Primary hyperparathyroidism (PHPT) is a relatively rare disease in Keeshond. Many veterinarians may never see a case in their entire careers. However, the Keeshond is 50 times more likely to be diagnosed with PHPT than other breeds, so Keeshond Dog owners must be familiar with this disease! PHPT is a curable disease! If treated early, dogs can enjoy a normal life. It’s up to Keeshond owners to inform our veterinarians that this unusual disease runs in the breed. We must make certain our dogs are screened for it!
The Keeshond Dog has four parathyroid glands. “Para” means “beside” the parathyroid glands are located in the neck, beside the thyroid gland. (People are often confused by the words thyroid and parathyroid. The parathyroid glands are located beside the thyroid, but they are separate glands. PHPT is not a thyroid problem!) The tiny parathyroid glands, normally less than 2 mm in diameter, produce parathyroid hormone (PTH.) PTH controls the calcium level in the dog’s blood. When the calcium level is low, the parathyroid glands secrete PTH, which causes the calcium level to rise. When the calcium level is normal, the parathyroid glands turn off they stop secreting PTH, so the calcium level doesn’t rise too high.
In PHPT, one or more of the parathyroid glands fail to turn off. They continue to secrete PTH, causing the blood calcium to continue rising to dangerous levels. In 80-85% of cases, this is caused by a benign tumor (called an adenoma) on one parathyroid gland. Occasionally, two or more parathyroid glands are involved, which is called hyperplasia. PHPT can also be caused by a malignant carcinoma, but in Keeshond dogs, this is very rare. The disease typically strikes middle-aged and older dogs. If PHPT is treated in the early stages, it can be cured with few or no permanent effects on the Keeshond. As the disease progresses and calcium levels continue to rise, painful calcium deposits form in the soft tissues of the body, the dog’s kidneys are damaged, and bone disease can occur. If untreated, the Keeshond eventually dies from severe kidney failure.
In the Keeshond, PHPT is a genetic disease transmitted by a dominant gene. To get PHPT, a dog only needs to inherit the defective gene from one parent. (So Keeshond mixes are at risk, too.) If a Keeshond with the abnormal gene is bred, half of his or her puppies will get the defective gene. If they live long enough, nearly all dogs with the defective gene will develop PHPT.
The signs of PHPT are subtle and insidious. In the early stages, the dog may have no symptoms. As the disease progresses, you may notice the dog is drinking more water and urinating more than usual. Gradually, the signs may include weakness, lethargy, shaking, decreased activity, loss of appetite and possibly weight loss. Many dogs develop calcium-containing bladder or kidney stones. By monitoring the dog’s blood calcium levels on a regular basis, PHPT can be caught and treated early, before the dog shows signs and kidney damage occurs.
Option 1: Monitoring blood calcium levels: Until recently, this was the only way to screen for PHPT. It is still an excellent option. It is essential for dogs who have the PHPT gene. Starting at age 5 years, a comprehensive blood panel should be done annually, including complete blood count (CBC) and blood chemistries. Beginning at age 7, we recommend a blood panel every 6 months. High blood calcium indicates possible PHPT. If the calcium is above normal, more diagnostic work must be done to determine whether the dog has PHPT or another illness.
Keeshond Dogs who test positive for the defective gene will almost certainly develop PHPT during their lifetimes. These dogs must have their calcium monitored closely (see option 1 above), to detect and treat PHPT in its early stages, before they suffer permanent kidney damage. Keeshonds who test negative do not have the PHPT gene and are not likely to develop PHPT. (Middle aged and older dogs should still have blood panels done at least annually, to detect other problems.) Reputable Keeshond breeders are now testing their dogs prior to breeding them. If the dam and sire are both PHPT negative, the puppies will be free of the PHPT gene. Before purchasing a Keeshond puppy, ask to see proof that both parents are PHPT negative!
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