Idiopathic hypercalciuria is the presence of excess calcium in the urine without obvious cause. This condition can lead to kidney stones or osteoporosis.

Hypercalciuria - idiopathic

Rosen C. Osteoporosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 264.

When a rabbit urinates a thick, creamy liquid, that means the rabbit has urine sludge and requires veterinary care.

Urine sludge, also known as bladder sludge, hypercalcinuria, and hypercalciuria, is a condition resulting from too much calcium in the urine. Urine sludge can be caused by a mix of lifestyle, diet, and genetic factors, and disease.

Urine sludge is often treated by a vet by flushing out the rabbit's bladder (under anaesthesia), and then sucking out or manually pushing out the sludge through the urethra. This procedure may need to be repeated a few times, and antibiotics may be prescribed, as well as nutritional supplements (like vitamin C or cranberry tablets).

A healthy diet, lots of water intake, a clean and comfortable environment, and plenty of exercise are also important factors in preventing and treating urine sludge.

See the related links/questions below for more info and helpful links.

Proteinuria is the medical term for excess protein in the urine.

Anything in the urine ends with the word -uria. Protein is simply protein, therefore protein in the urine is "proteinuria".

Other examples include blood in the urine (haematuria) and glucose in the urine (glycosuria).
Anything in the urine ends with the word -uria. Protein is simply protein, therefore protein in the urine is "proteinuria".

Other examples include blood in the urine (haematuria) and glucose in the urine (glycosuria).
hyperproteinuria
albuminuria

albuminuria

albuminuria
proteinuria