What is the differential diagnosis for a 38-year-old male with acute left-sided facial swelling and increasing weakness, status post craniotomy and cranioplasty, with a history of hypertension and seizures, and baseline right upper extremity hemiparesis?

Differential Diagnosis for Acute Left-Sided Facial Swelling and Increasing Weakness Post-Craniotomy

Immediate Life-Threatening Considerations

In a patient with acute left-sided facial swelling and increasing weakness within 2 hours post-craniotomy/cranioplasty, the primary concern is recurrent stroke (either ischemic or hemorrhagic) or post-cranioplasty cerebral edema with mass effect, which requires emergent neuroimaging and potential surgical intervention. 1

Critical Differential Diagnoses (Prioritized by Mortality Risk):

1. Recurrent Ischemic Stroke with Malignant Edema

• Most likely given the acute timeframe (2 hours) and new weakness in a patient with prior stroke history and baseline hemiparesis 1
• Look for: decreased level of consciousness, worsening of baseline right-sided weakness, new left facial droop, pupillary changes, or signs of herniation 1
• The American Heart Association/American Stroke Association guidelines emphasize that deterioration within 48 hours of stroke onset warrants consideration of decompressive craniectomy if medical therapy fails 1
• Patients status post craniotomy are at higher risk for recurrent events, particularly if the original indication was large vessel occlusion 2

2. Post-Cranioplasty Hemorrhagic Complications

• Intracerebral hemorrhage occurs in 1.65% of cranioplasty cases and can present with acute neurological deterioration 3
• Both supratentorial and infratentorial hemorrhagic infarctions have been reported after cranioplasty, with seizures as a presenting feature 2
• Reperfusion injury after cranioplasty can cause massive brain swelling, particularly in patients with pre-existing low-density brain lesions 4, 5
• Look for: sudden onset of symptoms 4-24 hours post-procedure, seizure activity, rapid decline in consciousness 2, 4

3. Massive Cerebral Edema/Brain Swelling Post-Cranioplasty

• Fatal cerebral swelling can occur 20+ hours after cranioplasty, presenting with coma and pupillary dilation 4
• Patients with pre-existing neurological deficits (like this patient's baseline hemiparesis) are at increased risk 3
• The mechanism involves altered CSF dynamics, venous stasis, and loss of cerebral autoregulation 6, 4, 5
• Look for: progressive decline over hours, signs of increased intracranial pressure, midline shift on imaging 4

4. Cerebral Venous Thrombosis (CVT)

• CVT can present with acute neurological deterioration, seizures, and hemorrhagic transformation 1
• Particularly relevant in post-craniotomy patients due to venous manipulation during surgery 1
• Presents with headache (if conscious), seizures (22% of cases), and can cause intraparenchymal hemorrhage (22% of cases) 6
• Look for: seizure activity, signs of increased ICP, hemorrhage on imaging with venous sinus thrombosis 1

5. Post-Surgical Sialadenitis (Lower Priority but Important)

• Acute sialadenitis after skull base surgery presents with submandibular swelling contralateral to the surgical site within 4 hours 1, 7
• However, this typically occurs after retrosigmoid or far-lateral craniotomies, not standard craniotomy/cranioplasty 1
• The facial swelling in this case is LEFT-sided (same side as surgical site based on context), making sialadenitis less likely 1, 7
• Look for: submandibular gland swelling, potential airway compromise (84% require emergent airway intervention), absence of intracranial pathology on imaging 1, 7

6. Seizure with Post-Ictal Weakness (Todd's Paralysis)

• Post-cranioplasty seizures occur in 14.81% of cases, particularly in patients with prior trauma or intracranial hemorrhage 3
• Given this patient's history of seizures and craniotomy, new seizure activity is highly plausible 3
• Todd's paralysis can cause transient weakness lasting hours to days, but would not explain facial swelling 3
• Look for: witnessed seizure activity, post-ictal confusion, transient weakness that improves over hours 2, 3

7. Intracranial Hypotension with Complications

• Spontaneous intracranial hypotension post-cranioplasty can cause postural headaches (83%), CVT (3% mortality), and hemorrhage 6
• Presents with subdural hematomas (11%), intraparenchymal hemorrhage (22%), and seizures (22%) 6
• Less likely to present acutely within 2 hours unless there was excessive CSF drainage 6, 4

Immediate Diagnostic Approach

Emergent Imaging (Within Minutes):

• Non-contrast head CT immediately to assess for hemorrhage, edema, mass effect, and herniation 1, 4
• CT venography if no hemorrhage identified to rule out venous thrombosis 1
• Look specifically for: midline shift, compressed basal cisterns, new hemorrhage, venous sinus filling defects 1

Clinical Assessment:

• Glasgow Coma Scale score and pupillary examination immediately 1
• Assess for signs of herniation: decreased consciousness, pupillary asymmetry, extensor posturing 1
• Evaluate airway patency given facial swelling 7
• Check for seizure activity or post-ictal state 3

Critical Management Pitfalls to Avoid

• Do not delay imaging for "observation" in a post-craniotomy patient with acute neurological change 1
• Do not assume facial swelling is benign sialadenitis without ruling out intracranial catastrophe first 1, 7
• Do not withhold anticoagulation for CVT even if hemorrhagic transformation is present, per AHA/ASA guidelines 1
• Maintain high suspicion for massive brain swelling if patient has low-density lesions on prior imaging 4
• Be prepared for emergent airway management if facial swelling progresses 7