A 68-year-old man is brought to the geriatric clinic by his daughter for a follow-up evalu… — USMLE Step 2 CK

A $68$ -year-old man is brought to the geriatric clinic by his daughter for a follow-up evaluation. For the past $3$ months, he has experienced profound sadness, anhedonia, early morning awakenings, and a $6$ -kg ( $13$ -lb) weight loss. Three weeks ago, he began stating that his "stomach has turned to dust" and now frequently refuses to eat.

Three weeks ago, his primary care physician diagnosed a major depressive episode and prescribed citalopram. The patient took it for $14$ days but stopped it entirely $7$ days ago because "it wasn't doing anything." His past medical history includes severe osteoarthritis, for which he takes daily tramadol.

His daughter privately reports that when the patient was $32$ years old, he had a distinct $6$ -week period where he slept only $2$ hours a night, exhibited pressured speech, and impulsively bought two boats, which led to a brief psychiatric hospitalization.

Vital signs are within normal limits. Physical examination is unremarkable.
Laboratory results show:
- Thyroid-stimulating hormone (TSH): $1.2$ $\mu$ U/mL (normal: $0.4$ – $4.0$ $\mu$ U/mL)
- Free thyroxine (T4): $0.5$ ng/dL (normal: $0.9$ – $2.4$ ng/dL)

Which of the following is the most appropriate next step in management?

Initiate quetiapineAnswer
B
Resume citalopram to complete an adequate therapeutic trial
C
Initiate phenelzine for treatment-resistant depression
D
Diagnose primary hypothyroidism and initiate levothyroxine
E
Diagnose schizophreniform disorder and initiate haloperidol

Answer

The most appropriate next step is to initiate quetiapine to treat bipolar depression with psychotic features.

The correct answer is to initiate quetiapine. This patient presents with a severe depressive episode characterized by melancholic and psychotic features (nihilistic delusions). However, his remote history of an episode involving decreased need for sleep, grandiosity, and hospitalization meets the criteria for a manic episode. Therefore, his true diagnosis is Bipolar I disorder, currently in a severe depressive episode. First-line treatments for bipolar depression that also effectively target psychotic symptoms include atypical antipsychotics such as quetiapine or lurasidone.

Step-by-Step Solution

Analyze the patient's current psychiatric presentation.

The patient meets criteria for a major depressive episode with psychotic features (nihilistic delusions, specifically Cotard's syndrome).

This establishes the severity of the current episode and the need to target both mood and psychosis.

Evaluate the patient's psychiatric history.

The history of a manic episode (decreased sleep, impulsivity, hospitalization at age

32

) changes the primary diagnosis from Major Depressive Disorder to Bipolar I Disorder.

A single manic episode is sufficient to diagnose Bipolar I Disorder, fundamentally altering the pharmacologic approach to depressive episodes.

Assess the pharmacological context and laboratory findings.

The patient prematurely stopped citalopram (which was actually protective against a manic switch), takes tramadol (serotonergic risk), and has central hypothyroidism (normal TSH, low T4).

This rules out resuming SSRIs, initiating MAOIs (due to drug interactions), and treating for primary hypothyroidism.

Select the optimal treatment for the established diagnosis.

Quetiapine is selected as it is FDA-approved for bipolar depression and provides antipsychotic coverage.

It treats both the bipolar depression and the psychotic features without the risk of antidepressant-induced mania.

Key Concept

Patients presenting with a major depressive episode must be meticulously screened for a history of mania; if present, the diagnosis is Bipolar Disorder, and antidepressant monotherapy should be avoided in favor of agents like quetiapine, lurasidone, or lithium.

Estimated Time:2m 0s

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