A 65-year-old man presents complaining of frequent falls and gait abnormalities. He first noticed the difficulty about 6 months ago. He has a history of hypertension, hypothyroidism, and hyperlipidemia. His current medications include amlodipine 10 mg daily, simvastatin 20 mg daily, and levothyroxine 75 μg daily. On neurologic examination, you observe his gait to be wide based with short shuffling steps. He has difficulty rising from his chair and initiating his gait. Upon turning, he takes multiple steps and appears unsteady. However, cerebellar testing is normal including heel to shin and Romberg testing. He has no evidence of sensory deficits in the lower extremities, and strength is 5/5 throughout all tested muscle groups. He shows no evidence of muscle spasticity on passive movement. His neurologic examination is consistent with which of the following causes?
A. Alcoholic cerebellar degeneration
B. Communicating hydrocephalus
D. Multiple system atrophy
E. Lumbar myelopathy
The answer is B. (See Harrison's 20th edition, Chapter 23) Characteristics on neurologic examination can assist with the localization of disease in gait disorders. In this case, the patient presents with signs of a frontal gait disorder or parkinsonism. The specific characteristics that would be seen with a frontal gait disorder are a wide-based stance with a slow and short shuffling steps. The patient may have difficulty rising from a chair and has a slow hesitating start. Likewise, there is great difficulty with turning, with multiple steps required to complete a turn. The patient has very significant postural instability. However, cerebellar signs are typically absent. Romberg sign may or may not be positive, and seated cerebellar testing is normal, including heel-to-shin testing and rapid alternating movements. Additionally, there should otherwise be normal muscle bulk and tone without sensory or strength deficits. The most common cause of frontal gait disorders (sometimes known as gait apraxia) is cerebrovascular disease, especially small-vessel subcortical disease. Communicating hydrocephalus also presents with a gait disorder of this type. In some individuals, the gait disorder precedes other typical symptoms such as incontinence or mental status change. Alcoholic cerebellar degeneration and multiple system atrophy present with signs of cerebellar ataxia. Characteristics of cerebellar ataxia include wide-based gait with variable velocity. Gait initiation is normal, but the patient is hesitant during turns. The stride is lurching and irregular. Falls are a late event. The heel-to-shin test is abnormal and the Romberg is variably positive. Neurosyphilis and lumbar myelopathy are examples of sensory ataxia. Sensory ataxia presents with frequent falls. The gait with sensory ataxia, however, is narrow based. Often the patient is noted to be looking down while walking. The patient tends to walk slowly but have path deviation. Gait is initiated normal, but the patient may have some difficulty with turning. The Romberg is typically unsteady and may result in falls.