Lloyd's sign indicates the presence of
renal calculus or
pyelonephritis
Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications ...
when pain is elicited by deep
percussion
A percussion instrument is a musical instrument that is sounded by being struck or scraped by a percussion mallet, beater including attached or enclosed beaters or Rattle (percussion beater), rattles struck, scraped or rubbed by hand or ...
in the back between the 12th rib and the spine.
It is closely related to
costovertebral angle tenderness, as the area of percussion is the same. However, Lloyd's sign is specifically defined as positive costovertebral angle tenderness along with the absence of tenderness when normal pressure is applied.
References
Nephrology
Abdominal pain
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