In myasthenia gravis, autoantibodies impair nerve-to-muscle signaling by attacking which structure?
Acetylcholine receptors on the muscle endplate
✓
Myelin sheaths of motor nerves
Dopamine-producing neurons in the brain
Calcium channels on motor nerve terminals
Correct Answer
Acetylcholine receptors on the muscle endplate
In myasthenia gravis, antibodies block, alter or destroy the nicotinic acetylcholine receptors at the neuromuscular junction, so acetylcholine cannot trigger normal contraction; some patients have antibodies to muscle-specific kinase instead. Myelin sheaths of motor nerves are damaged in multiple sclerosis. Dopamine-producing neurons in the brain are lost in Parkinson's disease. Calcium channels on motor nerve terminals are the target in Lambert-Eaton syndrome, a different disorder.
Category: Myasthenia Gravis Basics
Question 2
Which pattern of muscle weakness is typical of early myasthenia gravis?
Weakness is worst on waking and improves with activity
Strength is best in the morning and fades with repeated use
✓
Weakness is constant and unaffected by activity or rest
Weakness affects only one side of the body
Correct Answer
Strength is best in the morning and fades with repeated use
The hallmark of myasthenia gravis is fluctuating weakness that worsens with repeated activity, such as blinking, chewing or talking, and improves with rest, so strength is usually greatest in the morning. Weakness that is worst on waking and improves with activity is the reverse of this pattern. Weakness that is constant and unaffected by activity or rest does not fit the fatigable weakness of the disease. Weakness that affects only one side of the body suggests a stroke.
Category: Myasthenia Gravis Basics
Question 3
Imaging of a patient newly diagnosed with myasthenia gravis looks for enlargement or a tumor of which organ?
Thyroid gland
Spleen
Thymus
✓
Adrenal gland
Correct Answer
Thymus
The thymus is thought to give faulty instructions to developing immune cells in myasthenia gravis, and thymic hyperplasia or a thymoma is common, so CT or MRI of the chest is part of the workup. The thyroid gland can affect symptoms through hyper- or hypothyroidism, but it is not the organ imaged for a tumor linked to the disease. The spleen and the adrenal gland are not specifically linked to myasthenia gravis.
Category: Myasthenia Gravis Basics
Question 4
Which class of antibiotics can worsen muscle weakness in a patient with myasthenia gravis?
Cephalosporins
Sulfonamides
Glycopeptides
Aminoglycosides
✓
Correct Answer
Aminoglycosides
Aminoglycosides such as gentamicin interfere with neuromuscular transmission and can trigger an exacerbation; fluoroquinolones and some macrolides carry a similar warning. Cephalosporins are not among the classes standard references warn about. Sulfonamides are not a recognized trigger of myasthenic weakness. Glycopeptides such as vancomycin are not a recognized trigger either; their main concerns are kidney damage and infusion reactions.
Category: Myasthenia Gravis Basics
Question 5
The nurse times pyridostigmine so that its peak effect occurs at mealtimes. What is the purpose of this timing?
To improve chewing and swallowing
✓
To reduce stomach irritation
To increase absorption of the drug
To prevent insomnia at night
Correct Answer
To improve chewing and swallowing
Pyridostigmine strengthens the muscles used for chewing and swallowing, so matching its peak to meals helps the patient eat safely and lowers aspiration risk. Reducing stomach irritation is not the reason; food has no significant interaction with the drug. Increasing absorption of the drug is not the goal of this timing. Preventing insomnia at night is unrelated to the drug's purpose.
Category: Cholinesterase Inhibitors
Question 6
Pyridostigmine should be used with caution in a patient with which condition?
Open-angle glaucoma
Bronchial asthma
✓
Postoperative urinary retention
Tachycardia
Correct Answer
Bronchial asthma
Cholinesterase inhibitors increase acetylcholine at muscarinic sites in the airways, which can cause bronchoconstriction and bronchospasm, so asthma requires close monitoring. Open-angle glaucoma is treated with cholinergic drugs, which constrict the pupil and improve drainage. Postoperative urinary retention without obstruction is not a caution; cholinergic stimulation of the bladder is the basis of bethanechol therapy, and the concern with cholinesterase inhibitors is mechanical urinary obstruction. Tachycardia is not a concern because the drug slows the heart; the caution is for bradycardia and AV block.
Category: Cholinesterase Inhibitors
Question 7
A patient who takes pyridostigmine for myasthenia gravis receives succinylcholine during surgery. What effect should the team expect?
