If you see a child with this problem, I suggest waiting a few months and repeating the test. If a direct free T4 was ordered the first time, order a free T4 by equilibrium dialysis the second time. If both are low, the child can be referred to a pediatric endocrinologist, but unless there is either a poor growth rate or a history of central nervous system CNS disease or new CNS symptoms, the chance of pinpointing a cause e.
Children with a low free T4 level who are taking the seizure medications just mentioned may not have true hypothyroidism; the test result may be due to displacement of T4 from thyroid-binding globulin.
Most endocrinologists will treat to normalize the free T4 but will try to withdraw treatment if the child is taken off the seizure medication. Case 5. A 3-week-old child who had a birth weight of 7 lb 6 oz is sleeping a lot, feeding poorly, and not gaining weight well. The child passed his newborn thyroid screening but you want to rule out hypothyroidism anyway. The free T4 comes back 2. What does this mean?
Can the child be hypo- and hyperthyroid at the same time? Case 6. You find an enlarged, symmetric, and non-tender thyroid on a routine exam and obtain a free T4 and TSH, which are both normal. Should this child be referred? By urgent referral, I mean not simply asking the parents to call and schedule an appointment but faxing the test results to your local pediatric endocrinologist in the hope that the child can be seen on an expedited basis.
This list, you will notice, is short. Target patients for referral who are most likely to need evaluation and possibly treatment with either thyroid hormone or antithyroid medication. This will eliminate or greatly decrease the parental anxiety aroused by being told their child has a thyroid problem when none exists.
It will also allow those patients who truly need to be seen by a pediatric endocrinologist to be given appointments more promptly-the best of all possible worlds. The Endocrinologist ; J Clin Endocrinol Metab ; J Pediatr ; Moore DC: Natural course of 'subclinical' hypothyroidism in childhood and adolescence.
Arch Pediatr Adol Med ; Diez JJ, Iglesias P: Spontaneous subclinical hypothyroidism in patients older than 55 years: An analysis of natural course and risk factors for development of overt thyroid failure. Knudsen N, Laurberg P, Rasmussen LB, et al: Small differences in thyroid function may be important for body mass index and the occurrence of obesity in the population. T4, T3, free T4, free T3, and T-uptake. Clin Biochem ; Physicians should only claim credit commensurate with the extent of their participation in the activity.
Recognize what symptoms and test results do and do not warrant referral to a pediatric endocrinologist. Participants should study the article and log on to www. After passing the post-test and completing the online evaluation, a CME certificate will be e-mailed to them. The release date for this activity is January 1, The expiration date is January 1, Editors Toby Hindin, Karen Bardossi, and Lisa Maresca disclose that they do not have any financial relationships with any manufacturer in this area of medicine.
Manuscript reviewers disclose that they do not have any financial relationships with any manufacturer in this area of medicine. Author Paul Kaplowitz, MD, PhD discloses that he does not have any financial relationships with any manufacturer in this area of medicine. Conflicts, if any, are resolved through a peer review process. Faculty may discuss information about pharmaceutical agents, devices, or diagnostic products that are outside of FDA-approved labeling.
This information is intended solely for CME and is not intended to promote off-label use of these medications. If you have questions, contact the medical affairs department of the manufacturer for the most recent prescribing information. Faculty are required to disclose any off-label discussion. Thyroid testing: When to worry not often and when to reassure. January 1, Paul B. Kaplowitz, MD, PhD. They nevertheless arrive at the endocrinologist's office for three basic reasons: Because thyroid tests were ordered in the absence of any signs or symptoms suggestive of thyroid disease, or Because so many tests were ordered that there is a high probability of at least one "abnormal" result-i.
How thyroid hormones regulate thyroid function Thyroid hormones l-thyroxine known as T4 and triiodothyronine known as T3 have many important functions, but those that are most critical in children are promotion of normal myelination during brain development in the first two to three years of life and normal skeletal growth.
Ups and downs of thyroid function By far the most common cause of a progressive decline in thyroid function is autoimmune or Hashimoto's thyroiditis. To test or not to test Thyroid tests should be ordered mainly in these situations: Any child with an enlarged thyroid on physical examination More than one sign or symptom of hypothyroidism Goiter New onset of fatigue Cold intolerance Acquired growth failure may be only sign Constipation, dry skin Follow-up of abnormal newborn screening test result More than one sign or symptom of hyperthyroidism Hyperactivity, impulsive behavior Tachycardia Unexplained weight loss Heat intolerance Declining school performance Thyroid tests are not likely to be helpful in these situations: Obesity, unless it is of recent onset and there is also slowing of linear growth.
