Quiz 07/16/2022

Based on the findings on the muscle biopsy (trichrome stain) shown below, which of the following is most likely seen on examination of this patient?

A 55-year-old male presents to the clinic with a complaint of right lower extremity pain and weakness. On examination of the right lower extremity, there is decreased sensation to pinprick on the medial calf and foot, 4/5 strength with knee extension, and a mute patellar reflex. These findings are most likely due to radiculopathy of which of the following nerve roots?

A 48-year-old male with a history of a motor vehicle accident and right leg tibial plateau fracture was referred to a neurologist because of right leg weakness. He states he often catches his right foot while walking and stubs his toes when he walks barefoot. On examination, there is decreased strength with both ankle dorsiflexion and foot inversion. Weakness of which of the following muscles is responsible for the patient’s symptoms?

A 45-year-old male presents with left-sided neck and shoulder pain. On examination, there is right arm abduction weakness and decreased bicep and brachioradialis reflexes. An EMG was ordered and showed fibrillations of the deltoids, supraspinatus, and biceps muscles. EMG testing of the triceps, first dorsal interosseous, abductor policies brevis, and rhomboid muscles were normal. These findings are most likely due to radiculopathy of which of the following nerve roots?

Damage to which of the following muscles can lead to scapular winging?

A 27-year-old presents to the clinic with finger extension, wrist extension, shoulder abduction, and shoulder adduction weakness. There is also numbness along the lateral and posterior arm. Which of the following is the most likely cause of the patient’s symptoms?

A 24-year-old male presents to the clinic with numbness in the hands and feet. He has been experiencing these symptoms since his late teens, but the numbness has gotten progressively worse. Additionally, he has been stumbling and losing his balance more frequently in the past 18 months, and he received a new pair of glasses because he was having trouble with his vision at night. On physical exam, he has decreased sensation to vibration and pinprick in his bilateral lower extremities and palpable, enlarged nerves. Laboratory studies reveal an elevated level of phytanic acid. What is the most likely diagnosis?

This pathology slide is most consistent with which of the following diseases?

A 65-year-old man presents to the emergency room with progressive weakness over the course of several months. Examination shows pure motor weakness with no sensory involvement, decreased reflexes, and diffuse fasciculations. An EMG shows a conduction block of motor neurons outside of compression sites and normal sensory conduction velocities. Which of the following of most appropriate for treatment?

Which of the following dermatomes lies closest to the T2 dermatome, relative to the topographical position on the skin?

Concentrically-layered Schwann-cell processes (“onion bulbs”) are seen surrounding nerve fibers on nerve biopsy in which of the following diseases?

Which of the following nerves is a terminal branch of the posterior cord?

A 47-year-old female presents to the clinic with the chief complaint of slowly progressive proximal muscle weakness. Electromyography showed short duration, low amplitude motor unit action potentials. A muscle biopsy was performed and shown below. A diagnosis is made and the patient is started on a therapeutic agent. What is the most likely medication initiated?

A 57-year-old male with recently diagnosed small cell lung cancer (SCLC) is presenting to the electromyography lab with a one-month history of muscle cramps and muscle pain. Percussive myotonia is appreciated on examination. Electromyography showed myokymic discharges. Autoantibodies against which of the following channels are likely present in this case?

Anti-GQ1b antibodies are associated with which syndrome?

Which of the following CSF findings would be expected in a patient with AIDP?

A 65-year-old man comes to the clinic with a one-year history of difficulty walking. More recently, he has also noticed a tendency to drop things. On examination, he was found to have weakness in his bilateral lower limbs, predominantly in his quadriceps muscles, along with finger flexion weakness that is worse on the left side. His sensory examination was normal. Which of the following is the most likely diagnosis?

A 40-year-old male is referred to the clinic for a one-year history of progressive weakness of the upper and lower extremities. Past medical history is impressive for thrombocytopenia, anemia, and hepatosplenomegaly. Neurological examination shows 2/5 strength in the distal lower limbs bilaterally with diminished ankle and patellar reflexes. The sensory exam shows diminished vibratory and pinprick sensation in both legs. He also has a markedly orange discoloration of his tonsils. Genetic testing is performed which reveals a mutation in the ABCA1 gene. Which of the following is the most likely diagnosis?

