Hypercalcemia in horses refers to an elevated level of calcium in the bloodstream. This condition can result from various underlying causes, including dietary imbalances, certain medications, or diseases such as hyperparathyroidism and renal failure. Calcium is essential for numerous physiological processes, including bone formation, muscle contraction, and nerve function. However, excessive calcium levels can lead to health complications such as kidney damage, gastrointestinal disturbances, and cardiac irregularities. This page gathers peer-reviewed research studies and scholarly articles that explore the causes, pathophysiology, diagnosis, and management of hypercalcemia in equine health.
Townsend KS, Johnson PJ, Donnelly LL, LaCarrubba AM, Lattimer JC, Havis B, Springer NL, Kim DY.A 26-year-old mule gelding was evaluated for chronic weight loss and decreased appetite. The mule had been losing weight and intermittently hypophagic for approximately 7 months. Laboratory analysis of whole blood and plasma identified severe total hypercalcemia, marked hypophosphatemia, markedly increased parathyroid hormone concentration, and marked lymphocytosis. A sestimibi scan intended to identify parathyroid gland tissue was nondiagnostic. Results of flow cytometry and PCR for antigen receptor rearrangement (PARR) were consistent with a B cell lymphoproliferative disorder, likely chro...
Drozdzewska K, Gehlen H.The diagnosis of internal neoplasia in horses is challenging. Increased production of hormones physiologic for adult animals (e.g., adrenocorticotropin, norepinephrine, and erythropoietin) or typical for the foetal phase (alpha-fetoprotein, anti-Müllerian hormone, and parathyroid-hormone-related protein) might aid in tumour diagnostics. Thymidine kinase-1 and alkaline phosphatase are examples of intracellular enzymes, whose activity in the blood may increase in some neoplasia cases. Furthermore, inappropriate production of abnormal monoclonal or autologous antibodies can accompany lymphoma an...
Suva LJ, Cooper A, Watts AE, Ebetino FH, Price J, Gaddy D.Bisphosphonates (BPs) are characterized by their ability to bind strongly to bone mineral and inhibit bone resorption. However, BPs exert a wide range of pharmacological activities beyond the inhibition of bone resorption, including the inhibition of cancer cell metastases and angiogenesis and the inhibition of proliferation and apoptosis in vitro. Additionally, the inhibition of matrix metalloproteinase activity, altered cytokine and growth factor expression, as well as reductions in parameters of pain have also been reported. In humans, clinical BP use has transformed the treatment of post-m...
Schwarz B, Klang A, Schwendenwein I.A 14-year-old Zweibrücker Warmblood gelding was presented for evaluation of lethargy and headshaking. The horse had a history of bouts of lameness in different limbs and back problems. It also had many mild colic episodes in the past. Results of repeat laboratory tests had shown persistent hypercalcemia (4.8 mmol/L; reference interval [RI]: 2.0-3.2 mmol/L) for 1.5 years and later on hypophosphatemia (0.4 mmol/L; RI: 0.5-1.3 mmol/L) and mild hypermagnesemia (1.0 mmol/L; RI: 0.5-0.9 mmol/L). Parathyroid hormone (PTH) concentration was within the RI. Other causes of hypercalcemia, such as...
Gorenberg EB, Johnson AL, Magdesian KG, Bertin FR, Costa LRR, Theelen MJP, Durward-Akhurst SA, Cruz Villagrán C, Carslake H, Frank N, Tomlinson JE.Primary hyperparathyroidism is uncommon in equids. Objective: To describe the diagnostic findings and efficacy of treatment in equids with primary hyperparathyroidism. Methods: Retrospective case series describing 16 horses and one mule. Methods: Cases were identified by retrospective review of records at Cornell University and via an ACVIM listserv query. Inclusion criteria were an equid with hypercalcemia, normal renal function and high parathyroid hormone (PTH) or histopathological diagnosis of a parathyroid adenoma. Equids with normal PTH and PTH-related protein (PTHrP) in the face of hype...
LeRoy B, Woolums A, Wass J, Davis E, Gold J, Foreman JH, Lohmann K, Adams J.Hypercalcemia is common in horses with renal failure, but it is not known whether it impacts prognosis. Objective: The primary objective of this study was to determine whether hypercalcemia was associated with decreased likelihood of survival to discharge in horses with renal failure. Secondary objectives were to determine whether hypercalcemia was more common in acute (ARF) or chronic renal failure (CRF), whether feeding alfalfa was associated with hypercalcemia, and whether serum creatinine concentration was associated with survival. Methods: Medical records of 63 horses presented to referra...
