Acute Renal Failure and Anuria Associated with Vitamin D Intoxication in Two Alpaca ( <i>Vicugna pacos</i> ) Cria

Abstract

Vitamin D deficiency is the leading cause of rickets in growing llamas and alpacas in North America, New Zealand, and Australia.1–3 Prophylactic treatment with vitamin D supplements is a common husbandry practice in North America. This case report describes the clinical course, diagnostics, and pathological findings in 2 alpaca cria (Vicugna pacos), presenting at 18 days and 8 days of age, with presumptive vitamin D intoxication. Both cria developed tissue mineralization and acute renal failure after administration of excessive doses of vitamin D. Presentation of camelids with a history of vitamin D administration associated with hypercalcemia, hyperphosphatemia, and renal dysfunction strongly suggests vitamin D intoxication. Early recognition of these signs can improve clinical outcomes. A 2-day-old, 7 kg, male alpaca presented to the Ohio State University Veterinary Teaching Hospital (OSUVTH) for suspected septicemia associated with anorexia, lethargy, and potential failure of transfer of passive immunity. The cria was born unassisted, but birth was observed by the owner. The owner indicated that the dam did not have sufficient mammary secretions (colostrum) at birth to provide for the cria. Nine days after admission and successful treatment with parenteral fluids, ceftiofur (Naxcel)a and IV administered plasma (20 mL/kg body weight), the now-healthy cria and his dam were released to the owner. At home the cria was supplemented with goat's milk by nipple bottle every 2 hours to approximate 15% of body weight/d. In addition, the owner added 4.6 g of powdered goat colostrum supplement (Kaeco Colostrum Powder)b to each feeding for 7 days. This supplement contained not <2,750 IU of vitamin D3 per dose. The cria was fed every 2 hours for 12 doses/d over 7 days yielding a total cumulative dose of vitamin D3 of 231,000 IU (26,250 IU/kg or 3,750 IU/kg/d). The cria was readmitted to the Veterinary Teaching Hospital at 18 days of age for generalized weakness, anorexia, and depression. The cria remained able to stand, hold his head and neck up, and walk. The heart rate was 140 beats/min (reference range, 60–90 beats/min), the respiratory rate was 28 breaths/min (reference range, 10–30 breaths/min), the body temperature was 37.6 °C (reference range, 37.5–38.9 °C), and the cria weighed 8.8 kg.4 Thoracic auscultation was unremarkable. A CBC revealed a PCV of 36% (range 24–35%) and white blood cell count of 32.3 × 109/L (range 5.2–15.7 × 109/L), characterized by a mature neutrophilia (28.4 × 109/L; range 2.1–9.5 × 109/L) and monocytosis (1.9 × 109/L; range 0–0.6 × 109/L). The serum biochemical profile demonstrated azotemia (serum urea nitrogen [SUN] 48.5 mmol/L; range 1.48–24.4 mmol/L; creatinine 557 μmol/L; range 115–239 μmol/L), hyperphosphatemia (4.5 mmol/L; range 0.8–2.8 mmol/L), hypercalcemia (3.5 mmol/L; range 2.0–2.6 mmol/L), and hyperkalemia (9.4 mmol/L; range 3.6–6.5 mmol/L). The cria was hypoproteinemic (30 g/L; range 53–76 g/L) with hypoalbuminemia (16 g/L; range 26–47 g/L) and hypoglobulinemia (14 g/L; range 27–29 g/L). The serum cortisol concentration (215 nmol/L) at the time of admission was increased compared with other hospitalized alpacas (range 0–27.59 nmol/L).5 Ultrasonographic examination of each kidney demonstrated normal architecture and echodensity with increased echogenicity of the wall of the 3rd compartment (C3). Ultrasonographic imaging of the urinary bladder revealed it was small and contained minimal urine. Thoracic radiographs revealed normal cardiopulmonary structures, while abdominal radiographs confirmed gastric wall mineralization of the caudal and ventral margins of the 3rd gastric compartment (Fig 1). Abdominal radiographs of case 1, caudal and ventral margins of the 3rd gastric compartment with mineral dense appearance, consistent with gastric mineral accumulation or gastric wall mineralization (white arrows). Initial therapy included fluids (0.45% saline with 2.5% dextrose IV) at a rate of 40 mL/h by constant rate infusion and ceftiofur sodium (20 mg IV q24h). A 20 mL bolus of 50% dextrose IV and 5 U of regular insulinc SC were given in an effort to reduce serum potassium concentration. After rehydration (approximately 6 hours from start of fluid therapy) urine production was not evident and furosemided was administered in escalating