What is the diagnosis and recommended treatment for a patient with a family history of Parkinson's disease, presenting with weakness, pain, tremors, and a shuffling gait after a medication change, and seeking evaluation for a wheelchair and physical therapy?

Diagnosis: Drug-Induced Parkinsonism vs. Idiopathic Parkinson's Disease

The most likely diagnosis is drug-induced parkinsonism given the temporal relationship with medication changes two months ago, and the immediate priority is to identify and discontinue the offending medication while referring to a movement disorder specialist for definitive diagnosis. 1

Critical Diagnostic Considerations

Distinguishing Drug-Induced from Idiopathic Parkinson's Disease

Bradykinesia must be present alongside at least one other cardinal sign (resting tremor, rigidity, or postural instability) to diagnose any parkinsonian syndrome. 1, 2 This patient demonstrates:

• Shuffling gait (suggests bradykinesia and postural instability) 2
• Right hand tremor (resting tremor) 2
• Generalized weakness and pain (may reflect rigidity or medication side effects) 2

Key Differentiating Features

The temporal relationship with medication changes two months ago is the most critical diagnostic clue suggesting drug-induced parkinsonism rather than idiopathic Parkinson's disease. 3 Drug-induced parkinsonism typically:

• Develops within days to months of starting the offending medication 3
• Is often bilateral from onset (unlike idiopathic PD which is typically asymmetric initially) 4
• May improve or resolve with medication discontinuation, though this can take weeks to months 3

The patient's self-diagnosis of tardive dyskinesia is likely incorrect - tardive dyskinesia presents with rapid involuntary facial movements (blinking, grimacing, chewing) and extremity movements, not the resting tremor and shuffling gait described here. 3

Immediate Management Steps

1. Medication Review and Modification

Immediately review all medications started or changed in the past 2-3 months, particularly:

• Antipsychotics (typical agents like haloperidol, or atypical agents) - most common cause 3
• Antiemetics (metoclopramide, prochlorperazine) 3
• Calcium channel blockers (particularly cinnarizine, flunarizine) 3
• Valproic acid 3

Discontinue the offending agent if clinically feasible, or switch to an alternative that does not cause parkinsonism. 3 Early diagnosis and rapid withdrawal may improve the possibility of complete recovery. 3

2. Specialist Referral

Referral to a neurologist or movement disorder specialist is essential for correctly diagnosing the specific cause of parkinsonism. 1 This is non-negotiable given the diagnostic complexity and treatment implications.

3. Diagnostic Workup

Order MRI brain without contrast as the optimal initial imaging modality to rule out structural causes, vascular disease, or hydrocephalus. 1

Consider I-123 ioflupane SPECT/CT (DaTscan) if the diagnosis remains uncertain after medication withdrawal and clinical observation - this can differentiate true parkinsonian syndromes from drug-induced tremor. 1 However, DaTscan cannot distinguish between different neurodegenerative causes of parkinsonism.

Addressing the Patient's Specific Requests

Wheelchair Evaluation

Defer wheelchair prescription at this time. 3 Providing adaptive aids like wheelchairs may:

• Prevent restoration of normal movement and function 3
• Lead to muscle deconditioning 3
• Promote learned non-use 3
• Increase pain 3

Instead, focus on strategies that encourage normal movement patterns while the medication issue is being addressed. 3

Physical Therapy Approach

Physical therapy is appropriate, but should focus on specific interventions for parkinsonian symptoms rather than general pain management:

• Engage in tasks that promote normal movement, good alignment, and even weight-bearing (transfers, sit-to-stand, standing activities) 3
• Encourage even distribution of weight in sitting, transfers, standing, and walking to normalize movement patterns and muscle activity 3
• Incorporate anxiety management and distraction techniques during functional tasks 3
• Consider slow movement activities such as tai chi or yoga to regain movement control 3

Family History Considerations

The family history of Parkinson's disease in a relative increases suspicion for idiopathic PD but does not change immediate management. 4 Most Parkinson's disease is sporadic, though genetic factors play a role in some cases. 5 The temporal relationship with medication changes remains the dominant diagnostic feature suggesting drug-induced parkinsonism.

Monitoring and Follow-Up

If drug-induced parkinsonism is confirmed:

• Symptoms may take weeks to months to resolve after discontinuing the offending medication 3
• Some patients may have persistent symptoms, suggesting unmasking of underlying neurodegenerative disease 3
• Serial neurological examinations are essential to monitor for improvement or progression 1

If symptoms persist beyond 6 months after medication discontinuation, the diagnosis should be reconsidered and workup for idiopathic Parkinson's disease or other neurodegenerative parkinsonism should proceed. 4

Critical Pitfalls to Avoid

• Do not start dopaminergic therapy (levodopa, dopamine agonists) until drug-induced parkinsonism is ruled out and specialist evaluation is complete 4
• Do not prescribe anticholinergic medications for tremor without specialist guidance, as these have significant side effects in older adults 3
• Do not assume this is tardive dyskinesia based on patient self-diagnosis - the clinical presentation does not match 3
• Do not provide a wheelchair without first addressing the underlying cause and attempting rehabilitation 3