Taylor SD, Haldorson GJ, Vaughan B, Pusterla N.Gastric neoplasia of horses is incompletely described. Objective: Provide history, clinical signs, and clinicopathological and pathological findings associated with gastric neoplasia in horses. Methods: Twenty-four horses with gastric neoplasia. Methods: Retrospective study. History, clinical signs, and clinicopathological and pathologic findings in horses diagnosed histologically with gastric neoplasia were reviewed. Results: Horses ranged in age from 9 to 25 years (median 18 years at presentation). There was no apparent breed or sex predisposition. The most common presenting complaints were ...
Toribio RE, Kohn CW, Rourke KM, Levine AL, Rosol TJ.To determine effects of experimentally induced hypercalcemia on serum concentrations and urinary excretion of electrolytes, especially ionized magnesium (iMg), in healthy horses. Methods: 21 clinically normal mares. Methods: Horses were assigned to 5 experimental protocols (1, hypercalcemia induced with calcium gluconate; 2, hypercalcemia induced with calcium chloride; 3, infusion with dextrose solution; 4, infusion with sodium gluconate; and 5, infusion with saline [0.9% NaCl] solution). Hypercalcemia was induced for 2 hours. Dextrose, sodium gluconate, and saline solution were infused for 2 ...
Barton MH, Sharma P, LeRoy BE, Howerth EW.A 13-year-old gelding was examined because of weight loss, hyperglobulinemia, and hypercalcemia. Possible causes of hypercalcemia that were considered included renal failure, primary hyperparathyroidism, vitamin D toxicosis, and malignancy. There was no history of vitamin D ingestion, and serum creatinine and parathyroid hormone concentrations were normal, making renal failure and primary hyperparathyroidism unlikely. The hypercalcemia was suspected to be a result of malignancy, but thorough testing did not reveal any neoplastic disease. Eight months later, serum parathyroid hormone-related pr...
Pusterla N, Stacy BA, Vernau W, De Cock HE, Magdesian KG.The clinical findings in two horses with secretory multiple myeloma and secondary immunoglobulin A (IgA) monoclonal gammopathy were non-specific and included weight loss, pale mucous membranes, limb oedema and bacterial respiratory tract infection. Consistent laboratory abnormalities included hyperproteinaemia, hyperglobulinaemia, hypoalbuminaemia and hypercalcaemia. The diagnosis was based on the presence of IgA monoclonal gammopathy in serum and urine and bone marrow plasmacytosis (> 10 per cent). One horse was euthanased; it had neoplastic plasma cell infiltrates in its kidneys, spleen, ...
Toribio RE, Kohn CW, Sams RA, Capen CC, Rosol TJ.Abnormalities in calcium (Ca(2+)) homeostasis are reported in horses with several pathological conditions; however, there is little information on Ca(2+) regulation in horses. The objectives of the present study were to determine the Ca(2+) set-point in healthy horses, to determine whether the Ca(2+)/parathyroid hormone (PTH) response curves were characterized by hysteresis, and to determine if the order of experimentally induced hypocalcemia or hypercalcemia had an effect on PTH secretion. The Ca(2+) set-point and hysteresis were determined in 12 healthy horses by infusing Na(2)EDTA and calci...
Estepa JC, Aguilera-Tejero E, Mayer-Valor R, Almadén Y, Felsenfeld AJ, Rodríguez M.Measurement of parathyroid hormone (PTH) in horses was performed on plasma samples using 2 immunoradiometric assays: a human intact PTH assay and a rat amino-terminal PTH assay. The assays were validated by assessment of their precision, sensitivity and specificity, and also by evaluating PTH changes in the horse in response to variation in blood ionised calcium. Intra- and inter-assay variance, precision and sensitivity were similar for both human and rat assays; however, the rat assay was slightly more precise and sensitive than the human assay. Both assays detected an increase in PTH levels...
