positive coverage (vancomycin) is withheld unless specific indications (hemodynamic instability, catheter-site infection, skin/soft tissue infection, or severe pneumonia) are present to promote antibiotic stewardship.

Anahtar Kavram

High-risk febrile neutropenia requires immediate empiric intravenous monotherapy with an antipseudomonal beta-lactam; routine addition of MRSA or antifungal coverage is contraindicated unless specific clinical criteria are met.

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

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