2. A patient with a history of depression is being assessed by an advanced practice registered nurse (APRN). The patient takes Venlafaxine (Effexor XR) and recently took Diphenhydramine (Benadryl) for allergy symptoms. The APRN notes lower extremity rigidity, agitation, sweating, and a low-grade temperature. Which condition should the APRN suspect?

Answer: D

Explanation:

Serotonin syndrome

The symptoms presented by the patient, including lower extremity rigidity, agitation, sweating, and a low-grade temperature, align with the characteristics of serotonin syndrome, particularly given the recent use of Venlafaxine, an antidepressant that increases serotonin levels.

A) Psychosis

Psychosis is characterized by a disconnection from reality, including hallucinations and delusions, which are not indicated by the patient's symptoms. The physical symptoms such as rigidity and agitation are more indicative of a physiological reaction rather than a psychological disorder like psychosis.

B) Malignant hyperthermia

Malignant hyperthermia typically occurs in response to certain anesthetic agents and is characterized by muscle rigidity and a rapid increase in body temperature. However, this condition is not related to the medications the patient is taking and does not account for the agitation and sweating observed.

C) Pneumonia

Pneumonia primarily presents with respiratory symptoms such as cough, fever, and difficulty breathing, which are absent in this patient's presentation. While a low-grade fever is noted, the other symptoms do not support a diagnosis of pneumonia.

D) Serotonin syndrome

Serotonin syndrome is a potentially life-threatening condition resulting from excessive serotonergic activity in the nervous system. The combination of the patient's medication history and the symptoms of rigidity, agitation, sweating, and fever strongly suggest this diagnosis, especially following the recent use of Venlafaxine and Diphenhydramine.

Conclusion

Serotonin syndrome is definitively the correct diagnosis due to the specific symptoms and the patient's medication regimen that raises serotonin levels. The other options do not adequately explain the clinical presentation, making them less likely diagnoses in this scenario.