/study / lectures / Coexisting Disease

Anesthesia for Neurologic Disease

TEXT

Coexisting Disease · 9 min read

Seizures, MG, MS, Parkinson, ALS, stroke history, dementia, increased ICP. Each one rewrites your NMBD + induction agent + emergence plan.

PROGRESS0 / 8

After this lesson you can

3 min read8 sections

Adjust anesthetic for Parkinson's, epilepsy, MS, MG.
Avoid drugs that exacerbate seizures.
Anticipate myasthenic crisis vs cholinergic crisis.
Manage MS exacerbation triggers.

Epilepsy

KeyContinue antiepileptics perioperatively (give morning of).

Many AEDs induce hepatic enzymes (carbamazepine, phenytoin, phenobarbital) faster metabolism of NMBDs, opioids, volatiles.

Avoid pro-convulsant agents

meperidine (normeperidine)
methohexital high-dose
sevoflurane epileptiform activity (clinical seizures rare)
tramadol

Status epilepticus intra-op: load benzo + AED (fosphenytoin/levetiracetam) + propofol gtt.

Lacosamide IV available.

Seizure disorders classification and management: focal vs generalized seizures, status epilepticus, antiepileptic drugs (levetiracetam, phenytoin, valproate), and anesthetic considerations.

Myasthenia gravis

KeyAntibodies against post-synaptic ACh receptors reduced functional receptors.

Sensitivity to non-depolarizing NMBDs (use ¼-½ usual dose or omit entirely; many MG patients intubate with deep volatile + topical only).

Resistance to succinylcholine in mild disease, but unpredictable — avoid.

Pyridostigmine continued perioperatively (hold morning of major surgery is debated; current trend continue).

Cholinergic crisis (excess pyridostigmine) vs myasthenic crisis (under-treated) — Tensilon test edrophonium 1-2 mg distinguishes.

Risk of postop ventilation

thymectomy >6 yr disease
pyridostigmine >750 mg/day
VC <2.9 L
prior crisis

Sugammadex highly effective for rocuronium reversal in MG.

Heart failure classification and management: HFrEF (EF <=40%) vs HFpEF (EF >=50%); NYHA functional class; GDMT (ARNI/ACE-I, beta-blocker, MRA, SGLT2i); continue most meds perioperatively except hold ACE-I/ARB morning of surgery.

Lambert-Eaton (LEMS) — opposite of MG

KeyAntibodies against pre-synaptic voltage-gated Ca channels reduced ACh release.

Sensitivity to BOTH depolarizing AND non-depolarizing NMBDs.

Often paraneoplastic (small-cell lung CA).

Strength improves with repeated stimulation (vs MG fatigue).

Reduce NMBD doses dramatically; verify with TOF before incision.

Multiple sclerosis

KeyDemyelinating, relapsing-remitting typically.

Sensitive to hyperthermia (Uhthoff phenomenon) — symptom worsening with temp rise.

Avoid succinylcholine in patients with motor weakness (hyperkalemia risk from up-regulated extrajunctional receptors).

Spinal/epidural — historically avoided (concern for symptom exacerbation); current evidence does not contraindicate but discuss with patient + document.

Stress/surgery can precipitate relapse independent of anesthetic technique.

Succinylcholine contraindications and cautions: known/suspected hyperkalemia, burns >24–48 h, crush/denervation injury after 24–48 h, spinal cord injury, severe myopathy, MH history, open globe injury (relative), upregulated extra-junctional AChRs.

Parkinson disease

KeyContinue levodopa/carbidopa perioperatively (last dose morning of, restart immediately postop).

Long NPO consider IM/SQ apomorphine bridge.

Avoid

metoclopramide (D2 antagonist — worsens)
droperidol
phenothiazines
butyrophenones

Ondansetron is a selective 5-HT3 receptor antagonist with no clinically significant dopaminergic activity — SAFE in Parkinson disease (preferred over metoclopramide/droperidol for PONV).

Use propofol (some report dyskinesia, but mostly safe), volatile agents OK.

Autonomic dysfunction labile BP.

Dysphagia + aspiration risk (RSI consideration), reduced pulm reserve.

