Should circulatory shock heighten suspicion of hypoadrenocorticism?
Apr 01, 2004
Signalment Canine, Maltese, 2 years old, male, neutered, 8.4 lbs.
Physical examination The findings include rectal temperature 101.2° F, heart rate 165/min, respiratory rate 20/min, pink mucous membranes, normal capillary refill time, and normal heart and lung sounds. The dog has a non-painful abdomen but constipated stool palpated. The neurological examination is normal.
Ultrasound examination: Thorough abdominal ultrasonography was performed with the dog positioned in dorsal recumbency.
The left and right kidneys are similar in size, shape and echotexture. Each kidney shows an inhomogeneous texture in the renal cortex. The renal pelvis is slightly dilated in the right kidney. No masses or calculi were noted in either kidney. The urinary bladder is distended with urine and contains some urine sediment material. No masses or calculi noted. The left and right adrenal glands are similar in size and shape. The stomach, small intestines and colon are normal. The pancreas shows an inhomogeneous texture in its parenchyma.
Case management: In this case, most likely hypoadrenocorticism is present. There was no obvious evidence of cancer noted during this abdominal ultrasound study. At this point, an ACTH stimulation test is warranted now, and then therapy for hypoadrenocorticism is started with fluids and prednisone. After the results of the ACTH stimulation test are known, then Florinef or injectable mineralocorticoid is started. The following information may be helpful.
Review on hypoadrenocorticism Primary hypoadrenocorticism is most often diagnosed in young dogs. Secondary hypoadrenocorticism resulting from ACTH deficiency is relatively common in dogs afflicted with deficiencies of the pituitary gland.
Severe hyponatremia and hypochloremia associated with hyperkalemia are the hallmarks of hypoadrenocorticism. Although a serum Na:K ratio of less than 27:1 is considered suggestive of hypoadrenocorticism, it is never pathognomonic. Gastrointestinal disease, acute renal failure, and postrenal azotemia may also cause a low Na:K ratio. Some dogs with hypoadrenocorticism, especially those dogs with only a glucocorticoid deficiency, will not show the typical electrolyte disturbances. Azotemia and hyperphosphatemia are also associated with primary hypoadrenocorticism and make it difficult to differentiate from the azotemia of acute renal failure. The hematologic abnormalities are eosinophilia and lymphocytosis or normal eosinophil and lymphocyte counts in the face of any metabolic stress. The anemia of hypoadrenocorticism usually results from ongoing hemorrhagic gastroenteritis and not caused by the endocrine problem itself. Although hypoglycemia is more commonly associated with secondary or atypical hypoadrenocorticism, it is infrequently seen with primary hypoadrenocorticism. Urine specific gravity is frequently low and is attributed to an inadequate medullary gradient due to sodium depletion and decreased medullary blood flow. Dilute urine along with azotemia and hyperkalemia may easily be mistaken for acute renal failure.