USMLE Step 2 Quiz
Practice Neuromuscular And Movement Disorders in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
Question 1 / 18
0 of 18 answered
A 24-year-old medical student is in the intensive care unit after being diagnosed with Guillain-Barré syndrome. He is receiving intravenous immunoglobulin therapy. His muscle strength is stable, and he does not require mechanical ventilation at this time. He is alert and oriented.
In addition to respiratory status, this patient should be closely monitored for which of the following complications?
This quiz focuses on Neuromuscular And Movement Disorders, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 24-year-old medical student is in the intensive care unit after being diagnosed with Guillain-Barré syndrome. He is receiving intravenous immunoglobulin therapy. His muscle strength is stable, and he does not require mechanical ventilation at this time. He is alert and oriented.
In addition to respiratory status, this patient should be closely monitored for which of the following complications?
Explanation: Guillain-Barré syndrome is an inflammatory demyelinating polyneuropathy that affects not only motor nerves but also autonomic nerves. Autonomic dysfunction is a common and potentially life-threatening complication. Manifestations can include cardiac arrhythmias (tachycardia, bradycardia), blood pressure instability (hypertension or hypotension), urinary retention, and ileus. Therefore, patients require continuous cardiac and blood pressure monitoring. Increased intracranial pressure, seizures, and cognitive decline are not typical complications of GBS.
A 32-year-old woman presents with a 3-month history of double vision and drooping of her eyelids that worsens as the day progresses. She notes that her symptoms are most prominent in the evening when watching television. She also reports difficulty chewing her food during long meals. On physical examination, she has bilateral ptosis that worsens with sustained upward gaze for 60 seconds. Sensation and deep tendon reflexes are normal. There is no muscle atrophy.
Which of the following is the most appropriate initial test to confirm the diagnosis?
Explanation: This patient's presentation of fluctuating ptosis, diplopia, and bulbar weakness that worsens with activity is classic for myasthenia gravis (MG). The most appropriate initial test is serologic testing for acetylcholine receptor (AChR) antibodies, which is positive in about 85% of patients with generalized MG and has high specificity. If AChR antibodies are negative, testing for MuSK antibodies should be performed. Repetitive nerve stimulation studies show a decremental response in MG but are less specific and typically used when antibody testing is negative or to confirm the diagnosis functionally. Single-fiber EMG is the most sensitive test but is technically demanding and reserved for cases where other tests are inconclusive. CT scan of the chest to screen for thymoma is important but performed after confirming the diagnosis.
A 65-year-old man with a 40-pack-year smoking history presents with a 6-week history of progressive difficulty climbing stairs and getting up from a chair. He notes that his strength seems to improve for a short period after he starts moving around. On examination, he has 4/5 strength in the proximal muscles of his arms and legs. Deep tendon reflexes are absent. There are no sensory deficits. A chest x-ray reveals a 3-cm central lung mass.
The patient's neurologic symptoms are most likely caused by antibodies directed against which of the following targets?
Explanation: This patient's clinical picture of proximal muscle weakness that improves with activity (Lambert-Eaton facilitation), hyporeflexia, and a history of smoking with a lung mass is highly suggestive of Lambert-Eaton myasthenic syndrome (LEMS), a paraneoplastic syndrome most commonly associated with small cell lung cancer. The pathophysiology of LEMS involves autoantibodies directed against presynaptic P/Q-type voltage-gated calcium channels, which impairs acetylcholine release. Antibodies against postsynaptic ACh receptors cause myasthenia gravis. Antibodies against myelin basic protein are associated with multiple sclerosis, and antibodies against aquaporin-4 are seen in neuromyelitis optica.
A 72-year-old man is brought to the emergency department by his wife due to a 2-year history of progressive slowness of movement and difficulty with balance. He has had several falls recently. His wife also notes that his handwriting has become very small and his voice is much softer than it used to be. On examination, there is a low-frequency, pill-rolling tremor of the right hand at rest, which subsides with action. He has a shuffling gait with reduced arm swing and cogwheel rigidity on passive movement of his limbs.
Which of the following is the most appropriate initial medication for this patient?
Explanation: This patient presents with the classic triad of Parkinson disease: bradykinesia (slowness, soft voice, small handwriting), resting tremor, and rigidity. Given his age (>65) and significant functional impairment (falls), carbidopa-levodopa is the most effective and appropriate initial treatment. Dopamine agonists like pramipexole are often used in younger patients to delay levodopa-related motor complications but are less effective and have a higher risk of side effects (e.g., hallucinations) in older adults. Benztropine is an anticholinergic used primarily for tremor in younger patients and is poorly tolerated in the elderly. Amantadine offers mild symptomatic benefit but is less potent than levodopa.
