Nail and half nail sign, seen in uremia is

Ans. is 'b' i.e. Increased capillary density at the distal half of nails Half and Half nail are characterized by a band in the midportion of the nail separating the darker distal portion from the proximal white portion. They are a common occurrence in renal failure and are seen in l/3rd patients of renal failure.Pathophysiology of Half and half nailThey are also called Lindsay's nailTheir pathogenesis is not clearly understood.Two mechanisms have been proposed.increased melanin depositionthe proximal half of the nail appears white because of the edema associated with dilated capillary network According to Oxford text book of clinical nephrology 2nd/e chapter 11.3.11. "The so called "half-and half nail" in typical of uremia the distal portion of each nail bed is red, pink or brown, occupies 20-60 percent of the total nail length, and always sharply demarcated, the proximal portion has dull whitish ground glass appearance.When pressure is applied, the discoloration does not fade completely. This change can affect single nails, or all the nails, or all the nails of the hand or feet or both. Half and half nail often begins before dialysis. It occurs in 15-50% of patients on regular dialysis.The histology of the nail plate itself shows no change and it contains no melanin, the number of capillaries under the nail plate is increased, with remarkable thickening of the capillary walls.The increase in capillary density of the nail bed might account for the band.The disorder in probably partially reversible. In some patients a lightening of the colour and a decrease in the width of the brown are have been seen after months of observation