Kidney failure describes the inability of the kidneys to remove waste products from the blood. The kidneys may be thought of as blood filters. When aging causes the filtration process to become inefficient and ineffective, blood flow to the kidneys is increased in an attempt to increase filtration. This results in the production of more urine. The early clinical signs are increased water consumption and urination; while more advanced progression will include loss of appetite, depression, vomiting, diarrhea, and very bad breath or other oral health issues. In the final stages of the disease your pet may go into a coma. As a general rule, in most pets you cannot see outward signs of kidney damage until 75-80% of the kidneys are comprised.
The diagnosis of kidney failure is made by determining the level of two waste products in the blood: blood urea nitrogen (BUN) and blood creatinine. A urinalysis is also needed to complete the study of kidney function. Although BUN and creatinine levels reflect kidney failure, they do not predict it. A pet with marginal kidney function may have normal blood tests. If a pet is stressed with major illness or surgery, the kidneys may fail, sending the blood test values up quickly. Treatment varies for each pet and each situation so speak to your veterinarian.
It is recommended for senior pets that during their annual exams they have an ERD (Early Renal Detection) test, performed through a urine sample. During an annual exam your veterinarian may also recommend blood work or x-rays. If your pet shows any sign of renal (kidney) disease your veterinarian may recommend further testing such as a complete urinalysis to determine if your pet is losing protein or glucose through their urine. Your veterinarian may also recommend referral to another clinic for ultrasound, medications or a change in diet and/or home care with subcutaneous fluids.
Approximately 10% of dogs will develop some form of heart disease. 80% of the heart disease seen in dogs is mitral valve insufficiency. The earliest sign of a leaking mitral valve is normally a heart murmur. A heart murmur does not mean that heart failure is imminent. But as time goes on, the leak becomes more severe and more and more blood flows backward. This results in reduced pumping efficiency and eventually in congestive heart failure. When the heart is not properly pumping blood, the blood moves more slowly through the lungs. This results in small amounts of fluid leaking out of the capillaries into the air passageways. This fluid collection produces the earliest sign of heart failure – gagging as if trying to clear the throat, a chronic, hacking cough, and lack of stamina. Talk to your veterinarian about the best plan for your pet.