From the Guidelines
When evaluating a patient with a chronic left blown pupil, I would first ask about the onset and duration of the pupillary abnormality, any associated symptoms like headache, vision changes, or eye pain, and any history of trauma, surgery, or neurological conditions, as recommended by the most recent guidelines 1. The patient's medical history, including hypertension, diabetes, stroke, or aneurysm, is crucial in determining the potential cause of the blown pupil.
- A detailed medical and ocular history should include specific questions about patient symptoms, speed of onset of the strabismus, and possible associated unilateral or bilateral ptosis or other neurologic symptoms, such as ataxia, tremor, hemiplegia, sixth nerve or fourth nerve palsy, and noted pupillary asymmetry, and vision loss, as outlined in the adult strabismus preferred practice pattern 1.
- For the physical examination, I would assess visual acuity in both eyes and perform a complete cranial nerve examination, paying special attention to extraocular movements and other signs of oculomotor nerve dysfunction, as suggested by the guidelines 1.
- I would examine both pupils for size, shape, and reactivity to light (direct and consensual responses), and perform a swinging flashlight test to check for an afferent pupillary defect, which is essential in evaluating the patient's condition 1.
- Fundoscopic examination should be done to evaluate the optic disc and retina, and blood pressure measurement is essential, as recommended by the guidelines 1.
- A complete neurological examination, including mental status, motor, sensory, and cerebellar testing, should be performed to rule out any underlying neurological conditions, as outlined in the adult strabismus preferred practice pattern 1. The chronic nature of the blown pupil suggests that it may be physiologic anisocoria, Adie's tonic pupil, or previous oculomotor nerve damage, but it's crucial to rule out ongoing compression from aneurysm or mass lesion, especially if there are any accompanying neurological deficits, as emphasized by the most recent guidelines 1.
From the Research
Questions to Ask
- What is the patient's medical history, including any previous instances of head trauma or neurological conditions?
- Are there any symptoms accompanying the blown pupil, such as diplopia, ptosis, or headache?
- How long has the patient been experiencing the blown pupil, and has it been constant or intermittent?
Physical Exam Examination
- Assess the patient's cranial nerves, particularly the third cranial nerve, which controls eye movement and pupil size
- Check for signs of ptosis, diplopia, or limited eye movement
- Evaluate the patient's pupillary response to light and accommodation
- Perform a thorough neurological examination to identify any other potential deficits
Potential Causes
- Aneurysm compression of the third cranial nerve, as seen in cases of posterior communicating artery aneurysm 2, 3
- Traumatic brain injury, which can cause third cranial nerve palsy through various mechanisms, including direct shearing injury, traction injury, or vascular compression 4
- Systemic lupus erythematosus, which can cause isolated third cranial nerve palsy 5
- Carotico-cavernous aneurysm, which can cause pupil-sparing painful oculomotor neuropathy 6