Review Question - QID 217640

This patient presents with dizziness, blurry vision, and syncope after recently starting treatment for hypertension and benign prostatic hypertrophy, which are indicative of orthostatic syncope secondary to a medication side effect. Benign prostatic hypertrophy (BPH) is treated with alpha-1 adrenergic antagonists (e.g., tamsulosin), which commonly causes orthostatic hypotension after the first dose.

The hallmark of BPH treatment is alpha-1 adrenergic blockers, such as terazosin, tamsulosin, prazosin, and doxazosin. Terazosin, prazosin, and doxazosin have lower prostatic tissue specificity and can cause systemic side effects such as orthostatic hypotension, which can lead to syncope. Orthostatic hypotension typically presents with headaches and dizziness, although symptoms may be masked if the patient takes the medication before sleep. Tamsulosin is a prostate-specific agent that has fewer systemic side effects, but can cause retrograde ejaculation. While alpha-1 adrenergic blockers provide rapid symptomatic relief, the progression of BPH can be slowed by adding a 5-alpha reductase inhibitor (e.g., finasteride), especially in men with moderate or severe urinary obstruction symptoms. Orthostatic hypotension typically does not require treatment and resolves with the discontinuation of the medication.

Rivasi et al. review the causative agents of orthostatic hypotension. They highlight that medication review is the initial step in the diagnostic work-up of this condition. They recommend that non-pharmacologic treatments such as lifestyle modification be optimized prior to considering pharmacologic treatment of orthostatic hypotension.

Incorrect Answers:
Answer 1: Cardiac arrhythmias such as atrial fibrillation can cause syncopal episodes. However, these typically have no prodromal symptoms (e.g., dizziness, blurred vision). Also, the close temporal relationship of initiation of BPH treatment and syncope in this patient makes arrhythmia less likely than a medication side effect. Arrhythmias can be treated through rate or rhythm control medications.

Answer 2: Carotid sinus baroreceptor hypersensitivity can cause syncope as the brain responds to direct pressure on the carotid sinus (e.g., when wearing a tight-collared shirt) with a sudden decrease in blood pressure. This patient’s syncope was triggered by postural changes rather than carotid sinus pressure. Hypersensitivity can be treated with lifestyle changes.

Answer 3: Exaggerated autonomic response to a stimulus describes vasovagal or neurocardiogenic syncope. This presents with prodromal symptoms including nausea, diaphoresis, and a hot/cold sensation prior to syncope. Vasovagal syncope is less likely in this patient, who denies any of these prodromal symptoms. Also, the close temporal relationship of initiation of BPH treatment and syncope in this patient makes arrhythmia less likely than a medication side effect. This can be treated with lifestyle modification such as avoiding such stimuli.

Answer 5: Severe volume depletion can cause orthostatic hypotension due to insufficient intravascular blood volume. This would also present as syncope caused by a postural change. However, there are no signs of volume depletion in this patient (e.g., dehydration, hemorrhage). In contrast, this patient has moist mucous membranes, normal blood pressure, and a normal heart rate, which suggests normovolemic status. This can be treated with volume repletion.

Bullet Summary:
Medications (e.g., antihypertensives) are a common cause of orthostatic hypotension, which can present with syncope after a postural change.