calciumoksalat

Calcium oxalate is a chemical compound that forms the calcium salt of oxalic acid, with the formula CaC2O4. It occurs mainly in two hydrates: calcium oxalate dihydrate (weddellite, CaC2O4·2H2O) and calcium oxalate monohydrate (whewellite, CaC2O4·H2O). The salt is relatively insoluble in water and tends to form crystals under appropriate conditions.

Calcium oxalate is widespread in nature. In plants, it appears as crystals in tissues (raphides and druses) and is thought to deter herbivory. It is also present in many foods and beverages as an oxalate component. Diets high in oxalate-rich foods—such as spinach, rhubarb, beet greens, nuts, chocolate and tea—can contribute to body oxalate levels. The intestinal microbiota, particularly Oxalobacter formigenes, can degrade oxalate and reduce absorption; antibiotic use can disrupt this process.

In clinical medicine, calcium oxalate is the most common constituent of kidney stones, accounting for a large proportion of cases. Stone formation is influenced by urinary oxalate and calcium levels, citrate, urine volume, and pH. Symptoms of stones can include sudden flank pain, blood in urine, and sometimes infection. Diagnosis relies on imaging and analysis of stones or crystals in urine. Management emphasizes adequate hydration, dietary adjustments to limit oxalate intake while maintaining calcium, and citrate therapy to inhibit crystal formation; larger stones may require lithotripsy or surgical removal.

Prevention focuses on staying well hydrated, maintaining balanced calcium intake to reduce intestinal oxalate absorption, and addressing factors that raise urinary oxalate, including certain dietary patterns and gut microbiome health.