01Approach to the Critical Patient/attcp55

Immediate stabilization

›Airway threats from rigidity and aspiration

›Chest wall and diaphragmatic rigidity causing respiratory compromise

›Intubation if unable to maintain airway or SpO2 <90%

›Rapid sequence intubation preparation

›Aspiration risk from dysphagia and sialorrhea

›NPO status in acute crisis

›Suction at bedside

›If respiratory failure present, escalate to ICU immediately

›Class I recommendation for airway protection

›Hemodynamic instability from autonomic dysfunction

›Labile blood pressure targets

›MAP >65 mmHg

›Avoid aggressive antihypertensives unless SBP >180 mmHg

›Tachycardia management

›Identify and treat precipitating cause

›Avoid dopamine-blocking antiemetics (e.g., metoclopramide)

›IV fluid resuscitation for volume depletion and rhabdomyolysis

›Target urine output 200-300 mL/hr if CK markedly elevated

›Hyperthermia management

›External cooling measures

›Mist fans and surface cooling devices

›Ice packs to groin, axillae, and neck

›Acetaminophen 1000 mg IV or per NG q6h

›Avoid NSAIDs in rhabdomyolysis-associated AKI

›Temperature target <38.5°C

Monitoring and targets

›Monitoring bundle

02History/hx62

Presentation pattern

›Core acute syndrome

›Rapidly progressive rigidity

›Hours to days of worsening

›Lead-pipe rigidity not responsive to usual rescue doses

›Hyperthermia

›Temperature >38°C without apparent infectious source

›Fever in context of dopaminergic withdrawal

›Altered level of consciousness

›Stupor, mutism, or catatonic-like state

›Delirium or confusion

Medication and trigger history

›Dopaminergic medication changes

›Abrupt discontinuation or dose reduction

›Levodopa/carbidopa, dopamine agonists, amantadine, COMT inhibitors

›Most common precipitant of akinetic crisis

›Missed doses from practical barriers

›NPO status perioperatively or hospitalization

›Pharmacy issues or non-compliance

›Timing of last dose taken

›Onset of symptoms relative to missed doses

›Dopamine-blocking agent exposure

›Antipsychotics (haloperidol, olanzapine, quetiapine)

›Recent initiation or dose increase

›Differentiates NMS from akinetic crisis

›Antiemetics (metoclopramide, prochlorperazine, promethazine)

›Common iatrogenic cause in ED and inpatient settings

›Serotonergic drug exposure

03Physical Exam/exam47

Vital signs

›Hyperthermia

›Temperature >38°C, may exceed 40°C in severe crisis

›Core temperature via rectal probe preferred

›Fever without apparent infectious source suggests akinetic crisis

›Cardiovascular instability

›Tachycardia (most common)

›Sinus tachycardia from hyperthermia and autonomic dysfunction

›Labile blood pressure

›Hypertensive surges and hypotensive episodes may alternate

›Respiratory rate and oxygen saturation

›Tachypnea from chest wall and diaphragmatic rigidity

›Hypoxia requiring supplemental oxygen

Neurological exam

›Rigidity assessment

›Lead-pipe rigidity (uniform resistance through full passive ROM)

›Unresponsive to usual rescue levodopa doses distinguishes from off episode

›Cogwheel rigidity may be superimposed

›Severity distribution

›Axial and limb rigidity

›Chest wall involvement

›Level of consciousness

›GCS components individually

›Stupor, mutism, or catatonic-like state

›Delirium features

›Fluctuating course and inattention

›Reflexes

›Diminished or normal deep tendon reflexes

04Differential Diagnosis/ddx39

Primary diagnosis to confirm

›Akinetic crisis (Parkinsonism-Hyperpyrexia Syndrome)

›ICD-10: G20 (Parkinson's disease) with acute complication

›Classic tetrad: severe akinesia, hyperthermia, altered consciousness, autonomic dysfunction

›Triggered by dopaminergic withdrawal or intercurrent illness

Dangerous mimics

›Neuroleptic malignant syndrome (NMS)

›ICD-10: G21.0

›Clinically indistinguishable from PHS

›Key differentiator: exposure to dopamine-blocking agent (NMS) vs. withdrawal of dopaminergic therapy (PHS)

