ICD-10: I67.83 (Posterior reversible encephalopathy syndrome), I67.4 (Hypertensive encephalopathy), O15.0 (Eclampsia in pregnancy), O15.1 (Eclampsia in labor), O15.2 (Eclampsia in the puerperium), O15.9 (Eclampsia, unspecified as to time period), I16.1 (Hypertensive emergency), G40.901 (Epilepsy, unspecified, not intractable, with status epilepticus), R56.9 (Unspecified convulsions), G93.49 (Other encephalopathy, not elsewhere classified)
SCOPE: Diagnosis and management of posterior reversible encephalopathy syndrome (PRES) in adults across all care settings. Covers hypertensive emergency management, seizure treatment, identification and removal of causative agents (immunosuppressants, chemotherapy), eclampsia-specific management, MRI interpretation, hemorrhagic PRES complications, and recovery monitoring. Excludes pediatric PRES, chronic hypertensive encephalopathy without neuroimaging features, and isolated eclampsia management without PRES features (see obstetric protocols).
PRIORITY KEY: STAT = Immediate | URGENT = Within hours | ROUTINE = Standard | EXT = Extended/atypical cases | - = Not applicable to this setting
MRI brain without contrast (CPT 70551) with FLAIR, DWI, ADC, SWI/GRE sequences
STAT (within 24h of presentation); MRI is diagnostic gold standard for PRES
Bilateral symmetric vasogenic edema predominantly in posterior parietal-occipital regions on FLAIR; DWI normal or mildly restricted; ADC elevated (confirms vasogenic, not cytotoxic edema); SWI/GRE for hemorrhagic component
Pacemaker/defibrillator (non-MRI conditional); hemodynamic instability (stabilize BP first)
STAT
STAT
URGENT
STAT
CT head without contrast (CPT 70450)
Immediately on presentation; rule out hemorrhage, mass, hydrocephalus while awaiting MRI
May show posterior white matter hypodensities; rule out hemorrhagic PRES, mass lesion, or stroke; CT has low sensitivity for PRES (only ~50%)
Pregnancy (benefit outweighs risk)
STAT
STAT
-
STAT
CT angiography (CTA) head and neck (CPT 70496, 70498)
STAT if concern for stroke, cerebral venous thrombosis, or vasculitis
Rule out large vessel occlusion, cerebral venous thrombosis, vasculitis (beading); may show vasospasm/vasoconstriction in RCVS
Contrast allergy; severe renal impairment (benefit outweighs risk in emergency)
STAT
URGENT
-
STAT
ECG (12-lead) (CPT 93000)
STAT on presentation
Baseline; hypertensive cardiac strain; LVH; arrhythmia; QTc assessment for medications
None
STAT
STAT
ROUTINE
STAT
Chest X-ray (CPT 71046)
URGENT if dyspnea, pulmonary edema, or intubated
Pulmonary edema from hypertensive crisis; aspiration; cardiomegaly
Indication: Consider LP if meningitis/encephalitis is in differential (fever, meningismus, altered consciousness) or if cerebral venous thrombosis suspected. LP is NOT routinely required for PRES diagnosis.
Timing: URGENT if infection suspected; defer until BP controlled and imaging reviewed
Volume Required: 10-15 mL (standard diagnostic)
Study
Rationale
Target Finding
ED
HOSP
OPD
ICU
Opening pressure
Elevated ICP may be present in PRES; rule out idiopathic intracranial hypertension
10-20 cm H2O (may be elevated in PRES)
URGENT
ROUTINE
-
URGENT
Cell count (tubes 1 and 4)
Rule out meningitis/encephalitis
WBC <5, RBC 0
URGENT
ROUTINE
-
URGENT
Protein
Mild elevation may occur in PRES; significantly elevated suggests infection or CNS vasculitis
15-45 mg/dL (mildly elevated in PRES, up to 100)
URGENT
ROUTINE
-
URGENT
Glucose with serum glucose
Rule out infectious meningitis
>60% of serum glucose
URGENT
ROUTINE
-
URGENT
Gram stain and culture
Rule out bacterial meningitis
No organisms
URGENT
ROUTINE
-
URGENT
HSV PCR (CPT 87529)
Rule out HSV encephalitis if temporal lobe involvement or clinical suspicion
Negative
URGENT
ROUTINE
-
URGENT
Special Handling: CSF must be sent promptly for culture; hold tube for additional studies if needed
Contraindications: Space-occupying lesion with mass effect; uncorrected coagulopathy (INR >1.4 or platelets <50,000); hemodynamic instability; local skin infection at puncture site
Blood pressure reduction: Nicardipine IV (CPT 96365)
IV
First-line IV antihypertensive for hypertensive emergency with PRES; smooth titratable BP reduction without cerebral vasoconstriction