Faster recovery from paralysis
Inactivation of the succinylcholine
Prolonged neuromuscular blockade
✓
Marked tachycardia
Correct Answer
Prolonged neuromuscular blockade
Succinylcholine is broken down by plasma cholinesterase, and cholinesterase inhibitors slow that breakdown, so paralysis is intensified and lasts longer. Faster recovery from paralysis is the opposite of what occurs. Inactivation of the succinylcholine does not occur; its effect is enhanced. Marked tachycardia is not expected because cholinesterase inhibitors tend to slow the heart.
Category: Cholinesterase Inhibitors
Question 8
After surgery, a nurse uses a peripheral nerve stimulator to deliver four stimuli in a row and counts the muscle twitches. What does this train-of-four test assess?
Level of sedation
Severity of nerve pain
Blood level of the anesthetic
Depth of neuromuscular blockade
✓
Correct Answer
Depth of neuromuscular blockade
The train-of-four count shows how much neuromuscular blockade remains and whether more reversal drug, such as neostigmine, is needed; fewer twitches mean deeper blockade. Level of sedation is assessed with a sedation scale, not muscle twitches. Severity of nerve pain is assessed with a pain scale. Blood level of the anesthetic is measured by a laboratory test, not a twitch count.
Category: Cholinesterase Inhibitors
Question 9
Both myasthenic crisis and cholinergic crisis cause muscle weakness. Which finding points to cholinergic crisis?
Excessive salivation and tearing
✓
Generalized muscle weakness
Difficulty breathing
Difficulty swallowing
Correct Answer
Excessive salivation and tearing
Cholinergic crisis comes from too much cholinesterase inhibitor, so muscarinic signs such as heavy salivation, tearing, sweating, diarrhea and bradycardia accompany the weakness. Generalized muscle weakness occurs in both crises. Difficulty breathing occurs in both because respiratory muscles weaken. Difficulty swallowing occurs in both because bulbar muscles weaken.
Category: Crisis and Antidotes
Question 10
A patient with myasthenia gravis who takes pyridostigmine has increasing weakness along with drooling, abdominal cramping and a heart rate of 48. Which action should the nurse take?
Give the next scheduled dose early
Hold the next dose and notify the provider
✓
Give an extra dose of the drug now
Encourage oral fluids and recheck later
Correct Answer
Hold the next dose and notify the provider
These muscarinic signs with weakness suggest cholinergic crisis from excess drug, so cholinergic drugs are held until strength improves and the provider is notified at once. Giving the next scheduled dose early would add more drug and worsen the crisis. Giving an extra dose of the drug now would also deepen the crisis. Encouraging oral fluids and rechecking later delays care, and a weak patient may be unable to swallow safely.
Category: Crisis and Antidotes
Question 11
Which drug reactivates cholinesterase in a patient poisoned by an irreversible inhibitor such as an organophosphate insecticide?
Atropine
Naloxone
Pralidoxime
✓
Flumazenil
Correct Answer
Pralidoxime
Pralidoxime is a cholinesterase reactivator that frees the enzyme from an irreversible inhibitor; it has no effect on reversible inhibitors such as pyridostigmine. Atropine blocks muscarinic effects of the excess acetylcholine but does not reactivate the enzyme. Naloxone reverses opioids. Flumazenil reverses benzodiazepines.
Category: Crisis and Antidotes
Question 12
Azathioprine, an oral immunosuppressant used when myasthenia gravis is not controlled by cholinesterase inhibitors, carries a boxed warning for which risk?
Lactic acidosis
Suicidal thinking
Tendon rupture
Malignancy
✓
Correct Answer
Malignancy
Azathioprine blocks purine synthesis and suppresses the immune response, and its boxed warning is an increased risk of malignancy, such as lymphoma. Lactic acidosis is the boxed warning for metformin. Suicidal thinking is the boxed warning for antidepressants in young people. Tendon rupture is a boxed warning for fluoroquinolones.
Category: Myasthenia Gravis Immunotherapy
Question 13
High-dose glucocorticoids have brought a patient's myasthenia gravis symptoms under control. How should the glucocorticoid be stopped?
Tapered gradually before stopping
✓
Stopped abruptly once strength returns
Kept at the same high dose for life
Stopped and replaced by a second steroid
Correct Answer
Tapered gradually before stopping
Once symptoms are controlled, glucocorticoids are tapered slowly and then discontinued, because stopping abruptly after prolonged use can cause adrenal insufficiency and a flare of the disease. Stopped abruptly once strength returns risks adrenal crisis. Kept at the same high dose for life would expose the patient to the many adverse effects of high-dose steroids. Stopped and replaced by a second steroid does not reduce steroid exposure.
