Metabolic bone disease is not just one disease, but rather a general term for a collection of medical disorders that affect the bones:

• Nutritional Secondary Hyperparathyroidism (NSHP, most common)
• Renal Secondary Hyperparathyroidism (RSHP)
• Hypertrophic Osteopathy (HO)

MBD is a highly-preventable disease of neglect, and it is not typically seen in wild reptiles. A properly-kept red-eared slider should never develop MBD.

Symptoms

• Inactivity
• Sluggishness
• Muscle twitching/tremors
• Seizures
• Jerky movements
• Palpable bumps on the bones of the legs
• Swollen limbs
• Curved limbs
• Swollen or soft bottom jaw
• Softening of the shell and/or plastron
• Shell and/or plastron begin to curl upward
• Pyramiding
• Splayed legs
• Difficulty walking
• Crooked nails
• Beak distortion
• Bone fractures
• Cloacal prolapse

Cause

• Not enough UVB
• Algae or mineral buildup on shell
• Low basking temperature
• Calcium deficiency
• Vitamin D deficiency
• Vitamin D overdose
• Imbalanced nutrition
• Lack of whole prey in diet
• Protein-only diet

Treatment

If you suspect that your red-eared slider may have MBD, schedule an appointment with an experienced reptile veterinarian immediately. Early-stage MBD is much easier to treat and has fewer permanent consequences than later on.

UVB lighting is an absolute requirement for red-eared sliders. Strong, high-quality UVB (I only recommend the Zoo Med Reptisun 10.0 T5 HO or the Arcadia Desert 12%) can help a sick red-eared slider heal by prompting vitamin D3 synthesis. If you already have a UVB bulb installed, it may be a bad brand or too old. The bulbs recommended above should be replaced every 12 months. 

If the weather is good, it’s also a good idea to take your red-eared sliders outdoors between 10am-2pm when the sun is strongest to get natural UVB, which can speed recovery. Make sure the turtle has access to shade during this time, but the turtle shouldn’t be out for more than 1 hour. 30 minutes should be plenty if you’re already using artificial UVB. However, beware of days with a temperature over 90°F, as being outside for too long in these temperatures can cause a turtle to die of heatstroke without access to water.

Make sure to double-check your turtle’s basking temperatures as well. Heat and UVB are both needed for a reptile’s body to synthesize vitamin D properly. Use a temperature gun like the Etekcity 774 to check the temperature of the basking surface. If it reads below 92-95°F (33-35°C), then your basking temperature is too cool and you need a hotter heat bulb.

Further treatment will be prescribed by your vet. Exact treatment may vary based on what form of MBD your turtle has and how far it has progressed.

NOTE: MBD is not reversible. While the turtle can “heal” with the use of proper UVB lighting and calcium therapy, the damage done to its body — particularly the bones — will linger as scars. The best treatment for MBD is prevention!