5 mg/h :: IV :: continuous :: 5 mg/h IV infusion; increase by 2.5 mg/h every 5-15 min; max 15 mg/h; target 25% reduction in MAP in first hour then SBP 140-160 over next 2-6h
Severe aortic stenosis; decompensated heart failure; advanced hepatic failure
Continuous arterial line BP monitoring; neuro checks q15min during titration; avoid SBP <120 (risk of watershed ischemia)
STAT
STAT
-
STAT
Blood pressure reduction: Labetalol IV (CPT 96374)
IV
Alternative first-line IV antihypertensive; preferred if tachycardia present; safe in pregnancy/eclampsia
10-20 mg :: IV :: q10-20min :: 10-20 mg IV bolus over 1-2 min; may repeat or double dose q10-20 min; max 300 mg total; can also infuse at 0.5-2 mg/min
Second/third-degree heart block; severe bradycardia (<50 bpm); decompensated heart failure; severe asthma/COPD; cardiogenic shock
Blood pressure reduction: Clevidipine IV (CPT 96365)
IV
Ultra-short acting IV calcium channel blocker for rapid BP control; useful when precise titration needed
1-2 mg/h :: IV :: continuous :: 1-2 mg/h IV; titrate by doubling dose every 90 seconds initially; usual maintenance 4-6 mg/h; max 32 mg/h; max 21 mg/h average over 24h
Soy/egg allergy (lipid emulsion); severe lipid metabolism disorders; acute pancreatitis with hyperlipidemia
Blood pressure continuous; triglycerides if prolonged use (>72h); lipid load calculation
STAT
STAT
-
STAT
Blood pressure reduction: Hydralazine IV
IV
Second-line antihypertensive; commonly used in pregnancy/eclampsia when nicardipine unavailable
5-10 mg :: IV :: q20-30min :: 5-10 mg IV q20-30 min PRN; max 20 mg total; less predictable response than nicardipine
Severe coronary artery disease; aortic dissection; tachycardia (reflex)
Heart rate; blood pressure q5min after each dose; reflex tachycardia common
STAT
STAT
-
STAT
Eclampsia: Magnesium sulfate (CPT 96365)
IV
FIRST-LINE for eclampsia-associated PRES; prevents recurrent seizures; superior to phenytoin and diazepam for eclampsia seizures (Magpie Trial, Eclampsia Trial Collaborative Group)
4-6 g IV load over 15-20 min; 1-2 g/h maintenance :: IV :: continuous :: 4-6 g IV loading dose over 15-20 min, then 1-2 g/h continuous infusion; maintain serum Mg 4-7 mEq/L; continue 24-48h postpartum; reduce dose if Cr >1.0
Serum Mg q4-6h (target 4-7 mEq/L); deep tendon reflexes q1h (loss of patellar reflex = toxicity); respiratory rate (hold if <12); urine output (>25 mL/h); calcium gluconate at bedside as antidote
STAT
STAT
-
STAT
Seizure management: Levetiracetam (CPT 96374)
IV
First-line ASM for PRES-associated seizures (non-eclampsia); broad-spectrum; no hepatic metabolism; no drug interactions with immunosuppressants
1000-1500 mg IV load; 500-1000 mg IV/PO BID :: IV :: BID :: 1000-1500 mg IV loading dose over 15 min, then 500-1000 mg IV or PO BID; adjust for renal function (CrCl <50: reduce dose 50%)
Severe renal impairment (dose adjust, do not contraindicate); known hypersensitivity
Seizure monitoring; renal function; behavioral side effects (agitation, psychosis in 1-2%)
STAT
STAT
-
STAT
Seizure management: Lorazepam IV
IV
Rescue benzodiazepine for acute seizure termination; use while loading longer-acting ASM
4 mg IV push; may repeat x1 :: IV :: PRN seizure :: 4 mg IV push over 2 min; may repeat once in 5 min; max 8 mg; have airway equipment ready
Acute narrow-angle glaucoma; severe respiratory depression without ventilator support
Tacrolimus is common cause of PRES in transplant patients; must hold or significantly reduce dose until PRES resolves
Hold tacrolimus immediately; consult transplant team for alternative immunosuppression (switch to mycophenolate, sirolimus, or reduced-dose calcineurin inhibitor after resolution)
Acute rejection risk (must coordinate with transplant team before permanently discontinuing)
Tacrolimus trough levels; graft function monitoring; rejection surveillance
STAT
STAT
-
STAT
Immunosuppressant management: Hold cyclosporine
-
Cyclosporine neurotoxicity causes PRES; must hold or reduce dose until neurological recovery
Hold cyclosporine immediately; consult transplant team for alternative immunosuppression; may cautiously rechallenge at lower dose after full resolution with close monitoring
Acute rejection risk (coordinate with transplant team)
