All EMS presentations
NeurologicClinical presentation

Acute visual complaint

A streamlined, differential-led presentation for rapid clinical review.

Clinical snapshot

Twenty-second review

  • Acute visual change can result from retinal or cerebral ischemia, hemorrhage, pressure, inflammation, trauma, or metabolic disturbance.
  • Sudden monocular loss, field deficit, painful red eye, neurologic deficit, trauma, severe headache, or pregnancy hypertension symptoms is time-sensitive.
  • Keep hypoglycemia or medication effect in the differential; overlapping or concurrent illness remains possible.
  • For acute visual complaint, trends and combinations of findings are more informative than one isolated vital sign.
Differentials

Compare the clinical patterns

The repeated material is grouped inside each possibility. Open only the condition you need.

Serious4 conditions
Retinal artery occlusionTime-sensitive high-risk possibility

HPI

Clarify sudden or gradual; one eye or both; pain, headache or trauma.

Signs & symptoms

Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.

Focused exam

Record GCS components, pupils, speech, gaze, motor symmetry, sensation, coordination, and gait when safe; Compare findings with baseline and collateral history.

Brief pathophysiology

Retinal artery occlusion may cause acute visual complaint through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Neurologic differentials often have nonspecific vital signs. Glucose, pressure, oxygenation, and cardiac rate/rhythm help identify mimics and prevent secondary injury.

Blood glucose (mmol/L)

Check early

Hypoglycemia can mimic or worsen neurologic dysfunction.

Blood pressure (mmHg)

Trend pressure

Both hypo- and hypertension can be clinically important in neurologic disease.

Oxygen saturation (SpO₂)

Prevent hypoxemia

Low saturation can worsen brain injury or suggest an alternate cause.

Heart rate (bpm)

Assess rate / rhythm

Rhythm disturbance can cause cerebral hypoperfusion or embolic events.

Front-load in the triage report

  • Retinal artery occlusion: Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.
  • Sudden or gradual?
  • One eye or both?
StrokeTime-sensitive high-risk possibility

HPI

Clarify one eye or both; pain, headache or trauma; neurologic deficits.

Signs & symptoms

Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.

Focused exam

Compare findings with baseline and collateral history; Assess acuity when feasible, pupils, fields, gaze, eye appearance, pain, neurologic findings, BP context, trauma, and onset.

Brief pathophysiology

Stroke may cause acute visual complaint through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Stroke is a clinical diagnosis supported by time course and neurologic findings. Blood pressure and glucose affect eligibility and mimics; normal vitals do not exclude stroke.

Blood pressure (mmHg)

Often elevated

Hypertension is common in acute stroke; hypotension suggests another cause or poor perfusion.

Blood glucose (mmol/L)

Check every patient

Hypoglycemia can mimic focal deficit; hyperglycemia may accompany stress or diabetes.

Heart rate (bpm)

Assess rate / rhythm

An irregular rhythm may suggest atrial fibrillation but is not required.

Oxygen saturation (SpO₂)

Usually preserved

Hypoxemia requires correction and may indicate aspiration or another process.

Front-load in the triage report

  • Stroke: Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.
  • One eye or both?
  • Pain, headache or trauma?
Retinal detachmentTime-sensitive high-risk possibility

HPI

Clarify pain, headache or trauma; neurologic deficits; pupil and gross visual findings.

Signs & symptoms

Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.

Focused exam

Compare findings with baseline and collateral history; Assess acuity when feasible, pupils, fields, gaze, eye appearance, pain, neurologic findings, BP context, trauma, and onset.

Brief pathophysiology

Retinal detachment may cause acute visual complaint through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Neurologic differentials often have nonspecific vital signs. Glucose, pressure, oxygenation, and cardiac rate/rhythm help identify mimics and prevent secondary injury.

Blood glucose (mmol/L)

Check early

Hypoglycemia can mimic or worsen neurologic dysfunction.

Blood pressure (mmHg)

Trend pressure

Both hypo- and hypertension can be clinically important in neurologic disease.

Oxygen saturation (SpO₂)

Prevent hypoxemia

Low saturation can worsen brain injury or suggest an alternate cause.