A 55-year-old woman is evaluated for a tremor that has been present for several years. She reports that it primarily affects her hands and is most noticeable when she is trying to write, eat, or drink from a glass. She is embarrassed because people think she is nervous. She notes that having a glass of wine with dinner significantly improves the tremor. Her father had a similar tremor. On examination, a fine, high-frequency tremor is observed in both hands when her arms are outstretched. There is no tremor at rest. The remainder of the neurologic examination is normal.
Which of the following is the most appropriate first-line treatment for this patient's condition?
Explanation: This patient has essential tremor, characterized by bilateral action (postural and kinetic) tremor that improves with alcohol and has a positive family history. The two first-line pharmacologic treatments for essential tremor are propranolol (a non-selective beta-blocker) and primidone (an anticonvulsant). Among the choices given, propranolol is the most appropriate. Levodopa is used for Parkinson disease, which typically presents with resting tremor, bradykinesia, and rigidity. Gabapentin may have some efficacy but is considered a second-line agent. Clonazepam can be helpful but is also not first-line due to concerns about sedation and dependence.
A 45-year-old man presents with a 1-year history of involuntary, jerky movements of his limbs and face, which he is unable to suppress. His wife reports that he has also become more irritable and impulsive. His father died in his 50s from a 'neurologic disease that made him dance.' On examination, he exhibits choreiform movements and has difficulty maintaining a protruded tongue. Cognitive testing reveals deficits in executive function.
Genetic testing in this patient is most likely to reveal which of the following findings?
Explanation: The clinical presentation of chorea, psychiatric changes (irritability, impulsivity), and a positive family history is highly suggestive of Huntington disease. This is an autosomal dominant neurodegenerative disorder caused by an expanded number of CAG (cytosine-adenine-guanine) trinucleotide repeats in the huntingtin gene. A point mutation in the copper-transporting ATPase gene (ATP7B) causes Wilson disease. A deletion in the SMN1 gene causes spinal muscular atrophy. A GGGGCC repeat expansion in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia.
A 58-year-old woman presents with a 9-month history of progressive weakness. She initially noted difficulty with fine motor tasks like buttoning her shirt, followed by stumbling due to weakness in her left foot. On examination, she has asymmetric weakness, fasciculations, and atrophy in the muscles of her right hand and left lower leg. Deep tendon reflexes are 3+ in her arms and legs, and she has bilateral Babinski signs. Sensation, cognition, and extraocular movements are normal.
This patient's clinical findings are most characteristic of which of the following conditions?
Explanation: This patient's presentation with a combination of both upper motor neuron (UMN) signs (hyperreflexia, Babinski signs) and lower motor neuron (LMN) signs (asymmetric weakness, atrophy, fasciculations) is the hallmark of amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disease affecting motor neurons. Multiple sclerosis typically presents with sensory deficits and optic neuritis. Myasthenia gravis causes fluctuating weakness without UMN signs. Spinal muscular atrophy is a pure LMN disease and does not cause hyperreflexia or Babinski signs.
A 28-year-old woman presents to the emergency department with rapidly progressing weakness. She had a diarrheal illness 10 days ago. The weakness began in her legs and has now ascended to involve her arms. She is having difficulty walking. On examination, she has symmetric 3/5 weakness in her lower extremities and 4/5 weakness in her upper extremities. Deep tendon reflexes are absent throughout. Sensation is intact. Her vital signs are stable, but her vital capacity is 25 mL/kg.
What is the most appropriate next step in the management of this patient?
Explanation: This patient's presentation of acute, ascending, symmetric paralysis with areflexia following a recent gastrointestinal infection is characteristic of Guillain-Barré syndrome (GBS). While her vital capacity of 25 mL/kg is concerning and requires close respiratory monitoring, she does not yet require intubation (typically indicated when vital capacity drops below 15-20 mL/kg or with other signs of respiratory compromise). The most appropriate next step is to initiate disease-modifying treatment with intravenous immunoglobulins (IVIG) or plasmapheresis, both of which are equally effective first-line treatments that can halt disease progression. Diagnostic tests like MRI and lumbar puncture can be useful but should not delay treatment in a clinically obvious case.
A 52-year-old woman with a history of iron deficiency anemia presents with an uncomfortable sensation in her legs that occurs primarily in the evenings when she is trying to relax or sleep. She describes an irresistible urge to move her legs, which is temporarily relieved by walking around. These symptoms are causing significant sleep disturbance. Her neurologic examination is normal. Her ferritin level is 25 ng/mL (normal >50 ng/mL).
Which of the following is the most appropriate initial management for this patient?
