Like A Kidney Stone...

Found this amusing "kidney stone" themed cartoon while surfing, so I guess today's topic will be kidney stones.

Lots of great chemistry to learn with nephrolithiasis (the medical term for kidney stones). Basically, your pee is filled with all sorts of minerals and ions. When the concentration of certain minerals gets too high, there will actually be crystallization of these molecules which form a solid kidney stone. I hope I never have one, because I can just imagine how painful a stone moving through the ureter and urethra would be...

The cool thing for us nephrologists is that occasionally, if you're lucky, you can determine the identity of the crystallized mineral forming the kidney stone just by looking under the microscope at the urine and looking at the shape of the crystals. For instance, calcium oxalate crystals (which are quite common) look like tiny envelopes (left). A genetic disease called cystinuria results in highly stereotypic hexagonal crystals in the urine (right). And struvite stones, which form exclusively in the urine of patients with infection, often look like a "coffin-lids".