Heart rate (bpm)

Assess rate / rhythm

Rhythm disturbance can cause cerebral hypoperfusion or embolic events.

Front-load in the triage report

  • Retinal detachment: Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.
  • Pain, headache or trauma?
  • Neurologic deficits?
Acute glaucomaTime-sensitive high-risk possibility

HPI

Clarify neurologic deficits; pupil and gross visual findings; last known normal.

Signs & symptoms

Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.

Focused exam

Compare findings with baseline and collateral history; Assess acuity when feasible, pupils, fields, gaze, eye appearance, pain, neurologic findings, BP context, trauma, and onset.

Brief pathophysiology

Acute glaucoma may cause acute visual complaint through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Neurologic differentials often have nonspecific vital signs. Glucose, pressure, oxygenation, and cardiac rate/rhythm help identify mimics and prevent secondary injury.

Blood glucose (mmol/L)

Check early

Hypoglycemia can mimic or worsen neurologic dysfunction.

Blood pressure (mmHg)

Trend pressure

Both hypo- and hypertension can be clinically important in neurologic disease.

Oxygen saturation (SpO₂)

Prevent hypoxemia

Low saturation can worsen brain injury or suggest an alternate cause.

Heart rate (bpm)

Assess rate / rhythm

Rhythm disturbance can cause cerebral hypoperfusion or embolic events.

Front-load in the triage report

  • Acute glaucoma: Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.
  • Neurologic deficits?
  • Pupil and gross visual findings?
Common2 conditions
Migraine auraCommon presentation pattern

HPI

Clarify sudden or gradual; one eye or both; pain, headache or trauma.

Signs & symptoms

Positive visual phenomena or irritation may be less dangerous but require pattern recognition.

Focused exam

Record GCS components, pupils, speech, gaze, motor symmetry, sensation, coordination, and gait when safe; Compare findings with baseline and collateral history.

Brief pathophysiology

Migraine aura may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.

Vital-sign pattern

What the trend may show

Possible pattern

Neurologic differentials often have nonspecific vital signs. Glucose, pressure, oxygenation, and cardiac rate/rhythm help identify mimics and prevent secondary injury.

Blood glucose (mmol/L)

Check early

Hypoglycemia can mimic or worsen neurologic dysfunction.

Blood pressure (mmHg)

Trend pressure

Both hypo- and hypertension can be clinically important in neurologic disease.

Oxygen saturation (SpO₂)

Prevent hypoxemia

Low saturation can worsen brain injury or suggest an alternate cause.

Heart rate (bpm)

Assess rate / rhythm

Rhythm disturbance can cause cerebral hypoperfusion or embolic events.

Front-load in the triage report

  • Positive visual phenomena or irritation may be less dangerous but require pattern recognition.
  • Sudden or gradual?
  • One eye or both?
Ocular surface problemCommon presentation pattern

HPI

Clarify one eye or both; pain, headache or trauma; neurologic deficits.

Signs & symptoms

Positive visual phenomena or irritation may be less dangerous but require pattern recognition.

Focused exam

Compare findings with baseline and collateral history; Assess acuity when feasible, pupils, fields, gaze, eye appearance, pain, neurologic findings, BP context, trauma, and onset.

Brief pathophysiology

Ocular surface problem may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.

Vital-sign pattern

What the trend may show

Possible pattern

Neurologic differentials often have nonspecific vital signs. Glucose, pressure, oxygenation, and cardiac rate/rhythm help identify mimics and prevent secondary injury.

Blood glucose (mmol/L)

Check early

Hypoglycemia can mimic or worsen neurologic dysfunction.

Blood pressure (mmHg)

Trend pressure

Both hypo- and hypertension can be clinically important in neurologic disease.

Oxygen saturation (SpO₂)

Prevent hypoxemia

Low saturation can worsen brain injury or suggest an alternate cause.

Heart rate (bpm)

Assess rate / rhythm

Rhythm disturbance can cause cerebral hypoperfusion or embolic events.

