A 33-year-old woman is brought to the outpatient psychiatry clinic by her wife. The patien… — USMLE Step 2 CK

A 33-year-old woman is brought to the outpatient psychiatry clinic by her wife. The patient reports a 3-week history of profound sadness, overwhelming fatigue, increased appetite, and sleeping up to 14 hours a day. She states she has been unable to go to work because she "cannot concentrate on anything." Her medical history is significant for primary hypothyroidism diagnosed 5 years ago, for which she is prescribed levothyroxine. Laboratory tests obtained this morning show a thyroid-stimulating hormone (TSH) level of $1.5 \text{ mIU/L}$ (normal: $0.4-4.0 \text{ mIU/L}$ ) and a free thyroxine (T4) level of $1.2 \text{ ng/dL}$ (normal: $0.8-1.8 \text{ ng/dL}$ ).

Further psychiatric interview reveals that two years ago, the patient experienced a 10-day episode where she felt "on top of the world," required only 2 hours of sleep per night, started multiple simultaneous home renovation projects, and spoke so rapidly it was difficult to interrupt her. She was prescribed a medication at that time but discontinued it after a month. She currently takes no psychiatric medications.

Which of the following are appropriate pharmacological interventions for this patient's current episode? (Select all that apply)

Initiate quetiapineAnswer
Initiate lurasidoneAnswer
C
Initiate fluoxetine monotherapy
D
Increase the levothyroxine dose
E
Initiate venlafaxine monotherapy

Answer

The appropriate interventions are to initiate quetiapine and initiate lurasidone.

The patient's history of a manic episode (decreased need for sleep, grandiosity, pressured speech lasting over a week) paired with her current severe depressive episode confirms a diagnosis of Bipolar I Disorder, current episode depressed. The first-line pharmacological treatment for acute bipolar depression includes specific second-generation antipsychotics, notably quetiapine and lurasidone, which are highly effective and FDA-approved for this indication. These agents manage the depression without risking a manic switch.

Step-by-Step Solution

Diagnose the current psychiatric episode based on presenting symptoms.

The patient has 3 weeks of depressed mood, hypersomnia, fatigue, hyperphagia, and poor concentration, which meets the criteria for a major depressive episode.

Establishing the current affective state is necessary to guide acute pharmacological treatment.

Assess past psychiatric history to differentiate unipolar from bipolar depression.

The patient had a prior 10-day episode of grandiosity, decreased need for sleep, hyper-productivity, and pressured speech. This meets the criteria for a manic episode, establishing a diagnosis of Bipolar I Disorder.

The treatment for bipolar depression differs drastically from unipolar major depressive disorder, primarily regarding the use of antidepressants.

Evaluate laboratory results to rule out secondary causes of depressive symptoms.

The TSH and free T4 levels are normal, confirming that the depressive symptoms are psychiatric in origin and not due to undertreated hypothyroidism.

Medical mimics, such as hypothyroidism, must be ruled out before initiating psychotropic medications.

Select appropriate pharmacological therapies for Bipolar I depression.

First-line agents include specific atypical antipsychotics (quetiapine, lurasidone, cariprazine) or mood stabilizers (lithium, lamotrigine).

Antidepressant monotherapy must be strictly avoided in bipolar disorder due to the high risk of inducing mania.

Key Concept

Treatment of Acute Bipolar Depression

Estimated Time:1m 30s

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