Hi and welcome to HCM. It looks to me like possible kidney stones. Most small stones in patients with relatively mild hydronephrosis can be treated with observation and acetaminophen. More serious cases with intractable pain may require drainage with a stent or percutaneous nephrostomy. Treatment of nephrolithiasis involves emergency management of renal (ureteral) colic, including surgical interventions where indicated, and medical therapy for stone disease. In emergency settings where concern exists about possible renal failure, the focus of treatment should be on correcting dehydration, treating urinary infections, preventing scarring, identifying patients with a solitary functional kidney,. Kindly regards. Wish you a good health.