Front-load in the triage report

  • Positive visual phenomena or irritation may be less dangerous but require pattern recognition.
  • One eye or both?
  • Pain, headache or trauma?
Mimics2 conditions
HypoglycemiaImportant alternative presentation

HPI

Clarify sudden or gradual; one eye or both; pain, headache or trauma.

Signs & symptoms

Can blur vision and coexist with other pathology.

Focused exam

Record GCS components, pupils, speech, gaze, motor symmetry, sensation, coordination, and gait when safe; Compare findings with baseline and collateral history.

Brief pathophysiology

Hypoglycemia can resemble acute visual complaint through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Confirm low capillary glucose and reassess after treatment. Adrenergic signs may be absent in recurrent hypoglycemia or blunted by medications.

Blood glucose (mmol/L)

< 4.0 mmol/L

BCEHS defines hypoglycemia as blood glucose below 4.0 mmol/L.

Heart rate (bpm)

May rise

Adrenergic activation commonly produces tachycardia, but this is not universal.

Blood pressure (mmHg)

Often preserved

Blood pressure is not a reliable discriminator; hypotension suggests another or additional process.

Temperature (°C)

May fall

Hypothermia can accompany prolonged or severe hypoglycemia.

Front-load in the triage report

  • Can blur vision and coexist with other pathology.
  • Sudden or gradual?
  • One eye or both?
Medication effectImportant alternative presentation

HPI

Clarify one eye or both; pain, headache or trauma; neurologic deficits.

Signs & symptoms

Can blur vision and coexist with other pathology.

Focused exam

Compare findings with baseline and collateral history; Assess acuity when feasible, pupils, fields, gaze, eye appearance, pain, neurologic findings, BP context, trauma, and onset.

Brief pathophysiology

Medication effect can resemble acute visual complaint through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Neurologic differentials often have nonspecific vital signs. Glucose, pressure, oxygenation, and cardiac rate/rhythm help identify mimics and prevent secondary injury.

Blood glucose (mmol/L)

Check early

Hypoglycemia can mimic or worsen neurologic dysfunction.

Blood pressure (mmHg)

Trend pressure

Both hypo- and hypertension can be clinically important in neurologic disease.

Oxygen saturation (SpO₂)

Prevent hypoxemia

Low saturation can worsen brain injury or suggest an alternate cause.

Heart rate (bpm)

Assess rate / rhythm

Rhythm disturbance can cause cerebral hypoperfusion or embolic events.

Front-load in the triage report

  • Can blur vision and coexist with other pathology.
  • One eye or both?
  • Pain, headache or trauma?
Red flags

Findings that should escalate concern

  • Sudden painless vision loss
  • New neurologic deficit
  • Chemical exposure
  • Open-globe concern
  • Sudden monocular loss, field deficit, painful red eye, neurologic deficit, trauma, severe headache, or pregnancy hypertension symptoms is time-sensitive.
  • Retinal artery occlusion, stroke, retinal detachment, or acute glaucoma: Sudden loss, curtain, focal deficit, severe pain, or fixed pupil.
Related medications

Medication recognition

ApixabanRivaroxabanClopidogrelWarfarin
Related EMS presentations

Continue the clinical pathway

NeurologicStroke / TIATraumaHead injuryNeurologicHeadacheEndocrine/MetabolicHypoglycemiaNeurologicNew focal neurologic deficit
References

Clinical and academic sources

Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.

BCEHS Handbook — specific CPGs

  1. A02: Patient AssessmentBC Emergency Health Services Handbook

    Official BCEHS clinical practice guidance for patient assessment.

  2. H04: Eye InjuriesBC Emergency Health Services Handbook

    Official BCEHS clinical practice guidance for eye injuries.

Supporting clinical and academic evidence

  1. CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians

    Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.

  2. WHO Medical Emergency ChecklistWorld Health Organization

    A structured emergency assessment framework intended to reduce missed life-threatening conditions.

  3. Visual symptoms in acute stroke: a systematic review of observational studiesClinical Neurology and Neurosurgery · 2023

    Visual-field loss, diplopia, ocular-motor findings, and stroke as a time-sensitive cause of acute visual symptoms.