PONV multimodal prophylaxis using Apfel score (female, nonsmoker, h/o PONV/motion sickness, postop opioids); 0-1 factors low risk, ≥3 high risk. Combine agents from different classes: 5HT3 antagonist, dexamethasone, droperidol, scopolamine; TIVA with propofol if very high risk.

ALS + muscular dystrophy

KeyUp-regulated extrajunctional ACh receptors (denervation hypersensitivity) AVOID succinylcholine (hyperkalemic arrest).

Sensitivity to non-depolarizing NMBDs (reduce dose, monitor TOF).

Avoid trigger-positive volatiles in suspected/known MH-association myopathies (Duchenne, Becker — propofol-based TIVA + non-trigger gas-free machine).

Postop respiratory failure risk in advanced disease — discuss extubation criteria + advance directives pre-op.

Succinylcholine contraindication timing after burns: avoid 24-48 hours after burn injury through ~1 year due to extrajunctional ACh receptor upregulation causing life-threatening hyperkalemia. Alternative is rocuronium.

Stroke + dementia

KeyPrior stroke — defer elective surgery 6-9 months (stroke recurrence risk peaks early).

Maintain MAP at or above baseline; permissive HTN strategy in acute stroke care.

Avoid hypoperfusion intra-op (autoregulation impaired).

Carotid stenosis: target BP at upper baseline.

Dementia: longer postop delirium risk; minimize anticholinergics (avoid scopolamine, diphenhydramine, atropine), benzodiazepines (avoid pre-op midazolam in elderly), and prolonged general anesthesia where regional suffices.

Multimodal opioid-sparing reduces delirium.

Perioperative delirium risk factors and prevention: age, baseline cognitive impairment, polypharmacy, sleep disruption; prevent with reorientation, sleep hygiene, avoiding deliriogenic drugs, multimodal opioid sparing.

Elevated ICP

KeyMaintain CPP = MAP − ICP (target CPP ≥60 mmHg in adult TBI).

Avoidhypoventilation (CO₂ rise = cerebral vasodilation = ICP up), hypoxia, hyperthermia, jugular venous obstruction (neutral neck, head-up 30°), PEEP excess (controversial; modest PEEP usually OK).

Use

hyperventilation as temporizing measure (PaCO₂ 30-35 — short term only)
mannitol 0.25-1 g/kg or 3% saline (target Na 145-155)
CSF drainage

Avoid ketamine in classical teaching (modern data suggest safer than once thought, but still avoided with elevated ICP in NBCRNA-style answers).

Avoid succinylcholine if recent CVA + motor deficit (hyperK).

Anesthetic management for craniotomy: smooth induction, avoid coughing/HTN, maintain CPP, mild hyperventilation (PaCO2 30-35) only briefly, mannitol/hypertonic saline for ICP, avoid N2O with pneumocephalus.

⚠ Common pitfalls

Holding levodopa peri-op in Parkinson's — exacerbates rigidity + dysphagia.
Standard NMB doses in myasthenia — extreme sensitivity to non-depolarizers.
Volatiles + magnesium in MG — can precipitate respiratory failure.
Hyperthermia in MS — temporary worsening; aggressive temperature management.

💎 Clinical pearls

Parkinson's: continue levodopa, schedule first case of the day, avoid metoclopramide (D2 antagonist).
Myasthenia: pyridostigmine continued; sensitive to non-depolarizing NMB (1/10th dose); resistant to sux.
MS: avoid hyperthermia + acidosis; spinal traditionally avoided (relative contraindication).
Epilepsy: continue AEDs perioperatively; avoid pro-convulsant drugs (meperidine, low-dose enflurane).

Recap

Parkinson's: continue levodopa, schedule first case of the day, avoid metoclopramide (D2 antagonist).
Myasthenia: pyridostigmine continued; sensitive to non-depolarizing NMB (1/10th dose); resistant to sux.
MS: avoid hyperthermia + acidosis; spinal traditionally avoided (relative contraindication).
Epilepsy: continue AEDs perioperatively; avoid pro-convulsant drugs (meperidine, low-dose enflurane).

Mark each section done to complete the module.