Older man with Parkinson's disease: hallucinations, falls and a daughter who wants every psychotropic stopped
Mr S, 71, has had idiopathic Parkinson's disease for nine years. His regimen is levodopa/carbidopa 100/25 mg four times daily, pramipexole prolonged-release 1.5 mg each morning, rasagiline 1 mg daily, and quetiapine 25 mg at night, which his general practitioner added three weeks ago for poor sleep. He also takes oxybutynin 5 mg twice daily for urinary urgency. His daughter brings him to clinic with two weeks of vivid, formed visual hallucinations (small children walking in the garden) and fluctuating confusion that is worse in the late afternoon. Last week he fell at 2 a.m. while trying to chase the children and sustained a left Colles fracture. Blood pressure lying is 128/76 mmHg and standing at one minute 92/54 mmHg. MoCA is 19/30 but he is drowsy and inconsistent. He lives with his wife, who has mild cognitive impairment. The daughter asks that he be taken off every psychiatric drug at once. He still drives short distances to the temple.
1. Set out your working diagnosis, then the order in which you would change his medication, with the reasoning for each step and the monitoring you would arrange.
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Working diagnosis: probable Parkinson's disease dementia with superimposed delirium and drug-induced psychosis. The examiners want ranked, reversible contributors rather than a single label.
- Oxybutynin first. It is strongly anticholinergic, worsens confusion and contributes to falls. Stop it, treat urgency with behavioural measures and night-time fluid timing. If a drug is essential later, choose one with low CNS penetration, but preferably none.
- Pramipexole. Dopamine agonists are the commonest cause of formed visual hallucinations in PD. Taper and stop over one to two weeks; abrupt withdrawal risks dopamine agonist withdrawal syndrome, and the daughter should be warned that motor symptoms and sleep may transiently worsen.
- Quetiapine. Sedating, orthostatic and a fall risk, yet low-dose quetiapine is one of the safer antipsychotics in PD. Keep it briefly for sleep and distress, but review at one week so that you can attribute any change.
- Look for precipitants: urinalysis, chest examination, electrolytes, glucose, constipation, vision and hearing aids, opioid analgesia for the fracture, sleep environment.
- If psychosis persists after precipitants are removed: add rivastigmine (cognitive benefit, may reduce hallucinations in PD dementia), then low-dose quetiapine, then clozapine 12.5 mg at night with full blood count monitoring. Avoid haloperidol, risperidone and olanzapine; neuroleptic sensitivity in this group can be catastrophic.
Monitor motor function, lying and standing blood pressure, a falls diary, sleep and carer burden at one week and one month.
2. How would you weigh and manage the competing risks of falls and untreated psychosis over the next 72 hours, and what is your advice about driving?
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Treat this as one risk problem, not two. The 2 a.m. fall happened because he was acting on a hallucination; the fastest way to reduce falls is to treat the delirium and psychosis, not to sedate him. Adding a sedative as chemical restraint would raise the fall and aspiration risk.
Next 72 hours: stop oxybutynin and begin the pramipexole taper; correct any metabolic precipitant; nurse in a low bed with a sensor mat or overnight supervision, night light, commode within reach and glasses in place; review fracture analgesia; orthostatic precautions (slow transfers, hydration, lying and standing blood pressure); a familiar carer present in the evening when confusion peaks. Reassess with collateral history rather than repeated cognitive testing.
Driving: with fluctuating confusion and formed hallucinations he does not currently hold the capacity to judge his own driving safety. Advise him and his daughter clearly that he must not drive, put the advice in writing in the notes, and follow the local licensing notification rules, informing him if you are required to notify the authority. Frame it as temporary pending review in four to six weeks after the drug changes, not as a permanent ban, so that it is heard.
3. If the hallucinations persist despite stopping oxybutynin and pramipexole, how would you choose the next drug, and what would make you admit him?
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Sequence and reasoning matter more than the drug name. First confirm the diagnosis is PD dementia or dementia with Lewy bodies rather than delirium from an untreated cause (urine, chest, sodium, constipation, pain, sleep loss). A cholinesterase inhibitor is the logical next step because it treats cognition and may reduce hallucinations without worsening parkinsonism; rivastigmine has the best trial support in this population.
If an antipsychotic is still needed: quetiapine at the lowest dose is the usual first choice because parkinsonism worsens relatively little, but efficacy is modest. Clozapine is the agent with the strongest evidence for PD psychosis and the least motor worsening, but requires full blood count monitoring and slow titration, so it is a shared decision with the family. Never prescribe a typical antipsychotic or risperidone/olanzapine; document the neuroleptic sensitivity warning in the notes and on the drug chart, since he will present again to other teams.
Admission if: he cannot be kept safe at home (repeated falls, leaving the house at night), if there is aggression towards his wife, if oral intake or hydration fails, if delirium has an untreated medical cause needing inpatient work-up, or if the carer's own capacity to cope collapses. Mild, well-formed, non-distressing hallucinations with an intact carer are managed as an outpatient with a crisis plan and a named contact.