Chemotherapy-associated PRES: Hold offending agent
-
VEGF inhibitors (bevacizumab, sunitinib), cisplatin, gemcitabine, and other chemotherapeutic agents can cause PRES; hold until resolution
Hold offending chemotherapy agent immediately; consult oncology for alternative regimen or cautious rechallenge after resolution
Cancer treatment interruption (coordinate with oncology)
Neurological status; follow-up MRI before considering rechallenge
STAT
STAT
-
STAT
Intubation and airway protection
-
Airway protection for GCS <=8, refractory seizures, inability to protect airway, or respiratory failure
RSI per protocol :: - :: once :: RSI with propofol or etomidate preferred (avoid ketamine if severe hypertension); avoid succinylcholine if hyperkalemia risk; head of bed 30 degrees post-intubation
N/A
Ventilator settings; head of bed 30 degrees; sedation level; cuff pressure
Per institutional protocol :: IV/SC :: per protocol :: Insulin drip 0.5-1 unit/h IV for persistent BG >180; titrate to target 140-180 mg/dL; transition to SC sliding scale when stable and tolerating PO
Hypoglycemia
Blood glucose q1h if drip; q6h if sliding scale
STAT
STAT
-
STAT
Pantoprazole
IV/PO
GI prophylaxis; stress ulcer prevention in ICU patients
40 mg :: IV/PO :: daily :: 40 mg IV or PO daily
C. difficile risk with prolonged use
GI symptoms
-
ROUTINE
-
ROUTINE
Pneumatic compression devices
-
DVT prophylaxis; immobilized patients at high VTE risk
Bilateral SCDs :: - :: continuous :: Apply bilateral SCDs on admission; use whenever patient is in bed; remove only for ambulation and skin checks
Acute DVT in lower extremities
Skin checks daily
STAT
STAT
-
STAT
Enoxaparin
SC
DVT prophylaxis (start when seizures controlled and no hemorrhagic PRES)
40 mg :: SC :: daily :: 40 mg SC daily; adjust for renal function (CrCl <30: 30 mg daily); hold if hemorrhagic PRES
Active hemorrhagic PRES; platelet count <50,000; severe renal failure (dose adjust); recent LP (wait 12h)
Second-line ASM if levetiracetam insufficient for seizure control; broad-spectrum; avoid in pregnancy
20-40 mg/kg IV load; 500 mg IV q12h :: IV :: q12h :: 20-40 mg/kg IV loading dose (max 3000 mg) over 30-60 min; then 500 mg IV q12h; target level 50-100 mcg/mL
Valproic acid level (target 50-100); LFTs; CBC with platelets; ammonia if altered mental status
STAT
STAT
-
STAT
Seizure: Lacosamide IV
IV
Second-line ASM alternative; favorable drug interaction profile in transplant patients on immunosuppressants
200-400 mg IV load; 100-200 mg IV q12h :: IV :: q12h :: 200-400 mg IV loading dose over 15-30 min; then 100-200 mg IV or PO q12h; no renal adjustment needed
Second/third-degree heart block; severe cardiac conduction disease; PR interval >200 ms
Continuous BP; heart rate; intraocular pressure if glaucoma history; renal function
STAT
STAT
-
STAT
Refractory hypertension: Nitroprusside IV
IV
Last-resort IV antihypertensive for severe refractory hypertension; avoid if possible due to cerebral vasodilation and ICP elevation risk
0.25-0.5 mcg/kg/min :: IV :: continuous :: Start 0.25 mcg/kg/min; titrate by 0.25 mcg/kg/min; max 10 mcg/kg/min; limit duration (<48h) due to cyanide toxicity
Cr and K+ at 1-2 weeks after initiation; BP; angioedema watch
-
ROUTINE
ROUTINE
-
Oral antihypertensive: Metoprolol succinate
PO
Long-term BP control; preferred if concurrent tachycardia or coronary disease
25 mg daily; 50 mg daily; 100 mg daily; 200 mg daily :: PO :: daily :: Start 25-50 mg PO daily; titrate q1-2 weeks; max 200 mg/day
Baseline heart rate, BP, ECG
Heart block (2nd/3rd degree); severe bradycardia (<50 bpm); decompensated heart failure; severe asthma
Heart rate; BP; signs of heart failure; bronchospasm
-
ROUTINE
ROUTINE
-
Levetiracetam (oral transition)
PO
Continued seizure prophylaxis if seizures occurred during PRES; typically continue 3-6 months then taper if MRI normalized and EEG normal
500 mg BID; 750 mg BID; 1000 mg BID :: PO :: BID :: 500-1000 mg PO BID; dose based on acute loading; may taper at 3-6 months if PRES fully resolved on imaging
Renal function (adjust if CrCl <50)
Known hypersensitivity
Renal function; behavioral side effects; seizure diary
-
ROUTINE
ROUTINE
-
Immunosuppressant switch (transplant patients)
PO
