Nutritional Secondary Hyperparathyroidism ("Metabolic Bone Disease")
Alyssa Thomas, DVM
Metabolic Bone Disease is a layman’s term for a medical condition in which the body becomes so deficient of calcium, that calcium begins to be drawn out of the bones to replenish calcium elsewhere in the body for an animal to survive. This leads to soft bones- which can be painful, lead to deformities, and be predisposed to fractures. In later stages when there is no more calcium left to replenish circulating stores, vital functions become impaired and this condition becomes life-threatening.
There are two main forms of this disease process- one induced primarily by husbandry (nutritional secondary hyperparathyroidism, NSHP), and the other as a result of kidney dysfunction (renal secondary hyperparathyroidism, RSHP). NSHP is preventable through proper husbandry by balancing calcium intake, calcium to phosphorous ratios of dietary items, and vitamin D (through diet or proper lighting).
Dietary factors
- Vitamin D supplementation may be required in the diet of some species. These supplements are typically in combination with calcium and can be dusted on food items. It’s important to understand care requirements for each specific species to know if they need vitamin D provided in the diet; vitamin D can be over-supplemented, leading to calcification of tissues and organ failure, so always ensure you are giving only the recommended amount for your species.
- Calcium supplementation should be given according to care guides for your specific species (on salads or bugs, free-standing dishes). This can be provided on its own or in combination with other vitamins- although you may require both for proper care (ie a calcium with multivitamin only being offered once a week to not over supplement vitamins, while the rest of the week a pure calcium may be provided).
- Gutloading feeder insects can greatly improve their calcium content and calcium-to-phosphorous ratio. Powdered high calcium diets from Flukers or the Mazuri Better Bug Diet are excellent products that should be offered to the bugs for 24 hours leading up to them being fed to your reptile. Gel-based or cubed diets and most fresh produce do not achieve high enough calcium-to-phosphorus ratios and are not recommended.
Lighting
- UVB lighting is critical in some species to stimulate vitamin D production.
- Lights, even if visible light is still being emitted, should be changed every 6 months.
- Basking spots should be between 12 and 20 inches from the light to the basking area.
- No glass, mesh, or plexiglass should come between the rays of light and the basking spot as this may reduce the amount of UVB reaching your pet
- If appropriate for your species, outdoor enclosures provide plenty of UVB rays and extra lighting does not need to be supplemented.
If your pet is exhibiting signs of NSHP, they should be treated by a veterinarian. Recovery is often a long road, and some changes (such as spinal deformities) may be permanent- so prevention is key! If you ever have questions about how to care for your specific species of reptile, consult with your veterinarian.
