A pilot study in ophthalmology of inter-rater reliability in classifying diagnostic errors: an underinvestigated area of medical error.

BACKGROUND: Misdiagnosis is the least studied form of medical error. Before effective strategies to reduce misdiagnosis can be developed, there needs to be a better understanding of the factors that lead to these errors. AIM: To evaluate the applicability and reliability of three classification systems for misdiagnosis. DESIGN: Retrospective independent analysis of five cases by clinical experts. PARTICIPANTS: Three ophthalmologists trained in ocular oncology who devote at least 75% of their practice to ocular oncology. MAIN OUTCOME MEASURES: Percentage agreement in determining cause of misdiagnosis. RESULTS: Participants agreed a misdiagnosis occurred in all cases and the error was graded as serious 14 of 15 times (93%). Inter-rater agreement for root cause varied among the three classification systems from 47% to zero. CONCLUSIONS: Although there was excellent agreement among clinical experts of what constitutes serious misdiagnosis under idealized conditions, there is not a reliable method for categorizing the primary or root cause for these errors. The origins of misdiagnosis are complex, often multifactorial, and more difficult to categorize than other types of medical error. Misdiagnosis is a professional and public healthcare challenge that will require novel strategies to enable it to be successfully studied.

Capsular bag distention syndrome after combined cataract-lens implant surgery and Ahmed valve implantation.

PURPOSE: To describe the capsular bag distention syndrome after combined cataract extraction with posterior lens implant and aqueous drainage device. METHODS: Case report. RESULTS: A persistently shallow anterior chamber and low intraocular pressure developed after combined cataract extraction with posterior chamber lens implant and Ahmed aqueous drainage device. An optically empty space between the lens implant and posterior capsule was detected 18 days after surgery. The anterior chamber deepened within minutes after Nd:YAG posterior capsulotomy. CONCLUSION: The capsular bag distention syndrome needs to be included in the differential diagnosis of shallow anterior chamber with low intraocular pressure after combined cataract extraction and glaucoma valve implant surgery.

Anatomic and histopathologic findings following a failed ahmed glaucoma valve device.

Ahmed glaucoma valve implant (AGV) is one of the more commonly used implants in difficult glaucomas. The histology of a functioning bleb following AGV implantation and its anatomic relationship to the optic nerve when placed in the superionasal quadrant has been described. We report the histology of a failed bleb and the anatomic relationship between the optic nerve and the AGV end-plate when placed 9 mm from the limbus in a patient with neovascular glaucoma.

When is surgery research? Towards an operational definition of human research.

The distinction between clinical practice and surgical research may seem trivial, but this distinction can become a complex issue when innovative surgeries are substituted for standard care without patient knowledge. Neither the novelty nor the risk of a new surgical procedure adequately defines surgical research. Some institutions tacitly allow the use of new surgical procedures in series of patients without informing individuals that they are participating in a scientific study, as long as no written protocol or hypothesis exists. Institutions can justify this practice by viewing human research in narrow terms as an activity outlined in a formal protocol. Application of limited definitions, however, erodes patients' rights and risks losing public confidence in how biomedical research is conducted. I propose an operational definition of human research also be recognised. Enforcing more rigid and less ambiguous guidelines of human research may curtail enrolment into some studies, but it will also protect patients from being used as subjects without their knowledge.

Pseudoadenomatous hyperplasia of the conjunctiva.

PURPOSE: To describe the clinical and pathologic features of three patients with pseudoadenomatous hyperplasia of the conjunctiva. DESIGN: Observational case series with clinicopathologic correlation. METHODS: Case reports and clinical histories and examination of three biopsy specimens. MAIN OUTCOME MEASURES AND RESULTS: Pseudoglandular hyperplasia of the conjunctiva was associated with chronic inflammation, including eosinophils, in two patients, and squamous epithelial hyperplasia in a third. The pseudoglands are lined by varying proportions of squamous epithelium and goblet cells. CONCLUSIONS: Pseudoglandular hyperplasia of the conjunctiva can mimic a well-differentiated mucoepidermoid carcinoma. Awareness of this entity may help to prevent misdiagnosis and unnecessary surgery.

