This 10-minute true/false exam is designed by Northwestern Medical Review to assess your familiarity with the must-know essentials of kidney stones.

After completing the test, please check your answers against the answer key with associated explanations at bottom of this document. 

You may begin the test whenever you are ready. Our suggested total allowable time is 5 minutes!

1.       True/False: “Limiting salt intake and  increasing consumption of water and fluids minimize formation of all urinary stone types”. 

2.       True/False: “The best juice for most urinary stones is cranberry juice.”

3.       True/False: “Orange juice, lemon juice, and apple cider vinegar facilitate solubility of calcium oxalate crystals and help with their elimination.”

4.       True/False: “Orange juice, lemon juice, and apple cider vinegar are helpful in dissolving  uric acid (gout)  crystals and their elimination.”

5.       True/False: “Patients with cystine stones may most likely receive  allopurinol prescriptions to reduce their urine cysteine levels.”

6.       True/False: “In patients with genetic disease of cystinuria raising urine alkalinity (pH) by potassium citrate will increase solubility of cysteine stones and reduces crystallization of  cystine stones.”

7.       True/False: “Cystinuria is more common among females.”

8.       True/False: “The main value of stenting in patients with unilateral blockage  of their ureters is to avoid damage to their kidneys.”

9.       True/False: “Brushite and cystine stones are by far the most resistant urinary stones to shockwave lithotripsy.”

10.   True/False: “Acetohydroxamic acid is the desired  treatment for cystine stones.”

Answers

1.       True! No brainer! Limiting salt intake and  increasing consumption of water and fluids minimize formation of ALMOST ALL urinary stone types!

2.       False! In contrast to common beliefs, cranberry juice is contraindicated in patients with kidney stones, and in particular in those patients who are afflicted with the most common type of kidney stone, namely, calcium oxalate stones. It is shown that cranberry juice has high amounts of oxalic acid that predisposes oxalate crystallization. Cranberry juice is mainly suitable for urinary tract infections as it helps to flush the urinary tract and dilute the infectious load of the offending germs!

3.       True! Orange juice, lemon juice, and apple cider vinegar facilitate solubility of calcium oxalate crystals and help to  minimize their precipitation.”

4.       True! Orange juice, lemon juice, and apple cider vinegar are helpful in dissolving  uric acid (gout)  crystals or minimizing their precipitation”. In other words, the very same juices that are helpful in reducing precipitation of calcium oxalate stones are also workable  for gout stones!

5.       False! Only patients with uric acid (gout stones) may receive  allopurinol for reducing their blood uric acid level. For the genetic disease of cystinuria, drugs that alkalinize urine such as acetazolamide (a weak diuretic) and potassium citrate are commonly used. Please note that by far the most effective therapy for resistant stones of cystinuria is thiol-containing compounds like D-penicillamine and tiopronin. These medications bind the amino acid,  cysteine, eliminate it in the urine, and as a result they do not allow formation of cystine molecules that are more insoluble.

6.       True! Drugs that make the urine more alkaline (i.e., raise the urine pH) such as  potassium citrate and acetazolamide are helpful in minimizing crystallization of stones in patients with cystinuria. This treatment is accompanied by dietary salt and animal protein restriction. Actually, alkalization of the urine is helpful in reducing all types of stones except struvite stones.

7.       False! Cystinuria is more common among males. In contrast, struvite stones that are due to infections by urease-producing bacteria such as Proteus, are more common in females!

8.       True! Patients with stones that block urine flow through their affected (blocked) ureters are at risk of hydronephrosis (urine and fluids buildup in their kidney) and post-renal uremia. Placing stents that will promote urine drainage will facilitate restoration of the kidney’s function.

9.       True! Brushite and cystine stones are by far the most resistant urinary stones to shockwave lithotripsy. Note that brushite stones are calcium phosphate stones that are commonly associated with hyperparathyroidism.

10.   False! Acetohydroxamic  is indicated for struvite stones. Acetohydroxamic acid (Lithostat) inhibits urease enzymes that are produced by certain urinary tract bacteria (e.g., Proteus) and break/convert  urea to ammonia. Note that ammonia raises urine alkalinity and predisposes to struvite stone formation. In other words, lack of ammonia formation due to oral administration of  acetohydroxamic acid, reduces alkalinity of the urine, and as a result reduces struvite stone formation.

HOW TO EVALUATE YOUR PERFORMANCE

8+ correct items, awesome familiarity with kidney stone stories!

6 -7 correct items, above average familiarity with kidney stone stories!

4 – 5 correct items, below average familiarity with kidney stone stories!

Less than  3 correct items, you need to learn more about kidney stones, in particular if you’re at risk of having them!