• Among all the different types of renal stones present ,Calcium oxalate stones are the common type of kidney stones that affect people .
  • The stones are usually made up of calcium as the main substance/mineral.They are
  1. calcium oxalate 
  2. calcium phosphate.
  • Speaking about calcium oxalate in particular,These stones are made up of  calcium and oxalate which bind together to form calcium oxalate which turns into a hard mass .
  • They form under both acidic and alkaline conditions
  • The stone formation starts by nucleation of small ions in collecting tubes ,then the growth happens in the renal papillae and next the aggregation of calcium with oxalate happens in the renal pelvis .


B.What are the causes for Calcium oxalate stones?


  • The most prominent cause is excessive consumption of Calcium or Oxalate rich foods or drinks

        The  high levels of oxalates is available  in foods  such as Chocolates,beets,sweet potatoes ,Walnuts,nuts,raspberries,spinach,cacao powder ,green tea will affect 


  • Not drinking enough water will make the urine concentrated and results in low urine output 
  • Other risk factors include
    •            Previous history of renal stones :Somehow there is always  a suspicious chance of recurrence 
  • Dehydration 
  • Obesity
  • Excessive intake of VitaminC supplements, laxatives and antacids  
  • Increased uptake of Sodium,Sugars,Protein from animal meat
  • Diabetes
  • Inflammatory Bowel disease such as Crohn’s disease , Ulcerative Colitis
  • Hyperparathyroidism
  • Dent disease(genetic condition,which is basically rare type)


C.What are the possible symptoms of  Calcium oxalate stones or crystals ?


They may not show any symptoms until they start to move along the urinary tract or are struck which  causes interruption to urine flow.


The main symptoms are


  • Intense Pain in the lower back region or side 
  • Pain and difficulty during urination
  • Blood in urine
  • Cloudy urine
  • Foul smell of urine
  • Constant need to urinate
  • Fever ,chills 
  • Nausea,vomiting
  • Infections


Point to be noted: If the type of pain is colicky pain ,then

  • Intermittent, excruciating Pain in lower back and side with symptoms of nausea and vomiting

In Non-colicky pain

  • Continuous pain which is similar to the appendicitis pain

Renal colic 

  • Intense pain in form of wave with ureter stone 


D.How do you diagnose calcium oxalate stones?


There are certain tests which helps to rule out the presence or absence of stones,type of stones and sometimes location of the stones  also being evaluated


  • 24 hour urine test for checking oxalate levels,the normal range of oxalate level is 45mg/day.
  • Blood test 
  • Urine routine examination
  • Ultrasound
  • CT scan
  • X ray
  • Stone analysis in lab


E .How to prevent getting Calcium oxalate stones ?

There are about 6 steps to prevent from getting oxalate stones


1.Drinking plenty of water 


  • If drinking water is less or insufficient then the body gets dehydrated and less likely to form urine which carries the ca,oxalate minerals out of body
  • A minimum uptake of 2- 3 liters of water per day need to be consumed
  • Sometimes either a fruit juice or milk can be taken 
  • If juice is in the diet plan, not more than 1 serving per day is taken 
  • Should avoid drinking chocolate milk ,carrot juice,cranberry juice,green tea etc
  • The goal is to eliminate at least 2 liters of urine per day 
  • Consider drinking enough water during hot weather days,when physically active or having fever,nausea,vomiting, diarrhea
  • Adding citrate to the diet can bind with available calcium this preventing it to form calcium oxalate 


2.Limit Sodium Intake 


  • Less than 1 teaspoon of sodium should take per day 
  • If increased amount of sodium taken them the risks are higher
  • By following these simple steps can avoid getting stones 
    •            Avoid eating canned or processed foods
    •          Avoid eating fast foods
    •         Choose and Eat foods which have 5% or less than 5% of DV


3.Eat less protein food from animal source 


  •  Limit eating meat,fish,poultry 
  • Eggs are taken about 2 servings/day
  • Instead of meat protein try to choose vegetarian protein or plant based protein


4.Limit foods high in oxalates


  • Smaller intakes of oxalates would be a matter but excessive consumption can leads to stones 
  • Foods rich in oxalates are Chocolates,beets,oranges,dates,nuts etc
  • Eat more dairy or dairy products with meals 
  • By consuming enough calcium can decrease the oxalate levels
  • A cup of milk ,¾ cup of curd is taken


5.Avoid high calcium foods


  • Only calcium rich foods taken in limited amount is enough
  • Should not take any calcium supplements which causes oversupply of ca+2 to body which is not good


6.Avoid vitamin C


  • Food supplements with vit c are beneficial to health 
  • Should not taken in form of tablets (multivitamin tablets)or powders because they may lead to overdosage of only particular vitamins 


7.Maintain a healthy weight


  • Maintaining physical fitness is one of the most common way to prevent any kind of disease
  • For men at least l102cm body circumference is maintained whereas ,in women not more than 85 cm .


  1. Increased uptake of Potassium and phytates in diet 


F.Treatment for calcium oxalate stones


Pharmacological approach includes


  • Alpha-1a antagonists -tamsulosin which helps to dilate ureter 
  • Acetaminophen or ibuprofen is advised to relieve pain
  • NSAIDS -keterolac
  • Opioids such as Hydromorphone or morphine 
  • Ondansetron & promethazine for nausea and vomiting 
  • Thiazides-which increases calcium reabsorption from distal convoluted tubules
  • Natural inhibitors are also considered ,they are magnesium,citrate,mucoprotein (Tamm-horsfall) 


If stones are too large to pass


  • Percutaneous nephrolithotomy
  • Ureteroscopy
  • Shockwave lithotripsy(SWL) ,If stone size is <30mm
  • Lasers,other pneumatic device are used for its removal 


Frequently asked questions 


1.What does it mean when you have calcium oxalate crystals in urine?


