Welcome to your Muscle Disorders & Neuromuscular Pharmacology Arena
1.
A 40-year-old man with extensive burns sustained three weeks earlier requires emergency intubation. Succinylcholine is avoided. Which change most directly increases the risk associated with this drug?
2.
A 35-year-old woman receives succinylcholine before a brief procedure. Muscle fasciculations are followed by paralysis. Administration of neostigmine during the initial block would most likely:
3.
A patient with malignant hyperthermia develops metabolic acidosis, hyperkalemia and dark urine. Which process best links the primary muscle abnormality to these findings?
4.
A 29-year-old man receives repeated doses of succinylcholine during a prolonged procedure. Neuromuscular monitoring later demonstrates fading responses, although the motor end plate has repolarized. Which type of blockade has developed?
5.
A 32-year-old office worker develops painful neck-muscle spasm after a minor injury. Cyclobenzaprine is prescribed for short-term use. Which adverse-effect pattern is most consistent with this drug?
6.
A surgical patient has regained visible limb movement after receiving a non-depolarizing blocker. However, neuromuscular monitoring still shows incomplete recovery. Why should extubation be delayed?
7.
A patient develops malignant hyperthermia during surgery. Dantrolene is administered promptly. Which change directly produces its therapeutic benefit?
8.
A 38-year-old woman with multiple sclerosis has disabling lower-limb spasticity. Baclofen is prescribed. Which sequence best describes its therapeutic action?
9.
A child who survived paralytic poliomyelitis has permanent weakness of one leg. He can walk with a brace but cannot enter his classroom because it is located upstairs without accessible facilities. Which intervention most directly addresses the participation restriction?
10.
A newborn has generalized hypotonia, poor feeding and delayed motor development. Muscle biopsy shows centrally located nuclei in many fibres. Which category of disorder best fits this presentation?
11.
A 67-year-old man with ischemic heart disease receives pancuronium during surgery and develops an increase in heart rate. Which pharmacological property best explains this effect?
12.
A 45-year-old man with spinal-cord disease is treated with tizanidine. His muscle tone improves, but he develops dizziness, dry mouth and low blood pressure. Which receptor action explains both the benefit and the adverse effects?
13.
A 70-year-old man has slowly progressive difficulty extending his knees and gripping objects. Weakness is asymmetrical, and treatment for presumed inflammatory myopathy produces little benefit. Biopsy shows endomysial inflammation and vacuolated fibres containing abnormal proteins. Which diagnosis is most likely?
14.
A 55-year-old woman receiving prolonged glucocorticoid therapy develops painless proximal weakness. Creatine kinase is not markedly elevated, and biopsy shows muscle-fibre atrophy with little inflammation. Which mechanism best explains her weakness?
15.
Poliovirus is detected in wastewater from an area where no paralytic case has recently been reported. Several communities have missed children during vaccination activities. Which public-health interpretation is most appropriate?
16.
A 56-year-old man undergoes abdominal surgery under general anesthesia. Rocuronium is administered to facilitate muscle relaxation. At the end of surgery, he has weak respiratory efforts and train-of-four stimulation shows fading responses. Which mechanism best explains the persistent weakness?
17.
Two brothers have inherited dystrophin-related muscle disease. The older brother developed symptoms in early childhood and has rapidly progressive weakness. The younger brother developed milder weakness later in life. Which difference most likely explains the milder phenotype?
18.
A 47-year-old woman has progressive proximal weakness without skin lesions. Muscle biopsy shows cytotoxic lymphocytes surrounding and invading non-necrotic fibres. Which mechanism most directly accounts for her muscle injury?
19.
During surgery, atracurium administration is followed by flushing, hypotension and wheezing. Which mechanism best explains this combination?
20.
A 42-year-old woman with advanced liver and kidney disease requires neuromuscular blockade during emergency surgery. The anesthetist selects cisatracurium. Which property most strongly supports this choice?
21.
