Ureterolithiasis

Excerpt

Ureterolithiasis Overview

Ureterolithiasis is a worldwide disease affecting millions of people at a considerable cost and placing a significant burden on the global healthcare system. This disorder is also increasing in incidence and prevalence. Ureterolithiasis is associated with other systemic conditions, specifically cardiovascular disease, diabetes mellitus, metabolic syndrome, and obesity.

The condition often manifests with exceedingly painful flank pain radiating toward the groin. The pain occurs suddenly without warning. Episodes often recur after resolution. Unlike patients with an acute abdomen who wish to remain still, patients with ureterolithiasis typically want to move constantly, which is characteristic of colicky pain. Nausea and vomiting are commonly associated with acute ureterolithiasis. Lower urinary tract symptoms may occur when stones approach the bladder.

This unique clinical presentation, usually accompanied by hematuria (85%), makes it a relatively easy presumptive diagnosis to make in the emergency department. However, a definitive diagnosis generally requires imaging, preferably without contrast. Standard treatment involves appropriate analgesia, antiemetics, intravenous (IV) fluids, antibiotics when indicated, and medical expulsive therapy (α-blockers), which facilitate spontaneous stone passage in patients not requiring immediate surgical intervention.

Stone passage is usually determined by the stone's size, shape, and location, and the patient's ureteral anatomy. While most stones 5 mm and smaller pass spontaneously, stones with a diameter >7 mm and calculi that have not moved in 4 to 6 weeks may need surgical intervention. The 2 procedures most commonly performed to remove ureteral stones are ureteroscopy, usually with laser lithotripsy and stone basketing, and extracorporeal shockwave lithotripsy, which breaks stones into tiny fragments that can pass easily.

Ureterolithiasis associated with an infected kidney is potentially dangerous, causing obstructive pyelonephritis and urosepsis. Such situations require urgent renal pelvis surgical drainage. Definitive surgery of the ureteral stone is postponed until the infection is controlled and the patient has clinically recovered. Medical pyelonephritis cannot be clinically distinguished from the more dangerous obstructive pyelonephritis without appropriate imaging.

Hospitalization and urological surgical intervention are required in some cases. Urosepsis, renal abscess, infected stones, chronic kidney disease (CKD), obstruction, extravasation, ureteral scarring, avulsion, and stenosis are all possible complications of ureterolithiasis.

Afterward, kidney stone prevention testing with a 24-hour urine collection is suggested for all high-risk patients, including recurrent stone formers, patients with renal failure, solitary kidneys, and cystine stones, children with stones, immunocompromised individuals, and people with high surgical or anesthesia risk. Such testing is optional for all other stone formers and should be discussed with these patients. Successful stone prevention requires a willingness to commit to long-term compliance with therapy, as ureterolithiasis can recur.

Renal System Overview

The urinary system consists of the kidneys, ureters, bladder, and urethra. Kidneys filter blood to produce urine, which then travels through the ureters to the bladder for storage until elimination through the urethra during urination. Urine formation involves blood filtration in the kidneys to remove waste products and excess substances, followed by reabsorption of essential solutes and secretion of the rest. The kidneys also regulate urine concentration by adjusting water reabsorption, thus maintaining water and electrolyte balance in the body.

Kidney stones develop when certain substances in urine become highly concentrated and crystallize, forming solid masses. Factors contributing to stone formation include dehydration, dietary factors, metabolic disorders, and genetic predisposition. Once formed, kidney stones can travel down the ureters and become lodged at various points along the urinary tract, leading to obstruction and symptoms.

The ureters contain anatomical constrictions—the ureteropelvic junction (UPJ), pelvic brim, and ureterovesical junction (UVJ)—which are common sites for stone impaction. Nerves innervating the ureters include sympathetic (T10-L2), parasympathetic (S2-S4), and visceral sensory fibers from the renal plexus (T10-L1). Sympathetic nerves regulate blood flow and smooth muscle tone, while parasympathetic fibers control peristalsis. Sensory nerves transmit pain signals in response to stimuli such as distension or obstruction. Kidney stones lodged in the ureter can irritate sensory nerves, causing severe colicky pain (renal colic), the intensity and location of which depend on the stone's location and the degree of obstruction.