An enterolith is a mineral concretion or calculus formed anywhere in the gastrointestinal system. Enteroliths are uncommon and usually incidental findings but, once found, they require at a minimum watchful waiting. If there is evidence of complications, they must be removed. An enterolith may form around a nidus, a small foreign object such as a seed, pebble, or piece of twine that serves as an irritant. In this respect, an enterolith forms by a process similar to the creation of a pearl. An enterolith is not to be confused with a gastrolith, which helps digestion. In equines
Equine enteroliths are found by walking pastures or turning over manure compost piles to find small enteroliths, during necroscopy, and increasingly, during surgery for colic. Therefore, the incidence of asymptomatic enteroliths is unknown. Equine enteroliths are typically smoothly spherical or tetrahedral, consist mostly of the mineral struvite (ammonium magnesium phosphate), and have concentric rings of mineral precipitated around a nidus.Enteroliths in horses were reported widely in the 19th century, infrequently in the early 20th century, and now increasingly. They have also been reported in zebras: five in a zoo in California and one in a zoo in Wisconsin. Struvite enteroliths are associated with elevated pH and mineral concentrations in the lumen. In California, struvite enteroliths are associated also with a high proportion of alfalfa in the feed and less access to grass pasture. This association has been attributed to the cultivation of alfalfa on serpentine soils, resulting in high concentrations of magnesium in the alfalfa.
Oslers nodes are painful, red, raised lesions found on the hands and feet. They are associated with a number of conditions, including infective endocarditis, and are caused by immune complex deposition. Their presence is one definition of Oslers sign. Causes
Oslers nodes result from the deposition of immune complexes. The resulting inflammatory response leads to swelling, redness, and pain that characterize these lesions. The nodes are commonly indicative of subacute bacterial endocarditis. 10–25% of endocarditis patients will have Oslers nodes. Other signs of endocarditis include Roths spots and Janeway lesions. The latter, which also occur on the palms and soles, can be differentiated from Oslers nodes because they are non-tender.Oslers nodes can also be seen in

Systemic lupus erythematosus
Marantic endocarditis
Disseminated gonococcal infection
Distal to infected arterial catheter

Etymology
Oslers nodes are named after Sir William Osler who described them in the early twentieth century. He described them as "ephemeral spots of a painful nodular erythema, chiefly in the skin of the hands and feet." == References ==