Parkinsonism

Identify the subtype - The preop questions that separate them: does levodopa actually work, are the signs symmetric (points to drug-induced), was there early orthostatic hypotension and urogenital failure (MSA), early backward falls with vertical gaze palsy (PSP), or ventriculomegaly on MRI (NPH). It changes the aspiration risk, the hemodynamic plan, and whether a missed dose matters.

Never stop the dopaminergic drug - Abrupt withdrawal or dose reduction of levodopa triggers parkinsonism-hyperpyrexia syndrome: hyperthermia, rigidity, altered mental status, and autonomic instability that is clinically the same picture as neuroleptic malignant syndrome (NMS). Give the morning dose, book them early on the list, and restart by NG/OG tube as soon as the case is over. Ropinirole does the same thing on abrupt stop — withdrawal-emergent hyperpyrexia and confusion.

Levodopa dosing is fragile - It is dosed 3 to 12 times a day and absorbed in the small bowel, so any ileus, gastroparesis, or delayed NG access is a missed dose. Protein-heavy tube feeds compete for the same amino acid transporter and cut absorption.

Dopamine-blocking antiemetics - The metoclopramide label warns that patients with pre-existing Parkinson disease should get it "cautiously, if at all," because they can have an exacerbation of parkinsonian symptoms; prochlorperazine, droperidol, and haloperidol block D2 the same way. Reach for a non-dopaminergic antiemetic. If an acute dystonic reaction does happen, the label's own remedy is diphenhydramine 50 mg IM, with benztropine 1 to 2 mg IM as an alternative.

MAO-B inhibitors - Selegiline and rasagiline are on many of these charts. Levodopa with a nonselective MAOI causes hypertensive crisis, and selegiline above 10 mg/day loses its B-selectivity. Know which agent the patient is on before you reach for a sympathomimetic.

MSA — autonomic failure - Cardinal features are akinetic-rigid parkinsonism, cerebellar ataxia, and autonomic failure with orthostatic hypotension and urogenital dysfunction. Many arrive on fludrocortisone or midodrine. Expect labile pressure with induction, positive pressure, and position change, and give volume early.

PSP and CBD — dysphagia - Dysphagia is prominent, and aspiration pneumonia and sepsis are the most common causes of death in these syndromes. Treat them as a full stomach and secure the airway accordingly.

PSP — posture and eyes - PSP patients stand with axial rigidity and an extended posture rather than the flexed posture of PD, and pivot and fall backward. Pad and support the extended neck and back rather than forcing them into a flexed position. Blink rate is reduced enough that they use artificial tears at home — lubricate and tape early.

Lewy body dementia — antipsychotic sensitivity - LBD carries a documented sensitivity to antipsychotic drugs alongside visual hallucinations and fluctuating cognition. Do not reach for haloperidol or droperidol for postoperative agitation in these patients.

Anticholinergic burden - Benztropine and trihexyphenidyl are used for tremor and for drug-induced parkinsonism, and bring confusion, hallucinations, tachycardia, dry mouth, and urinary retention on their own. Stack anesthetic anticholinergics on top and you get postoperative delirium and retention.

Levodopa cardiovascular effects - Postural hypotension is the common one, and cardiac arrhythmias are reported. Have a low threshold for a preinduction ECG in a patient newly titrated or on high-dose therapy.

Parkinsonism-hyperpyrexia crisis - Treat it as NMS/parkinsonism-hyperpyrexia: stop any dopamine antagonist, restart the dopaminergic drug at the prior dose, cool aggressively, correct volume and electrolytes, and give bromocriptine or dantrolene for refractory cases. Send a CK and check for myoglobinuria and metabolic acidosis — rhabdomyolysis with acute renal decline is the usual course.

Parkinsonism is the motor syndrome of bradykinesia plus rigidity, resting tremor, and postural instability. Idiopathic Parkinson disease (PD) accounts for roughly 80% of it; the remaining fifth is secondary or atypical, and those behave differently in the OR.

Drug-induced parkinsonism follows D2 receptor blockade by antipsychotics and antiemetics and is typically symmetric and generalized. Vascular parkinsonism comes from lacunar infarcts and diffuse white matter ischemia in the basal ganglia — early gait and postural failure, pseudobulbar palsy with dysarthria and dysphagia, poor levodopa response. Normal pressure hydrocephalus can present as parkinsonism and reverses with shunting. The atypical Parkinson-plus syndromes — multiple system atrophy (MSA), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and Lewy body dementia (LBD) — add autonomic failure, dysphagia, vertical gaze palsy, and dementia, progress far faster, and barely respond to levodopa.