Calcium oxalate

What is calcium oxalate?

Calcium oxalate is a salt that consists of calcium ions and oxalate ions. Oxalate ions are organic acids that are found in many foods, such as spinach, rhubarb, nuts or chocolate. Oxalate ions can also be produced by the body itself, for example in the case of an excess of vitamin C or a disturbed intestinal flora.

Calcium oxalate in the urinary tract

One area where calcium oxalate can cause problems is the urinary tract. If there is too much calcium oxalate in the urine, it can precipitate into crystals or stones that can block or irritate the urinary tract. This can lead to pain, blood in the urine, urinary tract infections or kidney failure. The causes of increased calcium oxalate excretion can be varied, for example a genetic predisposition, a poor diet, chronic kidney disease or a metabolic disorder.

To reduce the risk of calcium oxalate stones, you should make sure that your dog drinks enough and urinates regularly. In addition, you should not give him food that contains too much calcium or oxalic acid. This includes dairy products, rhubarb, spinach and chocolate, for example. If your dog already has stones or is prone to them, your vet may recommend a special diet or prescribe medication. In some cases, the stones may need to be surgically removed.

Calcium oxalate in the joints

Another area where calcium oxalate can occur is in the joints. When calcium oxalate crystals are deposited in the joints, this is known as calcium pyrophosphate dihydrate arthropathy (CPPD) or pseudogout. This disease is similar to gout in humans and can lead to inflammation, swelling and pain in the affected joints. The causes of CPPD are not exactly known, but there are some factors that can increase the risk, such as advanced age, hyperparathyroidism or chronic kidney disease.

The treatment of CPPD usually consists of painkillers and anti-inflammatory medication. In severe cases, joint lavage or surgical removal of the crystals may also be necessary. To prevent CPPD, you should provide your dog with a balanced diet and exercise him regularly. You should also monitor his blood calcium and phosphate levels and treat any kidney or parathyroid disease.

Calcium oxalate in the teeth

A third area where calcium oxalate can occur is in the teeth. When calcium oxalate crystals form on the tooth surface, this is known as dental oxalosis. This condition is very rare in dogs and is usually discovered by chance during a dental examination. The symptoms can range from slight discoloration to severe destruction of the tooth enamel. The causes of dental oxalosis are not clear, but it is thought to be related to increased oxalic acid intake or production.

What are the disadvantages of calcium oxalate?

The main disadvantage of calcium oxalate is the formation of urinary stones, which can lead to serious health problems. Calcium oxalate urinary stones are very hard and usually cannot be dissolved by diet or medication. Surgery is often required to remove the stones.

Calcium oxalate urinary stones are most common in older, castrated male dogs that are overweight. Some dog breeds are also genetically predisposed to this type of urinary stone, such as Yorkshire Terriers, Lhasa Apso, Shih Tzu or Miniature Schnauzers.

How can you protect your dog from urinary stones?

To reduce the risk of urinary stones from calcium oxalate, you should follow these tips:

• Feed your dog a high quality food with low oxalate content. Avoid foods such as wheat, sweet potatoes, spinach or nuts.
• Make sure your dog drinks enough and urinates regularly. This dilutes the urine and flushes out possible crystals.
• Have your dog's urine tested regularly to check the pH value and the concentration of calcium and oxalate.
• Have your dog checked for possible diseases that can lead to increased calcium excretion, such as parathyroid disorders or vitamin D overdose.