Hypocalcemic Syndrome of African grey parrots
Michael Jones, DVM, DABVP
The exact etiology of this syndrome in African grey parrots is unknown, however, it is suspected that diets with an inappropriate Ca2+ : P ratio (seed diets) or diets with marginal calcium, vitamin A, vitamin D3 or phosphorus levels may contribute to the development of this disease.2,6 Other proposed etiologies include decreased levels of PTH6 dysfunctional parathyroid gland or dysfunctional PTH14 or an inability to effectively mobilize calcium from bone due to reduced osteoclast numbers in some African grey parrots.3
The disease is typically seen in young African grey parrots. Clinical signs include incoordination, weakness, falling from perches, seizures, collapse, opisthotonus and tetany.2,6 The diagnosis is based upon signalment, history, physical examination, plasma chemistry values (serum calcium levels less than 8.0 mg/dl)3 and response to parenteral calcium administration. Ionized calcium levels should be performed in order to better evaluate total body calcium. Demineralization of the skeleton to maintain normal calcium levels does not occur in this syndrome.
Parenteral administration of calcium gluconate (50-100 mg/kg IV slowly or IM diluted) (Vedco, Inc., 5503 Corporate Dr., St. Joseph, MO 64507 USA) is the treatment of choice and will often control seizures.2,3 Diazepam (0.5-1.0 mg/kg q 8-12 or as needed) (Valium, Roche Laboratories, 340 Kingsland St., Nutley, NJ 07110, USA) may also be required to control seizures. Long-term therapy involves placing the patient on a proper diet if the bird is not already on one and administration of calcium glubionate (25-150 mg/kg PO q 12h) (Neo-Calglucon, Rugby Laboratories, Inc., 2725 Northwoods Pky, Norcross, GA, USA) or calcium gluconate (1 ml/30ml drinking water) in addition to vitamin A/D3 supplementation.2,3 Vitamin A,D3 and E formulations should not be used in patients eating a formulated diet.2 Life-long calcium and vitamin supplementation may be required.2 Follow-up examinations should evaluate plasma calcium concentrations to assess the effectiveness of treatment. Additional follow-ups after several months of therapy may also be needed.2
Excerpt from the article How I diagnose and manage nutritional disease in birds - Michael Jones, DVM, DABVP
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