fixed dilated pupil differential diagnosis

Raised intraocular pressure is necessary for the diagnosis of this condition, and is measured using a Tonopen. 9 Due to the elevated intraocular pressure, the eye may feel hard to the touch. Patients with acute angle closure glaucoma present with conjunctival injection and a fixed, mid-dilated pupil measuring 5-6 mm in diameter. 6 As people age, their anterior chamber becomes more shallow and the lens thickens and moves anteriorly, 5 which makes this condition rare below the age of forty, with the peak incidence occurring in the sixth and seventh decades of life. 7 Other risk factors for acute angle closure glaucoma include a family history of the condition, being of Asian descent, female gender, hyperopic eyes, eyes with shallow anterior chambers, thick lens, and narrow irido-corneal angles. Medications that dilate the pupil have the potential to precipitate an attack these include adrenergic agents, drugs with anticholingeric effects, sulfa-based drugs, tricyclic antidepressants, anticonvulsants, and antiparkinsonian drugs. 6 Patients often describe onset of ocular pain when transitioning from a light to dark environment.

When the pupil is mid-dilated, the contact between the iris and the lens is maximal and the iris thickens, which worsens pupillary block. 5 The onset is often precipitated by dilation of the pupil. 4 Nausea and vomiting occurs as a result of autonomic stimulation, while blurred vision and colored haloes are a result of corneal edema. In addition patients may present with blurred vision, frontal headache, nausea and vomiting, photophobia, and colored halos around lights. Patients with acute angle closure glaucoma present with abrupt onset of pain in the affected eye. A thorough history and physical examination with documented raised intraocular pressure is imperative for diagnosis. Clinical PresentationĪs a result of the associated systemic symptoms, acute angle closure glaucoma carries a significant risk of being incorrectly diagnosed. The Pathophysiology and Treatment of Glaucoma. With permission from Weinreb RN, Aung T, Medeiros FA. This is referred to as “pupillary block.” 3 As pressure in the posterior chamber rises, the iris is pushed further forward and causes the angle between the peripheral iris, trabecular meshwork, and cornea to close, hence the name acute angle closure glaucoma. 2 In acute angle closure glaucoma, the flow to the trabecular meshwork is blocked by contact between the lens and the iris resulting in accumulation of aqueous humor in the posterior chamber. 1 In a normal eye, the aqueous humor is produced in the posterior chamber by the ciliary process and proceeds to flow through the pupil to the anterior chamber and out through the trabecular meshwork into Schlemm’s canal. Does your differential contain acute angle closure glaucoma? What is Acute Angle Closure Glaucoma?Īcute angle closure glaucoma is a condition characterized by raised intraocular pressure due to impaired outflow of aqueous humor from the posterior chamber of the eye. A quick physical exam reveals significant conjunctival injection and a fixed, mid-dilated pupil. She reports a diffuse headache and two episodes of vomiting. Upon further questioning, she reveals reduced vision in the affected eye and colored halos around lights. Coma or brain death: Severe brain damage may cause a change in the size and reactivity of the pupils.A 62 year old woman presents to your Emergency Department with a chief complaint of severe right eye pain.Surgery: Eye surgery may result in alterations in pupil size, which can be permanent.

Seizure: Sometimes seizures (a disruption of electrical activity in the brain) can cause changes in the pupils, which may be equal or unequal.

Migraine: While it is not common, migraines can cause anisocoria.

Vision loss: Significant vision defects can affect pupil size and reactivity.Increased intracranial pressure: This can result from a brain tumor, meningitis (inflammation of the fluid around the brain), or a stroke.Trauma: An injury affecting the eye or the brain may cause the pupils to be unequal.Inflammatory conditions, such as MS and sarcoidosis, also can do this. Inflammation: An infection affecting the eye or the cranial nerves can cause anisocoria.Cranial nerve damage: This can occur due to a stroke (a blockage of blood flow or bleeding in the brain), brain aneurysm (defect in a blood vessel), or a brain tumor.Multiple sclerosis (MS): MS is a chronic neurological disorder that causes symptoms affecting vision, movement, sensation, and more.

Fixed dilated pupil differential diagnosis