Meet Baby: A Dachshund with a challenging diagnosis
Baby, a spayed female Dachshund mix, came to Veterinary Referral Hospital of Hickory for an abdominal ultrasound, as recommended by her regular veterinarian. Baby was not eating, and she was having difficult bowel movements.
Baby came in through our emergency service, where all our walk-in patients are admitted. Emergency clinician Dr. Heather Rubi saw Baby first and did a physical exam, took X-rays, and drew blood to run a blood panel.
Baby’s physical exam showed nothing out of the ordinary. Her heart and lungs sounded normal, her ears, eyes, nose, and throat were normal, and Baby showed no signs of pain when Dr. Rubi pressed on her abdomen or checked her limbs. She was alert and responsive. Baby’s X-rays showed some gas in her stomach, but nothing else. Her stomach, small intestines, large intestines, bladder, heart, and lungs all appeared normal.
Dr. Rubi admitted Baby and gave her pantoprazole – used to treat acid reflux – and ondansetron – used to prevent nausea and vomiting. She also began IV fluid therapy. She then transferred Baby to the care of Dr. Scott Helms in our internal medicine service.
Baby’s bloodwork results showed Dr. Helms more than her X-rays and physical exams did. Her BUN (blood urea nitrogen), which measures nitrogen waste in the blood, result came back extremely high. The normal range for BUN is 9.0-29.0 mg/dl, and Baby’s was 99.3 mg/dl.
Some of her other levels were high as well, including her creatinine, phosphorus, calcium, total protein, and potassium. Her pH level was low, and her base excess was extremely low – normal range is between -5.0 to 5.0, and Baby’s was -7.9. This negative value indicates a base deficit from a relative excess of blood acids. Her sodium was also low.
Based on Baby’s history and her current presentation, Dr. Helms suspected that Baby may have hypoadrenocorticism, also known as Addison’s disease.
Addison’s disease is caused by a lower-than-normal production of hormones, such as cortisol, by the adrenal glands. Adrenal hormones are necessary to control salt, sugar, and water balance in the body. The disease most commonly affects young to middle-aged female dogs. Signs can be severe and sudden, or intermittent and with varying severity. Those signs include weakness, depression, lack of appetite, vomiting, diarrhea, and, occasionally, increased thirst and urine production.
When a dog is stressed, the adrenal glands produce more cortisol to help them deal with that stress. A dog with Addison’s disease cannot make enough cortisol, so, they cannot deal with stress. Therefore, hypoadrenocorticism often shows when a dog is put in a stressful situation.
Hypoadrenocorticism does not show on an X-ray, and the symptoms can be confused with symptoms of other conditions. Initial laboratory tests can provide suspicion of Addison’s disease – dogs with Addison’s often have low blood sodium and high blood potassium, as Baby did. However, to confirm the disease, the veterinarian must run an ACTH stimulation test.
Adrenocorticotropic hormone, or ACTH, is a hormone produced and secreted by the pituitary gland. When an ACTH stimulation test is performed, the veterinarian collects a blood sample, then injects ACTH, and collects another blood sample an hour later. The amount of cortisol in the blood samples is measured. With a healthy adrenal gland, ACTH increases the production of cortisol. If the second blood sample does not show increased cortisol levels, we know the patient’s adrenal gland ws unable to respond properly to the ACTH. When Dr. Helms ran the ACTH stimulation test on Baby, the results were consistent with hypoadrenocorticism.
The following day, Baby’s bloodwork showed improvements, thanks to the fluid therapy. Her pH was in the normal range, her sodium was only slightly elevated, her potassium was lower, and her chloride was now within the normal range. Her BUN, that was 99.3 previously, was now 28.9, and within the normal range.
Results of a urinalysis taken after Baby began fluid therapy showed a low specific gravity, which is a measurement of the kidney’s ability to concentrate urine. While a low specific gravity can be a sign of renal failure, Dr. Helms says about 60 percent of patients with Addison’s disease have a low specific gravity.
Baby’s final diagnosis was hypoadrenocorticism, or Addison’s disease. Dr. Helms prescribed Baby desoxycorticosterone pivalate injections – an injection given every 25 days to control her disease. She was also prescribed oral prednisone, a steroid replacement. He recommended rechecking Baby’s electrolytes and renal values in two weeks. He also gave Baby metronidazole for diarrhea, as many patients with Addison’s disease will have gastrointestinal disease as well. The metronidazole is an antibiotic that has a good spectrum of activity against gastrointestinal pathogenic bacteria that may overgrow in Addison’s patients, and has gastrointestinal anti-inflammatory effects.
Within the next couple of weeks, Baby came back for a check-up, and she is now doing well on her prescribed medications. She will continue her injections every 28 days to maintain her cortisol levels.
Sometimes you know something is wrong with your pet and the answers aren’t clear. VRHOH specialists are available for consults with veterinarians and patient evaluation and treatment at our hospital.