A 52-year-old woman is evaluated in the hospital for a new-onset fever. She was admitted 1… — USMLE Step 2 CK

A 52-year-old woman is evaluated in the hospital for a new-onset fever. She was admitted $12$ days ago for induction chemotherapy for acute myeloid leukemia. Her temperature is $38.8^\circ\text{C}$ ( $101.8^\circ\text{F}$ ), blood pressure is $114/72$ mm Hg, pulse is $98$ /min, and respirations are $16$ /min. Oxygen saturation is $98\%$ on room air. Physical examination reveals a right internal jugular central venous catheter; the insertion site is clean, dry, and without erythema or tenderness. There is no oral thrush or mucositis. Lung fields are clear to auscultation. The abdomen is soft and non-tender. Skin examination shows no rashes or induration.

Laboratory studies show:
Leukocyte count: $800/\text{mm}^3$
Absolute neutrophil count: $120/\text{mm}^3$
Hemoglobin: $8.4$ g/dL
Platelet count: $45,000/\text{mm}^3$

Urinalysis is negative for leukocyte esterase and nitrites. Chest radiography reveals no infiltrates. Blood and urine cultures are obtained. Which of the following is the most appropriate empiric pharmacotherapy for this patient?

A
Intravenous vancomycin and piperacillin-tazobactam
Intravenous piperacillin-tazobactamCevap
C
Intravenous ceftriaxone and azithromycin
D
Intravenous fluconazole and piperacillin-tazobactam
E
Oral ciprofloxacin and amoxicillin-clavulanate

Cevap

Intravenous piperacillin-tazobactam

The patient presents with neutropenic fever (absolute neutrophil count < 500/mm³ and fever). Because she is hospitalized and undergoing induction chemotherapy for acute myeloid leukemia, she is classified as high-risk. The standard of care for high-risk neutropenic fever is immediate empiric intravenous monotherapy with an antipseudomonal beta-lactam, such as piperacillin-tazobactam, cefepime, or meropenem. Additional coverage for Methicillin-resistant Staphylococcus aureus (MRSA) with vancomycin is not recommended initially unless there are specific indications, such as hemodynamic instability, severe sepsis, pneumonia, clinically suspected severe catheter-related infection (e.g., erythema, purulence at the site), or severe mucositis. Because this patient is hemodynamically stable and has a clean catheter site with no localizing signs of infection, monotherapy with piperacillin-tazobactam is the most appropriate next step.

Adım Adım Çözüm

Identify the clinical syndrome from the patient's presentation and laboratory findings.

The patient has neutropenic fever, defined as an absolute neutrophil count < 500/mm³ and a single oral temperature ≥ 38.3°C (or ≥ 38.0°C for > 1 hour).

Recognizing neutropenic fever dictates immediate, specific empiric antibiotic protocols due to high mortality risk.

Risk stratify the patient to determine the required route of administration.

The patient is hospitalized for induction chemotherapy, making her a high-risk patient who requires intravenous therapy.

Low-risk patients can sometimes be managed with oral antibiotics as outpatients, but high-risk features mandate intravenous administration.

Assess for indications for additional specific antimicrobial coverage (e.g., MRSA or fungal).

The patient is hemodynamically stable with a clean catheter site, clear lungs, and no mucositis.

Without specific indications like hemodynamic instability, suspected catheter-related infection, or pneumonia, adding vancomycin is unnecessary and violates antibiotic stewardship principles.

Select the appropriate empiric monotherapy.

Intravenous antipseudomonal beta-lactam monotherapy (e.g., piperacillin-tazobactam, cefepime, or meropenem).

These agents provide broad-spectrum coverage, particularly against Pseudomonas aeruginosa and other Gram-negative bacilli, which are highly lethal in neutropenia.

Anahtar Kavram

High-risk patients with neutropenic fever should be treated empirically with intravenous antipseudomonal beta-lactam monotherapy; vancomycin should be withheld unless specific indications (e.g., hemodynamic instability, suspected catheter infection) are present.

Tahmini Süre:1m 0s

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Konular

Bu konudan daha fazla soru