Duration: 10 Minutes (2 minutes reading time + 8 minutes performance)
Location: General Practice / Outpatient Clinic
Learning Objectives
- Physical Examination: Conduct a focused assessment of the cranial nerves (specifically II, III, IV, and VI).
- Clinical Reasoning: Differentiate between nerve palsies based on physical findings.
- Communication: Explain clinical findings and the next steps in management using patient-centered language.
Patient Profile
- Name: Mr. David Miller
- Age: 58 years old
- Ethnicity: Caucasian
- Occupation: Accountant
- Social History: Smoker (10/day for 30 years), lives with wife, sedentary lifestyle.
Presenting Complaint
Mr. Miller presents with a 24-hour history of “seeing double” (diplopia) and a slightly droopy right eyelid. He denies any trauma or recent illness.
Contextual Information
- History of Presenting Complaint (HPC): Double vision is worse when looking to the left. It disappears when he closes one eye.
- Past Medical History (PMH): Type 2 Diabetes (diagnosed 10 years ago, poorly controlled), Hypertension.
- Medications: Metformin 1g BD, Ramipril 10mg OD.
- Allergies: Nil.
Exam Instructions
Candidate Instructions:
- Take a brief, focused history regarding the double vision.
- Perform a focused neurological examination of the relevant cranial nerves.
- Explain your findings and your preliminary diagnosis to the patient.
- Outline the immediate management plan.
Standardised Patient (SP) Instructions:
- Demeanor: You are anxious but cooperative. You are worried you might be having a stroke.
- The Symptom: If asked, the double vision is “side-by-side” (horizontal). It goes away if you cover either eye.
- The Exam: * When the candidate performs the “H-test,” your right eye stays “stuck” in the middle when you try to look toward your nose (adduction).
- Your right eyelid is drooping (ptosis), but your pupil is normal size and reacts to light.
- Key Question: “Doctor, is this a stroke? Am I going to lose my sight?”
Examiner Checklist Items:
- Introduces self and gains informed consent.
- Assesses visual acuity (CN II) and pupils.
- Performs the “H-shape” test for extraocular movements (CN III, IV, VI).
- Identifies the combination of ptosis and limited adduction/elevation.
- Correctly identifies a Pupil-Sparing Third Nerve Palsy (likely diabetic mononeuropathy).
- Communicates the need for urgent specialist referral/imaging.
Key Clinical Findings
| Feature | Finding | Clinical Significance |
| Vital Signs | BP 155/95, HR 82, Temp 36.8°C | Chronic hypertension noted. |
| Visual Acuity | 6/6 Bilaterally (with glasses) | CN II is intact. |
| Pupils | Equal, round, reactive to light (PERRLA) | Crucial: Suggests a medical (ischemic) cause rather than a surgical (aneurysm) cause. |
| Ptosis | Present on the right side (partial) | Suggests CN III involvement. |
| Eye Movement | Right eye cannot move medially, up, or down | CN III Palsy. |
Communication Triggers (Murtagh’s Approach)
- Open-Ended Opening: “Mr. Miller, I understand you’ve been having some trouble with your vision. Can you tell me more about that in your own words?”
- Clarification: “When you see double, are the two images side-by-side or one on top of the other?”
- Empathy: “I can see you’re worried about a stroke; we are going to do a thorough check to see exactly what’s happening.”
- Lay Language: Instead of “Ptosis,” use “drooping of the eyelid.” Instead of “Adduction deficit,” use “difficulty moving the eye toward the nose.”
Assessment & Marking Guide
| Domain | Competency |
| History Taking | Explores onset, nature of diplopia (monocular vs binocular), and vascular risk factors. |
| Physical Exam | Systematic CN exam. Correct “H-test” technique. Checks for pupil involvement. |
| Clinical Logic | Correctly identifies the 3rd nerve as the culprit. Notes “pupil sparing.” |
| Management | Orders BSL/HbA1c. Refers to Ophthalmology/Neurology for urgent review. |
| Professionalism | Maintains eye contact, addresses patient anxiety, and ensures patient comfort. |
Sample Answers / Model Performance
Suggested History Questions:
- “Does the double vision go away if you cover one eye?” (Differentiates ocular vs. neurological causes).
- “Have you had any headaches or pain behind the eye?” (Red flag for aneurysm).
- “How has your blood sugar been lately?”
Explaining the Diagnosis:
“Mr. Miller, based on the exam, the nerve that controls your eye muscles—the Third Cranial Nerve—isn’t working properly. This is causing the eyelid to droop and the double vision. In patients with diabetes, this is often caused by a lack of blood flow to that specific nerve. The good news is that your pupil is reacting normally, which makes a serious brain bleed or aneurysm less likely, but we still need to act quickly. I’m going to refer you to a specialist today for further scans to be absolutely sure.”