doses every 30 minutes for 2 hours (1.1–4.4 mg/kg) in an effort to reverse anuria. Seven hours after initiating fluid therapy and diuresis, the bladder had an ultrasongraphic diameter of 1.7 cm and no urination had been observed since admission. SUN (59 mmol/L) and creatinine (663 μmol/L) continued to be abnormal after 10 hours of therapy. Phosphorus (4.5 mmol/L), total calcium (3.3 mmol/L), and potassium (9.2 mmol/L) were nearly unchanged. At this time the cria's condition began deteriorating and the owner elected euthanasia. At necropsy, the cortex and medullary regions of both kidneys possessed miliary, gritty, white foci. The outer medulla of both kidneys had a 2 mm thick gritty white band of discoloration and the cortex of both kidneys had miliary gritty white foci (Fig 2). Additionally, the endothelial surface of the ascending aorta had a 1 × 3 cm gritty white plaque. The urinary bladder was small, contracted and contained <1 mL of clear yellow urine. Right kidney from case 1. Sagittal section of the kidney demonstrating mineralization of the renal medulla consistent with metastatic calcification (arrow). Areas of hyperemia surround the tissue mineralization in the renal medulla extending into the renal papilla where gritty mineralized tissue is evident (*). Histopathology of the kidneys revealed marked multifocal interstitial, tubular, and widespread glomerular mineralization with tubular nephrosis (Fig 3). Microscopically, widespread mineralization of the renal interstitium and the renal tubular and glomerular basement membranes was observed (Fig 3). Tubular necrosis with regeneration and luminal accumulation of proteinaceous material was observed in both mineralized and nonmineralized tubules. Although not detected grossly, moderate multifocal mineralization of the gastric mucosa of the 3rd compartment was observed microscopically (Fig 4). Histopathologic evidence of renal lesions present in the outer cortices, cortico-medullary junction and renal pelvis of 2 Alpaca cria described in this case using hematoxylin and eosin and Von Kossa stain for calcium salts. As highlighted by Von Kossa (calcium salts) stain, mineralization of the kidney was marked and widespread in both cases. Glomerular mineralization (*) was extensive in the outer cortex (Outer cortex) of both cases but was only associated with overt disruption of the glomerular tuft in case 2. Interstitial mineralization was most severe in the renal pelvis (pelvis) in case 1 and at the corticomedullary (CM junction) junction in case 2. Tubular basement membranes were extensively mineralized in both cases. Acute tubular necrosis (highlighted in the boxed area) with infrequent tubular regeneration (not shown) was a prominent feature in case 1 but was only occasionally observed in case 2. In both cases, mineralization of the kidney was associated with marked tubular proteinosis (arrow). Bar = 100 μm. In addition to the kidney, mineralization was observed in multiple other organs. Mineralization of C3 mucosal basement membranes (arrow) in case 1 was mild and not associated with other microscopic lesions at this site. Mineralization of the pulmonary interstitium in case 2 was marked, widespread and associated with edema and alveolar histiocytosis. Mineralization of the liver in case 2 was multifocal, marked and associated with disruption of hepatic parenchyma, hepatocellular necrosis, hemorrhage, and influx of mononuclear cells. Bar = 100 μm. Serum and kidney tissues adjacent to those taken for histopathologic evaluation were submitted for vitamin D analysis.e The 25-OH-vitamin D3 level in the serum was 663 nmol/L (normal range for alpacas 50–200 nmol/L); and kidney tissue concentration was 282.0 nmol/L (normal range 2–11 nmol/L; > 85 nmol/L suggests intoxication). An 8-day-old, male, Suri alpaca cria presented to OSUVTH for anorexia and lethargy. The owners administered 100,000 IU of vitamin D (ADE paste) PO once daily for the 1st 5 days of life for a total cumulative dose of 500,000 IU (65,909 IU/kg; 12,987 IU/kg/d for 1st 5 days of life). After the 5th day the cria was presented to the referring veterinarian for anorexia and was treated with camelid plasma IV, 7,500 IU of vitamin D3 (ADE injectable, SC) and ceftiofur (25 mg SC q12h) and gentamicin (20 mg SC q24h). Four days later the cria had not improved and became progressively more lethargic with severe epiphora, chemosis, and anuria. A biochemical profile taken