Study guide
26.1 Postoperative Seizures, Hemorrhage, Ischemia, and Hyperperfusion (04.A, C, D, H)
ABIM Neurocritical Care Subspecialty Certification Exam
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 Eligibility, Practice Pathway, and the IM Training Route 1.3 Format, Scoring, Pearson VUE, and Score Reports 1.4 How to Use This Independent Study Guide
2 ICU Neurologic Exam, Cerebral Physiology, and CSF
2.1 Neurological Examination in the ICU 2.2 Cerebral Physiology, ICP, CBF, and Autoregulation 2.3 CSF Physiology
3 Core Neuropharmacology
3.1 Osmotic Agents 3.2 Anti-Seizure Drugs 3.3 Anesthetics, Sedatives, Analgesia, and Paralytics 3.4 Antihypertensives, Vasopressors, and Inotropes
4 Reperfusion Drugs, Airway, and Ventilation
4.1 Thrombolytics, Anticoagulants, and Antiplatelets 4.2 Reversal of Anticoagulation After Acute Hemorrhage 4.3 Airway Management and Tracheostomy 4.4 Mechanical Ventilation
5 Hemodynamics and Shock
5.1 Hemodynamic Monitoring 5.2 IABP, Temporary VADs, LVAD, and ECMO 5.3 Diagnosis and Management of Shock
6 Nutrition, Temperature, and ICU Prophylaxis
6.1 Nutrition (01.J) 6.2 Temperature Control (01.K) 6.3 ICU Prophylaxis, Delirium, and Early Mobility (01.L)
7 General Trauma
7.1 Emergency Evaluation of Polytrauma, Chest, and Abdominal Trauma 7.2 Long-Bone Fractures and Fat Embolism 7.3 Burns, Electrical Injury, and Hanging/Strangulation
8 Pulmonary Critical Care
8.1 Pulmonary Physiology and ARDS (01.N.1–2) 8.2 PE, Pneumonia, and Pulmonary Edema (01.N.3, 7–8) 8.3 COPD, Asthma, PAH, and Bronchoscopy Basics (01.N.4–6, 9)
9 Cardiovascular Critical Care
9.1 Cardiovascular Physiology, Stress Cardiomyopathy, ACS, and Valves 9.2 Arrhythmias and Pacing 9.3 Acute Aortic Dissection and Cardiac Ultrasound
10 Renal and Infectious Disease
10.1 AKI, RRT, and Renal Drug Dosing 10.2 Acid-Base and Electrolyte Disorders 10.3 Severe Sepsis, Septic Shock, and Infective Endocarditis 10.4 Antimicrobial Use and Infection in the Immunosuppressed
11 Endocrine and Salt-Water Disorders
11.1 Pituitary Apoplexy, DI, and Panhypopituitarism (01.R.1–4) 11.2 SIADH and Cerebral Salt Wasting (01.R.5–6) 11.3 Thyrotoxicosis, Myxedema, Adrenal Crisis, and Dysglycemia (01.R.7–9)
12 Gastrointestinal Critical Care
12.1 GI Physiology, Acute Abdomen, Bleed, Ileus, and Perforation (01.S.1–5) 12.2 Mesenteric Ischemia and Abdominal Compartment Syndrome (01.S.6–7) 12.3 Fulminant Liver Failure, Cirrhosis Decompensation, and Hepatic Dosing (01.S.8–10)
13 Hematologic Disorders
13.1 Anemia, Transfusion, Thrombocytopenia, Coagulopathy, and DIC (01.T.1–4) 13.2 VTE in the Neuro ICU (01.T.5) 13.3 Chemo/Immune, SCT, CAR-T, Sickle Cell, and TMA (01.T.6–10)
14 Neuroimaging
14.1 CT of Brain and Spine 14.2 MRI and CT/MR Perfusion 14.3 Noninvasive Angiography and Catheter Angiography
15 EEG, EMG, and CSF Analysis
15.1 EEG, Standard and Processed (02.B) 15.2 Basic EMG Interpretation (02.G) 15.3 CSF Analysis (02.H)
16 ICP, TCD, and Multimodality Monitoring
16.1 ICP Monitoring (02.C) 16.2 Transcranial Doppler (02.D) 16.3 Brain-Tissue Oxygen and Multimodality Monitoring (02.E–F)
17 Brain Death and Bedside Procedures
17.1 Brain Death Prerequisites and Clinical Exam (02.I) 17.2 Apnea Testing and Ancillary Studies (02.I) 17.3 Vascular Access, Thoracic Echo, and Lung Ultrasound (02.J–L)
