Muehrcke's nails


Muehrcke's nails or Muehrcke's lines are changes in the fingernail that may be a sign of an underlying medical condition. The term refers to a set of one or more pale transverse bands extending all the way across the nail, parallel to the lunula. In contrast to Beau's lines, they are not grooved, and in contrast to Mees' lines, the thumb is usually not involved.
Muehrcke's lines are a strong indicator of hypoalbuminemia, which can result from a variety of different causes.
The lines are actually in the vascular bed underneath the nail plate. As such, they do not move with nail growth, and disappear when pressure is applied to the nail : this distinguishes them from "true leukonychia striata" such as Mees' lines. As in Terry's and half-and-half nails, the pattern is thought to be formed by bands of localized edema exerting pressure on the surrounding capillaries.

Physiology

The appearance of Muehrcke's lines is associated specifically with marked hypoalbuminemia indicating decreased protein synthesis, which may occur during periods of metabolic stress, or in hypoalbuminemic states such as the nephrotic syndrome or dietary protein deficiency. They are also seen in patients with end-stage kidney disease on hemodialysis, Hodgkin's disease, pellagra, and sickle cell anaemia.
The lines remain visible as long as protein intake is inadequate or synthesis is impaired, and they should disappear upon return to normal function.
In extreme conditions, Muehrcke's lines may also arise from physical changes in peripheral circulation: one case study reported appearance of the lines in a healthy subject following ascent to 8,848 meters on Mount Everest.

History

Muehrcke's lines were described by American physician Robert C. Muehrcke in 1956. In a study published in BMJ, he examined patients with known chronic hypoalbuminemia and healthy volunteers, finding that the appearance of multiple transverse white lines was a highly specific marker for low serum albumin, was associated with severity of the underlying condition, and disappeared upon successful treatment or direct infusion of HSA.