From Dog

Hyperphosphatemia is defined as an elevated level of circulating phosphorus (Pi).

Normal canine blood levels of phosphorus are 2.5 - 7.7 mg/dL.

Physiologically elevated serum and plasma Pi concentrations are commonly noticed in rapidly growing large pups due to enhanced intestinal phosphorus uptake and decreased renal phosphorus excretion.

Pathologically causes of hyperphosphatemia include:

  • Dehydration
  • Disease
- Chronic renal disease - due to decreased phosphorus excretion as a result of hyperparathyroidism[1]
- hypoparathyroidism - due to increased renal phosphorus reabsorption
- hypothyroidism[2]
- unbalanced homemade diets deficient in phosphorus[3]
- vacuolar hepatopathy[4]
- Babesia spp[5]
- Leptospira spp[6]
  • Trauma - causing tissue release of phosphorus
  • Spurious - hemolysis
  • Toxins
- ingestion of grapes or raisins[7]
- vitamin D toxicosis
- xylitol toxicosis[8]
- Allopurinol associated with treatment of Leishmania spp[9]

With vitamin D toxicosis in dogs, a concurrent hypercalcemia is commonly observed.

In chronic severe cases, concomitant hypocalcemia may result from precipitation of excessive phosphorus with calcium and cause muscle fasciculations and tetanic muscle contractions. In sustained cases, precipitation of calcium-phosphate salts results in extraskeletal tissue mineralization with a potentially fatal outcome.

Treatment is dependent upon underlying cause, but management of hyperphopsphatemia involves aggressive intravenous fluid therapy, low phosphate diets and oral phosphate binders[10].

Fluids devoid of calcium such as physiologic saline such as isotonic saline solution (0.9% sodium chloride) is recommended.


  1. Cortadellas O et al (2010) Calcium and phosphorus homeostasis in dogs with spontaneous chronic kidney disease at different stages of severity. J Vet Intern Med 24(1):73-79
  2. Seelig DM et al (2008) Goitrous hypothyroidism associated with treatment with trimethoprim-sulfamethoxazole in a young dog. J Am Vet Med Assoc 232(8):1181-1185
  3. Hutchinson D et al (2012) Seizures and severe nutrient deficiencies in a puppy fed a homemade diet. J Am Vet Med Assoc 241(4):477-483
  4. Zimmerman KL et al (2010) Hyperphosphatasemia and concurrent adrenal gland dysfunction in apparently healthy Scottish Terriers. J Am Vet Med Assoc 237(2):178-186
  5. Camacho AT et al (2004) Azotemia and mortality among Babesia microti-like infected dogs. J Vet Intern Med 18(2):141-146
  6. Goldstein RE et al (2006) Influence of infecting serogroup on clinical features of leptospirosis in dogs. J Vet Intern Med 20(3):489-94
  7. Eubig PA et al (2005) Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992-2002). J Vet Intern Med 19(5):663-674
  8. Murphy LA & Coleman AE (2012) Xylitol toxicosis in dogs. Vet Clin North Am Small Anim Pract 42(2):307-312
  9. Koutinas AF et al (2001) A randomised, blinded, placebo-controlled clinical trial with allopurinol in canine leishmaniosis. Vet Parasitol 98(4):247-261
  10. Damment SJ (2011) Pharmacology of the phosphate binder, lanthanum carbonate. Ren Fail 33(2):217-224