RESUMO
Resumen La lesión de la mucosa asociada a cristales es un cuadro clínico importante en un subconjunto de pacientes urémicos a los que se les administran resinas de intercambio catiónico como el sulfonato de poliestireno sódico (Kayexalate) y sevelamer para el tratamiento de la hiperpotasemia y la hiperfosfatemia, respectivamente. La necrosis colónica en estos pacientes es rara, pero puede estar asociada a una lesión gastrointestinal mortal, con una tasa de mortalidad del 33%. Los secuestrantes de ácidos biliares son otro tipo de resina que teóricamente son biológicamente inertes. Se presentan dos casos de colitis asociada a cristales. El primer paciente tenía antecedentes de múltiples intervenciones quirúrgicas y patologías del tracto gastrointestinal, y estaba en manejo con colestiramina. Se realizó una sigmoidectomía en la que se encontraron varios focos de cristales. El segundo paciente tenía antecedente de enfermedad renal crónica que requirió el uso de Kayexalate y se presentó al servicio de urgencias con una hemorragia grave del tracto gastrointestinal inferior. Se realizó una colectomía parcial en la que se detectaron cambios morfológicos relacionados con el depósito de cristales. Las resinas pueden producir un amplio espectro de lesiones mortales de la mucosa, por lo que el diagnóstico precoz es fundamental para disminuir la mortalidad y mejorar el pronóstico. Sin embargo, es incierto si el consumo de colestiramina y Kayexalate, así como el depósito de sus cristales en el tracto gastrointestinal son el factor causal de la lesión de las mucosas. Por tanto, la presencia de resinas debería ayudar a establecer el diagnóstico correcto y el tratamiento médico oportuno para evitar resultados nocivos.
Abstract Crystal-associated mucosal injury is a crucial clinical picture in a subset of uremic patients who are given cation exchange resins such as sodium polystyrene sulfonate (Kayexalate) and sevelamer to treat hyperkalemia and hyperphosphatemia, respectively. Colonic necrosis in these patients is rare but may be associated with fatal gastrointestinal injury, with a mortality rate of 33%. Bile acid sequestrants are another type of resin that is theoretically biologically inert. Two cases of colitis associated with crystals are presented. The first patient had a history of multiple surgeries and pathologies of the gastrointestinal tract and was treated with cholestyramine. A sigmoidectomy was performed in which several crystal foci were found. The second patient had a history of chronic kidney disease requiring Kayexalate and attended the emergency department with severe lower GI bleeding. A partial colectomy was performed in which morphological changes related to the deposit of crystals were detected. Resins can cause a broad spectrum of malignant mucosal lesions, so early diagnosis is essential to reduce mortality and improve prognosis. However, it is uncertain whether the consumption of cholestyramine and kayexalate, as well as the deposition of their crystals in the GI tract, are the causative factor of mucosal damage. Therefore, resins should help establish the correct diagnosis and prompt medical treatment to avoid harmful results.
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Bile-acid diarrhoea(BAD)is a common cause of chronic diarrhoea,resulting from the excess amounts of bile acids enter the colon.The understanding of people about the cause of this diarrhea is still relatively limited for a variety of reasons.Clin-ically,75SeHCAT is the first-line diagnostic test,Other diagnostic tests including the measurement of serum 7α-hydroxy-4-cholesten-3-one(C4)、serum fibroblast growth factor 19(FGF19)、fecal bile acids and the empirical treatment of bile acid sequestrants(BAS). First-line treatment is with BAS for BAD,primarily cholestyramine,Newer BAS such as colestipol and colesevelam have fewer side effects. Obeticholic acid(OCA),as a new drug,maybe have a significant future.This article gives an overview on the etiology,pathogen-esis、diagnosis and treatment progress of BAD.
RESUMO
Chronic diarrhea is usually associated with a number of non-infectious causes. When definitive treatment is unavailable, symptomatic drug therapy is indicated. Pharmacologic agents for chronic diarrhea include loperamide, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, diosmectite, cholestyramine, probiotics, antispasmodics, rifaximin, and anti-inflammatory agents. Loperamide, a synthetic opiate agonist, decreases peristaltic activity and inhibits secretion, resulting in the reduction of fluid and electrolyte loss and an increase in stool consistency. Cholestyramine is a bile acid sequestrant that is generally considered as the first-line treatment for bile acid diarrhea. 5-HT3 receptor antagonists have significant benefits in patients with irritable bowel syndrome (IBS) with diarrhea. Ramosetron improves stool consistency as well as global IBS symptoms. Probiotics may have a role in the prevention of antibiotic-associated diarrhea. However, data on the role of probiotics in the treatment of chronic diarrhea are lacking. Diosmectite, an absorbent, can be used for the treatment of chronic functional diarrhea, radiation-induced diarrhea, and chemotherapy-induced diarrhea. Antispasmodics including alverine citrate, mebeverine, otilonium bromide, and pinaverium bromide are used for relieving diarrheal symptoms and abdominal pain. Rifaximin can be effective for chronic diarrhea associated with IBS and small intestinal bacterial overgrowth. Budesonide is effective in both lymphocytic colitis and collagenous colitis. The efficacy of mesalazine in microscopic colitis is weak or remains uncertain. Considering their mechanisms of action, these agents should be prescribed properly.