Finley MR, Rebhun WC, Dee A, Langsetmo I.An 8-year-old castrated male Paint Horse was referred because of generalized pruritus, alopecia, and intermittent fever. Results of gross evaluation of the skin and microscopic evaluation of skin scrapings were inconclusive. Histologic examination of skin biopsy specimens revealed vasculitis. The horse had persistent hypercalcemia; therefore, lymphosarcoma was considered a possibility. Ultrasonography revealed hypoechoic nodules within the parenchyma of the spleen and liver. Results of microscopic evaluation of an aspirate from a splenic nodule were suggestive of lymphosarcoma. The condition o...
Peauroi JR, Fisher DJ, Mohr FC, Vivrette SL.A 14-year-old Arabian gelding had weight loss and anorexia of 3 weeks' duration. Results of repeated laboratory tests revealed persistent hypercalcemia and serum phosphorus concentration that was within or less than the reference range. Parathyroid hormone concentration was high. Histologic examination of specimens obtained at necropsy revealed parathyroid adenoma. A diagnosis of primary hyperparathyroidism attributable to a functional parathyroid adenoma was made. Abnormalities in calcium and phosphorus concentrations were similar to those seen with primary hyperparathyroidism in dogs, in whi...
Frank N, Hawkins JF, Couëtil LL, Raymond JT.A 17-year-old pony mare was admitted for evaluation of progressive enlargement of the facial bones during the preceding 9 months. Laboratory testing revealed that the pony had hypercalcemia, hypophosphatemia, high urinary fractional excretion of phosphorus, and high serum concentration of intact parathyroid hormone (185.1 pmol/L; reference range, 0.25 to 2.0 pmol/L). On the basis of these findings, a diagnosis of primary hyperparathyroidism was made by ruling out nutritional secondary hyperparathyroidism, chronic renal disease, and pseudohyperparathyroidism resulting from neoplasia. Although p...
Rosol TJ, Nagode LA, Robertson JT, Leeth BD, Steinmeyer CL, Allen CM.Humoral hypercalcemia of malignancy was evident in a horse that had a locally invasive ameloblastoma of the left hemimandible. Surgical removal of the neoplasm resulted in prompt return of serum calcium and parathyroid hormone concentrations to within reference limits. The tumor contained parathyroid hormone-related protein, as demonstrated by immunohistochemistry and western blot analysis. It is likely that production of this protein by the neoplasm was important in the pathogenesis of the hypercalcemia. The case represented a sporadic form of humoral hypercalcemia of malignancy attributable ...
Jaeschke G, Rudolph R.Clinicopathological aspects of equine leukosis are discussed in a review. Among various other findings, only hypercalcaemia accompanied by paraneoplastic syndrome in the course of equine leukosis, increased values of alkaline phosphatase as usual in tumorous diseases, and hypalbuminaemia and hypergammaglobulinaemia in mesentric and intestinal forms of equine leukosis seem to have some diagnostic and pathogenetic significance. Changed values of further parameters are more or less non-specific concomitant signs, indicating that other organs or organ systems have been affected. However, in case o...
Karcher LF, Le Net JL, Turner BF, Reimers TJ, Tennant BC.An 18-year-old Appaloosa mare was examined because of squamous cell carcinoma of the vulva, anorexia with pronounced weight loss, and hypercalcemia. The tumor had developed rapidly over a period of 3 months and externally extended ventrally involving the perineum and the dorsal aspect of the udder. Necropsy examination demonstrated a large primary squamous cell carcinoma of the vulva, perineum, and mammary gland with metastases to the supramammary, sublumbar, deep inguinal, and mediastinal lymph nodes. No gross renal lesions were observed and, histologically, there was only mild vacuolation of...
Mair TS, Yeo SP, Lucke VM.Two horses with deposits of lymphosarcoma, one in the spleen, the other in the mediastinum, several lymph nodes and kidneys, lost weight rapidly and became depressed and weak. They were hypercalcaemic and post mortem examination revealed extensive calcification of the heart and major vessels. There was no evidence of bone marrow metastases in the one horse whose marrow was examined, and the thyroid and parathyroid glands of both horses were grossly normal.
Roussel AJ, Lin YC, Strait JR, Modransky PD.Radioimmunoassay for parathyroid hormone (PTH) in equids was performed on blood samples from healthy equids and equids with hypercalcemia and hypophosphatemia. The assay was validated for equine carboxy-terminal PTH. Manipulation of serum ionized Ca in healthy equids by infusing Na2 EDTA and CaCl2 produced an expected increase and decrease, respectively, in measurable immunoreactive PTH. Intra-assay and interassay coefficients of variation were 2.6% and 11.7%, respectively. The range of PTH valves for healthy mature horse mares and geldings maintained on pasture was less than 0.27 ng/ml to 0.9...