by the referring veterinarian revealed a total serum calcium of 3.99 mmol/L and ionized calcium of 1.68 mmol/L. This cria was lethargic on presentation. The heart rate was 150 beats/min, the respiratory rate was 66 breaths/min, and the body temperature was 38.3°C. The cria weighed 7.7 kg. Thoracic auscultation was unremarkable. The conjunctiva were swollen and there was bilateral epiphora. The CBC revealed a PCV of 29% and white blood cell count of 15.6 × 109/L characterized by mild mature neutrophilia (14.4 × 109/L; range 2.1–9.5 × 109/L), lymphopenia (0.6 × 109/L; range 0.9–4.4 × 109/L). The serum biochemical profile revealed azotemia (SUN 85.7 mmol/L, creatinine 548 μmol/L), hyperphosphatemia (3.3 mmol/L), hypercalcemia (3.8 mmol/L), and hypoproteinemia (42 g/L) with mild hypoalbuminemia (24 g/L) and hypoglobulinemia (18 g/L). The serum cortisol (60.7 nmol/L) was also increased. Vitamin D intoxication was suspected based upon the history of supplementation and the hypercalcemia, hyperphosphatemia, azotemia, and anuria. Transabdominal ultrasonography and thoracic and abdominal radiography were performed revealing limited urine production (urinary bladder < 1.5 cm) and a thin mineral opaque rim outlining the subcapsular cortex of both kidneys. Initial therapy included treatment with fluids (Ringer's with 1% dextrose and 10 mmol KCl/L IV) at a rate of 2 mL/kg/h and ceftiofur sodium (2 mg/kg IV q12h). A Tenckoff peritoneal dialysis catheterf was placed into the abdominal cavity to perform peritoneal dialysis. Dialysis with 60 mL (8 mL/kg body weight) of warmed Dianeal PD-2 peritoneal dialysis solutiong with 1% dextrose was initiated by intraperitoneal instillation every 45 minutes. Before each infusion, dialysis fluid from the previous infusion was aspirated from the abdomen. Dialysis and administration of fluids continued for 3 days. Treatment was monitored with clinical assessment, periodic evaluation of SUN, creatinine, calcium, phosphorous, and potassium levels and ultrasonographic estimation of urine volume within the bladder. The amount of fluid recovered from the abdomen averaged 90% of the volume previously infused. After 5 hours of treatment the SUN (121 mmol/L) and creatinine (619 μmol/L) had increased. Therefore, the volume of dialysis fluid infused was increased to 16 mL/kg body weight every 45 minutes. After 17 hours of dialysis, serum concentrations of urea nitrogen (92 mmol/L) and creatinine (707 μmol/L) remained elevated; thus, the amount of dialysis fluid was increased to 24 mL/kg/mL every 45 minutes. Clinically, the cria remained lethargic and anorexic. In spite of continued fluid administration (IV and peritoneal dialysis) for 3 days, the SUN (66 mmol/L) and creatinine (998 μmol/L) remained essentially unchanged. However, serum total calcium decreased to 2.7 mmol/L. Throughout the entire course of treatment urine production was absent and the bladder remained small and devoid of hypoechoic fluid on ultrasonographic examination. The cria became unable to rise, did not nurse, and became dyspneic after 3 days of treatment, and the owner elected euthanasia. At necropsy, the gross appearance of the deep inner cortex of both kidneys was characterized by fine, radiating pale streaks. This pale region was adjacent to a region of outer medulla that was discolored dark red. The urinary bladder was empty. On histopathologic evaluation of the kidney, there was marked, diffuse glomerular mineralization with tubular necrosis and abundant accumulation of proteinaceous material within tubular lumina in sections from both kidneys (Fig 3). No normal glomeruli were present in histologic sections of the kidneys; all glomeruli were mineralized with effacement of the normal architecture of the glomerular tuft. Although not detected grossly, peripheral alveolar mineralization, alveolar histiocytosis, and marked edema were evident in the lung (Fig 4). In liver sections there was hepatocellular necrosis with multifocal mineralization (Fig 4). Serum and kidney samples revealed serum 25-OH-vitamin D3 of 602 nmol/L and kidney tissue 25-(OH)-vitamin D3 concentration of 350 nmol/L.e These cases occurred where it is a common practice to provide supplemental vitamin D to camelids during periods of reduced sunlight in North America; however, the appropriate dosage, dosage interval, and product formulations of vitamin D are often not clearly understood by camelid owners. Both cases described