Chapter 45: Syncope and Dizziness

Learning Objectives

• Define and understand the typical presentations of syncope and dizziness.

• Outline the common causes of syncope and dizziness.

• Discuss age-related physiologic changes that predispose older adults to syncope and dizziness.

• Detail pathophysiology and etiology of syncope and dizziness.

• Discuss management and prevention of syncope and dizziness.

Key Clinical Points Syncope:

1. Syncope is a common symptom throughout life; however, its presentation is often atypical in older adults who are less likely to have a warning or prodrome prior to syncope, and often have amnesia for loss of consciousness. Syncope is also one of many causes of falls in the older adult.

2. The etiology of syncope in older adults is typically multifactorial and often medication related. Modification or cessation of cardiovascular, psychotropic, and other medications is often needed to prevent syncope in older adults.

3. Causes of syncope can be cardiac or noncardiac. Cardiac causes are most prevalent in older adults and are associated with increased morbidity and mortality.

4. Age-related physiologic changes that predispose older adults to syncope include baroreflex impairment, decreased cerebral blood flow, reduced renal salt and water conservation, decreased thirst, impaired early diastolic ventricular filling, and an age-related decrease in vascular response to sympathetic activity.

5. Monitoring blood pressure during common daily activities is a useful tool to identify causes of syncope; and implantable loop recorders are recommended as an early diagnostic tool in the evaluation of unexplained syncope given the relatively high diagnostic yield.

1. Dizziness is an abnormal perception of the body’s relationship to space, which is often described as postural instability or imbalance. In older adults, it is often associated with fear of falling, mood disorders, polypharmacy, and functional disability.

2. Dizzy symptoms can be classified into four subtypes, which present with different temporal patterns: vertigo, presyncope, disequilibrium, and other.

3. Patients frequently complain of dizziness alone or as a prodrome to syncope or falls.

4. Several age-related changes increasing older adults’ susceptibility to dizziness include reduction in sensory receptors of the vestibular system, decreased vision and visual-vestibular reflexes, and decreased proprioceptive sense.

5. Visual, proprioception and balance exams, with and without eyes closed, as well as hearing assessment are all important elements of the dizziness work-up. Neuroimaging and specialized vestibular testing should be reserved for patients with chronic dizziness, vertigo, and/or focal neurologic findings.

6. Patients with chronic vestibular diseases (Meniere disease, labyrinthitis, vestibular neuritis, and ototoxicity) may benefit from vestibular desensitization exercises.

7. In the absence of a single etiology, treatment of each contributing factor can reduce dizzy symptoms.