Misdiagnosis of Third Nerve Palsy.

BACKGROUND: This study identifies the diagnostic errors leading to misdiagnosis of 3rd nerve palsy and to aid clinicians in making this diagnosis. The objective of this article is to determine the incidence of misdiagnosis of 3rd cranial nerve palsy (3rd nerve palsy) among providers referring to a tertiary care neuro-ophthalmology clinic and to characterize diagnostic errors that led to an incorrect diagnosis. METHODS: This was a retrospective clinic-based multicenter cross-sectional study of office encounters at 2 institutions from January 1, 2014, to January 1, 2017. All encounters with scheduling comments containing variations of "3rd nerve palsy" were reviewed. Patients with a documented referral diagnosis of new 3rd nerve palsy were included in the study. Examination findings, including extraocular movement examination, external lid examination, and pupil examination, were collected. The final diagnosis was determined by a neuro-ophthalmologist. The Diagnosis Error Evaluation and Research (DEER) taxonomy tool was used to categorize the causes of misdiagnosis. Seventy-eight patients referred were for a new diagnosis of 3rd nerve palsy. The main outcome measure was the type of diagnostic error that led to incorrect diagnoses using the DEER criteria as determined by 2 independent reviewers. Secondary outcomes were rates of misdiagnosis, misdiagnosis rate by referring specialty, and examination findings associated with incorrect diagnoses. RESULTS: Of 78 patients referred with a suspected diagnosis of 3rd nerve palsy, 21.8% were determined to have an alternate diagnosis. The most common error in misdiagnosed cases was failure to correctly interpret the physical examination. Ophthalmologists were the most common referring provider for 3rd nerve palsy, and optometrists had the highest overdiagnosis rate of 3rd nerve palsy. CONCLUSIONS: Misdiagnosis of 3rd nerve palsy was common. Performance and interpretation of the physical examination were the most common factors leading to misdiagnosis of 3rd nerve palsy.

Failure to Obtain Urgent Arterial Imaging in Acute Third Nerve Palsies.

BACKGROUND: Isolated third nerve palsy may indicate an expanding posterior communicating artery aneurysm, thus necessitating urgent arterial imaging. This study aims to assess the rate and duration of delays in arterial imaging for new isolated third nerve palsies, identify potential causes of delay, and evaluate instances of delay-related patient harm. METHODS: In this cross-sectional study, we retrospectively reviewed 110 patient charts (aged 18 years and older) seen between November 2012 and June 2020 at the neuro-ophthalmology clinic and by the inpatient ophthalmology consultation service at a tertiary institution. All patients were referred for suspicion of or had a final diagnosis of third nerve palsy. Demographics, referral encounter details, physical examination findings, final diagnoses, timing of arterial imaging, etiologies of third nerve palsy, and details of patient harm were collected. RESULTS: Of the 110 included patients, 62 (56.4%) were women, 88 (80%) were white, and the mean age was 61.8 ± 14.6 years. Forty (36.4%) patients received arterial imaging urgently. Patients suspected of third nerve palsy were not more likely to be sent for urgent evaluation (P = 0.29) or arterial imaging (P = 0.082) than patients in whom the referring doctor did not suspect palsy. Seventy-eight of 95 (82%) patients with a final diagnosis of third nerve palsy were correctly identified by referring providers. Of the 20 patients without any arterial imaging before neuro-ophthalmology consultation, there was a median delay of 24 days from symptom onset to imaging, and a median delay of 12.5 days between first medical contact for their symptoms and imaging. One patient was harmed as a result of delayed imaging. CONCLUSIONS: Third nerve palsies were typically identified correctly, but referring providers failed to recognize the urgency of arterial imaging to rule out an aneurysmal etiology. Raising awareness of the urgency of arterial imaging may improve patient safety.

Optimizing the antisepsis protocol: Effectiveness of 3 povidone-iodine 1.0% applications versus a single application of povidone-iodine 5.0.

PURPOSE: To determine the minimum effective concentration of povidone-iodine that reduces the bacterial load by 3-log10, the U.S. Food and Drug Administration requirement for antiseptic agents, and to study alternative dosing schedules of povidone-iodine to optimize its bactericidal effect. SETTING: Microbiology Laboratory, Evanston Hospital, Evanston, Illinois, USA. DESIGN: Experimental study. METHODS: A standard 0.5 McFarland solution of Staphylococcus epidermidis was applied to blood agar plates. The plates were treated with a single application of povidone-iodine solutions from 10.0% to 0.1% to define the range of interest. Another set of plates received 3 applications of various povidone-iodine solutions. Microbial growth was evaluated after 24 hours. Standard deviations with 99.0% and 99.9% confidence intervals for each concentration were estimated and used to estimate the minimum concentration that reduced the colony counts by at least 3-log10. RESULTS: Povidone-iodine at 2.5% and higher concentrations was effective in eliminating S epidermidis with a single application. Three 30-second applications of povidone-iodine at concentrations of 0.7% and higher resulted in at least a 3-log10 reduction of colonies. CONCLUSIONS: Povidone-iodine 5.0% has been the standard of care for preoperative ocular antisepsis for 3 decades. Povidone-iodine 0.7% was as effective as a bactericidal agent when applied multiple times. This suggests povidone-iodine 1.0%, applied in three 30-second applications for preoperative surface disinfection might be as effective for preoperative antisepsis.