in this report were examined for depression, lethargy, and anorexia and were found to have acute, anuric renal failure. Azotemia, hyperphosphatemia, and hypercalcemia were present in both crias, and one had hyperkalemia. Since both cria presented with anuria and did not respond to treatment we were unable to obtain urine for determination of renal concentrating ability. Cria #1 (18 days of age) had a mature neutrophilia and monocytosis with normal lymphocyte count, whereas Cria #2 (2 days of age) had a mild neutrophilia and lymphopenia. These findings were suggestive of a stress response, which was supported by the elevated serum cortisol in both animals.5 Other possible explanations for leukocytosis, mature neutrophilia could potentially include Gram-positive bacterial sepsis, inflammatory response to tissue mineralization, renal lesions, or both.6 Both cria presented with low normal serum albumin, which decreased further after treatment was initiated. Although both cria produced minimal urine during hospitalization, we speculate that urine produced in the early stages of the disease before admission might have contained increased protein (proteinuria) which could contribute in part to decreased plasma albumin concentration. Further, after anuria developed, fluid retention could have further reduced serum albumin concentration by dilution. In case #2, the loss of serum proteins into the dialysate may also have been a contributing factor. We did not measure protein concentration in the dialysate to explain this laboratory abnormality. In both cria, hyperphosphatemia, hypercalcemia, and azotemia were suggestive of vitamin D intoxication.7 The preliminary clinical diagnosis of vitamin D intoxication was supported by the historical information and increased serum concentrations of calcium and phosphorus with apparent, acute intrinsic renal failure that did not respond to fluid therapy. The radiographic and ultrasound examinations also proved supportive of vitamin D intoxication through detection of tissue mineralization. These observations were later confirmed at postmortem examination as widespread soft tissue mineralization, grossly and microscopically. Increased vitamin D concentrations in serum and kidney tissue confirmed the diagnosis of vitamin D toxicosis in both cases. Studies performed in alpacas suggest that single parenteral doses of vitamin D (1,000–2,000 IU/kg body weight) provide adequate amounts of vitamin D to crias for up to 7–11 weeks.3 These authors recommend administering a single dose of vitamin D to South American camelids of 1,000–2,000 IU/kg bodyweight in late autumn and again in midwinter in locations where reduced sunlight and ultraviolet light occur.3 Using these recommendations, the total dose for the 1st cria would have been 7 days this cria 231,000 IU vitamin D3 (26,250 a over the of the range of The cria 500,000 IU vitamin D3 over 5 days a the of the dosage This normal serum vitamin D3 concentrations in The 1st found that alpaca cria of age) have serum 25-OH-vitamin D3 concentrations from to whereas alpaca of age) have 25-OH-vitamin D3 from to In this cria and alpaca were to IU vitamin and IU vitamin by concentrations of 25-OH-vitamin D3 in all treated were increased by 2 days and remained the cria for in the IU/kg 7 in the IU/kg all treated had increased plasma 25-OH-vitamin D3 for the of the (16 of the treated cria or plasma 25-OH-vitamin D3 concentrations in the range observed in the 2 cria presented in this In a the plasma 25-OH-vitamin D3 concentrations in male alpacas of age) on which were not supplemented with vitamin D3 from to nmol/L over a In a 3rd serum concentrations of 25-OH-vitamin D3 in vitamin D and alpaca cria range was to be nmol/L before vitamin D treatment, whereas days after treatment, serum 25-OH-vitamin D3 had increased to The treatment of vitamin D deficiency in this report included a single of IU of 25-OH-vitamin or IU of 25-OH-vitamin D3 PO every 2 or a single dose of 100,000 IU vitamin D3 normal 25-OH-vitamin D3 were nmol/L in in age from 1 to 85 be that these were to cria of body and the supplementation was sufficient to alpaca or cria serum 25-OH-vitamin D3 The 2 cria in this report presented with serum 25-OH-vitamin D3 concentrations of 663 nmol/L and 602 nmol/L which for vitamin D3 in normal camelid cria, in male alpacas as as vitamin D3 and alpaca cria after supplementation with or of 25-OH-vitamin The 2 cria on vitamin