What is the best course of action for a patient with a history of uterine mass, presenting with acute dizziness, aphasia, and altered sensorium, after a normal initial cranial computed tomography (CT) scan?

Urgent MRI Brain with Diffusion-Weighted Imaging

This patient requires immediate MRI brain with and without contrast, including diffusion-weighted imaging (DWI), to evaluate for acute stroke, given the acute onset of aphasia and altered sensorium with a normal initial CT scan. 1

Critical Clinical Context

This presentation represents a high-risk scenario where:

• Acute aphasia is a focal neurologic deficit indicating stroke until proven otherwise 1
• Normal head CT does not exclude acute ischemic stroke, as CT has poor sensitivity for early infarction, particularly in the first 6-24 hours 1
• The history of uterine mass raises concern for cardioembolic stroke from potential tumor embolization or hypercoagulability associated with malignancy 1, 2

Immediate Diagnostic Algorithm

First-Line Imaging: MRI Brain

• Obtain emergent MRI brain with DWI sequences to detect acute ischemia with high sensitivity, even when CT is normal 1
• Include MR angiography (MRA) of the head and neck to evaluate for large vessel occlusion or dissection 1
• Administer gadolinium contrast to assess for tumor-related complications (hemorrhagic metastases, venous sinus thrombosis) given the uterine mass history 1

Why MRI Over Repeat CT

• MRI detects 70% of ischemic strokes missed on initial presentation with altered mental status 1
• DWI sequences identify acute infarction within minutes of onset, while CT may remain normal for hours 1
• MRI better characterizes small infarcts, posterior circulation strokes, and brainstem lesions that commonly present with dizziness and altered sensorium 1

Concurrent Evaluation While Arranging MRI

Laboratory Assessment

• Check complete blood count, comprehensive metabolic panel, and coagulation studies to identify metabolic causes and assess bleeding risk 1
• Obtain troponin and ECG to evaluate for cardioembolic source 2
• Measure CA-125 if not already done, as elevated levels with uterine mass suggest potential metastatic disease 1

Neurologic Examination Details

• Document specific aphasia type (expressive vs. receptive) to localize lesion 1
• Assess for additional focal deficits: facial droop, arm drift, visual field cuts 1
• Perform NIHSS scoring if stroke protocol available 2

Alternative Diagnoses to Consider

If MRI Shows No Acute Stroke

• Autoimmune encephalitis: Consider anti-LGI1 antibodies, particularly if hyponatremia present 3
• CNS infection: Obtain lumbar puncture if MRI shows no mass effect, checking cell count, protein, glucose, and meningitis/encephalitis panel 3, 4
• Seizure with postictal state: Review for subtle seizure activity, obtain EEG 3
• Paraneoplastic syndrome: Given uterine mass, check paraneoplastic antibody panel (anti-Yo, anti-Hu) 5

Critical Pitfalls to Avoid

• Do not rely on normal CT to exclude stroke in this presentation - CT sensitivity for acute ischemia is only 12-26% in the first 6 hours 1
• Do not delay MRI for metabolic workup - "time is brain" in acute stroke, and aphasia represents a large territory at risk 2
• Do not attribute symptoms solely to dizziness/vertigo - the presence of aphasia and altered sensorium indicates this is NOT isolated peripheral vertigo 1
• Do not forget cancer-related complications: hypercoagulability, tumor emboli, and metastatic disease are all possible with known uterine mass 1, 2

Uterine Mass Considerations

Imaging the Primary Tumor

• Defer pelvic imaging until neurologic emergency is addressed 1
• Once stabilized, obtain pelvic MRI with contrast to characterize the uterine mass and assess for metastatic disease 1, 6
• High-risk uterine tumors (serous, clear cell, carcinosarcoma) have propensity for extrauterine spread and neurologic complications 1

Oncologic Workup

• CT chest/abdomen/pelvis with contrast to stage disease if malignancy confirmed 1
• Consider PET/CT if high-grade histology suspected 1