Dr. Jean Dodds, een zeer wel gerespecteerd expert op het gebied van schildklierziektes bij de hond, heeft een stuk over Sub-clinical (borderline-low) Hypothyroidism beschreven in haar boek The Canine Thyroid Epidemic.
Some dogs with suppressed thyroid functioning still tsest within the laboratory's "normal" references ranges. These dogs are said to suffer from sub-clinical- or borderline-low hypothyroidism. Sub-clinical hypothyroidism is a controversial topic within the veterinary community, since dogs with borderline-low hypothyroidism often display none of the typical clinical symptoms of full-blown hypothyroidism (weight gain, skin and coat problems, and lethargy, for example). However, there is substantial empirical evidence that animals with borderline-low hypothyroidism experience increased issues of aberrant behavior, especially aggression, and also commonly suffer from inflammatory bowel disease.
Understanding how to diagnose sub-clinical hypothyroidism is critical, especially when many veterinarians simply dismiss borderline readings as normal because they fall within the laboratory's reference ranges.
A dog is generally considered to suffer from sub-clinical hypothyroidism if his hormone levels fall within the lower 50% of the normal range. To calculate the 50% point, simply add the lower and highest values of the range and divide by two. For example, in an adult dog, the 50% point is calculated as follows:
T4
Normal range = 1.40-3.50 ug/dl
1.40 + 3.50 = 4.9
4.9 / 2 = 2.43
2.43 = 50% of the normal range for adult T4.
Free T4
Normal range = 0.85-2.30 ng/dL
0.85 + 2.30 = 3.15
3.15 / 2 = 1.58
1.58 = 50% of the normal range for adult free T4
T3
Normal range = 35-70 ng/dL
35 + 70 = 105
105 / 2 = 52.5
52.5 = 50% of the normal range for adult T3
Free T3
Normal range = 1.6-3.5 pg/mL
1.6 + 3.5 = 5.1
5.1 / 2 = 2.55
2.55 = 50% of the normal range for adult free T3
If your dog's thyroid levels fall in the lower 50% of the reference range and he exhibits aberrant behavior or other signs related to hypthyroidism, he may benefit from hormone supplementation. Talk to your veterinarian about a low-level trial dose of thyroxine. If you notice positive changes in your dog's behavior or other clinical issues once he's on the medication and follow-up testing shows an improvement in his thyroid levels, it's certainly worth continuing to administer the medication for the long-term.
Ik wil wel het volgende opmerken. Als je vraagt naar een schildklieronderzoek, dan worden er standaard geen free T3, free T4, free TSH levels en het TgAA meegenomen. Daar moet je bewust naar vragen en dan pas wordt dat mee gepakt. Dodds waarschuwt daarom te allen tijde bij schildklieronderzoek ook alle free waardes mee te nemen, want die zijn bepalend in hoeverre de schildklier nog echt in functie is.
Misschien heb je hier iets aan.