Scurvy

“Scurvy, a disease caused by a deficiency of vitamin C, affected many soldiers, North and South, during the Civil War. Scurvy’s earliest symptoms included sluggishness, depression, and muscular weakness (possibly what many doctors diagnosed as ‘debility’ or ‘debilitas‘). The patient then developed a sallow complexion, gum problems, and loose teeth [and in the next stage] skin hemorrhages began to appear. Because scurvy patients also had internal bleeding of the joints, they often suffered pains that were sometimes attributed to rheumatism. If such a patient did not receive food with vitamin C, he suffered further weakness, bleeding, damage to internal organs, and, finally, death.”
Glenna R. Schroeder-Lein. The Encyclopedia of Civil War Medicine (Armonk, New York: M.E. Sharpe, 2008), pages 271-272