Calcium oxalate crystals are  most common cause of renal stones .They are hard clumps of minerals which bind together 


2.How do you treat calcium oxalate crystals in urine?


Oral intake of phosphates and citrate helps prevent formation and also vitamin B-6 can be effective in people with hyperoxaluria.


3.Is it normal to have calcium oxalate in urine?


Yes,it is normal to have oxalate in urine  which is a natural product of metabolism of the body .This means this should leave the body through urine .If not ,the oxalate levels get too high and have high chances of availability for calcium to bind and form kidney stones .So following diet ,fitness,Drinking enough water can eliminate the excessive oxalates.


4.What causes too much oxalate in urine?


The condition of too much oxalate is known as hyperoxaluria.To much oxalate can cause serious complications .Can be due genetic diseases,high Oxalate foods,or any intestinal disorders . Totally depends on the time of diagnosis and treatment.


5.What foods to avoid if you have calcium oxalate kidney stones?


The foods to avoid are Chocolates,cacao powder,spinach,wheat,limit animal proteins,eat less canned or processed foods which may contain high salts,limit sugar intake and so on.


6.What is the fastest way to get rid of oxalates?


  • Drinking plenty of water to help your body flush oxalates out. 
  • Consuming enough calcium, which binds to excessive oxalates during digestion. 
  • Limiting sodium and sugar intake, which may contribute to kidney stones at high levels. 
  • Getting the recommended amounts of vitamin C — too much can increase oxalic acid production in your body 
  • Eating phytates or potassium rich food 


7.What drink is good for kidney stones?


  • Water is absolutely the best fluid to drink.
  • You can also drink ginger ale, lemon-lime sodas, and fruit juices in limited amounts .
  • Drink enough liquids throughout the day to make at least 2 quarts (2 liters) of urine for every 24 hours.
  • Drink enough to have light-colored or pale  urine. Dark yellow,red urine is a sign you are not drinking enough.


8.What should you not drink with kidney stones?


  • Drinks like lemonade,  fruit juices are naturally high in citrate that helps keep kidney stones at bay.
  • But hold back on foods and drinks flavored with high sugars or, especially, high-fructose corn syrups

9.Can lemon water get rid of kidney stones?


  • The ingestion of the lemon juice can get rid of excessive oxalates and also vitamin c available in lemon water helps in reabsorption of calcium levels and decreases the availability of free calcium to oxalate 
  • Citrate and oxalate compensate for their opposite effect calcium oxalate harmful?


  • Yes ,if it is in excessive levels . It’s normal for calcium and small amounts of oxalate to be in the urinary tract at the same time.
  • For people with high levels of sensitivity or incidence, diets high in oxalates can cause kidney stones.
  • They also have  increased risk of other health problems


11.The normal level of urine oxalate excretion


  • Normal levels of urinary oxalate are less than 40 mg per day. 
  • “Optimal” daily levels of urinary oxalate are less than 25 mg per day or less than 15 mg/L of urine.


12.What are symptoms of high oxalates?


  • Pain and difficulty during urination
  • Foul smell
  • Cloudy urine
  • Hematuria 
  • painful bowel movements.
  • grainy stools.
  • skin rashes or hives.
  • mood changes.
  • fatigue.
  • dizziness.
  • painful urination.
  • difficulty focusing
  • Nausea,vomiting 
  • Fever ,chills 

13.risk of kidney stones is the same during pregnancy as it is during other times of your life?


  • Kidney stones can cause enough complications during pregnancy
  • Even though the risk of kidney stones is not less during pregnancy , extra oxalate in your urine can promote stone formation and cause potential risk.


14.How can I lower calcium in my urine naturally?


  • To lower the calcium levels in urine naturally , your healthcare  provider or dietician  might suggest you to eat more vegetables and fruits and less animal products, such as dairy and meat. 
  • If you’re an older adult, your Dietician or health care provider may recommend to   add more potassium and reduce the salty foods,sugars  in your diet do you treat calcium oxalate crystals in urine?


  • Prescription doses of vitamin B-6 can be effective in reducing oxalate in the urine
  •  But in few people ,oral preparations of phosphates and citrate help prevent the formation of calcium oxalate crystals


16.Is apple cider vinegar good for stones ?


  • Laboratory study found that apple cider vinegar was effective in  reducing the formation of kidney stones.
  • Apple cider vinegar contains acetic acid.
  • Acetic acid helps dissolve kidney stones. In addition to flushing out the kidneys, 
  • Apple cider vinegar may also help to ease the pain caused by the stones. 


17.Is bananas high in oxalates?


  • No,bananas are low in oxalates
  • Infact ,Bananas are  helpful remedy against kidney stones, as they are rich in potassium, vitamin B6 and magnesium etc


18.What fruit is good for kidneys ?


  • Fruits such as pine apples,grapes are considered good for kidneys
  • Additionally they provide anti- inflammatory action


19.what is oxalate dumping?


  • The irritation caused by ejected  oxalate crystals and oxalic acid released into the system is called oxalate dumping .


20.How long does it take to dump oxalates ?


  • It takes about  8-20 weeks to dump oxalate
  • This may vary each week which last for 3-6days
  • There are even chances of multiple oxalate dumps .


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