Significant difference between three observers in the assessment of intraepidermal nerve fiber density in skin biopsy

<p>Abstract</p> <p>Background</p> <p>The determination of Intraepidermal Nerve Fiber Density (IENFD) in skin biopsy is a useful method for the evaluation of different types of peripheral neuropathies. To allow a reliable use of the method it is necessary to determine interobserver reliability. Previous studies dealing with this topic used limited suitable statistical methods.</p> <p>Methods</p> <p>In the present study three observers determined the IENFD and estimated the staining quality of the basement membrane for an adequate quantity of 120 skin biopsies (stained with indirect immunofluorescence technique) from 68 patients. More adequate statistical methods like intraclass correlation coefficient and Bland Altman Plot were chosen to estimate interobserver reliability.</p> <p>Results</p> <p>We found an unexpected significant difference in IENFD between the observers (p < 0.05) and so the results of this study are not in line with the high interobserver reliability reported before (intraclass correlation coefficient: 0.73). The Bland Altmann Plot showed a variance growing with rising mean. The difference in IENFD between the observers and the resulting low interobserver reliability is likely caused by different interpretations of the standard counting rules. There was no significant difference in IENFD between observers for biopsies with a well-defined basement membrane. Thus skin biopsies with an inexactly defined basement membrane should not be used diagnostically for the determination of IENFD.</p> <p>Conclusion</p> <p>These results emphasise that standardisation of the method is extremely important and at least two observers should analyse skin biopsies with critical IENFD near the cut-off values.</p

Interrater Reliabilität der intraepidermalen Nervenfaserdichte Bestimmung in einer Hautbiopsie

Die Bestimmung der IENFD ist eine neue Methode zur Diagnostik peripherer Neuropathien. Um einen sicheren Einsatz zu gewährleisten ist eine ausreichende Interrater Reliabilität zu fordern. Im Rahmen der vorliegenden Arbeit wurden 120 Hautbiopsien ausgewertet. Drei Untersucher bestimmten die IENFD. Die Ergebnisse dieser Arbeit zeigten einen signifikanten Unterschied zwischen den IENFD Werten. Für die Interrater Reliabilität ergab sich ein ICC von 0,73. Der signifikante Unterschied und die niedrige Interrater Reliabilität sind am ehesten auf eine unterschiedliche Interpretation der Auszählregeln zurückzuführen. Eine Standardisierung der Methode ist unbedingt erforderlich, um diagnostische Sicherheit der IENFD Bestimmung in einer Hautbiopsie zu verbessern

Recurrent Strokes due to Transient Vasospasms of the Extracranial Internal Carotid Artery

Vasospasms of the intracranial arteries are a well-known complication of subarachnoid hemorrhage and are also frequently encountered in other disorders such as migraine, cerebral vasculitis or reversible cerebral vasoconstriction syndrome. In contrast, recurrent spontaneous vasospasms of the extracranial circulation appear to be extremely rare and have most often been associated with migraine. We present a patient with recurrent strokes due to spontaneous transient vasospastic occlusions of the internal carotid artery (ICA) without migraine over a time period of at least 13 years. Initially, the patient had presented with a bilateral ICA occlusion and a cerebral infarct on the right side. While the right ICA remained occluded, a reopening of the left ICA could be detected 3 days after this initial event. In subsequent years, both duplex sonography and magnetic resonance angiography revealed recurrent occlusions of the left ICA, which resolved spontaneously within days. This case and other rare previous reports indicate that recurrent non-migrainous vasospasms of the extracranial carotid artery likely reflect a distinct entity which can cause ischemic strokes