Explanation: This patient has restless legs syndrome (RLS). An important secondary cause of RLS is iron deficiency. Before initiating symptomatic treatment with dopamine agonists (e.g., pramipexole) or alpha-2-delta ligands (e.g., gabapentin), it is essential to check iron stores and replete them if low. In patients with RLS and a serum ferritin level <75 ng/mL, oral iron supplementation is recommended as the initial management, as it can significantly improve or resolve symptoms.
A 35-year-old woman is evaluated for sustained, involuntary twisting of her neck to the right, which is associated with pain. The symptoms have been present for 4 months and are worse with stress. She can temporarily correct the head position by gently touching her chin. Neurologic examination is otherwise normal.
Which of the following is the most effective treatment for this patient's condition?
Explanation: This patient has cervical dystonia (spasmodic torticollis), a form of focal dystonia characterized by sustained muscle contractions causing abnormal neck posturing. The ability to temporarily correct the posture with a sensory trick ('geste antagoniste') is a classic feature. The most effective and first-line treatment for focal dystonias is intramuscular injection of botulinum toxin into the affected muscles (e.g., sternocleidomastoid, trapezius). This selectively weakens the overactive muscles, relieving the abnormal posture and pain. Oral medications like baclofen are less effective and have more systemic side effects. IVIG is not indicated. Physical therapy can be a helpful adjunct but is not the primary treatment.
A 68-year-old man is evaluated after a stroke affecting his left internal capsule. On examination of his right side, he has increased muscle tone, a pronator drift, and hyperreflexia (3+). When the sole of his right foot is stroked, his great toe extends upward.
These physical examination findings are characteristic of damage to which of the following?
Explanation: The patient's findings of spasticity (increased tone), hyperreflexia, and a positive Babinski sign (upgoing great toe) are classic signs of an upper motor neuron (UMN) lesion. The internal capsule contains corticospinal tracts, which are UMN pathways. Lower motor neuron lesions cause flaccid paralysis, atrophy, fasciculations, and hyporeflexia. Neuromuscular junction disorders cause fluctuating weakness without reflex changes. Peripheral sensory nerve damage causes sensory loss.
A 45-year-old woman presents with a 4-month history of progressive difficulty rising from a chair and combing her hair. She has no facial weakness, diplopia, or ptosis. On examination, she has symmetric 4/5 weakness in the deltoids, hip flexors, and neck flexors. Sensation and reflexes are normal. Laboratory studies show a creatine kinase level of 6,000 U/L. An anti-Jo-1 antibody test is positive.
Which of the following is the most likely diagnosis?
Explanation: This patient's presentation of symmetric proximal muscle weakness, a markedly elevated creatine kinase (CK) level, and a positive anti-Jo-1 antibody is classic for polymyositis, an idiopathic inflammatory myopathy. The absence of facial/ocular weakness and the high CK level differentiate it from neuromuscular junction disorders like myasthenia gravis or LEMS, where CK is typically normal. Amyotrophic lateral sclerosis involves both upper and lower motor neuron signs, which are absent here.
A 45-year-old woman with myasthenia gravis presents to the emergency department with severe, rapidly worsening shortness of breath. She had an upper respiratory infection for the past 3 days. She is using her accessory muscles to breathe, and her speech is limited to single words. Her oxygen saturation is 94% on room air. An arterial blood gas shows a pH of 7.38, PaCO2 of 40 mm Hg, and PaO2 of 85 mm Hg. A measurement of her negative inspiratory force (NIF) is -15 cm H2O (normal < -25 cm H2O).
What is the most appropriate next step in management?
Explanation: This patient is in myasthenic crisis, a life-threatening exacerbation of myasthenia gravis characterized by respiratory muscle weakness leading to respiratory failure. Despite normal oxygenation and PaCO2, the clinical signs of respiratory distress (accessory muscle use) and the severely reduced negative inspiratory force (NIF <-20 cm H2O is an indication) signify impending respiratory collapse. The most appropriate next step is to secure the airway with endotracheal intubation and initiate mechanical ventilation. Edrophonium is a diagnostic tool and not used for management. Increasing pyridostigmine can worsen secretions and is not sufficient for respiratory failure. While the crisis was likely triggered by an infection, securing the airway is the immediate priority.
A 60-year-old man with a history of type 2 diabetes mellitus presents with a 6-month history of burning pain and numbness in his feet. The symptoms began in his toes and have gradually spread up to his ankles. He describes the sensation as 'walking on pins and needles.' On examination, there is decreased sensation to light touch and pinprick in a stocking-like distribution. Ankle reflexes are absent bilaterally. Vibration sense is diminished at the great toes.
