Falls and Drop Attacks

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Chapter 3 Falls and Drop Attacks

Everyone occasionally loses balance and sometimes falls, but repeated and unprovoked falls signal a potentially serious neurological problem. Considering the large number of potential etiologies, it is helpful to determine whether a patient has suffered a drop attack or an accidental fall. The term drop attack describes a sudden fall occurring without warning that may or may not be associated with loss of consciousness. Falls, on the other hand, reflect an inability to remain upright during a postural challenge. This most commonly affects individuals with chronic neurological impairment. When associated with loss of consciousness, drop attacks are likely due to a syncopal or epileptic event. Patients with preserved consciousness during a drop attack may harbor midline tumors in the third ventricle or in the posterior fossa. Transient ischemic attacks (TIAs) involving the posterior circulation or the anterior cerebral artery distribution can manifest in the same monosymptomatic manner. Narcoleptics experience cataplexy, and patients with Meniere disease may fall abruptly as a result of otolith dysfunction. Patients with lower-extremity weakness, spasticity, rigidity, sensory loss, or ataxia frequently fall. Middle-aged women may fall with no discernible cause. Finally, the elderly, with their inevitable infirmities, fall frequently and with potentially disastrous consequences. These associations permit a classification of falls and drop attacks, presented in Box 3.1.

The medical history is essential in evaluating patients with falls and drop attacks. The situational and environmental circumstances of the event must be ascertained. To help establish a diagnosis from among the wide range of possible causes, a detailed interview of the patient or of a witness to the fall is required. Aside from the patient’s gender and age, which affect fall risk, answers to the following basic questions should be elicited:

The neurological examination is equally important and can establish whether falls may be related to a disorder of the central or peripheral nervous system. Specific abnormalities include motor or sensory deficits in the lower limbs; the rigidity, tremor, and ocular motor abnormalities associated with Parkinson disease (PD) or progressive supranuclear palsy (PSP); ataxia, spasticity, cognitive impairment, and other signs suggestive of a neurodegenerative disorder or multiple sclerosis. Patients with normal findings on the neurological examination and no history of associated neurological or cardiac symptoms present a special challenge. In such patients, magnetic resonance imaging (MRI) and vascular imaging can be considered to rule out a clinically silent midline cerebral neoplasm, hindbrain malformation, or vascular occlusive disease. The workup is otherwise tailored to the clinical circumstance and may include cardiac and autonomic studies, nocturnal polysomnography, and in rare circumstances, genetic and metabolic testing if related conditions are suspected. Patients who frequently experience near-falls without injuries may have a psychogenic disorder of station and gait.

Loss of Consciousness

Syncope

The manifestations and causes of syncope are described in Chapter 2. Severe ventricular arrhythmias and hypotension lead to cephalic ischemia and falling. With sudden-onset third-degree heart block (Stokes-Adams attack), the patient loses consciousness and falls without warning. Less severe causes of decreased cardiac output, such as bradyarrhythmias or tachyarrhythmias, are associated with a prodromal sensation of faintness before the loss of consciousness. Elderly patients with cardioinhibitory sinus syndrome (“sick sinus syndrome”), however, often describe dizziness and falling rather than faintness, because of amnesia for the syncopal event. Thus, the history alone may not reveal the cardiovascular etiology of the fall. By contrast, cerebral hypoperfusion due to peripheral loss of vascular tone usually is associated with a presyncopal syndrome of progressive lightheadedness, faintness, dimming of vision, and “rubbery”-feeling legs. But even in the context of positive tilt table testing, up to 37% of patients report a clinically misleading symptom of true vertigo (Newman-Toker et al., 2008). So-called “cardiogenic vertigo” and downbeat nystagmus may also occur with asystole (Choi et al., 2010).

Orthostatic hypotension conveys a markedly increased risk of falling in the elderly and is particularly problematic in frail persons with additional risk factors for falling (Mussi et al., 2009) (see “Aged State” later in this chapter). Sudden drops in young persons, particularly when engaged in athletic activities, suggest a cardiac etiology. Exertional syncope requires a detailed cardiac evaluation to rule out valvular disease, right ventricular dysplasia, and other cardiomyopathies.

Transient Ischemic Attacks

Drop attacks secondary to TIAs are sudden falls occurring without warning or obvious explanation such as tripping. Loss of consciousness either does not occur or is only momentary; the sensorium and lower limb strength are intact immediately or shortly after the patient hits the ground. The neurological examination should not reveal lower limb motor or sensory dysfunction between episodes. If such abnormalities are present, it can be impossible to distinguish drop attacks from the falls associated with sensorimotor impairment of the lower limbs. The vascular distributions for drop attacks from TIAs are the posterior circulation and the anterior cerebral arteries.