Stones and UTI Karina and Cameron

Name some common stone sites.. Renal tract (urolithiasis) Appendix (faecolith) Salivary glands (sialolithiasiss) Gallbladder/ biliary tree (cholelithiasis) Prostate Veins (phleboliths) Salivary stones: usually found in Wharton’s duct and presents with pain and welling of the gland.

Gallstones How do they present? What investigations would you do? Asymptomatic, abdo pain (epigastric and right shoulder pain due to irritation of diaphragm C1-C5), positive murphy’s sign, jaundice and fever What investigations would you do? Bloods: LFTs/amylase, USS and ERCP/MRCP Gallstones are more common in females than males. Most stones are cholesterol based due to high fat diets/ hypercholesterolaemia; others may be pigment stones due to haemolytic disorders e.g. high serum bilirubin.

Renal Stones How do they present? Loin to groin pain (Can’t get comfortable and may radiate to testicles) Sweating Haematuria Vomiting Irritative voiding Why do you get this loin to groin pain? What initial investigations would you carry out? Urine dipstick (haematuria) Imaging: KUB – Do this immediately if there is also fever present as it could be pylonephrosis. Sensory nerve route Renal plexus Abdomino-aortic plexus Hypogastric plexus (superior) T12 More common males than females. Risk factors: age (peak 20-30 years), fluid intake, family history and diet/BMI. L1/2

Renal Stones What are the types of renal stone? Calcium (oxalate and phosphate), Urate, Struvite, Cystine and Others Which are the most common? Ca oxalate (60%) They can be seen in different radiolucencies. What order are they seen in on xrays? Ca> struvite > cystine> urate (urate are not seen on xray but can be seen on US and CT) What stone causes this classic pattern? Staghorn calculi of struvite stones

Risk factors Calcium stones What are the two main causes of hypercalciuria? Hyperparathyroidism and malignancy are most common. Rare genetic disorders and sarcoidosis/TB also come into play. What are the causes of hyperoxaluria? Primary hyperoxaluria, caused by genetic defects; Secondary hyperoxaluria, caused by increased ingestion of eg spinach/rhubarb/tea or enteric causes. Struvite stones What is the usual cause of struvite stones? Chronic UTI with urea-splitting bacteria …and hence what are the risk factors for this type of stone? Female, catheters, neurogenic bladders, urinary tract abnormalities, stagnant urine Enteric causes of hyperoxaluria – excess exposure to bile salts of bowel mucosa, as occurs with a variety of intestinal disorders, causes increased absorption of oxalate. Related conditions include Crohn’s and chronic pancreatic and biliary tree disease.

Risk factors II Cystine stones What causes the formation of cystine stones? Autosomal recessive disorder, resulting in failure of renal tubular reabsorption of cystine. It then crystallises in the urine. Uric acid stones What other condition might a patient with uric acid stones have? Gout – both result from accumulation of urate, an end product of purine metabolism. What are some common dietary sources of purines which should be avoided with these two conditions? Alcohol, red meat, liver/sweetbreads/kidney, fish Some patients with calcium stones also have hyperuricosuria. It is believed that calcium salts precipitate on an initial nidus (site of formation/deposition) of uric acid. Another risk factor for uric acid stones is acidity: at lower pHs, urate precipitates more easily to form stones.

Renal stones Where do renal stones get stuck? Pelvic ureteric junction (PUJ) Pelvic brim Vesicoureteric junction (VUJ) Bladder urethra outlet When would you need to remove the stones? Pain/ failure to pass Recurrent infection Bleeding Renal impairment Some jobs e.g. pilot

UTI What are the risk factors for UTI? Female, sex, exposure to spermicide in females, diabetes, pregnancy (often not picked up until pylonephritis – so routine dipstick), menopause, immunosuppression, stones, catheter (nearly always infected so pointless sending off a sample), malformation. A UTI infection can affect any part of the urinary tract. Bladder: cystitis (most common); Prostate: prostatitis; Renal pelvis: pyelonephritis What is the clinical presentation of a UTI? Frequency, pain on voiding (dysuria), suprapubic pain and tenderness, haematuria, smelly urine, pyuria. Loin pain, fever, oliguria and systemic symptoms suggest involvement of pelvis of the kidney  pylonephitis. What is the most common UTI pathogen? E coli (>70%) What tests would you use to confirm UTI? MSU: dipstick: nitrites (gram negative bacteria will reduce nitrates to nitrites) and leukocytes. If the patient also presents with loin pain, fever and tenderness send for US to exclude obstructed pyelonephrosis. Which antibiotic are simple/uncomplicated UTI’s treated with? Trimethoprim

UTI How would acute pyelonephritis present? Loin to groin pain, vomiting, malaise, fever, rigors There may be small renal abscess and streaks of pus in the renal medulla. CT scams will often show wedge shaped areas of inflammation. What is reflux nephropathy (aka chronic pyelonephitis)? Normally the vesicouteric valve and junction acts to allow urine to enter from above, but not leave the bladder via this route when the bladder contracts. If this valve is compromised urine will go up the ureters and into the kidney – leading to kidney damage. This is more common in children and when the base of the bladder grows it may stop being a problem.

Questions Dysuria, frequency, cloudy urine Nitrites and leukocyte esterases present in the urine Short urethra Clean the peri-uthreal region and take a mid stream sample.

E coli Frequent sexual intercourse, female, older age, diabetes, reduced immunity, poor hygiene

Questions?