In addition to glycemic control, which of the following is the most appropriate initial pharmacologic treatment for this patient's symptoms?
Explanation: This patient has painful diabetic peripheral neuropathy. The first-line treatments for neuropathic pain include tricyclic antidepressants (TCAs) such as amitriptyline, serotonin-norepinephrine reuptake inhibitors (SNRIs) such as duloxetine, and gabapentinoids such as gabapentin or pregabalin. Among the given options, amitriptyline is the most appropriate choice. Opioids like oxycodone are not recommended as first-line therapy due to limited evidence of efficacy and risks of tolerance, dependence, and abuse. NSAIDs like ibuprofen are generally ineffective for neuropathic pain. SSRIs like sertraline are less effective for neuropathic pain compared to TCAs and SNRIs.
A 62-year-old man with Parkinson disease, treated with carbidopa-levodopa for 7 years, presents for follow-up. He reports that the medication is less effective than before, and he experiences a return of his motor symptoms about 3 hours after each dose. When the medication is working, he has developed involuntary writhing movements of his arms and trunk. On examination, he has choreiform movements when his motor function is at its peak.
The involuntary movements are best described as which of the following?
Explanation: This patient is experiencing motor complications of long-term levodopa therapy. The return of parkinsonian symptoms before the next dose is known as 'wearing-off.' The involuntary writhing, choreiform movements that occur when the medication effect is at its maximum are termed peak-dose dyskinesias. These are caused by excessive dopaminergic stimulation in a sensitized striatum. Off-period dystonia occurs when levodopa levels are low. Akathisia is a sense of restlessness. Myoclonus is characterized by brief, shock-like muscle jerks.
A 55-year-old woman presents to her primary care physician with weakness and fasciculations in her arms and legs. On examination, she has diffuse muscle atrophy, flaccid tone, and reflexes are 0/4 throughout. Plantar reflexes are downgoing. Sensation and cognition are intact. Electromyography shows widespread denervation potentials.
These findings are most consistent with a lesion affecting which of the following structures?
Explanation: The patient's clinical presentation consists exclusively of lower motor neuron (LMN) signs: weakness, muscle atrophy, fasciculations, flaccid tone, and areflexia. The anterior horn cells of the spinal cord contain the cell bodies of LMNs. Diseases affecting these cells, such as spinal muscular atrophy or the LMN component of ALS, would produce these findings. Lesions of the corticospinal tracts (upper motor neurons) would cause spasticity and hyperreflexia. Posterior column lesions cause loss of vibration and proprioception. Basal ganglia dysfunction causes movement disorders like Parkinsonism or chorea.
A 40-year-old female office worker presents with a 3-month history of numbness and tingling in her right thumb, index, and middle fingers. The symptoms are worse at night and often awaken her from sleep. She finds relief by shaking her hand. On examination, there is weakness of thumb abduction and a positive Tinel sign at the wrist. Tapping over the carpal tunnel elicits paresthesias in the median nerve distribution.
Which of the following is the most accurate test to confirm the diagnosis?
Explanation: The patient's symptoms are classic for carpal tunnel syndrome, which is caused by compression of the median nerve at the wrist. While the diagnosis is often made clinically, nerve conduction studies (NCS) are the most accurate diagnostic test. NCS can confirm the diagnosis, determine the severity of nerve compression, and rule out other neuropathies. Wrist X-rays are not useful unless a fracture is suspected. MRI of the cervical spine would evaluate for cervical radiculopathy, which can present similarly but typically involves neck pain and different sensory distribution. TSH is checked to rule out hypothyroidism as a secondary cause but does not confirm the diagnosis of carpal tunnel syndrome itself.
A farmer is brought to the emergency department after being found confused in a field. He is diaphoretic, salivating profusely, and has pinpoint pupils. He is incontinent of urine and stool. Auscultation of the lungs reveals diffuse wheezing and rhonchi. Muscle examination shows widespread fasciculations and weakness.
The patient's neuromuscular symptoms (fasciculations and weakness) are primarily due to overstimulation of which type of receptor?
Explanation: This patient has organophosphate poisoning, which inhibits acetylcholinesterase, leading to an excess of acetylcholine. The overstimulation of muscarinic receptors causes the DUMBBELLS symptoms (Diarrhea, Urination, Miosis, Bronchospasm/Bradycardia, Emesis, Lacrimation, Salivation). However, the neuromuscular effects, including fasciculations and subsequent paralytic weakness, are caused by overstimulation of nicotinic acetylcholine receptors at the neuromuscular junction. Alpha-adrenergic and dopamine receptors are not primarily involved in this pathophysiology.