McCoy DJ, Beasley R.Hypercalcemia associated with malignancy was diagnosed in a 2-year-old Thoroughbred filly admitted because of weight loss and reduced exercise tolerance of approximately 2 months' duration. Laboratory findings included hypercalcemia, hypophosphatemia, anemia, marked neutrophilia with lymphopenia and eosinopenia, and normal immunoreactive parathyroid hormone concentration. At necropsy, a 53.6-kg tumor was located in the cranioventral aspect of the abdominal cavity. Gross renal lesions were not noticed. Bone tissue appeared to be normal on gross and histologic examinations. The parathyroid gland...
Tennant B, Bettleheim P, Kaneko JJ.Chronic renal failure associated with hypercalcemia and hypophosphatemia was diagnosed in 6 horses. The renal lesions in 5 of the horses were classified as chronic glomerulonephritis and in the sixth, as chronic interstitial nephritis/pyelonephritis. There was no evidence of primary hyperparathyroidism or pseudohyperparathyroidism, thus suggesting that hypercalcemia associated with advanced renal failure in horses is related to a unique role of the equine kidney in calcium homeostasis.
Brobst DF, Lee HA, Spencer GR.An 11-year-old mare with polyuria, polydipsia, and azotemia was found to be hypercalcemic and hypophosphatemic. The concentration of calcium in a single collection of urine was within normal limits, although urinary inorganic phosphate concentration was lower than normal. After a brief period of supportive treatment, the mare died. At necropsy, the kidneys were found to be shrunken and fibrous. Histologically, the lesions were those of glomerulonephritis.
Meuten DJ, Price SM, Seiler RM, Krook L.Pseudohyperparathyroidism was diagnosed in a mature stallion presented for anorexia, weight loss, pollakiuria and constipation. Laboratory findings included hypercalcemia, hypophosphatemia, anemia and isosthenuria. Thoracocentesis indicated an exfoliating squamous cell carcinoma. At necropsy, a squamous cell carcinoma of the stomach with metastases to the abdominal and thoracic cavities was diagnosed. No osseous metastases were found. No gross or microscopic renal lesions were noted. Bone tissue showed arrested resorption, and the parathyroid gland was atrophic.
Suva LJ, Cooper A, Watts AE, Ebetino FH, Price J, Gaddy D.Bisphosphonates (BPs) are characterized by their ability to bind strongly to bone mineral and inhibit bone resorption. However, BPs exert a wide range of pharmacological activities beyond the inhibition of bone resorption, including the inhibition of cancer cell metastases and angiogenesis and the inhibition of proliferation and apoptosis in vitro. Additionally, the inhibition of matrix metalloproteinase activity, altered cytokine and growth factor expression, as well as reductions in parameters of pain have also been reported. In humans, clinical BP use has transformed the treatment of post-m...
Taylor SD, Haldorson GJ, Vaughan B, Pusterla N.Gastric neoplasia of horses is incompletely described. Objective: Provide history, clinical signs, and clinicopathological and pathological findings associated with gastric neoplasia in horses. Methods: Twenty-four horses with gastric neoplasia. Methods: Retrospective study. History, clinical signs, and clinicopathological and pathologic findings in horses diagnosed histologically with gastric neoplasia were reviewed. Results: Horses ranged in age from 9 to 25 years (median 18 years at presentation). There was no apparent breed or sex predisposition. The most common presenting complaints were ...
Toribio RE, Kohn CW, Rourke KM, Levine AL, Rosol TJ.To determine effects of experimentally induced hypercalcemia on serum concentrations and urinary excretion of electrolytes, especially ionized magnesium (iMg), in healthy horses. Methods: 21 clinically normal mares. Methods: Horses were assigned to 5 experimental protocols (1, hypercalcemia induced with calcium gluconate; 2, hypercalcemia induced with calcium chloride; 3, infusion with dextrose solution; 4, infusion with sodium gluconate; and 5, infusion with saline [0.9% NaCl] solution). Hypercalcemia was induced for 2 hours. Dextrose, sodium gluconate, and saline solution were infused for 2 ...