Even severe hypothyroidism generally causes only modest five to 10 lb weight gain, which is mostly water, not fat. Hypothyroidism in infants is almost always detected on newborn screening and will not affect weight gain more than linear growth Hair falling out History of thyroid disease in a relative without any thyroid-related signs or symptoms Hyperactivity alone without goiter or any other hyperthyroid symptoms.
Which tests should you order? In general, only two tests are needed for initial thyroid screening: TSH. This is the essential screening test, because a result that falls within the normal range between 0. The problem with TSH assays is the interpretation of mildly elevated or slightly decreased levels. Free T4. This test has largely replaced total T4, since it measures only the biologically active fraction 0.
In contrast, a low total T4 can be seen in children mostly males who are born deficient in thyroid binding globulin TBG but have normal free T4 levels and are thus euthyroid. A teenage girl on birth control pills will often have an elevated total T4 due to an increased concentration of TBG but the free T4 will be normal.
There are two methods for measuring free T4: the more accurate but more expensive and time-consuming "equilibrium dialysis" method, and the faster and less expensive "direct" or "non-dialysis" method. For screening purposes, the direct free T4 assay is quite satisfactory. Which tests NOT to order The following tests are not relevant or not worth ordering except under certain cirmstances: T3 uptake.
This test does not measure thyroid function at all, but thyroid-binding protein saturation. September 13, Associations between thyroid tests TSH and death from all causes, heart disease and cancer was studied. The reference normal range for the TSH test in this survey was 0. A similar study was then also done in the survey from later years between to that also had the thyroid hormone free T 4 levels available.
Overall, a higher risk of death from heart disease and cancer as well as death from all causes was noted in those individuals who had the TSH levels in the low normal average 0. Further analysis of the groups from to no such association with high TSH or low free T 4 levels. If they are normal Levothyroxine replacement would make you feel dreadful.
If your FT4 and FT3 levels are low there is no natural route to improve them. You must have some form of thyroid hormone replacement ie Levothyroxine, Liothyronine T3 or natural dessicated thyroid extract NDT. Levothyroxine is the NHS therapy. T3 is very difficult to get prescribed by NHS and when it is it is usually only when a specialist recommends it. NDT isn't licensed for UK use so most patients have a private prescription or buy online and self medicate.
Hi Clutter- can I please ask are you medically trained? I've fought so hard this year to tell doctors not to rely on the TSH, particularly because of the head injury.. I would think with a TSH of you'd feel very ill so everything may be due to head injury you suffered and not the thyroid gland.
TSH is from the pituitary gland so maybe there's a problem with that at present. This is just a guess. This is a link I've just read:. It's just an observation. Perhaps because a catastrophic thyroid failure means that hypothyroid symptoms haven't built up over years. If the patient is frail or old mcg might be too much of a shock to the system but 50mcg is very conservative dosing in an otherwise fit patient under 50 years of age.
I think it probably depends on what dose you were already on. I was on mcg and he raised it to I've been on Synthroid for nearly 20 years, and this is the first time it has sky-rocketed. He'll do it in 25mcg increments. My thyroid was slightly enlarged but has shrunk over the last few months which would lead me to believe the thyroid is improving but blood tests remain the same- it's so confusing and like I said I'm not sure where to turn now so any help would be really appreciated.
A bang to the head can upset brain signalling chemicals. This is what the TSH is. It is a signal from the brain to the thyroid to make more hormone or cut back production.
You cannot and must not rely on the proper working of hypothalamus and pituitary. I never would rely on TSH for you. I'd very much prefer never to rely in TSH. If TSH is ainappropriately high, you could already have too much thyroid hormone. By the time you have taken any especially if prescribed on the basis of TSH you will be over-medicated. It is dangerous medical practice. I though high TSH suggests low thyroid hormone? But here you say I could have too much thyroid hormone?
How can doctors even know who needs what level of hormone? We're all different and not carbon cut outs so one person may need one level where's another person a totally different level? It's just mental. Doctors do everything by the book and according to rules and treat us all as the same person.
If your pituitary has gone wrong, as after a head injury, it can produce too much TSH. That is, more than would be indicated by the thyroid hormone levels in your blood.
It misses both ends of pituitary issues - where the pituitary is not producing enough TSH and when it is producing too much. TSH only indicates thyroid hormone levels at all accurately when the pituitary and the hypothalamus are working as expected.
Even then, our individual set-points can and do vary. The results are of no use without the lab ref ranges. Typically results and ranges will look like:. Ranges vary from lab to lab and across regions so it is essential to provide the ranges provided by your lab on your results for people to interpret the results.
Smilas,for folk to advise you need to post the ranges shown in brackets after each result. Lab ranges differ and its important to see where each result is within the range.
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