A 20-year-old female presents to the clinic with weakness and numbness in the right leg. She states that earlier in the day she was taking a long nap on her right side, and when she awoke, her entire leg felt like pins and needles. When she got up, she felt that she was dragging her right leg on the floor. She has had similar experiences in other limbs over the years but symptoms would slowly improve over weeks. Nerve conduction studies showed a right common peroneal nerve conduction block and mildly decreased conduction velocities of all nerves tested. Her mother reports that her father had similar episodes before he passed away from an unrelated illness. Which of the following is the most likely diagnosis?

Which of the following is the mechanism of action of riluzole?

Which of the following autoantibodies are associated with myasthenia gravis?

A 40-year-old male presents to the clinic with difficulty swallowing. On additional questioning, he reports difficulty walking, falls, and dysarthria. Examination shows bilateral facial weakness, fasciculations, and gynecomastia. A CAG trinucleotide repeat on which of the following genes is the cause of this disease?

A 60-year-old woman with a history of diabetes is presenting to the neurology clinic with a 4-month history of burning/tingling in her bilateral toes. Neurological examination revealed 5/5 strength in all muscle groups, normal reflexes, and intact sensation to light touch in the bilateral lower extremities. There was mildly decreased sensation to pinprick in the 1^st toe bilaterally. Which of the following tests is the most likely to be diagnostic for this patient?

A 65-year-old female presents with a complaint of burning and tingling of her feet. Symptoms started in her toes two years ago and now extend up to her ankles. Neurological examination showed normal strength and intact sensation to light touch and vibration but an impaired sensation to pinprick in the first toes bilaterally. If performed, which of the following studies would likely be abnormal?

Which of the following is the genetic mutation commonly seen in patients with hereditary neuropathy with liability to pressure palsy (HNPP)?

A four-year-old boy with no significant past medical history is brought to your clinic due to difficulty walking. His mother states that he began walking at 12 months of age, but in the past few months, he seems to be more fatigued and weak when walking. On physical exam, his calves seem to be abnormally large. This disorder is caused by what mutation?

Parents bring their 3-year-old son to the clinic for difficulty walking. On examination, the patient has a waddling gait and enlarged calf muscles. When rising from a seated position he has to rely extensively on his arms to stand up. Which of the following is the most likely inheritance pattern of the genetic disorder affecting this patient?

A 6-year-old female is seen in the clinic for decreased balance and numbness in her fingers and toes. Her father, who is with her at the clinic visit, states that she was developmentally normal until 2 years of age, at which time she began to have frequent falls. During the past year, she has also developed slurred speech. The neurological exam reveals truncal ataxia, ataxic gait, scanning speech, and decreased sensation to vibration and pinprick in her extremities. The ocular exam reveals irregular capillary dilation of the retina and skin. What is the most likely diagnosis?

Congenital muscular dystrophies are most often associated with which of the following pathophysiologies?

A 42-year-old man with a 6-month history of progressive muscle weakness has a nerve biopsy performed. Based on the toluidine blue (left) and trichrome (right) stain slides shown, which of the following is the most likely diagnosis?

Eteplirsen is an effective treatment in patients with Duchenne muscular dystrophy (DMD) that have which of the following dystrophin mutations?

Which of the following medications, when taken alongside statin therapy, increases the risk of statin-induced myopathy?

A 3-year-old girl is admitted to the hospital with a 2-day history of constipation, lethargy, and a weak cry. Repetitive stimulation performed at 20 Hz revealed incremental response. What is the likely cause of this patient’s illness?

Which of the following is the most classic finding of early inclusion body myositis?

The paraspinal muscles are innervated by which of the following?

Which of the following is the most sensitive test for myasthenia gravis (MG)?

What is the mechanism of action of pregabalin?