Toribio RE, Kohn CW, Sams RA, Capen CC, Rosol TJ.Abnormalities in calcium (Ca(2+)) homeostasis are reported in horses with several pathological conditions; however, there is little information on Ca(2+) regulation in horses. The objectives of the present study were to determine the Ca(2+) set-point in healthy horses, to determine whether the Ca(2+)/parathyroid hormone (PTH) response curves were characterized by hysteresis, and to determine if the order of experimentally induced hypocalcemia or hypercalcemia had an effect on PTH secretion. The Ca(2+) set-point and hysteresis were determined in 12 healthy horses by infusing Na(2)EDTA and calci...
Barton MH, Sharma P, LeRoy BE, Howerth EW.A 13-year-old gelding was examined because of weight loss, hyperglobulinemia, and hypercalcemia. Possible causes of hypercalcemia that were considered included renal failure, primary hyperparathyroidism, vitamin D toxicosis, and malignancy. There was no history of vitamin D ingestion, and serum creatinine and parathyroid hormone concentrations were normal, making renal failure and primary hyperparathyroidism unlikely. The hypercalcemia was suspected to be a result of malignancy, but thorough testing did not reveal any neoplastic disease. Eight months later, serum parathyroid hormone-related pr...
Mair TS, Yeo SP, Lucke VM.Two horses with deposits of lymphosarcoma, one in the spleen, the other in the mediastinum, several lymph nodes and kidneys, lost weight rapidly and became depressed and weak. They were hypercalcaemic and post mortem examination revealed extensive calcification of the heart and major vessels. There was no evidence of bone marrow metastases in the one horse whose marrow was examined, and the thyroid and parathyroid glands of both horses were grossly normal.
Frank N, Hawkins JF, Couëtil LL, Raymond JT.A 17-year-old pony mare was admitted for evaluation of progressive enlargement of the facial bones during the preceding 9 months. Laboratory testing revealed that the pony had hypercalcemia, hypophosphatemia, high urinary fractional excretion of phosphorus, and high serum concentration of intact parathyroid hormone (185.1 pmol/L; reference range, 0.25 to 2.0 pmol/L). On the basis of these findings, a diagnosis of primary hyperparathyroidism was made by ruling out nutritional secondary hyperparathyroidism, chronic renal disease, and pseudohyperparathyroidism resulting from neoplasia. Although p...
Meuten DJ, Price SM, Seiler RM, Krook L.Pseudohyperparathyroidism was diagnosed in a mature stallion presented for anorexia, weight loss, pollakiuria and constipation. Laboratory findings included hypercalcemia, hypophosphatemia, anemia and isosthenuria. Thoracocentesis indicated an exfoliating squamous cell carcinoma. At necropsy, a squamous cell carcinoma of the stomach with metastases to the abdominal and thoracic cavities was diagnosed. No osseous metastases were found. No gross or microscopic renal lesions were noted. Bone tissue showed arrested resorption, and the parathyroid gland was atrophic.
Tennant B, Bettleheim P, Kaneko JJ.Chronic renal failure associated with hypercalcemia and hypophosphatemia was diagnosed in 6 horses. The renal lesions in 5 of the horses were classified as chronic glomerulonephritis and in the sixth, as chronic interstitial nephritis/pyelonephritis. There was no evidence of primary hyperparathyroidism or pseudohyperparathyroidism, thus suggesting that hypercalcemia associated with advanced renal failure in horses is related to a unique role of the equine kidney in calcium homeostasis.
Peauroi JR, Fisher DJ, Mohr FC, Vivrette SL.A 14-year-old Arabian gelding had weight loss and anorexia of 3 weeks' duration. Results of repeated laboratory tests revealed persistent hypercalcemia and serum phosphorus concentration that was within or less than the reference range. Parathyroid hormone concentration was high. Histologic examination of specimens obtained at necropsy revealed parathyroid adenoma. A diagnosis of primary hyperparathyroidism attributable to a functional parathyroid adenoma was made. Abnormalities in calcium and phosphorus concentrations were similar to those seen with primary hyperparathyroidism in dogs, in whi...
