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Flashcards in Renal Stones Deck (30)
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What is urolithiasis?

Formation of stones in the urianary tract


Where is the commenest place for renal stones to form?

The renal pelvis


What are the causes of stones??

Bladder outflow obstruction, urethral stricture, neurpothaic bladder and the prostate obstruction, presence of a foreign body cathether non abdorbable sutures, and some are passed down form the upper urianary tract


What are calcium stones made of?

Calcium oxalate usually with calcium phosphate (65%) calcium phosphate alone in 15% uric acid in 3-5% adn struvite infection stones, including for example urease stones in 10-15%


What are the other types of renal stones apart from calcium stones?

Cytesine stones, occur ina rare genetic condition cystinuria, or drug stones such as indinavir for ammonium acid urate stones


Why do urinary stones form?

If there is urine supersaturation with minerals, as the solute holds more moneral than it can hold inn solution, which can occur due to a decrease in water content and an increase in mineral content or a decrease in the solubility of a solute in urine, for example a change in pH


What conditions can cause an increase in mineral content?

Hypercalacemia and hypercalciuria, hyperoxaluria, hypeurcaemia and hyperuricosuria, and cysteniuria


What conditions can cause a decrease in the solubaility of a substance in urine?

Some solutes are more soluable at a high Ph and others at a leo pH, acid urine favurs the formation or calcium oxalate and uric acid stones, alkaline urine favours the formation of calcium phosphate stones, cna occur in renal tubular acidosis in persistenley alakline urine and can cause the formation of citrate stones


How do renal stones form?

The majoritity 74% of calcium stones appear to grow like stalacitilies attached to the exposed intersitial deposits of calcium phosphate, a randallas plaque on the tips of the renal papillae core of calcium depsoits surrounded by the calcium phophate, otherwise the stones formed of the ducts of bellini or free in solution


What are the conditions associate eith calcium oxalate stones?

5% are associated with hypercalcemia and hypercaluria, such as in hyperparathyoridoms and 55% have hypercalciuria without huperthryrodiims 5% are assoicated wiht hyperoxaluria


What are the actions of PTH to in rease the serum calcium?

Increasing osteoclastic resorption of bone, increasing intestinal absorption of calcium, intercreasing syntheisis of 1,25. (OH2) D3 and increasing the renal tubular resoprtion of calcium and ipncreasing the excretion of phosphate


What are the actions of vitamin D?

Increases the calcium absorption in the gut, and increase the calcification and the reabsoption in the blood


What are the actions of calcitonin?

Produced by the thyroid c cells, and decreases serum calcium by inhbiting osetoclastic bone reabsoprtion, and incaseing renal excretion of calcium and phosphate


What are some of the possibly causes of hypercalciuria?

Idiopathic, as it appears most patients have increased absorption from the GIT, hypercalcemia p, excessive dietary intake of calcium, excessive reabsorption of the calcium from the skeleton due to prolonged immobilisation and weightlessness


What are some of the causes ofnhypersecretion of PTH?

Primiary a parathryoidhypeplasia or a functional tumour. Or secondary to renal failure, which causes the retention of phosphate and hence hypercalcmeia and ectopic, secretion of a PTH related protein but a malignant tumour


What are some of the causes of the destruction of bone tissue?

Primary tumour of bone marrow, diffuse skeletal Metases, and pagets disease of bone caused by accelerated bone turnover and immobilisation of bones, for example not moving after breaking a bone


What are some of the other mechansims causing hypercalcemia?

Excessive vitamin D ingestion, thiazide direutics, sacordosis (macrophages activate a vitamin D precursor) and therefore the milk-alkali synrdome, due to a excessive calcium intake


What are the main signs of hypercalcemia?

There is severe muscle weakness, and there is painful bones and fractures renal stones, abdominal groans, constipation, peptic ulcers, and pancreatitis and the gallstones, and therefore the psychic moans and the depression and the lethargy


What is hyperpxaluria?

This is a rare autosomal genetic disorders of oxalate synthesis, and the increase intestinal oxalate absorption to GI disease usually with an intestinal resection, increased absorption of the oxalate colon, and dietary habits of hihg oxalate intake and a low calcium intake


What are some of the sturvitie stones?

They are usually secondary to infeciton with organisms that are the enzymes urease whcih hydrolyses by the enzymes which hydrolyses the urea to ammonium hydrolxylate, also production of organic matrix, and these are often large to form a staghorn calculus and this fill the sataghorn calculus


What is hyperuricameia?

Uric acid is the end point of purine metabolism, there is hyperuricameia which is seen in idiopathic gout, and is an increase cell turnover such as after chemotherapy, and in dehydration of possibly acidic urine and in dehydration, especially yin the formation of acidic urine


How do renal stones present?

Asymptomatic, can only be seen on a radiography, renal colic, or if the stones are in the kidney, there is a dull ache in the lonins, recurrent UTIs, renal fialure, urianary tract obstruction, and if fluid intake is increased, the resilt is an increase in pain


What is renal colic?

Excrutiating pain, bouts are lasting 20-60 minutes, caused by perstatic contractions or spasms of the ureters to trt and expel the pain, and it radiates from the flant to the iliac fossa and testes/ labium. And is often accompanied by nausea and vomiting


Where does the pain in renal colic radiate?

The iliac fossa to the testes/ labium, and this is the disturbution of the 1 st lumbar nerve root, and thsi due to the embroyoligcal link between urinary tract, GIT and the gonads


What are some of the investigations that are made in urolithus?

MSU' there is RBCs, urinary casts, urinary cyrstals and culutre, and serum, lookin on the urea, creatinine, and electrolyts, as a plain abdominal x ray is useful to look at if the strains are radiopaque as well as a CT of the kidney ureter and bladder, can pass sorones throug a sieze


What are the sizes of urinary stones that can be pased?

< 5mm can be passed, > 7mm requires urological intervention


What are the complications of urianry stones that can occur?

Acute pyelonephritis +\- gram negative septiceae,oa, and there is pressure necrosis of the renal parenchyma, urainarry obstruction and hydronephrosis an ulceration through the wall of the collecting system


How can we treat urinary stones?

Analgesia, uteroscopy, percutaneous nephrolitomy, and extraperoal shock wave lothroscopy


What is extracporeal shock wave lithotropsy?

Most commonly used in stones near the renal pelvis, delevers external focus and high intensity pulses of ultrasonic energy, takes 30-60 minites, and fragments the stone, adn then they can pass the stones


How can you prevent stones from occuring in the first place?

Decrease urine supersaturation, drink more water, decrease of excretion of calcium or oxalate, and the thiazide direutic, and the potassium citrate used to alkalinise the urine, which reduces the risk of calcium oxalate and uric acid stones, and forms soluble complexes with calcium but can induce the calcium phophate stones