Choroidal neovascular membranes: reproducibility of angiographic interpretation.

PURPOSE: To determine interobserver agreement for classifying choroidal neovascular membranes in age-related macular degeneration. METHODS: Six fluorescein angiograms of choroidal neovascular membranes were interpreted by 21 retina specialists. Reliability was measured by percent agreement and kappa coefficient. RESULTS: Interobserver agreement of membrane types ranged from perfect concordance for a small, classic membrane to near-random classification for a complex pattern. Mean kappa coefficient was.64. Interobserver agreement of membrane size was most variable for intermediate size lesions (mean kappa coefficient =.40). CONCLUSION: Fluorescein angiographic interpretation of choroidal neovascular membrane type and size can vary considerably. Interobserver agreement is better for membrane type than for membrane size.

Pathologic findings in late endophthalmitis after glaucoma filtering surgery.

OBJECTIVE: To report the clinicopathologic features of four eyes enucleated for late-onset bleb-related endophthalmitis. STUDY DESIGN: Retrospective case series. MATERIALS: Four enucleated eyes. METHODS: The clinical and histopathologic features of four patients who underwent enucleation for late-onset endophthalmitis after glaucoma filtering surgery were reviewed. RESULTS: The eyes were enucleated for endophthalmitis one to five years after trabeculectomy. Two of the four eyes had trabeculectomy with adjunctive mitomycin-C. All four eyes had streptococci cultured from the aqueous and/or vitreous. Common pathologic features included inflammation involving the anterior segment, lens and choroid. One eye exhibited focal granulomatous uveitis. CONCLUSIONS: Late-onset endophthalmitis after glaucoma filtering surgery is often due to streptococcal species and rapidly progresses over a few days. Phacoanaphylaxis with associated granulomatous uveitis may contribute to the poor prognosis in this setting.

Comparison of different biomaterials for glaucoma drainage devices: part 2.

BACKGROUND: Inflammation associated with biomaterials may contribute to the failure of glaucoma drainage devices. OBJECTIVE: To compare the inflammatory reaction associated with the insertion of Krupin silicone, Molteno polypropylene, and Acrosof end plates in the subconjunctival space of rabbits. METHODS: Similar-sized glaucoma end plates made of 3 different biomaterials were sutured to the sclera in the superotemporal quadrant of the rabbit eye. Thirty eyes of 15 albino New Zealand rabbits were randomly assigned to the 3 groups. Conjunctival vascular hyperemia was graded in a masked fashion among the 3 groups. At the end of 3 weeks, the enucleated eyes were examined histologically and by scanning electron microscopy. RESULTS: Molteno polypropylene was associated with more inflammation both in clinical observations and based on histological grading. Silicone and Acrosof were associated with less intense inflammation. One polypropylene end plate was extruded on day 21. CONCLUSIONS: Polypropylene appears to be more inflammatory than silicone. Flexible biomaterials appear to be less inflammatory than rigid ones. CLINICAL RELEVANCE: Bleb failure following glaucoma drainage device implantation could be related to the biomaterial-associated inflammation. Choosing a biomaterial with the least inflammatory potential might enhance the success rate of the glaucoma drainage device. Arch Ophthalmol. 2000;118:1081-1084

Mycobacterium chelonae conjunctivitis and scleritis following vitrectomy.

The atypical, or nontuberculous, mycobacteria are opportunistic pathogens that usually cause infection following accidental trauma or surgery. These organisms are ubiquitous in nature but have been found with increasing frequency in other environments that include medical offices and surgical suites. Management of atypical mycobacterial ocular infections can be difficult because in vitro antibiotic activity does not always correlate with in vivo efficacy and because normal immune defenses against mycobacteria may work too slowly to prevent irreversible damage to infected ocular tissues. This report describes a patient who developed a severe ocular infection due to Mycobacterium chelonae after vitrectomy. Despite eradication of the infection, the eye became blind and painful. Arch Ophthalmol. 2000;118:1125-1128

Primary malignancies of the thyroid: epidemiologic analysis of the Florida Cancer Data System registry.

