KMU Past Paper Practice

Question:

A 56-year-old man develops progressive slowness of movement and rigidity. His father and an older brother developed similar symptoms at relatively young ages. Which interpretation best explains the importance of this family history?

Options:

Correct Answer: Inherited susceptibility may contribute to nigral neurodegeneration

Explanation: Familial clustering, particularly with relatively early disease, supports genetic susceptibility affecting neuronal survival; Parkinson disease still reflects interaction between susceptibility and other factors.

Question:

Histological examination of the substantia nigra from a patient with Parkinson disease shows marked neuronal loss. Which accompanying tissue response would be expected at the site of this chronic neuronal degeneration?

Options:

Correct Answer: Reactive gliosis

Explanation: Chronic CNS neuronal loss produces reactive gliosis as glial cells respond to tissue injury; acute inflammatory and necrotizing patterns are not typical of Parkinson disease.

Question:

A 67-year-old man has a rhythmic hand tremor while sitting quietly. When he reaches for a cup, the tremor becomes less prominent. Which feature of Parkinson disease does this pattern represent?

Options:

Correct Answer: Resting tremor related to basal ganglia dysfunction

Explanation: Parkinsonian tremor is most prominent at rest and commonly decreases during purposeful voluntary movement, distinguishing it from an intention tremor.

Question:

During examination of a patient with Parkinson disease, the physician passively flexes the patient’s wrist and feels intermittent ratchet-like resistance rather than smooth continuous resistance. Which explanation best accounts for this finding?

Options:

Correct Answer: Tremor is superimposed on underlying rigidity

Explanation: Cogwheel rigidity results when Parkinsonian tremor is superimposed on the increased resistance to passive movement produced by rigidity.

Question:

A man with established Parkinson disease initially had tremor and slowness but now begins falling when turning and has difficulty recovering after being displaced backward. Which progression of the disease best explains this new problem?

Options:

Correct Answer: Impairment of postural reflexes

Explanation: Postural instability tends to become more prominent later in Parkinson disease and reflects impaired automatic postural responses, increasing the risk of falls.

Question:

A 64-year-old man being evaluated for early Parkinson disease reports that food has seemed less fragrant for several years, preceding his motor symptoms. Which interpretation of this history is most appropriate?

Options:

Correct Answer: It may represent an early non-motor manifestation

Explanation: Reduced olfaction can precede the classic motor syndrome and reflects involvement of neural systems beyond the nigrostriatal motor pathway.

Question:

A patient with Parkinson disease reports chronic constipation, disturbed sleep and progressive motor symptoms. Which explanation best integrates these findings?

Options:

Correct Answer: Neurodegeneration extends beyond motor dopaminergic circuits

Explanation: Parkinson disease can involve autonomic and other neuronal systems, explaining constipation, sleep disturbance and other non-motor manifestations.

Question:

A patient with Parkinson disease has troublesome tremor despite relatively preserved mobility. The physician selects a drug intended to reduce the relative cholinergic influence within the basal ganglia. Which pharmacological class best fits this therapeutic aim?

Options:

Correct Answer: Central antimuscarinic agent

Explanation: Central antimuscarinic drugs such as trihexyphenidyl reduce the relative cholinergic predominance produced by dopamine deficiency and can be particularly useful for tremor.

Question:

A patient with Parkinson disease has good improvement in rigidity with levodopa but develops troublesome treatment-related involuntary movements. Which additional antiparkinsonian drug has a useful role in reducing these dyskinesias?

Options:

Correct Answer: Amantadine

Explanation: Amantadine enhances dopaminergic function and also has a useful role in reducing levodopa-induced dyskinesia; dopamine-blocking or depleting drugs would worsen Parkinsonism.

Question:

A clinician wants to use a dopamine-receptor agonist but wishes to avoid an ergot-derived drug because of concern about fibrotic complications. Which drug best fits this requirement?

Options:

Correct Answer: Pramipexole

Explanation: Pramipexole is a non-ergot dopamine agonist, whereas bromocriptine is an ergot derivative associated with fibrotic complications.