Category: Myasthenia Gravis Immunotherapy
Question 14
Damage to which brain structure, essential for forming new memories, explains why short-term memory loss is an early sign of Alzheimer's disease?
Cerebellum
Hippocampus
✓
Medulla oblongata
Basal ganglia
Correct Answer
Hippocampus
The hippocampus is essential for forming new memories, and it and the adjacent entorhinal cortex are damaged early, so short-term memory is lost first; later damage to the cerebral cortex impairs speech and reasoning. The cerebellum coordinates movement. The medulla oblongata controls breathing and heart rate. The basal ganglia help control movement and are mainly affected in Parkinson's disease.
Category: Alzheimer's Pathology
Question 15
Neurofibrillary tangles inside neurons in Alzheimer's disease are made of which abnormal protein?
Beta-amyloid
Alpha-synuclein
Tau
✓
Myelin basic protein
Correct Answer
Tau
Tau normally stabilizes microtubules, but in Alzheimer's disease it becomes sticky and clumps into tangles, so transport within the neuron fails and the cell dies. Beta-amyloid forms the plaques outside neurons. Alpha-synuclein forms Lewy bodies in Parkinson's disease. Myelin basic protein is a component of myelin and is a target in multiple sclerosis.
Category: Alzheimer's Pathology
Question 16
Which finding is typical of late-stage Alzheimer's disease?
Getting lost in familiar places
Mild forgetfulness of recent events
Trouble planning and doing math
Loss of bladder and bowel control
✓
Correct Answer
Loss of bladder and bowel control
In late Alzheimer's disease the person loses speech, swallowing, mobility and bladder and bowel control and becomes fully dependent on caregivers. Getting lost in familiar places, mild forgetfulness of recent events and trouble planning or doing math are earlier findings, while the person can still function with some independence.
Category: Alzheimer's Pathology
Question 17
Which cholinesterase inhibitor is also approved for mild to moderate dementia associated with Parkinson's disease?
Rivastigmine
✓
Donepezil
Galantamine
Pyridostigmine
Correct Answer
Rivastigmine
Rivastigmine is approved for Alzheimer's disease and for mild to moderate dementia of Parkinson's disease, and it comes as capsules, oral solution and a patch. Donepezil is approved for Alzheimer's disease. Galantamine is approved for mild to moderate Alzheimer's disease. Pyridostigmine acts mainly in the periphery and is used for myasthenia gravis, not dementia.
Category: Alzheimer's Drugs
Question 18
A patient taking donepezil asks whether a nighttime sleep aid containing diphenhydramine is safe to use. What is the concern?
It speeds the metabolism of donepezil
Its anticholinergic action opposes donepezil
✓
It causes a hypertensive crisis with donepezil
It raises donepezil to toxic levels
Correct Answer
Its anticholinergic action opposes donepezil
Diphenhydramine is a first-generation antihistamine with strong anticholinergic effects, so it blocks the acetylcholine that donepezil works to preserve and can worsen confusion in older adults. It speeds the metabolism of donepezil is not the mechanism of this interaction. It causes a hypertensive crisis with donepezil is not a known effect. It raises donepezil to toxic levels is incorrect; the problem is opposing action, not higher levels.
Category: Alzheimer's Drugs
Question 19
Which drug can raise memantine blood levels by making the urine more alkaline?
Ascorbic acid
Acetaminophen
Sodium bicarbonate
✓
Docusate
Correct Answer
Sodium bicarbonate
Memantine is excreted mostly unchanged in the urine, and alkaline urine sharply slows its elimination, so drugs such as sodium bicarbonate and carbonic anhydrase inhibitors can cause accumulation. Ascorbic acid acidifies urine, which would speed memantine elimination rather than raise its level. Acetaminophen does not alter urine pH. Docusate is a stool softener with no effect on urine pH.
Category: Alzheimer's Drugs
Question 20
A patient receiving lecanemab, an amyloid beta-directed antibody, has scheduled MRI scans during treatment. Which adverse effect are the scans monitoring for?
Demyelinating lesions
Pituitary enlargement
Blocked flow of spinal fluid
Brain swelling or small bleeds
✓
Correct Answer
Brain swelling or small bleeds
Lecanemab removes amyloid from the brain and can cause amyloid-related imaging abnormalities, which are areas of brain swelling or small bleeds seen on MRI; they are usually temporary. Demyelinating lesions are the hallmark of multiple sclerosis. Pituitary enlargement is not a known effect of the drug. Blocked flow of spinal fluid describes hydrocephalus, which is not an expected adverse effect.
Category: Alzheimer's Drugs