PURPOSE: Descriptive epidemiology of thyroid cancer in Florida. METHODS: The Florida Cancer Data System (FCDS) registry was used to identify patients with the different histologic subtypes of thyroid cancer occurring in Florida from 1981 through 1993. RESULTS: The FCDS recorded 5746 primary malignancies of the thyroid. The average annual incidence of all types of thyroid cancer was 37.0 cases/1,000,000 population. One type of thyroid cancer (papillary carcinoma) accounted for the overall increase during the 13 years of this study. There was no difference in incidence based on Hispanic ethnicity, but the incidence in Blacks was half that of Whites, and Blacks showed less advanced disease at the time of diagnosis. CONCLUSIONS: The increase in incidence of only one histologic type of thyroid cancer suggests that the increasing rate is not an artifact related to the utilization of new diagnostic technologies. The lower incidence and tendency to have less advanced thyroid cancer in Blacks would indicate that racial differences in thyroid cancer are not likely explained by socioeconomic factors such as access to medical care. A substantial amount of the difference in incidence between Whites and Blacks is explained by differences in age distribution.

Eyelid tumors: accuracy of clinical diagnosis.

PURPOSE: To determine the accuracy, specificity, and sensitivity of the clinical diagnosis of malignant tumor of the eyelid. METHOD: Analysis of consecutively submitted biopsy specimens of the eyelid for 1 year to a regional ophthalmic pathology laboratory. RESULTS: Agreement was noted between clinical and histopathologic diagnoses on 72 (84%) of 86 eyelid biopsy specimens received over 12 months. Ten (11.6%) clinical diagnoses of suspected malignant eyelid tumor showed benign skin conditions, and four (4.6%) clinical diagnoses of presumed benign conditions proved to be malignant. CONCLUSIONS: The clinical assessment of eyelid malignancy by ophthalmologists is reasonably good when evaluated in terms of sensitivity (87.5%) and specificity (81.5%) of diagnosis. Lesions giving rise to the false-negative diagnosis of malignancy tend to be nodules with unremarkable surface features.

Indeterminate melanocytic proliferations of the conjunctiva.

OBJECTIVE: To test the hypothesis that a subset of conjunctival melanocytic proliferations exists that cannot be reproducibly classified as benign, malignant, or indeterminate. METHODS: Three groups of excisional biopsy specimens of conjunctival melanocytic proliferations were evaluated by a panel of 5 ophthalmic pathologists. These groups included lesions that we considered to represent benign (group 1 [n = 5]), malignant (group 2 [n = 5]), and indeterminate melanocytic proliferations (group 3 [n = 5]). The panel classified the same sections in all 3 groups in a randomized, masked fashion, first without and then with a clinical history of patient age, sex, and race. The kappa statistic was used to quantify the degree of agreement among observers. RESULTS: There was strong concordance among the panel members for both group 1 (benign [kappa = 0.76]) and group 2 (malignant [kappa = 0.70]) melanocytic proliferations. There was no concordance of the panel for group 3 (indeterminate) lesions (kappa = -0.045). The concordance for groups 1 and 2 and lack of concordance for group 3 lesions were independent of knowledge of clinical history of age, sex, and race. CONCLUSION: A subset of melanocytic proliferations of the conjunctiva exists that cannot be reproducibly classified by pathologists as benign, malignant, or indeterminate.

A pseudoepidemic of postoperative scleritis due to misdiagnosis.

OBJECTIVE: To describe a pseudoepidemic of infectious scleritis following eye surgery. METHODS: Retrospective cohort study with selected procedural and laboratory investigations. RESULTS: Twenty-one patients with postoperative scleritis were identified during a 2-month outbreak. Neither an infectious etiology nor a causative pre-, intra-, or postoperative exposure was found. The clinical findings, when carefully reviewed, were consistent with poor surgical-wound closure. CONCLUSIONS: The art of clinical diagnosis involves the subjective interpretation of clinical history, physical findings, and laboratory results. A repeated error in the interpretation of clinical findings can simulate an outbreak of disease. Clinicians may be reluctant to concede misdiagnosis.

