A 53-year-old man comes to the office due to occasional shaking of his right hand for the last 3 months. He frequently notices the shaking while resting in an armchair and watching television. It often stops when he reaches for the remote to change the channel. The shaking becomes more pronounced when the patient is engaged in mental tasks. He drinks coffee and occasionally has a glass of wine at dinner; these have no effect on the tremor. His left hand has no symptoms. The patient has no weakness, numbness, paresthesias, or gait dysfunction. There is no other significant medical history and he takes no medications. Which of the following is most likely responsible for this patient's condition?

Question

A 53-year-old man comes to the office due to occasional shaking of his right hand for the last 3 months.  He frequently notices the shaking while resting in an armchair and watching television.  It often stops when he reaches for the remote to change the channel.  The shaking becomes more pronounced when the patient is engaged in mental tasks.  He drinks coffee and occasionally has a glass of wine at dinner; these have no effect on the tremor.  His left hand has no symptoms.  The patient has no weakness, numbness, paresthesias, or gait dysfunction.  There is no other significant medical history and he takes no medications.  Which of the following is most likely responsible for this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d48a_40de_bc81_b31edf3036ec_MD0003_00 This patient's presentation is consistent with a resting tremor, a low-amplitude/low-frequency (4-6 Hertz) tremor that typically starts in one hand. The motion is often described as having a "pill-rolling" quality. The tremor may progress to involve other extremities, jaw, face, tongue, and lips. Unlike essential and cerebellar tremors, resting tremor does not usually involve the entire hand. Parkinson disease (PD) commonly presents initially with the classic tetrad of resting tremor, rigidity, postural instability, and bradykinesia. Parkinsonian tremors are more pronounced with distractibility (eg, performing mental tasks) and re-emergence (tremor goes away with movement and then re-emerges when the movement is stopped). A tremor is very often the first presenting sign. PD is due to progressive loss of dopaminergic neurons in the basal ganglia that interrupts neurologic connections from the basal ganglia to the thalamus and motor cortex. (Choice B) Cerebellar dysfunction can cause postural, action, or intention (worsens as the hand moves closer to its target) tremors. The tremors have a lower frequency (3-4 Hz) than those in PD. Although severe cerebellar dysfunction can cause resting tremor, patients usually develop other signs (eg, nystagmus, ataxia, dysmetria). (Choice C) Corticospinal tract lesions usually cause upper motor neuron findings (eg, spasticity, hyperreflexia). However, tremor is not present. (Choice D) Essential tremor is the most common tremor and affects up to 5% of the population (familial in about 50% of cases). Essential tremors typically present as action/postural tremors in the upper extremities that worsen at the end of goal-directed activities (eg, reaching for a pen). They usually affect bilateral upper extremities but can also involve the head, chin, voice, and trunk. (Choice E) Orthostatic tremor is a postural tremor considered to be a variant of essential tremor. Orthostatic tremor occurs in the legs immediately on standing and is relieved by sitting down. It is usually high frequency (14-18 Hz) without other clinical signs or symptoms. (Choice F) Large-fiber peripheral neuropathy may present with action or postural tremors. The tremors are due to impaired proprioceptive input into the brain and cerebellum. Patients can also develop weakness, loss of proprioception, sensory ataxia, areflexia, and loss of sensation or paresthesias. (Choice G) Physiologic tremor is a benign tremor with low amplitude and high frequency (10-12 Hz) that is not visible under ordinary conditions. Unlike the resting tremor seen in this patient, physiologic tremors are postural tremors (eg, holding arms outstretched). Physiologic tremors are usually worsened with emotional or physical stress, toxic/metabolic derangements, caffeine, or drug withdrawal. This patient has no change in tremor with coffee intake. Educational objective: Resting tremor is often the presenting symptom of Parkinson's disease. It is usually a "pill-rolling" tremor that starts in one hand and can progress to involve other extremities, jaw, face, tongue, and lips. References: Cerebral causes and consequences of parkinsonian resting tremor: a tale of two circuits? (http://www.ncbi.nlm.nih.gov/pubmed/22382359) What is essential tremor? (http://www.ncbi.nlm.nih.gov/pubmed/23591755)

A 53-Year-Old Man Comes to the Office Due to Occasional Shaking