Kidney Stones Flashcards
nephrolithiasis - overview
*aka renal calculi (kidney stones)
*most commonly calcium oxalate, but many other types exist
nephrolithiasis - risk factors
*prior nephrolithiasis
*positive family history
*low fluid intake
*metabolic diseases: gout, obesity, DM, HTN
*medications (allopurinol, chemotherapy, loop diuretics, indinavir, acyclovir, sulfadiazine, triamterene)
*bariatric surgery: postcolectomy / postileostomy
*specific enzyme deficiencies
*type 1 RTA (caused by alkaline urinary pH and associated hypocitraturia)
*hyperparathyroidism
nephrolithiasis - history/PE
*sx typically develop when stone moves from renal pelvis into ureter [note - stones in the kidney do NOT cause sx]
*presents with: acute onset of severe, COLICKY [waxes/wanes] flank pain that may radiate to the groin; associated with nausea/vomiting
*patients are uncomfortable and shift position frequently (as opposed to those with peritonitis, who lie still)
nephrolithiasis - diagnosis
*UA may show gross or microscopic hematuria
*gold standard: NONcontrast CT of abdomen & pelvis
*ultrasound is preferred for pregnant pts and children (when low likelihood for another pathology)
*plain x-rays of abdomen useful for following progression/tx of larger stones
nephrolithiasis - diagnosis in pregnant pts
*ultrasound of kidneys & bladder = preferred initial test in pregnant pts
nephrolithiasis - complications
*post-obstructive kidney damage → hydronephrosis with lab abnormalities
*untreated nephrolithiasis can → CKD/ESRD
*note - hydronephrosis indicates obstruction that is at risk for impairing renal blood flow
nephrolithiasis - management/treatment (overview)
*labs: BMP (eval electrolytes & creatinine; look for AKI) & urinalysis (eval for hematuria or infxn)
*best initial tx: hydration & analgesia
-preferred analgesia: IV ketorolac, acetaminophen
*alpha-receptor blockers (tamsulosin) and calcium channel blockers (nifedipine) reduce ureteral spasms and facilitate passage of ureteral stones < 10mm, reducing need for analgesics
nephrolithiasis - variations in treatment
*treatment varies according to size & diameter of stone:
< 5 mm: may pass spontaneously
< 10 mm: higher rate of spontaneous passage with alpha-blocker or CCB therapy
5-20 mm: may be treated with show wave lithotripsy or ureteroscopy
> 20 mm: percutaneous nephrolithotomy
nephrolithiasis - dietary changes for prevention
*increased fluid intake (most important)
*normal calcium intake
*decreased sodium intake
nephrolithiasis - indications for urologic consult
- stone size > 9mm
- refractory pain/vomiting
- signs of sepsis or complete obstruction
nephrolithiasis - treatment algorithm