A 57-year-old male with recently diagnosed small cell lung cancer (SCLC) is presenting to the electromyography lab with a one-month history of muscle cramps and muscle pain. Percussive myotonia is appreciated on examination. Electromyography showed myokymic discharges. Autoantibodies against which of the following channels are likely present in this case?

A 56-year-old male comes to the clinic with a burning and tingling sensation in his feet and hands for the past 4 months. He has a history of morbid obesity and underwent gastric bypass surgery last year. On physical exam, he has 3+ ankle and patellar reflexes. He also has a positive Babinski and positive Romberg sign. There is impaired position and vibration sense in his big toe bilaterally. This patient’s condition is most likely due to a deficiency of which of the following?

A 56-year-old female presents to the clinic with right posterior leg pain. On examination, there is decreased sensation of the right posterior calf and weakness in right ankle plantarflexion. EMG testing shows fibrillations of the gastrocnemius and gluteus maximus muscles. EMG testing of the tibialis anterior, gluteus medius, and tensor fascia lata were normal. What is the most likely etiology of this patient’s symptoms?

You are evaluating a 1-year-old who has had delayed motor development and diffuse weakness since birth and presents now to the hospital for a first-time seizure. The physical exam is notable for 3/5 deltoid abduction, 4-/5 hip abduction, 4-/5 hip flexion, and 4-/5 hip extension. He is unable to walk but is meeting cognitive milestones. An MRI brain is done and shows diffuse scattered T2 FLAIR white matter hyperintensities.

If genetic testing is performed, a mutation in which of the following genes would be most expected?

A 78-year-old male with a past medical history of diabetes presents to the clinic with a 2-year history of progressive lower extremity numbness and pain. He describes the pain as “pins and needles”. Physical examination reveals loss of pinprick sensation to the ankles bilaterally, mute Achilles reflexes, and moderate difficulty with tandem gait. A diagnosis is made based on examination and clinical history. What is the mechanism of action of the most appropriate first-line therapeutic agent?

A 62-year-old 50 kg female with a history of myasthenia gravis presents to the hospital with shortness of breath and generalized weakness felt to be secondary to a myasthenic crisis. Her medication history in the chart states she is currently taking pyridostigmine 60 mg QID, prednisone 20 mg daily, and just started cyclophosphamide 4 weeks ago. She was safely intubated in the ED with a NIF of -18 cm H2O and a VC of 600 ml. Select the appropriate next steps regarding pharmacotherapy and management for a myasthenic crisis.

I. Discontinue pyridostigmine
II. Increase the dose of prednisone
III. Increase the dose of azathioprine
IV. Consult general surgery for thymectomy
V. Consider PLEX or IVIg therapy
VI. Start rituximab

A 47-year-old female presents to the clinic with the chief complaint of slowly progressive proximal muscle weakness. Electromyography showed short duration, low amplitude motor unit action potentials. A muscle biopsy was performed and shown below. A diagnosis is made and the patient is started on a therapeutic agent. What is the most likely medication initiated?

A 6-month-old male is admitted to the ED for acute respiratory failure. On examination, he has generalized weakness, diffuse hypotonia, and areflexia. He was admitted to the pediatric Intensive Care Unit and intubated. A chest X-ray showed a narrow chest. EMG/NCS was performed showing axonal motor polyneuropathy with tongue fasciculations and signs of chronic denervation. What is the most likely pathologic etiology causing this presentation?

Congenital muscular dystrophies are most often associated with which of the following pathophysiologies?

A patient with a history of a right shoulder anterior dislocation comes to the clinic with the chief complaint of right arm numbness. On examination, there is a loss of sensation to light touch on the lateral portion of the upper arm. Based on the sensory disturbance, which of the following nerves is most likely injured?

A 5-year-old male presents because of muscle stiffness. His symptoms are worse during the colder winter months and with gym class at school. He sometimes becomes so stiff he can hardly breathe. Examination shows no muscle atrophy or hypertrophy but myotonia is present. Upon further questioning, you learn he has an older brother with similar symptoms. What is the likely dysfunctional gene in this patient?