Cholecalciferol toxicosis/poisoning (Vitamin D poisoning) results from exposure to high levels of cholecalciferol. High levels of cholecalciferol can result in severe hypercalcemia (high levels of calcium in the blood) and mineral deposits in the kidneys, GI tract, liver, blood vessels, myocardium, and other soft tissues.
Sources of cholecalciferol include:
- Certain types of rodenticides
- Vitamin D supplements
- Prescription calcitriol medications
- Prescription topical products containing calcipotriene
- Poorly formulated diets, etc.
Cholecalciferol and its by-products are highly fat-soluble. which slows down the elimination from body tissue. Therefore, the hypercalcemia that occurs with cholecalciferol toxicosis can persist long after serum levels have returned to normal.
Diagnosis includes a history of ingestion of cholecalciferol products.
Clinical Signs
Clinical signs generally occur within 12-36 hours of exposure, although some cases may take up to 72 hours. Clinical signs can include:
- Anorexia,
- Lethargy (tiredness)
- Weakness
- Vomiting
- Constipation or diarrhea
- Melena (bloody feces)
- Hematemesis (blood in the vomit)
- Hypersalivation (drooling)
- Frequent urination
- Excessive drinking
- Hindlimb paresis
- Seizures
- Slow heart rate
- Abdominal pain
- Kidney pain
- Hyperthermia
- And/or oropharyngeal erosions.
In addition to taking your pet's history and clinical signs, your veterinarian will likely perform blood chemical analysis, urinalysis, blood pressure measurement, electrocardiography, and other tests. Your veterinarian may also recommend Calcitriol and Calcifediol (25[OH]D) tests.
Immediate Treatment
May include:
- Emesis (induced vomiting)
- Administration of activated charcoal
- Administration of cholestyramine or colestipol
- Administration of intralipid emulsion
In addition, your veterinarian will treat for the hypercalcemia (treatment may include diuretics, glucocorticoids, bisphosphonates, etc.) and the hyperphosphatemia (with phosphate binders).
Supportive therapy may include hydration and a low calcium diet.
Daily calcium level monitoring may be required for four days. After calcium levels have normalized, your veterinarian will usually continue to monitor calcium, phosphorus, and kidney function daily for a while. A typical monitoring program, for patients whose calcium levels have normalized, might include testing for another five to seven days, then two to three times per week for two weeks, then weekly for another two weeks.
Prognosis
The prognosis is generally good for pets that have ingested low amounts of cholecalciferol, have mild to normal Ca levels, and have no clinical signs.
Symptomatic patients and those that have ingested potentially lethal dosages need prompt decontamination and treatment.
Even with veterinary care, the prognosis is guarded for patients that have clinical signs of poisoning.
If high doses of cholecalciferol are ingested, prolonged treatment may be necessary due to the potential for progressive metastatic calcification (spread) to other tissues.