A 31-year-old man with a history of treatment-resistant schizophrenia is evaluated during … — USMLE Step 3

A 31-year-old man with a history of treatment-resistant schizophrenia is evaluated during a routine follow-up visit. He was started on clozapine $6$ weeks ago after failing trials of risperidone, aripiprazole, and haloperidol. He is currently maintained on a stable dose of $300 \text{ mg/day}$ . The patient is of Northern European descent. He reports feeling well, with a significant reduction in his auditory hallucinations, and has no fever, chills, sore throat, or malaise. His temperature is $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), blood pressure is $122/78 \text{ mmHg}$ , and pulse is $82/\text{min}$ . Routine laboratory testing reveals a total leukocyte count of $4,200/\mu\text{L}$ and an absolute neutrophil count of $1,350/\mu\text{L}$ . Prior to initiating clozapine, his absolute neutrophil count was $3,600/\mu\text{L}$ . Which of the following is the most appropriate next step in the management of this patient?

Continue clozapine and monitor the absolute neutrophil count three times weeklyCevap
B
Discontinue clozapine indefinitely and initiate a trial of olanzapine
C
Order a bone marrow aspiration and biopsy
D
Discontinue clozapine and initiate carbamazepine
E
Continue clozapine and prescribe empiric ciprofloxacin prophylaxis

Cevap

Continue clozapine and monitor the absolute neutrophil count three times weekly.

The correct management for this patient is to continue clozapine and monitor the absolute neutrophil count (ANC) three times weekly. According to the Clozapine Risk Evaluation and Mitigation Strategy (REMS) guidelines for patients in the general population (without benign ethnic neutropenia), an ANC between

1,000/\mu\text{L}

and

1,499/\mu\text{L}

constitutes mild neutropenia. In this scenario, clozapine should not be discontinued; instead, the clinician must increase the frequency of ANC monitoring to three times weekly until the ANC reaches or exceeds

1,500/\mu\text{L}

. Treatment interruption is only required if the ANC falls below

1,000/\mu\text{L}

(moderate neutropenia), and permanent discontinuation is mandated if the ANC drops below

500/\mu\text{L}

(severe neutropenia/agranulocytosis).

Adım Adım Çözüm

Evaluate the patient's absolute neutrophil count (ANC) against the standard reference thresholds.

The patient's ANC is

1,350/\mu\text{L}

Accurate interpretation of the ANC is required to apply the Clozapine Risk Evaluation and Mitigation Strategy (REMS) guidelines.

Determine the neutropenia severity category for a patient without Benign Ethnic Neutropenia (BEN).

An ANC between

1,000/\mu\text{L}

and

1,499/\mu\text{L}

is classified as mild neutropenia.

Management protocols strictly depend on the precise severity classification of neutropenia.

Apply the guideline-directed management for mild neutropenia.

The correct action is to continue clozapine therapy and increase ANC monitoring frequency to three times weekly.

Mild neutropenia does not warrant therapy interruption, but closer surveillance is mandated until the ANC returns to

\ge 1,500/\mu\text{L}

Anahtar Kavram

Clozapine REMS guidelines mandate that patients with mild neutropenia (ANC

1,000 - 1,499/\mu\text{L}

) should continue clozapine therapy but undergo increased ANC monitoring (three times weekly) until the count normalizes.

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Konular

Bu konudan daha fazla soru