Estepa JC, Aguilera-Tejero E, Mayer-Valor R, Almadén Y, Felsenfeld AJ, Rodríguez M.Measurement of parathyroid hormone (PTH) in horses was performed on plasma samples using 2 immunoradiometric assays: a human intact PTH assay and a rat amino-terminal PTH assay. The assays were validated by assessment of their precision, sensitivity and specificity, and also by evaluating PTH changes in the horse in response to variation in blood ionised calcium. Intra- and inter-assay variance, precision and sensitivity were similar for both human and rat assays; however, the rat assay was slightly more precise and sensitive than the human assay. Both assays detected an increase in PTH levels...
Rosol TJ, Nagode LA, Robertson JT, Leeth BD, Steinmeyer CL, Allen CM.Humoral hypercalcemia of malignancy was evident in a horse that had a locally invasive ameloblastoma of the left hemimandible. Surgical removal of the neoplasm resulted in prompt return of serum calcium and parathyroid hormone concentrations to within reference limits. The tumor contained parathyroid hormone-related protein, as demonstrated by immunohistochemistry and western blot analysis. It is likely that production of this protein by the neoplasm was important in the pathogenesis of the hypercalcemia. The case represented a sporadic form of humoral hypercalcemia of malignancy attributable ...
Karcher LF, Le Net JL, Turner BF, Reimers TJ, Tennant BC.An 18-year-old Appaloosa mare was examined because of squamous cell carcinoma of the vulva, anorexia with pronounced weight loss, and hypercalcemia. The tumor had developed rapidly over a period of 3 months and externally extended ventrally involving the perineum and the dorsal aspect of the udder. Necropsy examination demonstrated a large primary squamous cell carcinoma of the vulva, perineum, and mammary gland with metastases to the supramammary, sublumbar, deep inguinal, and mediastinal lymph nodes. No gross renal lesions were observed and, histologically, there was only mild vacuolation of...
Pusterla N, Stacy BA, Vernau W, De Cock HE, Magdesian KG.The clinical findings in two horses with secretory multiple myeloma and secondary immunoglobulin A (IgA) monoclonal gammopathy were non-specific and included weight loss, pale mucous membranes, limb oedema and bacterial respiratory tract infection. Consistent laboratory abnormalities included hyperproteinaemia, hyperglobulinaemia, hypoalbuminaemia and hypercalcaemia. The diagnosis was based on the presence of IgA monoclonal gammopathy in serum and urine and bone marrow plasmacytosis (> 10 per cent). One horse was euthanased; it had neoplastic plasma cell infiltrates in its kidneys, spleen, ...
Gorenberg EB, Johnson AL, Magdesian KG, Bertin FR, Costa LRR, Theelen MJP, Durward-Akhurst SA, Cruz Villagrán C, Carslake H, Frank N, Tomlinson JE.Primary hyperparathyroidism is uncommon in equids. Objective: To describe the diagnostic findings and efficacy of treatment in equids with primary hyperparathyroidism. Methods: Retrospective case series describing 16 horses and one mule. Methods: Cases were identified by retrospective review of records at Cornell University and via an ACVIM listserv query. Inclusion criteria were an equid with hypercalcemia, normal renal function and high parathyroid hormone (PTH) or histopathological diagnosis of a parathyroid adenoma. Equids with normal PTH and PTH-related protein (PTHrP) in the face of hype...
Schwarz B, Klang A, Schwendenwein I.A 14-year-old Zweibrücker Warmblood gelding was presented for evaluation of lethargy and headshaking. The horse had a history of bouts of lameness in different limbs and back problems. It also had many mild colic episodes in the past. Results of repeat laboratory tests had shown persistent hypercalcemia (4.8 mmol/L; reference interval [RI]: 2.0-3.2 mmol/L) for 1.5 years and later on hypophosphatemia (0.4 mmol/L; RI: 0.5-1.3 mmol/L) and mild hypermagnesemia (1.0 mmol/L; RI: 0.5-0.9 mmol/L). Parathyroid hormone (PTH) concentration was within the RI. Other causes of hypercalcemia, such as...
LeRoy B, Woolums A, Wass J, Davis E, Gold J, Foreman JH, Lohmann K, Adams J.Hypercalcemia is common in horses with renal failure, but it is not known whether it impacts prognosis. Objective: The primary objective of this study was to determine whether hypercalcemia was associated with decreased likelihood of survival to discharge in horses with renal failure. Secondary objectives were to determine whether hypercalcemia was more common in acute (ARF) or chronic renal failure (CRF), whether feeding alfalfa was associated with hypercalcemia, and whether serum creatinine concentration was associated with survival. Methods: Medical records of 63 horses presented to referra...