18 Coma, Anoxia, and Intracranial Hypertension
18.1 Coma and Other States of Altered Consciousness (03.A) 18.2 Global Anoxia-Ischemia and Post-Resuscitation Encephalopathy (03.A.1) 18.3 Toxidromes, ICU Delirium, and Hypertensive Encephalopathy (03.A.2–4) 18.4 Intracranial Hypertension as a Disease State (03.B)
19 Acute Ischemic Stroke
19.1 IV Reperfusion Therapy (03.C.3) 19.2 Mechanical Thrombectomy Windows and Imaging Selection (03.C.3) 19.3 Malignant Hemispheric Infarction and Basilar Artery Occlusion (03.C.1–2)
20 Intraparenchymal Hemorrhage
20.1 Intracerebral Hematoma (03.D.1) 20.2 Cerebellar Hematoma (03.D.2) 20.3 Intraventricular Hemorrhage (03.D.3)
21 SAH, CVST, and Spinal Cord Infarction
21.1 Aneurysmal Subarachnoid Hemorrhage (03.E.1) 21.2 Non-Aneurysmal SAH (03.E.2) 21.3 Cerebral Venous Sinus Thrombosis (03.F) 21.4 Spinal Cord Infarction (03.G)
22 Vascular Anomalies and Traumatic Brain Injury
22.1 Unruptured Aneurysm, Cavernoma, AVM, and Dural AVF (03.H) 22.2 Diffuse Axonal Injury and Cerebral Contusions (03.I.1–2) 22.3 Epidural Hematoma, Subdural Hematoma, and Penetrating Injury (03.I.3–4, 7) 22.4 Arterial Dissection and Carotid-Cavernous Fistula (03.I.5–6)
23 Spine, Hydrocephalus, and CNS Infection
23.1 Spinal Cord Injury, Central Cord, and Neurogenic Shock (03.J) 23.2 Unstable Spine Fractures (03.K) 23.3 Hydrocephalus and CSF Diversion (03.L) 23.4 Acute CNS Infections (03.M)
24 Seizures and Neuromuscular Emergencies
24.1 Status Epilepticus and Seizures (03.N) 24.2 Guillain-Barré Syndrome (03.O.1) 24.3 Myasthenic Crisis (03.O.2) 24.4 Motor Neuron Disease, Acute Myopathies, Rhabdomyolysis, and CINM (03.O.3–6)
25 Inflammatory Disease, Neuro-Oncology, and Special Populations
25.1 Fulminant Demyelinating Diseases (03.P) 25.2 Autoimmune Encephalitis and Acute Autonomic Hyperactivity (03.Q–R) 25.3 Neuro-Oncology and Treatment Complications (03.S) 25.4 Pregnancy/Post-Partum, Post-Transplant, and Pediatric Patients (03.T–U)
26 Neurosurgical and Perioperative Complications
26.1 Postoperative Seizures, Hemorrhage, Ischemia, and Hyperperfusion (04.A, C, D, H) 26.2 Infection, CSF Leak, and Pneumocephalus (04.B, E, F) 26.3 Complications of EVD and Lumbar Drain (04.G, I)
27 Ethics, Prognostication, and Organ Donation
27.1 Communication, Decision-Makers, Advance Directives, and DNR (05.A, B, G) 27.2 Uncertainties of Prognostication and the Self-Fulfilling Prophecy (05.C) 27.3 Palliative Care, Withdrawal, Withholding, and Futility (05.D–F) 27.4 Donation After Cardiac Death and Care of the Organ Donor (05.H–I)
26.1 Postoperative Seizures, Hemorrhage, Ischemia, and Hyperperfusion (04.A, C, D, H)
Key Takeaways Explain This Topic AI
Early postoperative seizures occur within 7 days and are provoked by the operation, blood, or edema; a late seizure after day 7 raises the chance of unprovoked recurrence and is treated as new epilepsy until a reversible cause is found.
Load an antiseizure drug after a postoperative seizure. Routine long prophylaxis is not required for most seizure-naive craniotomy or aneurysmal subarachnoid hemorrhage patients; if a short course is used, levetiracetam for about 7 days is the usual modern choice, not phenytoin.