The placebo effect.

Placebos have been traditionally regarded as deceptive therapies and have not been understood in the broader context of social symbols and of interpersonal factors that surround the healing process itself. Although the power of inert substances to heal is well recognized, the placebo effect also influences the outcome of conventional therapies. The role of the placebo in modern medicine is poorly defined because of a lack of a common understanding of what the placebo effect is and because of the negative connotions associated with its use. The response rate to placebo varies by illness. The natural course of disease and patient or physician bias can be misinterpreted as a placebo response. In research, the placebo effect is therapeutic noise to be removed by placebo-controlled trials. Few studies are designed to measure the placebo response rate directly. Placebos are a reminder of how little is known about mind-body interaction. The placebo effect may be one of the most versatile and underused therapeutic tools at the disposal of physicians.

Adverse periocular reaction after blood transfusion.

PURPOSE: To describe a patient with an acute conjunctival and periocular reaction after blood transfusion. METHODS: Case report and literature review. RESULTS: A 67-year-old woman sustained a self-limited periocular reaction characterized by bilateral turgescence and redness of the conjunctiva and eyelids after blood transfusion. More than 100 similar reactions of this type have been reported by the Centers for Disease Control and Prevention. CONCLUSIONS: The cause of this periocular transfusion reaction is unclear, but this type of reaction is being investigated by the Centers for Disease Control and Prevention. This case suggests that mild transfusion complications, even if unusual, may be under-reported.

Comparison of different biomaterials for glaucoma drainage devices.

OBJECTIVES: To compare the inflammatory reaction associated with the insertion of silicone and polypropylene endplates and endplates made of a new biocompatible polymer, Vivathane, in the rabbit subconjunctival space. METHODS: Similar-sized endplates made of 3 different biomaterials were sutured to the sclera in the superotemporal quadrant of the rabbit eye. Thirty eyes of 15 albino New Zealand rabbits were randomly assigned to the 3 groups. Conjunctival vascular hyperemia was graded in a masked fashion among groups. At the end of 3 weeks, the enucleated eyes were examined histologically and using scanning electron microscopy. RESULTS: Polypropylene and Vivathane were associated with significantly more inflammation in clinical observations and based on histological grading. Silicone was associated with the least amount of inflammation. Three polypropylene and 1 Vivathane plate were extruded between the second and third week. CONCLUSIONS: Silicone is the most inert of the 3 materials tested. Inflammation associated with biomaterials may contribute to the failure of the glaucoma drainage devices. CLINICAL RELEVANCE: Bleb inflammation may be related to the biomaterial being used as the endplate. Endplates should be handled carefully during surgery to avoid creating rough spots.

Eyes removed for primary ulcerative keratitis with endophthalmitis: microbial and histologic findings.

OBJECTIVES: To study the microbiological and histological findings in patients whose eyes are removed for primary ulcerative keratitis with suppurative endophthalmitis. METHODS: Survey of consecutive cases of ulcerative keratitis with histologically defined endophthalmitis treated by enucleation or evisceration. RESULTS: Eighteen cases of ulcerative keratitis with suppurative endophthalmitis were identified. Thirteen corneal ulcers were culture positive (72%). Microorganism were found in histologic sections of the anterior segment of 9 eyes (50%), but no microorganisms were identified in the vitreous. Two eyes (11%) had culture-positive endophthalmitis. Half of the patients in this study who had undergone elective intraocular surgery had done so within 4 months of enucleation. CONCLUSIONS: Considerable vitreous inflammation can occur with microbial keratitis in the absence of histologically demonstrable microorganisms in the vitreous. Microbial keratitis associated with suppurative endophthalmitis is usually caused by virulent organisms. The factors that contributed to the spread of purulent inflammation inside the eye could not be assessed in this morphologic study because of the lack of clinical data.