Townsend KS, Johnson PJ, Donnelly LL, LaCarrubba AM, Lattimer JC, Havis B, Springer NL, Kim DY.A 26-year-old mule gelding was evaluated for chronic weight loss and decreased appetite. The mule had been losing weight and intermittently hypophagic for approximately 7 months. Laboratory analysis of whole blood and plasma identified severe total hypercalcemia, marked hypophosphatemia, markedly increased parathyroid hormone concentration, and marked lymphocytosis. A sestimibi scan intended to identify parathyroid gland tissue was nondiagnostic. Results of flow cytometry and PCR for antigen receptor rearrangement (PARR) were consistent with a B cell lymphoproliferative disorder, likely chro...
Jaeschke G, Rudolph R.Clinicopathological aspects of equine leukosis are discussed in a review. Among various other findings, only hypercalcaemia accompanied by paraneoplastic syndrome in the course of equine leukosis, increased values of alkaline phosphatase as usual in tumorous diseases, and hypalbuminaemia and hypergammaglobulinaemia in mesentric and intestinal forms of equine leukosis seem to have some diagnostic and pathogenetic significance. Changed values of further parameters are more or less non-specific concomitant signs, indicating that other organs or organ systems have been affected. However, in case o...
McCoy DJ, Beasley R.Hypercalcemia associated with malignancy was diagnosed in a 2-year-old Thoroughbred filly admitted because of weight loss and reduced exercise tolerance of approximately 2 months' duration. Laboratory findings included hypercalcemia, hypophosphatemia, anemia, marked neutrophilia with lymphopenia and eosinopenia, and normal immunoreactive parathyroid hormone concentration. At necropsy, a 53.6-kg tumor was located in the cranioventral aspect of the abdominal cavity. Gross renal lesions were not noticed. Bone tissue appeared to be normal on gross and histologic examinations. The parathyroid gland...
Brobst DF, Lee HA, Spencer GR.An 11-year-old mare with polyuria, polydipsia, and azotemia was found to be hypercalcemic and hypophosphatemic. The concentration of calcium in a single collection of urine was within normal limits, although urinary inorganic phosphate concentration was lower than normal. After a brief period of supportive treatment, the mare died. At necropsy, the kidneys were found to be shrunken and fibrous. Histologically, the lesions were those of glomerulonephritis.
Roussel AJ, Lin YC, Strait JR, Modransky PD.Radioimmunoassay for parathyroid hormone (PTH) in equids was performed on blood samples from healthy equids and equids with hypercalcemia and hypophosphatemia. The assay was validated for equine carboxy-terminal PTH. Manipulation of serum ionized Ca in healthy equids by infusing Na2 EDTA and CaCl2 produced an expected increase and decrease, respectively, in measurable immunoreactive PTH. Intra-assay and interassay coefficients of variation were 2.6% and 11.7%, respectively. The range of PTH valves for healthy mature horse mares and geldings maintained on pasture was less than 0.27 ng/ml to 0.9...
Finley MR, Rebhun WC, Dee A, Langsetmo I.An 8-year-old castrated male Paint Horse was referred because of generalized pruritus, alopecia, and intermittent fever. Results of gross evaluation of the skin and microscopic evaluation of skin scrapings were inconclusive. Histologic examination of skin biopsy specimens revealed vasculitis. The horse had persistent hypercalcemia; therefore, lymphosarcoma was considered a possibility. Ultrasonography revealed hypoechoic nodules within the parenchyma of the spleen and liver. Results of microscopic evaluation of an aspirate from a splenic nodule were suggestive of lymphosarcoma. The condition o...
Drozdzewska K, Gehlen H.The diagnosis of internal neoplasia in horses is challenging. Increased production of hormones physiologic for adult animals (e.g., adrenocorticotropin, norepinephrine, and erythropoietin) or typical for the foetal phase (alpha-fetoprotein, anti-Müllerian hormone, and parathyroid-hormone-related protein) might aid in tumour diagnostics. Thymidine kinase-1 and alkaline phosphatase are examples of intracellular enzymes, whose activity in the blood may increase in some neoplasia cases. Furthermore, inappropriate production of abnormal monoclonal or autologous antibodies can accompany lymphoma an...