Operative-bed hematoma usually declares in the first 6–24 hours. Remote cerebellar hemorrhage after CSF loss shows streaky cerebellar blood (zebra sign) and is a venous, CSF-hypovolemia injury, not a failed clip.
After aneurysm or AVM surgery, arterial infarcts follow parent-vessel stenosis, perforator injury, or thromboembolism; venous infarcts follow a sacrificed or thrombosed draining vein and are often hemorrhagic.
Cerebral hyperperfusion after carotid endarterectomy, carotid stenting, or AVM resection presents with ipsilateral headache, seizure, or hemorrhage; the treatment is blood-pressure control, not induced hypertension.
Last updated: September 2026
A patient who was following commands in the recovery area and now is not is a clock, not a narrative. Independent ExamFinch teaching for ABIM Neurocritical Care outline items 04.A, 04.C, 04.D, and 04.H is the four-way split you run before you reach for a sedative: postoperative seizure , hematoma , ischemic stroke (arterial or venous), and cerebral hyperperfusion . Those entities share a declining examination and they do not share a blood-pressure target. This chapter is perioperative complication recognition. Disease-state subarachnoid hemorrhage, AVM natural history, and carotid stenosis decision-making live in earlier chapters; here the question is what the operation just did.
This is not an American Board of Internal Medicine, American Board of Psychiatry and Neurology, American Heart Association, or neurosurgical-society product. Name the source when a number comes from a trial or a guideline, and do not imply official endorsement of this guide.
Early versus late postoperative seizures, and when to load
The International League Against Epilepsy treats a seizure within 7 days of an acute brain insult as an acute symptomatic (early) seizure. After a craniotomy, that insult is cortical irritation, blood, edema, electrolyte shift, or a hematoma you have not imaged yet. Late postoperative seizures begin after day 7. Early seizures do not, by themselves, diagnose epilepsy. Late seizures have a much higher risk of unprovoked recurrence and are treated as new epilepsy until you find a reversible trigger (abscess, residual tumor, hyponatremia, missed hematoma).
Load an antiseizure drug (ASD) when a postoperative seizure has already occurred, when the examination is too poor to detect convulsions and continuous EEG shows electrographic seizures, or when the patient already had epilepsy and missed doses. A first early seizure after craniotomy is not “just a twitch”: image first if the patient does not wake cleanly, then load. Levetiracetam is the usual intensive-care load (for example 20–30 mg/kg intravenous, then a maintenance schedule) because it does not require level-chasing and does not interact with nimodipine the way phenytoin does. Phenytoin still appears in older stems; it is a worse perioperative choice because of hypotension with rapid infusion, rash, and enzyme induction.
Prophylaxis without a prior seizure is a shorter, more political question:
Setting What high-quality sources actually say Exam translation
Severe TBI Temkin and colleagues ( NEJM 1990): phenytoin for 7 days cut early seizures ( 3.6% versus 14.2% ) and did not prevent late epilepsy A 7-day course after severe TBI is defensible; weeks of phenytoin is not
Aneurysmal SAH 2023 AHA/ASA aSAH guideline: treat a new-onset seizure for 7 days ; do not routinely give prophylaxis; consider a short course in high-risk anatomy (ruptured MCA aneurysm, intraparenchymal clot, high-grade SAH, hydrocephalus, cortical infarct); avoid phenytoin Load after a seizure; do not start phenytoin “because everyone with SAH seizes”
Seizure-naive supratentorial craniotomy (tumor and mixed series) A 2026 Neurocritical Care Society statement: either a short prophylactic course or no ASD is acceptable; if a drug is used, prefer levetiracetam over phenytoin; ≤7 days is not inferior to a long course for late-seizure prevention A week of levetiracetam is common practice, not a lifetime prescription
Seizure-naive brain metastases Congress of Neurological Surgeons guidance: routine ASDs do not clearly reduce seizures and phenytoin adds harm Do not load every metastasis for a week of phenytoin
Worked contrast: a seizure-naive convexity meningioma wakes, has a 60-second focal-to-bilateral tonic-clonic event at hour 4, CT is clean — load levetiracetam and keep a short course. A Hunt-Hess 2 anterior-communicating aneurysm that never seized does not need phenytoin “for the clip.” A late seizure on postoperative day 18 after glioblastoma resection is a new epilepsy workup and a longer ASD plan, not another 7-day “prophylaxis” sticker.