D3 supplementation whereas the alpacas and llamas previously vitamin D supplementation by or Further, the we for supplementation a single parenteral dose or body once or As a the crias developed serum and tissue concentrations of vitamin D3 as a of supplementation at and over days. The total total cumulative body and daily in 231,000 IU IU/kg or 3,750 IU/kg/d over 7 days in Cria and 500,000 IU vitamin D3 IU/kg or 12,987 IU/kg/d PO over 5 days in cria We that total dose and to be for of increased serum and tissue concentrations of vitamin D treated a single alpaca with 1 dose of IU/kg vitamin D with no signs of acute accumulation over time may be Since North American cria milk have limited of vitamin D and are it been that supplementation during periods of reduced sunlight and is to vitamin D daily vitamin D of 30 IU/kg to for most Increased vitamin D in hyperphosphatemia and hypercalcemia after excessive of calcium and phosphorus from the renal tubular of calcium and and of calcium and phosphorus from soft tissue mineralization of the of calcium and phosphorus at with mineralization of tubular basement membranes is a of D in In addition to these lesions, mineralization of the glomerular was prominent in both of these cria, which only been described in with mineralization of the glomerular basement membranes in or it might a of this disease in Mineralization of tubular in histopathologic from one of cases is a that also been described in and a with is also possible these lesions may with doses of vitamin D. consistent with tubular were evident in histopathologic sections of both of the cria mineralization of the and glomeruli would cause further loss of renal Both cria had extensive renal mineralization at The levels of 25-OH-vitamin D in the renal tissue of both cases D as the cause for tissue The findings of azotemia and hypercalcemia are to of ionized failure can in increased serum calcium concentrations with or an associated in ionized ionized hypercalcemia can in both acute and renal ionized calcium is to contribute to mineralization and other of is that with renal failure can hypercalcemia not associated with an in ionized The ionized calcium concentrations in these cria were elevated and mmol/L in cases 1 and it is that increased ionized calcium was for the of tissue mineralization associated with increased 25-(OH)-vitamin D As ionized calcium was elevated in the of low serum albumin, we this the increased total serum calcium concentrations observed in both cria were associated with in ionized increased total and concentrations in the of increased 25-(OH)-vitamin D3 are the of The of anuria to the of the renal in these 2 cases. with D not anuria and can with supportive An of treatment is to the hypercalcemia and dialysis, as in case #2, is one to serum In this cria, dialysis was associated with of serum calcium within 3 however, anuria and azotemia The in serum calcium may have from the peritoneal dialysis. However, in ionized calcium and concentrations may also have in further tissue mineral contributing to further in serum a was in both however, it also was not successful in urine production or serum be by the into renal tubular fluid before it can calcium more on the ascending of is that was not able to be by the extensively of the cria in this Vitamin D is an supplement for crias, at appropriate This report that supplementation of camelids with excessive doses of vitamin D can as observed in other vitamin D be in crias born in the and and not for South American be to to Cria presenting with increased serum concentrations of calcium and renal and historical of vitamin D imaging with radiographs and or ultrasonography to the of soft tissue mineralization. These findings may be while of 25-(OH)-vitamin D be performed in all suspected for D as this is the for vitamin D since vitamin D is to this In those in renal it is to also measure ionized calcium, as ionized and total calcium is to be severe in other with renal failure. Early recognition and of hypercalcemia by IV administration of fluids for rehydration and of urine production are Although not in the 2 cria described in this the of and as for hypercalcemia and hyperphosphatemia associated with D in camelids can have potential in the South American however, further a and Colostrum for for and State Acute Dialysis g Dianeal PD-2 1.5 peritoneal dialysis The authors the of the of Veterinary of The Ohio State of Veterinary