›Same treatment principles apply

›DSM-5 diagnostic criteria overlap with both

›Serotonin syndrome

›ICD-10: T43.201A

›Hyperreflexia and clonus distinguish from PHS

›Myoclonus and shivering prominent

›Onset within 24 hours of serotonergic agent initiation

›Sepsis with altered mental status

›ICD-10: A41.9

›May coexist as the precipitating trigger

›Blood cultures, urinalysis, CXR to exclude concurrent infection

›Malignant hyperthermia

›ICD-10: T88.3

›Exposure to volatile anesthetic agents or succinylcholine

›Intraoperative or immediate post-anesthetic context

Secondary mimics

›Lethal catatonia

›ICD-10: F20.2

05Laboratory Tests/lt44

Rhabdomyolysis workup

›Creatine kinase (CK)

›Markedly elevated, often >10,000 U/L in established crisis

›May be normal early in crisis and rise over 24-48 hours

›Serial measurements every 6-12 hours

›Target downtrend before discharge consideration

Renal and electrolyte panel

›Basic metabolic panel

›Creatinine and BUN for AKI severity

›Rhabdomyolysis-induced AKI requires aggressive hydration

›Potassium

›Hyperkalemia from muscle breakdown

›Peaked T waves on ECG correlate with hyperkalemia

›Calcium

›Hypocalcemia common with rhabdomyolysis

›Replace cautiously if symptomatic

›Bicarbonate

›Metabolic acidosis from AKI and hypoperfusion

Infection and inflammation labs

›Complete blood count

›Leukocytosis common in crisis

›Not specific for infection in this context

›Thrombocytopenia as early DIC sign

›Blood cultures (two sets)

›Mandatory to exclude infectious trigger

›Bacteremia may precipitate crisis

›Urinalysis with microscopy

›Myoglobinuria

06Diagnostic Tests/dt52

Scoring Systems

›Woodbury three-stage NMS/akinetic crisis severity system

›Stage 1: Rigidity, temperature elevation, consciousness disturbance

›Treatment urgency: restore dopaminergic therapy

›Stage 2: Autonomic instability added

›ICU-level monitoring and supportive care

›Stage 3: Multi-organ failure

›Maximum intervention, consider dantrolene and ICU

›No validated scoring system exists specifically for akinetic crisis severity

›Hoehn and Yahr staging (baseline PD severity)

›Stage 1-2: Unilateral or bilateral, no postural instability

›Lower risk for crisis

›Stage 3-5: Postural instability to wheelchair or bed-bound

›Higher crisis risk and more severe presentations

MRI

›Brain MRI indications in akinetic crisis

›Not routinely required in typical presentation

›CT head preferred acutely for speed

›Indications for MRI over CT

›Clinical suspicion for NMDA-receptor encephalitis

›Atypical rigidity distribution (focal)

›Suspected posterior fossa lesion

›MRI brain with DWI

›Excludes acute ischemic stroke

›Encephalitis workup (FLAIR for cortical signal changes)

›No specific MRI finding diagnostic for akinetic crisis itself

CT

›CT head without contrast

07Disposition/dispo40

ICU admission criteria

›ICU mandatory for severe presentations

›Hyperthermia >39°C

›Risk of DIC and rhabdomyolysis progression

›Hemodynamic instability

›MAP <65 mmHg or labile BP requiring vasopressors

›Respiratory compromise

›Chest wall rigidity impeding ventilation

›Aspiration pneumonia with hypoxia

›CK >10,000 U/L with rising creatinine

›Rhabdomyolysis requiring intensive hydration monitoring

›Altered consciousness (GCS <13)

›Airway protection risk

Step-down or telemetry admission

›Milder presentations with stable vitals

›Inability to take oral medications requiring parenteral route

›IV amantadine or subcutaneous apomorphine management

›Moderate rigidity without hyperthermia

›Requires medication optimization and monitoring

›Continuous cardiac monitoring for QTc and arrhythmias

Observation indications

›Subacute motor worsening without crisis features

›Lacking hyperthermia, CK elevation, or consciousness disturbance

›Prolonged off episode requiring dose adjustment

›Medication reconciliation and monitoring needed

Consultation triggers

›Neurology / Movement Disorders

›All cases: urgent consultation

08Treatment/t86

Dopaminergic restoration (cornerstone of treatment)

