What type of casts and crystals were found?
Casts of red blood cells may suggest glomerulonephritis, while white blood cell casts may suggest a kidney infection or pyelonephriris. Crystals may occur normally such as calcium oxalate crystals , however, cystine crystals are rare and may be due to an underying metabolic problem.
Other factors need to be considered also such as the amount of protein in the urine. Was a 24 hour urine collection done, a urine cultur done ?Was a CBC done? Serum cholesterol, serum calcium levels , BUN ,Creatinine if indicated?
Your scans did not show any stones that could cause an obsruction,. However, diagnoses for pyelonephritis is usually clinical.
Keep in touch with your current physicians for any headaches, fever or vomiting. Continue your medications and inform them of your progress. Drink plenty of fluids, eat well and take lots of rest. If the pain becomes severe and associated symptoms like fever and vomiting appear do not hesitate to seek consult at the ER.
Other differentials like glomerulonephritis may present with hypertension, change in the character of the urine, swelling of the extremities.
Do keep us posted regarding your physician's advice.