Fixed dilated pupils

In overdose, the antihistamines cause convulsions, hallucinations, excitement, ataxia, incoordination, and athetosis. On exam patients may exhibit fixed, dilated pupils with a flushed face, sinus tachycardia, urinary retention, dry mouth, and fever. At high doses the patient can become comatose, which is often followed by cardiorespiratory collapse and death within 2 to 18 hours (Babe and Serafin, 1996). Treatment of overdose is mainly supportive, with efforts to manage the anti-colinergic effects. 

Dilated episcleral vessels are a clue to abnormal anastamoses between branches of the external carotid artery and orbital branches of the internal carotid artery, distal to severe internal carotid artery disease. With extreme ischemia, ischemic oculopathy may develop, with impaired visual acuity, eye pain, rubeosis of the iris (dilated blood vessels), fixed dilated pupil, low-pressure glaucoma, cataract and corneal edema. 

Respiratory depression, convulsion, coma, cyanosis, apnea, circulatory collapse, fixed dilated pupils... 

Severe/overdose sudden complete loss of vision with fixed, dilated pupils. 

Two patients in intensive care treated with infusions of large amounts of alcuronium developed fixed dilated pupils. Within 6-24 hours after stopping the infusion the pupils became normally reactive again (9). 

This is a very important and dangerous adverse effect, since the presence of fixed dilated pupils may lead to the mistaken diagnosis of brain death in coma patients if other neurological diagnostic procedures are not carried out. 

Rao U, Milligan KR. Fixed dilated pupils associated with alcuronium infusions. Anaesthesia 1993 48(10) 917. 

Acute overdosage with antimuscarinics produces both peripheral and CNS symptomatology. The quaternary ammonium compounds do not readily penetrate the CNS and thus exhibit minimal central effects even at toxic doses. Patients with anticholinergic toxicity will typically show peripheral symptoms including dry mouth, thirst, fixed dilated pupils, flushed face, fever, hot, dry, red skin, urinary retention, hyperthermia, hypotension, tachycardia, and increased respiratory rate. In addition to tachycardia, cardiac manifestations may include EKG abnormalities similar to those produced by quini-dine. Speech and swallowing may be impaired in association with blurred vision. Other peripheral signs and symptoms may include nausea and vomiting. 

Toxic effects Sedation, reduced mental alertness, apnea, cardiovascular collapse, hallucinations, tremors, seizures, dry mouth, flushed skin, and fixed, dilated pupils (reverses when drug is withdrawn)... 

Anesthesia Administer sodium pentobarbital intraperitoneaUy to mouse or rat at 60 mg/kg. Verify animal death by absence of cardiac pulse and presence of fixed/dilated pupils. Pinch animal in foot to verify absence of response. 

Most common Dry mouth (67%) drowsiness (less than 17%) transient impairment of eye accommodation including blurred vision and dilation of the pupils. Unilateral fixed and dilated pupil has been reported, apparently from accidentally touching one eye after manipulation of the patch. 

Strychnine Used in medicine and in rat poisons. Dilated pupils, terrified expression, fixed grin, weak and feeble pulse, body arches so that it rests on the head and heels, then relaxes, the body shudders and collapse results... 

Approximately 10% of untreated saccular aneurysms rebleed within hours and another 30% within a few weeks (Brilstra et al. 2002). Subsequently, the rebleeding rate is approximately 2-3% per aimum. Deterioration is usually sudden, with reduced conscious level or fixed dilatation of the pupils in ventilated patients. 

A unilateral fixed and dilated pupil in an ambulatory and otherwise healthy patient is seldom associated with a significant neurologic disorder. Yet, historically, the practitioner... 

The following sections consider the most common disorders associated with a unilateral fixed and dilated pupil, including third-nerve palsy, anticholinergic mydriasis, iris sphincter atrophy, and adrenergic mydriasis. Because a dilated pupil does not always characterize Adie s syndrome, this disorder has been discussed separately. 

If, however, the patient exhibits only a unilateral fixed and dilated pupil without evidence of ptosis or extraocular muscle involvement, the clinician should perform the pilocarpine test, first using a 0.125% solution to reveal any cholinergic hypersensitivity as evidence for Adie s pupil. If there is no local iris damage by slit-lamp examination, no sector palsy of the iris sphincter, and no cholinergic hypersensitivity demonstrated by the 0.125% pilocarpine test, then the condition might be associated with interruption of the preganglionic innervation to the iris sphincter (i.e., third-nerve palsy). If the patient has third-nerve palsy, topically instilled pilocarpine in moderate concentrations activates the muscarinic receptor sites on the iris sphincter. Therefore if 0.125% pilocarpine reveals no cholinergic hypersensitivity, the practitioner... 

Anticholinergic mydriasis, also known as pharmacologic blockade or atropinic mydriasis, refers to a fixed and dilated pupil resulting from the instillation or inoculation into the eye of drugs or substances with anticholinergic properties. Medical personnel such as doctors, nurses,... 

The practitioner should be alert to the possible inoculation into the eye of any drug or substance with anticholinergic properties, including plants, cosmetics, perfumes, or medicines. Unilateral fixed and dilated pupils have been reported after the use of antiperspi-rants, transdermal scopolamine (Transderm Scop) for the prophylaxis of motion sickness, and from direct droplet contamination associated with the use of anticholinergic aerosols for treatment of acute asthma and other airflow obstructions. 

The classic presentation of a patient with acute ACG includes complaints of eye pain, headache, blurred vision, photophobia, the perception of halos around lights, nausea, and vomiting. Clinical signs include an edematous cornea, a fixed mid-dilated pupil, ciliary injection, high lOP, convex iris (iris bombe), and cells and flare in the anterior chamber. There may also be evidence of previous episodes such as peripheral anterior synechiae, anterior subcapsular lens opacities (glaukomflecken), sector iris atrophy, an irregular pupil, and a narrow angle in the contralateral eye. 

Clinical manifestations of overdose may include either CNS depression (sedation, reduced mental alertness, apnea, and CV collapse) or CNS stimulation (insomnia, hallucinations, tremors, or convulsions). Atropine-like symptoms, such as dry mouth, flushed skiu, fixed and dilated pupils, and GI symptoms, are common, especially in children. 

Sensory systems Fixed dilatation of the pupils at the end of posterior fossa surgery has been attributed to infiltration of the scalp with bupivacaine [27 ]. 

Gadhinglajkar S, Sreedhar R, Gopal-krishnan CV. Fixed dilatation of pupils at the end of posterior fossa surgery due to bupivacaine scalp infiltration. Neurol India 2010 58 497-8. 

Nervous system Fixed, dilated, asymmetric pupils developed in two patients during continuous intravenous therapy with gamma-hydroxybutyrate, in the absence of cerebral herniation [49 ]. 

Fixed and dilated pupils not responding to bright light... 

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