›Oral / enteral levodopa/carbidopa

›Reinstate at prior home dose immediately

›Via NG or OG tube if unable to swallow

›Most critical intervention; do not delay

›Avoid high-protein enteral feeds concurrent with levodopa

›Protein competes with levodopa for intestinal absorption

›Separate by at least 1 hour

›IV amantadine

›200 mg IV BID to TID

›One of the few parenterally available dopaminergic agents

›Dose-reduce in renal impairment (CrCl <60 mL/min)

›Mechanism: NMDA antagonist and dopamine releaser

›Subcutaneous apomorphine

›Rapid-acting dopamine agonist; useful when enteral route unavailable

›Onset 5-15 minutes

›Requires anti-emetic pre-treatment with domperidone (not metoclopramide)

›Dose: 2-6 mg SC per dose

›Titrate by 1 mg increments based on motor response

›Subcutaneous foslevodopa

›Emerging parenteral option (off-label for crisis)

›Case reports support efficacy (Loeffler et al., 2024)

›Subcutaneous infusion providing continuous levodopa delivery

›Bromocriptine (adjunctive dopamine agonist)

›2.5 mg PO/NG q8h

›Titrate to effect based on motor response

›Adjunct when levodopa reinstatement insufficient

Rhabdomyolysis management

›Aggressive IV fluid resuscitation

›Normal saline or lactated Ringer's IV

›Target urine output 200-300 mL/hr

›Hourly urine output monitoring via Foley

›Adjust rate based on CK trend and urine output

›Reduce rate when CK falling and urine output adequate

›Urine alkalinization (selective use)

›Sodium bicarbonate IV if urine pH <6.5 and CK >5000 U/L

›Target urine pH 6.5-7

›Monitor for metabolic alkalosis

Anti-rigidity and hyperthermia therapies

›Dantrolene sodium

›1-2.5 mg/kg IV for severe rigidity and hyperthermia

›Maximum single dose 10 mg/kg/day

›Monitor LFTs during prolonged use (hepatotoxicity risk)

›Mechanism: inhibits sarcoplasmic reticulum calcium release

›Reduces muscle rigidity independent of dopaminergic pathway

›Evidence: Class IIb based on expert consensus and case series

›Lorazepam

›1-2 mg IV for mild-to-moderate rigidity and agitation

›May repeat every 4-6 hours as needed

›Useful for procedural facilitation and comfort

Complication management

›Electrolyte correction

›Hyperkalemia

›Calcium gluconate 1 g IV for cardiac protection if ECG changes

›Insulin 10 units IV with dextrose 50% 50 mL for acute lowering

›Sodium bicarbonate IV for acidosis-driven hyperkalemia

›Hypocalcemia

›Replace only if symptomatic (tetany, seizures, QTc >500 ms)

›Calcium gluconate 1-2 g IV slowly

›Hemodynamic support

›BP instability from autonomic dysfunction

›Clonidine 0.1-0.2 mg PO for hypertensive surges

›Nicardipine 5-15 mg/hr IV infusion for severe hypertension

›Norepinephrine 0.05-0.3 mcg/kg/min for hypotension

›Infection treatment

›Treat identified infections with targeted antibiotics

›Aspiration pneumonia: ampicillin-sulbactam 3 g IV q6h or piperacillin-tazobactam 4.5 g IV q6h

›Adjust based on culture results

›Agitation and delirium

›Dexmedetomidine infusion preferred

›0.2-1.4 mcg/kg/hr titrate to sedation target

›Avoids dopamine-blocking agents

›Lorazepam as alternative

›Avoid antipsychotics (worsen PD crisis)

Adjunctive therapies (limited evidence)

›High-dose IV methylprednisolone

›Proposed adjunctive therapy based on limited trial data

›1 g IV daily for 3 days in refractory cases

›Mechanism: anti-inflammatory modulation

›Electroconvulsive therapy (ECT)