Question:

Soon after beginning levodopa therapy, a patient experiences prominent nausea and vomiting. Which pharmacological event contributes most directly to this early adverse effect?

Options:

Correct Answer: Dopaminergic stimulation of the chemoreceptor trigger zone

Explanation: Dopamine formed from levodopa can stimulate the chemoreceptor trigger zone and produce nausea and vomiting, particularly when peripheral conversion is not adequately limited.

Question:

A 71-year-old man with Parkinson disease has a history of significant cardiac arrhythmia. Levodopa therapy is being considered. Which property of the drug explains the need for additional caution?

Options:

Correct Answer: Peripheral catecholaminergic effects may increase cardiac excitability

Explanation: Peripheral conversion of levodopa can increase catecholaminergic activity and predispose susceptible patients to cardiac arrhythmias.

Question:

A patient being considered for levodopa therapy has a newly detected irregular pigmented skin lesion that has not yet been evaluated. Which approach is most appropriate?

Options:

Correct Answer: Evaluate the suspicious lesion before routine levodopa use

Explanation: Levodopa is used cautiously in patients with suspicious pigmented lesions because dopamine and melanin share biochemical precursor pathways; the lesion should be appropriately assessed.

Question:

A patient taking bromocriptine for Parkinson disease develops new compulsive gambling and excessive spending despite no previous behavioral history. Which pharmacological effect best explains this change?

Options:

Correct Answer: Excessive dopamine-receptor stimulation

Explanation: Dopamine agonists can produce impulse-control and behavioral disturbances because excessive dopaminergic stimulation affects reward and motivational pathways.

Question:

A patient receives intermittent apomorphine therapy and repeatedly develops intense nausea shortly after treatment. Which adverse-effect profile is most consistent with this drug?

Options:

Correct Answer: Nausea with postural hypotension

Explanation: Apomorphine is a potent dopamine agonist and commonly produces dopaminergic adverse effects such as nausea, vomiting, postural hypotension and somnolence.

Question:

A patient taking levodopa is started on selegiline. His mobility improves, but his pre-existing involuntary movements become more troublesome. Which explanation best accounts for this change?

Options:

Correct Answer: Reduced dopamine breakdown enhances levodopa’s central effect

Explanation: By inhibiting MAO-B, selegiline prolongs central dopamine action and can therefore intensify levodopa-related dopaminergic effects, including dyskinesia.

Question:

A 62-year-old woman develops rigidity and slowed movement after repeated treatment for nausea. Which medication in her history would provide the strongest pharmacological explanation for these new symptoms?

Options:

Correct Answer: Prochlorperazine

Explanation: Prochlorperazine blocks dopamine D2 receptors and can reduce basal ganglia dopaminergic signaling sufficiently to produce drug-induced Parkinsonism.

Question:

A patient develops Parkinsonian features while receiving a drug that does not primarily block dopamine receptors but reduces monoamine storage in presynaptic vesicles. Which mechanism is responsible for the motor syndrome?

Options:

Correct Answer: Depletion of presynaptic dopamine stores

Explanation: Drugs such as reserpine and tetrabenazine can produce Parkinsonism by depleting monoamines, including dopamine, rather than by direct postsynaptic receptor blockade.

Question:

An older patient develops new bilateral bradykinesia after several months of treatment for a chronic neurological disorder. No dopamine-blocking antipsychotic or antiemetic is being used. Which medication should still be considered as a possible cause?

Options:

Correct Answer: Valproate

Explanation: Valproate is a recognized non-neuroleptic cause of drug-induced Parkinsonian features, particularly in susceptible patients.

Question:

A patient receiving an essential dopamine-blocking psychiatric medication develops troublesome Parkinsonian symptoms. Complete withdrawal of psychiatric treatment is not clinically appropriate. Which management principle best addresses both problems?

Options:

Correct Answer: Consider an alternative with lower extrapyramidal liability

Explanation: When dopamine-blocking therapy remains necessary, reducing exposure or selecting an alternative with lower extrapyramidal effects addresses the drug cause while preserving required psychiatric treatment.