Is your cat has diarrhea, is vomiting unusually, appears lethargic and has no appetite; it could be suffering from hydronephrosis. In cats, this illness is basically when the pelvis and kidney swells causing the flow of urine to be obstructed from any part of the urinary tract. It blocks the long narrow tubes that transfer urine from the kidney to the urinary bladder, known as the ureters.

The pain is said to be so painful and excruciating that your cat may seem disoriented as it suffers from it. At times, the illness could appear without any warning or prior symptoms. Sometimes, the pain can be sudden and unbearable.

The term hydronephrosis itself means that your cat's ureter and the renal areas have filled with urine to a point where it is obstructing any flow. Since the kidneys filter a cat’s urine out of the blood, it is important to watch out for any blood that may pass in your cat’s urine. This at times could be the only symptom that you can spot since a cat will never really show any other signs.

If the valve located in these tubes is un-obstructed, the urine flows out of these muscular tubes. However when blocked, urine cannot escape and gets caught. This causes the swelling to develop in the upper urinary tract. If the obstruction happens below the bladder, then the protective valve protects the upper tract. However, even if it is protected, there is nowhere for the urine to pass through to so it goes back to the original source. This can prove to be dangerous considering that this will start deteriorating the kidneys. At times, this obstruction may not be a complete blockage. While this is far more common that complete blockage, it is possible that it will damage beyond repair.

While there are several causes for hydronephrosis in a cat, the most common is when stones are formed in the kidney, ladder or urinary tract. They cause the blood in the cat’s urine. The pain associated with these stones is severe and can be sudden. These stones usually appear when there is less urine passing or more passing of stone forming materials like calcium and phosphate.

Another potential cause of hydronephrosis is the formation of masses or tumors in the cat’s retroperitoneal area or abdomen that surrounds cat’s kidneys. These are generally formed by abnormal growth cells. However, they are not always cancerous.

All in all, your cat may never even let you know that it is suffering from hydronephrosis. It is up to you as an owner to look out for signs like excess drinking of water or decreased thirst and loss for appetite. One of the surest signs is blood in the cat’s urine. This is generally a solid indication that something is wrong.