# Renal Calculi --- **Renal calculi**, (singular: **calculus**) commonly known as **kidney stones** are buildups of [[mineral|minerals]] in the [[urinary system|urinary tract]]. Calculi that are less than 4mm are able to pass out of the body on their own—larger stones may need medical interventions such a lithotripsy or ureteroscopy procedure. Renal calculi are very painful, but aren't usually fatal. >[!abstract] Terminology > Stones in the [[urinary system|urinary tract]] are also called **urolithiasis**, and stones in the kidney are called **nephrolithiasis**. The terms are sometimes used interchangeably, but technically all nephrolithiasis are urolithiasis because the kidneys are a part of the urinary tract. That's all too confusing so we're just going to stick with "stones" or simular. ![[renal calculi.png]] ## Types of Stones Stones can be of a variety of substances, depending the circumstances. Sometimes there is a mix of substances as well. Generally speaking stones are formed because too much of a substance accumulates in the urine. - **Calcium based stones** - 80% of stones are calcium based. These can be either **calcium phosphate** or **calcium oxalate**, or sometimes a mix of both - **calcium oxalate** - [[Magnesium]] inhibits calcium oxalate stones, so low Mg can contribute to the formation of these stones - eating foods high in **oxalate**: avocados, dates, grapefruit, kiwi, orange, raspberries, spinach, tomato sauce - can caused by an excess of dietary [[calcium]], vitamin C or vitamin D, but also evidence suggests calcium binds to oxalate in a way that allows it to pass out of the urine, so it's contradictory - **Struvite based stones** - 10% of stones - More common in AFAB people because it's associated with UITs, which are more common in this population. - only associated with certain bacteria (but not *E. coli* for some reason) - **Uric acid stones** - 9% of stones - diarrhea and [[gout]] - **Cystine based stones** - 1% of stones - typically only seen in children with a genetic disorder called **cystinuria** ## Risk Factors The big overarching risk factors are it have to do with fluid balance (too [[fluid volume deficit|little fluid]] means high concentrations of the substances) and dietary intake. - AMAB people - High salt diets - Salt competes with calcium in the kidneys, so a high sodium diet contributes specifically to that, but also generally causes more water to be retained. - high oxalate diets - low magnesium - dehydration - high animal protein intake - high uric acid and calcium ## Signs & Symptoms The signs and symptoms of renal calculi depend on where in the system they are. In some cases stones cause no symptoms and slowly damage the nephrons. - Stones in the renal pelvis - flank pain (costovertebral) - hematuria - pyuria - renal colic - sudden acute pain in the kidney area that's caused by obstruction of the urine flow out of the kidney - Stones in the ureter - excruciating, wave-like, radiating pain - Stones in the bladder - irritation - hematuria ## Complications The complications of renal calculi also depend on where in the system they are in. - Stones in the renal pelvis - few - Stones in the ureter - can cause an obstruction of the flow of urine - hydronephrosis - Stones in the bladder - frequent, painful urination - chronic bladder discomfort - hydronephrosis - decrease in renal function ## Diagnostic Tests - x-ray ## Treatment The best treatment for renal calculi consists of preventing them from forming in the first place. Hydration is the single best thing you can do to prevent these. If they are already formed, there are three commonly used procedures, ureteroscopy, lithotripsy and endourologic/percutaneous removal. - **Ureteroscopy** is to get a stone out of the ureter. They enter with a special device that enters through the urethra and it goes through the bladder and up into the ureter where it snags the stone and drags it out. Sometimes they might break it up into smaller pieces first. - **Lithotripsy**, or **extracorporeal shock water lithotripsy** is when they use sound waves to break up the stones in vivo where they can be passed out the urine. - **Percutaneous nephrolithotomy** is when they take a special tool and just go in through the skin. ## Nursing Considerations - patient education - care after treatment ___