What are examples of acute neurological deficits that require urgent evaluation?

Acute Neurological Deficits Requiring Urgent Evaluation

Any patient presenting with sudden onset focal neurological symptoms requires immediate emergency evaluation within minutes to hours, as these represent potential stroke or other life-threatening conditions where time directly determines outcome. 1, 2

Classic Stroke Presentations

Motor Deficits

• Unilateral arm or leg weakness/paralysis is the most common presentation requiring immediate stroke evaluation 1, 3
• Facial droop or asymmetry, particularly when combined with arm weakness, indicates high stroke probability 2
• The combination of left arm numbness with facial weakness or speech disturbance carries a 72% probability of stroke 2

Speech and Language Disturbances

• Sudden aphasia (inability to speak or understand language) requires urgent imaging to exclude stroke 1
• Dysarthria (slurred speech) particularly when combined with other focal signs 1

Visual Symptoms

• Sudden monocular vision loss (amaurosis fugax) represents retinal artery occlusion or impending stroke 3
• Sudden binocular visual field defects or complete blindness suggest posterior circulation stroke 1
• Acute diplopia (double vision) especially with other brainstem signs 1

Sensory Deficits

• Isolated hemibody numbness still represents high stroke risk despite being sensory-only 2
• Patients with unilateral numbness within 48 hours have 10% risk of completed stroke within the first week 2

Altered Consciousness and Encephalopathy

Decreased Level of Consciousness

• Sudden confusion, drowsiness, or coma requires immediate evaluation for stroke (particularly basilar artery occlusion), intracranial hemorrhage, or metabolic causes 1, 4
• Patients with major hemispheric infarctions or cerebellar strokes with brainstem compression present with decreased consciousness 1

Acute Encephalopathy

• Changes in consciousness ranging from impaired attention to delirium with psychotic symptoms may indicate drug toxicity, metabolic derangement, or posterior reversible encephalopathy syndrome (PRES) 1
• Acute confusion with focal signs (paresis, speech disorders, seizures, cranial nerve dysfunction) suggests structural brain lesion requiring urgent imaging 1

Posterior Circulation and Brainstem Syndromes

Cerebellar Symptoms

• Acute ataxia (inability to coordinate movements) particularly in adults or when accompanied by other neurological signs 1
• Sudden vertigo with nausea/vomiting when combined with other focal deficits suggests cerebellar or brainstem stroke 1
• Dysarthria, dizziness, and vestibulocochlear eye movement disorders developing 2-5 days after certain chemotherapy may indicate acute cerebellar syndrome 1

Cranial Nerve Deficits

• Sudden cranial nerve palsies especially when multiple or bilateral 1
• Ophthalmoplegia (eye movement paralysis) particularly with ataxia and areflexia (Miller-Fisher syndrome) 1

Seizures and Epileptic Phenomena

• New-onset seizures in adults require urgent evaluation to exclude stroke, hemorrhage, or mass lesion 1
• Status epilepticus represents a neurological emergency requiring immediate intervention 5

Vascular Emergencies

Subarachnoid Hemorrhage

• Sudden severe headache reaching maximal intensity immediately ("thunderclap headache") requires urgent CT and possible lumbar puncture 1
• Headache with new neurological deficit mandates immediate imaging 1

Acute Limb Ischemia

• Absent pulse with the "6 P's" (Pain, Pallor, Pulselessness, Paresthesias, Poikilothermia, Paralysis) indicates acute arterial occlusion requiring immediate vascular surgery consultation 2

Traumatic Brain Injury Context

• Any focal neurological deficit following trauma with decreased Glasgow Coma Scale requires urgent CT and neurosurgical evaluation 1
• Pupillary abnormalities in trauma patients indicate potential herniation requiring immediate intervention 1

Critical Time-Dependent Features

Patients presenting within 48 hours of symptom onset are at highest risk and require same-day comprehensive stroke evaluation 2. The therapeutic window for thrombolysis is 3-4.5 hours, making every minute critical 6. For large vessel occlusion, thrombectomy can be performed up to 24 hours in selected patients, but earlier intervention yields better outcomes 7.

Common Pitfall

Do not wait for laboratory results before obtaining neuroimaging—brain CT must be performed immediately to differentiate ischemic from hemorrhagic stroke, as this fundamentally changes treatment 6. The only exception is checking INR in patients on warfarin before thrombolysis 6.