›Reserved for refractory life-threatening cases

›Increases dopaminergic sensitivity transiently

›Requires anesthesia and resuscitation capability

Prophylaxis

›DVT prophylaxis

›Subcutaneous heparin 5000 units q8-12h or enoxaparin 40 mg SC daily

›Immobility from rigidity is a major VTE risk factor

›Stress ulcer prophylaxis

›Pantoprazole 40 mg IV daily if mechanically ventilated

›Pressure injury prevention

›Frequent repositioning every 2 hours

›Pressure-relieving mattress

09Special Populations/sp59

Pregnancy

›Epidemiology in pregnancy

›Parkinson's disease in pregnancy is rare

›Young-onset PD (YOPD) patients may be reproductive age

›Akinetic crisis in pregnancy carries maternal and fetal risk

›Medication safety considerations

›Levodopa/carbidopa

›Limited human safety data; animal studies show skeletal malformations

›Risk-benefit favors continuation in crisis given life-threatening presentation

›Amantadine

›Teratogenic in animal models; avoid in first trimester if possible

›Single case reports of safe use in later pregnancy

›Dopamine agonists (bromocriptine, apomorphine)

›Category C agents; limited data

›Bromocriptine used for hyperprolactinemia in pregnancy (some safety data)

›Dantrolene

›Animal data reassuring; use if rigidity and hyperthermia severe

›Obstetric involvement

›Maternal hyperthermia risk to fetal brain

›Aggressive cooling mandatory

›Fetal heart rate monitoring continuous

›Delivery planning if late pregnancy with severe crisis

›Obstetrics consultation urgent

Geriatric

›Increased prevalence and complexity

›PD predominantly affects those >60 years

›Baseline cognitive impairment frequent

›Polypharmacy risk heightened

10Background/b72

Epidemiology

›Prevalence and incidence of PD

›Parkinson's disease affects approximately 1% of individuals >60 years

›Second most common neurodegenerative disease after Alzheimer's

›Global prevalence estimated at 6.1 million (2016 data)

›Incidence increases with age

›17.4 per 100,000 person-years overall

›Risk doubles each decade after age 60

›Akinetic crisis incidence

›Approximately 0.3% of PD patients per year experience akinetic crisis

›Significant underdiagnosis likely

›Mortality significant if unrecognized and untreated

›Recurrence rate documented in survivors

›Prior crisis is itself a risk factor for recurrence

›Outcomes data

›31.3% of patients fail to recover to pre-crisis baseline (Robottom et al., 2011)

›Recovery typically occurs over days to weeks when treatment initiated promptly

›Complications include rhabdomyolysis, DIC, AKI, aspiration pneumonia, PE, cardiac arrhythmias, and critical illness neuromyopathy

›ED management gap

›Less than one-third of PD patients receive home carbidopa-levodopa in the ED

›Fewer than 10% receive it on time (Elder et al., 2026)

›Represents a major preventable harm

Pathophysiology

›Dopamine deficiency and akinetic crisis

›Substantia nigra pars compacta dopaminergic neuron degeneration is the PD hallmark

›Loss of nigrostriatal dopamine signaling causes motor dysfunction

›In advanced PD, residual dopaminergic capacity is minimal

›Abrupt withdrawal removes the only remaining dopaminergic drive

›Leads to acute and severe striatopallidal imbalance

›Dopamine deficiency causes direct hyperthermia via hypothalamic dysregulation

›Relationship to NMS

›Pathophysiologically identical to neuroleptic malignant syndrome

›Both result in acute dopamine receptor hypostimulation in striatum and hypothalamus

›Hypothalamic thermoregulatory failure causes hyperthermia

›Striatal dopamine depletion causes rigidity

›Sympathetic nervous system dysregulation drives autonomic instability

›Rhabdomyolysis mechanism

›Sustained isometric muscle contraction from rigid muscles

›ATP depletion in muscle fibers leads to membrane failure

›Calcium influx causes myofibril destruction

›Myoglobin release causes renal tubular obstruction and direct toxicity

›Acute tubular necrosis in severe rhabdomyolysis

›DIC mechanism

›Severe hyperthermia and rhabdomyolysis trigger systemic inflammatory response

›Tissue factor release activates coagulation cascade

›Consumptive coagulopathy with thrombocytopenia and low fibrinogen

Therapeutic Considerations

›Dopaminergic therapy is the cornerstone

›Restoration of dopaminergic tone reverses all features of akinetic crisis

›Levodopa/carbidopa is the most effective agent

›IV amantadine provides parenteral alternative

›Speed of reinstatement correlates with outcome

›Every hour of delay worsens rigidity cycle (dysphagia → missed doses → more rigidity)