If the patient is still unresponsive after a reported seizure, treat status epilepticus as in chapter 24 and obtain a noncontrast CT before you blame residual anesthetic. Nonconvulsive seizures after craniotomy are common enough that a poor examination plus a dirty EEG is not “ICU psychosis.”
Hematoma at the operative bed versus remote hemorrhage
Operative-bed hematoma is bleeding into the cavity you just left: residual tumor bed, evacuated hematoma cavity, clip site, or the epidural space under a bone flap. Most clinically important bed hematomas declare in the first 6 hours ; almost all announce themselves within 24 hours (Taylor and colleagues, 1995, remain the series boards still paraphrase). The story is wake-then-decline, a blown pupil on the operative side, or a sudden hypertension that is the Cushing response, not “pain.” Risk factors you can name: incomplete hemostasis, residual vascular nidus, hypertension in the first hours, coagulopathy, antiplatelet agents that were not reversed, and thrombocytopenia. The move is STAT CT , reverse what is reversible, and call the operating room — not another 4 mg of morphine.
Remote hemorrhage is blood away from the surgical field . The pattern you must not miss is remote cerebellar hemorrhage (RCH) after supratentorial craniotomy, aneurysm clipping, or spinal surgery with large CSF loss. CSF hypovolemia lets the cerebellum sag, stretching bridging veins; the bleed is venous . CT shows streaky blood in the cerebellar sulci — the zebra sign — sometimes with hydrocephalus from fourth-ventricle compression. This is not a “missed posterior-circulation aneurysm” until you have thought about the drain and the CSF leak. Clamp or raise any suction subgaleal or lumbar drain, stop overdrainage, reverse coagulopathy, and decompress if the patient is herniating. Remote supratentorial hematomas also occur with hypertension and coagulopathy; they are arterial or venous depending on the scan, but they are still not the clip site.
- Feature Operative-bed hematoma Remote cerebellar hemorrhage
- Where Cavity, epidural flap, clip or nidus site Cerebellum, often distant from the incision
- Clock Hours 0–24, often <6 h Intraoperative to ~48 h; many within 10 h
Mechanism Arterial or venous bleeding at the field; hypertension; coagulopathy CSF hypovolemia, cerebellar sag, venous tear
CT clue Extra density in the bed, shift, flap tension Zebra-sign cerebellar sulcal blood
First moves CT, reverse coagulopathy, control BP, return to OR if mass effect Stop CSF overdrainage, CT, treat hydrocephalus, decompress if needed
Do not call every new blood on the first postoperative CT a “surgical disaster.” A thin cavity film after a glioblastoma resection is expected. Expanding hematoma plus decline is the emergency.
Arterial versus venous infarct after aneurysm or AVM surgery
Arterial infarct after clipping or AVM resection follows the arteries you operated on. Parent-vessel stenosis or occlusion from a clip that kinks the M1, A2, or a perforator; intraoperative thrombosis; embolus from a temporary clip; and, later, delayed cerebral ischemia from vasospasm after aneurysmal SAH (chapter 21) all produce arterial maps. Named perforator disasters: recurrent artery of Heubner after anterior-communicating work (caudate and anterior limb of internal capsule), lenticulostriates after MCA aneurysm clipping, and brainstem perforators after basilar-apex surgery. The deficit appears as the patient fails to wake or drops a dense, territorial examination. CTA, catheter angiography, or a return trip to the microscope answers “is the vessel open?” Diffusion MRI confirms the infarct once the patient is stable enough to travel.
Venous infarct follows sacrifice or thrombosis of a vein that still mattered. Classic setups: vein of Labbé or a dominant temporal bridging vein during a subtemporal approach; superior sagittal sinus or cortical veins during a parasagittal meningioma; and AVM draining-vein thrombosis when the nidus is only partly gone and a residual feeder still pressurizes a compromised vein. Venous infarcts are often hemorrhagic , more edema than a clean MCA wedge, and they do not respect a single arterial tree. Treatment is blood-pressure sanity, seizure control, and — when the vein is thrombosed and the nidus is gone — sometimes anticoagulation after a hard conversation about the fresh cavity. Do not anticoagulate a residual AVM because the scan “looks venous.”
