Rectal ulcer due to Kayexalate deposition - an unusual case

SUMMARY Sodium polystyrene sulfonate (PSP) or Kayexalate is a cation-exchange resin, widely used in the management of hyperkalaemia due to renal disease. A rare, yet potentially dangerous, adverse event related to sodium polystyrene sulfonate use is intestinal mucosal injury, especially in the colon. The injury to the gastrointestinal mucosa can range from mild and superficial to wall necrosis and bowel perforation. The mechanism that leads to mucosal damage remains unclear. However, it is believed that sorbitol, commonly given to counteract PSP's tendency to cause constipation, may play an important role in the development of gastrointestinal injury. Other potential risk factors are uraemia or end-stage renal disease, hemodynamic instability, solid organ transplantation, postoperative status and concomitant opioid administration. The authors present a case of diarrhoea and haematochezia after the administration of PSP without sorbitol, in a patient with hyperkalaemia due to acute kidney injury, in the absence of other risk factors. A colonoscopy was performed and revealed a rectal ulcer which histological findings were suggestive of mucosal injury due to Kayexalate deposition. This case supports the concept that this widely used drug can itself, without sorbitol, cause injury to the gastrointestinal wall. Even though this is a rare adverse effect, the widespread use of this medication may put a large population at risk.

RESUMO O polistireno sulfonato de sódio (PSP) ou kayexalato é uma resina de troca iônica, amplamente usada no tratamento da hipercalemia associada à doença renal. Um efeito adverso raro, mas potencialmente grave, dessa terapêutica é a agressão à parede do trato gastrointestinal, principalmente ao nível do cólon, que pode ser ligeira e superficial ou culminar em necrose e perfuração intestinal. O mecanismo pelo qual o PSP lesa a mucosa intestinal não é totalmente conhecido. Contudo, pensa-se que o sorbitol, frequentemente administrado em simultâneo para contrabalançar o efeito obstipante do PSP, possa ter um papel preponderante no desenvolvimento de lesão gastrointestinal. Outros potenciais fatores de risco são a presença de uremia ou doença renal em estágio terminal, instabilidade hemodinâmica, pós-operatório, pós-transplante renal e a administração concomitante de opioides. Os autores descrevem um caso de diarreia e hematoquesias após a administração de PSP sem sorbitol, numa paciente com hipercalemia secundária a lesão renal aguda, sem outros fatores de risco para o desenvolvimento desse efeito adverso. A investigação etiológica com colonoscopia revelou a presença de uma úlcera retal, cujo estudo histológico foi compatível com lesão por deposição de cristais de kayexalato. Este relato incomum reforça o conceito de que este fármaco de uso frequente, mesmo na ausência de sorbitol, pode ser lesivo para a mucosa intestinal. Assim, e apesar de este ser um efeito adverso raro, a utilização difundida do PSP coloca uma vasta população em risco.

Tratamiento quirúrgico de la úlcera penetrante de aorta ascendente: casos clínicos / Penetrating ulcer of the ascending aorta treated surgically: report of two cases

Penetrating aortic ulcer (PAU) is an ulceration of an atherosclerotic plaque which disrupts the aortic internal elastic lamina and that can evolve to an intramural hematoma (IH), aortic dissection or aortic rupture. We report two cases with PAU. A 73 year-old woman with a history of hypertension, presented with acute chest pain of three days of evolution and a hypertensive emergency. An electrocardiogram showed ST-segment elevation and elevated cardiac enzymes. Computed tomography (CT) scans showed an acute ascending aortic mural hematoma secondary to PAU and hemopericardium. Replacement of ascending aorta was performed with a vascular prosthesis with extracorporeal circulation (ECC). PAU and IH were confirmed by histopathology. A 62-year old woman with a history of hypertension, diabetes and chronic obstructive pulmonary disease, consulted for abdominal pain of two days of evolution. A thoracic-abdominal CT scan visualized an uncomplicated PAU and an abdominal aortic aneurysm. Because of abdominal pain and signs of peritoneal irritation, an exploratory laparotomy was performed finding a typhlitis. Resection and ileo-ascendo-anastomosis were performed. A new CT scan showed PAU with high risk of rupture without a clinical acute aortic syndrome. The patient was operated replacing the ascending aorta with a vascular prosthesis using ECC. Three PAU were found. Histopathology confirmed the diagnosis. Both patients evolved without postoperative complications.

[Non traumatic penetrating atherosclerotic ulcer of the thoracic descending aorta without associated intramural hematoma:a case report]

Penetrating atheromatous ulcer is the condition in which ulceration of an aortic atherosclerotic lesion penetrates the internal elastic lamina into the media. Differentiation of penetrating atheromatous ulcer from other causes of acute aortic syndrome such as intramural haematoma and aortic dissection is difficult. The main symptom is a severe, acute chest pain radiating to the inter-scapular area, similar to classical acute aortic dissection of the thoracic aorta. In present article a case of a 52 years old woman with long- standing retrosternal chest pain and with penetrating atherosclerotic aortic ulcer in descending aorta was reported. Unlike the predominant picture of this disease, associated intramural hematoma was not seen