›Contraindicated medications in PD crisis

›All typical and atypical antipsychotics

›Block dopamine D2 receptors and worsen crisis

›Haloperidol, droperidol, quetiapine, olanzapine, risperidone

›Dopamine-blocking antiemetics

›Metoclopramide, prochlorperazine, promethazine

›Use domperidone, ondansetron, or trimethobenzamide as alternatives

›Anticholinergics in elderly

›Cognitive worsening and delirium risk (AGS Beers Criteria 2023)

›Evidence base

›No randomized controlled trials for akinetic crisis treatment

›Evidence primarily from case series and expert consensus

›Malignant Syndrome Research Group Consensus Statement (Ikebe et al., 2003) guides management

›Dantrolene evidence: Class IIb based on expert consensus

›ECT evidence: Case reports only; reserved for refractory cases

›Prevention strategies

›Patient education on medication compliance

›Never abruptly stop dopaminergic medications for any reason

›Carry a Parkinson's Alert Card listing time-critical medications

›Perioperative planning

›Coordinate with surgery/anesthesia to maintain dopaminergic medications perioperatively

›NG tube administration if NPO required

11Patient Discharge Instructions/pdi40

copy discharge instructions

›What happened to you

›You had a Parkinson's disease crisis (also called an akinetic crisis or parkinsonism-hyperpyrexia syndrome)

›This is a life-threatening emergency caused by sudden worsening of Parkinson's disease

›It can be triggered by missing Parkinson's medications or by illness like infection

›Your Parkinson's medications are critical

›Never stop your Parkinson's medications suddenly

›This is the most dangerous thing you can do and can trigger another crisis

›Take your medications at the exact scheduled times every day

›Set alarms or use a pill organizer if this helps

›If you cannot swallow your medications, come to the emergency department immediately

›Do not wait for your next dose time

›When to return to the emergency department immediately

›Fever above 38°C (100.4°F)

›Especially with stiffness or confusion

›Severe muscle stiffness that is worse than usual

›Confusion or inability to stay awake

›Dark brown or red-colored urine

›Inability to swallow or take medications by mouth

›Chest pain, difficulty breathing, or fast heart rate

›Protecting yourself from another crisis

›Tell every doctor, nurse, dentist, and pharmacist about your Parkinson's medications

›Carry a list of all your medications with you at all times

›Carry a Parkinson's Alert Card

›States that your medications must be given on time even in hospital

›Tell your care team if you are scheduled for any surgery or procedure

›Your Parkinson's medications must continue before, during, and after procedures

›Watch for medications that worsen Parkinson's disease

12References/r48

Guidelines and key sources

›Ikebe S, Harada T, Hashimoto T, et al.

›Prevention and Treatment of Malignant Syndrome in Parkinson's Disease: Consensus Statement of the Malignant Syndrome Research Group

›Parkinsonism and Related Disorders, 2003

›Primary consensus document guiding akinetic crisis management

›Robottom BJ, Weiner WJ, Factor SA.

›Movement Disorders Emergencies Part 1: Hypokinetic Disorders

›Archives of Neurology, 2011

›Key reference for epidemiology, risk factors, and outcomes data

›Onofrj M, Bonanni L, Cossu G, et al.

›Emergencies in Parkinsonism: Akinetic Crisis, Life-Threatening Dyskinesias, and Polyneuropathy During L-Dopa Gel Treatment

›Parkinsonism and Related Disorders, 2009

›Comprehensive clinical review with treatment protocols

›Pötter-Nerger M, Schrader C, Jost WH, Höglinger G.

›The Akinetic Crisis in Parkinson's Disease: The Upper End of a Spectrum of Subacute Akinetic States

›Journal of Neural Transmission, 2024

›Updated spectrum classification and DBS considerations

›Elder NM, Lash EM, Tomkins-Tinch C.

›An Underrecognized Problem: Missed and Delayed Carbidopa-Levodopa Administration in Emergency Department Patients With Parkinson's Disease

›Academic Emergency Medicine, 2026

›Evidence for ED medication administration failure in PD

›Factor SA, Burkhard PR, Caroff S, et al.

›Recent Developments in Drug-Induced Movement Disorders: A Mixed Picture

›The Lancet Neurology, 2019

›Subcutaneous apomorphine and dopaminergic options

›Loeffler MA, Mengel A, Single C, Weiss D, Feil K.

›Subcutaneous Foslevodopa in Akinetic Crisis: A Case Report From the Neurological Intensive Care Unit

›Frontiers in Medicine, 2024

Evidence & Review

Evidence & Review