Switch to non-calcineurin inhibitor immunosuppression to prevent PRES recurrence; coordinate with transplant team
Per transplant team :: PO :: per protocol :: Common switches: mycophenolate mofetil 500-1000 mg PO BID or sirolimus 2-5 mg PO daily; agent and dose per transplant team recommendation based on organ type and rejection risk
Transplant team approval; graft function assessment; rejection risk stratification
Agent-specific; varies by alternative chosen
Graft function; drug levels; rejection surveillance; CBC; LFTs; renal function
PRES is typically reversible with prompt treatment; most patients recover fully with aggressive BP control and removal of the offending cause
STAT
ROUTINE
ROUTINE
-
Call 911 immediately if new or worsening headache, seizure activity, vision changes, confusion, or difficulty speaking (may indicate PRES recurrence or complication)
-
ROUTINE
ROUTINE
-
Take all blood pressure medications as prescribed; do NOT skip doses or stop medications without physician guidance as this can trigger recurrence
-
ROUTINE
ROUTINE
-
Monitor blood pressure at home daily; keep a BP log; report readings consistently above 140/90 to your physician
-
ROUTINE
ROUTINE
-
If you had seizures with PRES, do NOT drive until cleared by neurology (typically after imaging resolution and seizure-free period per state law)
-
ROUTINE
ROUTINE
-
If PRES was caused by an immunosuppressant medication, do NOT resume the medication without explicit transplant team or oncology approval
-
ROUTINE
ROUTINE
-
Visual changes from PRES usually improve over days to weeks; report any persistent vision problems at follow-up
-
ROUTINE
ROUTINE
-
Report any new headaches, confusion, or seizures immediately as these may indicate incomplete resolution or recurrence
-
ROUTINE
ROUTINE
-
Pregnancy counseling: if eclampsia-related PRES, discuss future pregnancy risks and preeclampsia prevention (low-dose aspirin prophylaxis) with OB
BP controlled on oral medications; seizure-free >24h on oral ASMs; neurological exam at or near baseline; improving vision; follow-up MRI and neurology scheduled within 2-4 weeks; underlying cause identified and addressed; reliable social support and medication access
Admit to monitored floor (stepdown)
Mild PRES with BP controlled on IV medications with planned oral transition; seizures controlled; GCS 14-15; stable imaging without hemorrhage; oral intake tolerated; no ICU-level monitoring needs
Admit to ICU
Severe hypertensive emergency requiring arterial line and IV antihypertensive titration; hemorrhagic PRES; recurrent seizures or status epilepticus; GCS <13 or declining; respiratory compromise requiring intubation; eclampsia requiring magnesium drip with continuous monitoring; posterior fossa edema with brainstem compression risk
Transfer to higher level of care
Need for neurocritical care not available at current facility; need for emergent delivery (eclampsia) with inadequate OB/NICU support; need for neurosurgery (hemorrhagic PRES with mass effect); need for dialysis not available
Outpatient follow-up
Neurology in 2-4 weeks for clinical assessment and follow-up MRI review; ophthalmology if persistent visual symptoms; nephrology for ongoing renal issues; transplant clinic within 1-2 weeks if immunosuppressant adjustment made; OB for postpartum eclampsia follow-up; PCP for long-term BP management
v1.1 (January 30, 2026)
- Added ICU venue column to Section 4B (Patient Instructions) and Section 4C (Lifestyle & Prevention) for 4-column consistency
- Standardized structured dosing format for insulin (regular), pneumatic compression devices, intubation/airway protection, and immunosuppressant switch
- Fixed exercise, stress management, and preeclampsia prevention rows in 4C to include HOSP ROUTINE for discharge counseling
- Added REVISED date to header metadata
- Checker/rebuilder pipeline pass: score improved from 50/60 (83%) to 56/60 (93%)
v1.0 (January 30, 2026)
- Initial template creation
- Full 8-section format with comprehensive PRES management
- Covers hypertensive emergency, eclampsia, immunosuppressant-related, and chemotherapy-associated PRES
- Structured dosing format for all medications
- Evidence citations with PubMed links
APPENDIX A: PRES Diagnostic Criteria and MRI Interpretation¶