Question 836
{"accessible":true,"alternatives":[{"id":4229,"text":"congenital cystinuria"},{"id":4230,"text":"hyperparathyroidism"},{"id":4231,"text":"medication with loop diuretics"},{"id":4232,"text":"poorly controlled gout"},{"id":4233,"text":"repeated/chronic infection"}],"archived":false,"correctAlternativeId":4233,"explanation":"\u003cp\u003eThis is the classical appearance of a \u003ca href=\"/articles/staghorn-calculus-kidney\" title=\"Staghorn calculus (kidney)\"\u003estaghorn calculus\u003c/a\u003e which are composed of struvite (MAP, magnesium ammonium phosphate) and are usually seen in the setting of recurrent urinary tract infection with urease-producing bacteria (e.g. Proteus, Klebsiella, Pseudomonas and Enterobacter). Urease hydrolyzes urea to ammonium and increase in the urinary pH.\u003c/p\u003e\u003cp\u003eStruvite accounts for approximately 70% of the composition of these calculi, and is usually mixed with calcium phosphate thus rendering them opaque on both plain films and CT. Uric acid and cystine are the underlying component of a minority of these calculi.\u003c/p\u003e","id":836,"imageUrl":"https://prod-images-static.radiopaedia.org/images/454730/65eb2b5abfa9feb14b427542b9ec5f_big_gallery.jpg","imageAttribution":{"kind":"case","rID":9733},"imageAttributionCaseInfo":{"title":"Staghorn calculus","contributor_name":"Natalie Yang","contributor_param":"yangnatalie","case_rid":9733,"case_param":"staghorn-calculus"},"firstQuestionPath":"/questions/2641","nextQuestionPath":"/articles/urolithiasis/questions/835","relatedArticles":[{"id":49825,"title":"Renal tract calculi (summary)","link":"/articles/renal-tract-calculi-summary?lang=us"},{"id":9910,"title":"Staghorn calculus (kidney)","link":"/articles/staghorn-calculus-kidney?lang=us"}],"alsoUsedIn":[{"id":149,"kind":"RestrictedPage","title":"Page 149 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/149"}],"stem":"\u003cp\u003eWhat is the most likely underlying cause of this renal stone?\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/836"}],"attemptsPercentages":[{"alternativeId":"4229","percentage":13},{"alternativeId":"4230","percentage":17},{"alternativeId":"4232","percentage":5},{"alternativeId":"4231","percentage":3},{"alternativeId":"4233","percentage":61}],"promptToLogin":false,"questionManager":false,"articleId":"urolithiasis"}