A 58-year-old man develops progressive weakness and wasting of the right leg after compression of a peripheral motor nerve. Muscle biopsy shows groups of small angular fibres. Some remaining fibres are arranged in clusters of the same histochemical type. Which process best explains the latter finding?
22.
A child with early muscle weakness undergoes biopsy. Muscle fibres contain central areas with reduced oxidative enzyme activity. The abnormality is associated with disturbed intracellular calcium handling. Which diagnosis is most likely?
23.
A public-health team compares two disorders. Disease X causes many premature deaths, while disease Y causes prolonged severe disability with few deaths. Which measure allows both forms of health loss to be combined for comparison?
24.
A patient has proximal weakness, preserved sensation and elevated muscle enzymes. Electrophysiological testing is planned to distinguish primary muscle disease from loss of motor-nerve supply. Which combination is most appropriate?
25.
A patient with prolonged apnea after succinylcholine recovers after several hours of ventilatory support. Which investigation would best help explain the event and guide future anesthetic planning?
26.
A patient with longstanding motor-neuron disease undergoes muscle biopsy. Several large groups of fibres are severely atrophic because an expanded motor unit has subsequently lost its nerve supply. Which pathological pattern is represented?
27.
A patient receives neostigmine to reverse residual vecuronium-induced paralysis. Glycopyrrolate is administered at the same time. Which effect of increased acetylcholine is glycopyrrolate intended to prevent?
28.
Shortly after induction of anesthesia with a volatile agent and succinylcholine, a patient develops rapidly rising carbon dioxide production, generalized muscle rigidity and tachycardia. Which event is most central to this reaction?
29.
During suspected malignant hyperthermia, the patient’s temperature is only mildly elevated, but end-tidal carbon dioxide rises unexpectedly and muscle rigidity is present. Which interpretation is most appropriate?
30.
A man develops severe muscle pain and weakness after exposure to a myotoxic substance. Serum muscle enzymes are markedly elevated, and urine becomes dark. Which sequence best explains the renal complication?
31.
A patient taking baclofen for chronic spasticity stops the medication abruptly. He develops severe rebound spasticity, agitation and seizures. Which explanation is most appropriate?
32.
A district reports high childhood vaccination coverage, but a child presents with sudden flaccid weakness. Public-health authorities investigate the case urgently because many infections may occur without paralysis. Which surveillance approach is most directly indicated?
33.
A 30-year-old woman presents with progressive proximal weakness. Sensory examination is normal. Creatine kinase is elevated, but the cause remains uncertain after initial assessment. Which investigation would best demonstrate the distribution of active muscle edema and fatty replacement before selecting a biopsy site?
34.
A rehabilitation programme enables a patient with residual poliomyelitis to live for several additional years with improved mobility and independence. Which measure is most suitable for expressing the health benefit gained?
35.
A 4-year-old boy has frequent falls, a waddling gait and difficulty rising from the floor. Genetic testing identifies a severe dystrophin-gene abnormality. Which cellular event most directly initiates repeated muscle-fibre necrosis?
36.
A 6-year-old boy with progressive proximal weakness has calf enlargement and a positive Gowers sign. Which finding would favour Duchenne muscular dystrophy over spinal muscular atrophy?
37.
A 40-year-old woman presents with difficulty climbing stairs and lifting objects above her head. Examination shows symmetrical proximal weakness and a photosensitive rash. Biopsy demonstrates inflammation around small vessels and connective tissue between fascicles. Which additional finding is most likely?
38.
A 24-year-old man remains paralyzed and apneic for an unexpectedly long period after receiving succinylcholine. He is conscious but unable to move. Which immediate management is most appropriate?
39.
A patient receiving gentamicin requires a non-depolarizing neuromuscular blocker during surgery. Postoperatively, recovery from paralysis is delayed. Which mechanism most likely contributed to this interaction?
40.
A muscle biopsy from a boy with progressive childhood weakness shows marked fibre-size variation, necrotic fibres, regenerating fibres, internal nuclei and increasing endomysial fibrosis. Which pathological process best accounts for this combination?