Arterial infarct Venous infarct
Typical after Clip stenosis, perforator injury, thromboembolism, later vasospasm Bridging-vein sacrifice, sinus injury, AVM vein thrombosis
- Map Arterial territory or perforator cluster Cortical/subcortical edema, often hemorrhagic, not one artery
- Extra clue Absent vessel on CTA/DSA Slow venous phase, thrombosed vein, residual AVM
Trap Calling hyperperfusion “vasospasm” and raising BP Calling venous blood an “operative-bed hematoma” without looking at the veins
Normal perfusion pressure breakthrough (NPPB) after AVM resection is the AVM-specific cousin of hyperperfusion (next heading): chronically steal-conditioned brain suddenly sees full arterial pressure. Surrounding edema and hemorrhage are not always a residual nidus, but residual nidus must still be excluded with angiography.
Cerebral hyperperfusion after CEA, CAS, and AVM resection
Cerebral hyperperfusion syndrome (CHS) follows carotid endarterectomy (CEA) or carotid artery stenting (CAS) when a chronically hypoperfused hemisphere loses autoregulation and then receives a sudden jump in flow. The clinical triad boards expect is ipsilateral throbbing headache , seizure , and intracerebral hemorrhage (or focal edema that looks like a stroke until you check the pressure and the TCD). Onset is hours to about 2 weeks , with many cases in the first 7 days . A Vascular Quality Initiative analysis (published 2025) found CHS in about 0.25% of carotid revascularizations, more often after transfemoral CAS than after CEA or transcarotid revascularization; uncontrolled hypertension roughly doubled the odds. That rarity is why the syndrome is missed: the nurse calls it a migraine and the intern raises the pressure “for the new stroke.”
Transcranial Doppler that shows a marked jump in ipsilateral middle-cerebral velocity (classically a doubling of the preoperative baseline, or a large absolute increase) supports the diagnosis when you have a window. Perfusion imaging shows ipsilateral hyperperfusion, not a mismatch core. Treatment is blood-pressure reduction , not induced hypertension. Many units keep postoperative pressure below 140/90 mm Hg , and drop further (sometimes toward 120/80 mm Hg ) once CHS is suspected. Prefer agents that do not raise cerebral blood flow: labetalol or clonidine . Pure vasodilators (nitroprusside, high-dose dihydropyridine infusions) can worsen hyperemia. Treat the seizure with an ASD. Do not give intra-arterial vasodilators as if this were vasospasm.
The same physiology follows AVM resection (NPPB) and some extracranial-intracranial bypasses. Staged embolization exists to shrink that risk; your ICU job is still a tight pressure plan and a low threshold to re-image hemorrhage.
Timeline table you can carry into a stem
Clock Seizure Hematoma Ischemia Hyperperfusion
0–6 h Emergence seizure; image if they do not wake Peak window for bed hematoma Clip/perforator/thrombus; check the vessel Early CHS if pressure is wild
6–24 h Early provoked seizure Still bed hematoma; start thinking remote cerebellar Completing arterial or venous infarct Headache and seizure from CHS
Days 2–7 Still “early” if ≤7 d; wean prophylaxis if used Less often a fresh bed bleed unless coagulopathy Vasospasm/DCI after SAH; venous thrombosis Classic CHS/NPPB window
After day 7 Late seizure ≈ epilepsy risk Delayed bleed: coagulopathy, residual AVM, abscess later Delayed vasospasm still possible after SAH CHS can linger to ~2 weeks
Exam traps
Treating a 4-hour decline after craniotomy as residual propofol. Starting phenytoin for every clipped aneurysm. Calling zebra-sign cerebellar blood a “posterior-circulation embolus from the heart.” Raising blood pressure for ipsilateral headache and seizure the day after CEA. Anticoagulating a residual AVM because the hemorrhage “looks venous.” Keeping levetiracetam for 6 months after an uneventful, seizure-naive meningioma because “the brain was touched.”
In practice
Hour 3 after a temporal glioblastoma: the patient seizes, then the pupil enlarges — CT first, not a second levetiracetam push as the only move; bed hematoma beats “early seizure” when the eye is blown. Hour 8 after sitting-adjacent CSF-lossy aneurysm clipping: delayed wake, zebra-sign cerebellum — clamp the suction drain. Day 2 after CEA for a 90% stenosis: ipsilateral pounding headache and a first seizure at systolic 190 mm Hg — this is CHS, lower the pressure with labetalol, do not start a vasospasm hypertension protocol. Day 12 after AVM resection: a late seizure with a clean cavity — that is a late seizure, not a reason to invent a 7-day prophylaxis rule after the fact.