[Music] [Applause] [Music] hi this is tom from zero2finals.com in this video i'm going to be going through kidney stones and you can find written notes on this topic at zero to finals dot com slash kidney stones or in the urology section of the zeroed finals surgery book so let's jump straight in kidney stones are also referred to as renal calculi urolithiasis and nephrolithiasis they're hard stones that form in the renal pelvis where the urine collects before it travels down the ureters kidney stones may be asymptomatic until they irritate or they get stuck in the ureters they might get stuck at any point along the ureters but most often this happens at the vesico ureteric junction which is the junction between the ureter and the bladder there are two key complications to kidney stones the first is obstruction which can lead to an acute kidney injury because urine can't drain away from the kidney and so there's back pressure into the kidney affecting the function and the second is infection with obstructive pyelonephritis or infection in the kidney caused by obstruction so the infective matter builds up in the kidney tissue let's talk about the types of kidney stones calcium-based stones are the most common type of kidney stone and this accounts for about 80 percent of kidney stones having a raised serum calcium level or hypercalcemia and a low urine output are key risk factors for calcium collecting into a stone there are two types of calcium stones calcium oxalate which is the more common type and calcium phosphate stones the other types of kidney stones include uric acid stones and uric acid stones are not visible on x-rays struvite stones and struvite is a chemical that's produced by bacteria and these are associated with infection and cysteine stones and these are associated with cysteine urea which is an autosomal recessive disease next let's talk about staghorn calculus a staghorn calculus is where the stone forms into the shape of the renal pelvis giving it a similar appearance to the antlers on a deer stag the body of the staghorn calculus sits in the renal pelvis with the horns extending into the renal calyces a staghorn calculus may be seen on plane x-ray films most commonly this occurs with stones made of struvite in patients with recurrent upper urinary tract infections the bacteria can hydrolyze the urea which is found in the urine into ammonia and this creates the solid struvite let's talk about the presentation of kidney stones renal stones may be asymptomatic and never cause any issues a symptom called renal colic is the presenting complaint in symptomatic kidney stones renal colic is unilateral loin to groin pain which can be excruciating and some people describe it as worse than childbirth and it's colicky meaning that it fluctuates in severity as the stone moves and settles in position patients with renal colic often move restlessly due to the pain they may also experience hematuria or blood in the urine nausea and vomiting reduced urine output and symptoms of sepsis if infection is present let's talk about the investigations a urine dipstick test usually shows hematuria or blood in the urine in cases of kidney stones a normal urine dipstick does not exclude kidney stones urine dipsticks are also helpful to exclude infection blood tests can help establish signs of infection and also the kidney function checking the serum calcium helps identify hypercalcemia or a raised calcium level which may have been the cause of the kidney stones an abdominal x-ray can show calcium-based stones but uric acid stones will not show up they are radiolucent meaning that they don't show up on x-rays a non-contrast computer tomography or ct scan of the kidneys ureters and bladder which is called a ctkub is the initial investigation of choice for diagnosing kidney stones the nice guidelines from 2019 recommend a ct kub within 24 hours of the presentation an ultrasound of the kidneys ureters and bladder or an ultrasound kub is a less preferred alternative to a ct scan a negative result does not exclude kidney stones ultrasound is less effective at identifying kidney stones but it is helpful in pregnant women and children stones can be analyzed to determine the type which is useful to help establish the cause and reduce the risk of recurrence a tom tip for you remember hypercalcemia or a raised calcium level as a cause of kidney stones you can remember the presenting features of hypercalcemia with the pneumonic renal stones painful bones abdominal groans and psychiatric hormones the three causes of hypercalcemia to remember are calcium supplements hyperparathyroidism and cancer for example myeloma breast cancer or lung cancer let's talk about management non-steroidal anti-inflammatory drugs are the most effective type of analgesia for example intramuscular or rectal diclofenac iv paracetamol is an alternative where nsaids are not suitable opiates are not very helpful for pain management and they're not routinely used antiometics are used to treat nausea and vomiting for example metaclopramide procloperazine or cyclazine antibiotics are required if infection is present watchful weighting is usually used in stones that are less than five millimeters in size as there's a fifty to eighty percent chance that these will pass without any interventions watchful weighting may also be suitable for patients with stones that are five to ten millimeters depending on individual factors it can take several weeks for the stones to pass tamzilosin which is an alpha blocker can be used to help aid the passage of stones surgical interventions are required for large stones for example 10 millimeters or more and also for stones that don't pass spontaneously or where there's complete obstruction or infection so let's talk in more detail about the surgical options first let's talk about extracorporeal shockwave lithotripsy or eswl this involves an external machine that generates shock waves and directs them at the stones under x-ray guidance the shock waves break the stone into smaller parts which makes it easier for them to pass there's another surgical option called uretoscopy and laser lithotripsy and this involves a camera inserted via the urethra bladder and ureter to identify the stone the stone is then broken up using targeted lasers and the smaller pieces of stone are easier to pass another option is percutaneous nephrolithotomy and percutaneous nephrolithotomy is performed in theaters under a general anaesthetic a nephroscope which is a small camera on a stick is inserted via a small incision in the patient's back the scope is inserted through the kidney to assess the ureter when stones are identified tools can be used to break the stones into smaller pieces and remove them the nephrostomy tube may be left in place after the procedure to help drain the kidney the final surgical option is open surgery an open surgical procedure can be used to access the kidneys and remove the stones this is rarely needed as other less invasive methods are usually effective finally let's talk about recurrent kidney stones one episode of kidney stones predisposes patients to further episodes the nice guidelines from 2019 recommend advising patients to increase their oral fluid intake to 2.5 to 3 liters per day add fresh lemon juice to water this is because citric acid binds to urinary calcium reducing the formation of stones avoid carbonated drinks as cola drinks contain phosphoric acid which promotes calcium oxalate formation and the development of stones reduce dietary salt intake to less than six grams per day and maintain a normal calcium intake in the diet interestingly a low dietary calcium may increase the risk of kidney stones other common recommendations include for calcium stones reducing the intake of oxalate rich foods for example spinach beetroot nuts rhubarb and black tea for uric acid stones reducing the intake of purine-rich foods for example kidney liver anchovies sardines and spinach and generally limiting the dietary protein intake there are two medications that may be used to reduce the risk of recurrence of kidney stones and these are potassium citrate which is used in patients with calcium oxalate stones and a raised urinary calcium and thiazide diuretics for example in dapamide and these are also used in patients with calcium oxalate stones and a raised urinary calcium thank you for watching this video if you liked the video left a comment or subscribe to the channel thank you so much it really helps zero to finals is not just a youtube channel there's also a website with detailed notes illustrations and questions an instagram account where new questions are posted every day to help you test your knowledge books flash cards and much more i also have a personal channel where i share my thoughts and tips on learning medicine and you can find links to everything in the description of this video see you next time