She was told by her prior physician, that her thyroid function test was normal in the past. She was started on levothyroxine 25 mcg daily with dose adjustment based on TSH levels.
Fetal production begins at 10-12 weeks of gestation. Thyroxine is important for fetal neural development throughout pregnancy, but particularly so in the first trimester. Maternal hypothyroidism has been associated with learning difficulties in euthyroid children, and with increased fetal loss.
(1) Confirm the diagnosis and laboratory results. Frank primary hypothyroidism by laboratory definition requires low levels of thyroid hormones (total and free T4 and T3) and elevated TSH. The finding of a persistently elevated TSH level is not enough to confirm the diagnosis here, it is also crucial to measure thyroid hormone levels (T4 and.
6 I screen patients that get this far along the diagnostic pathway with measurement of tissue transglutaminase antibodies and, if positive, send them for GI evaluation, usually including small bowel biopsy and stool fat measurements.
Central hypothyroidism: in these patients there is hypothalamic or pituitary failure, usually leading to normal or only mildly raised TSH in the presence of low serum T4 and T3, with overt hypothyroidism (but no goitre).
The practical approach may be to measure TSH in those patients who have persistent, nonspecific complaints - women in particular, and the elderly. 6 Borderline results may need to be repeated at a consistent time of day, with consistent fasting status.
(Postgrad Med J. 2006 November; 82(973 e27. doi: 10.1136/pmj.2006.049809). Copyright 2006 The Fellowship of Postgraduate Medicine (reprinted with permission). Tan MJ, Tan F, Hawkins R, Cheah WK, Mukherjee JJ. A Hyperthyroid Patient with Measureable Thyroid-stimulating Hormone Concentration A Trap for the Unwary.
SUMMARY OF THE STUDY The authors studied 715 patients from the Department of Family Medicine of the Mayo Clinic in Rochester, Minnesota who, in 2006 had been a) diagnosed with hypothyroidism b) were taking L-T4 replacement and c) had a normal TSH level.
Ann Acad Med Singapore. 2006;. Despres N, Grant AM. Antibody interference in thyroid assays: a potential for clinical misinformation. Clin Chem. 1998;. Pan XH, Zhang SZ, Chen HQ, Xiang MX, Wang JA.
Increased values indicate hypothyroidism. The test is both sensitive and specific. Serum TSH concentrations have a logarithmic relationship with serum thyroxine, so that a doubling in thyroxine produces a hundredfold change in TSH.
Two months later, because there was no symptom improvement and her TSH was elevated at 12.7 mIU/L on a dose of levothyroxine 200 mcg daily, she was referred to the Endocrinology Department for further evaluation.
4 Although I have occasionally performed this test, I do not find it to be generally helpful unless it demonstrates completely 'normal results, thereby supporting patient noncompliance. Unfortunately, there.
For example, a recent patient I was referred was a 40-year-old woman from a neighbouring community who was diagnosed with hypothyroidism 1 year prior to her visit. In brief, at that time she expressed symptoms compatible with hypothyroidism, such as severe constipation, fatigue and a modest amount of weight gain, and her thyroid gland was.
Replacement therapy is not recommended in asymptomatic individuals with subclinical hypothyroidism but with TSH 5-10 mIU/L, no goitre, and negative anti-thyroid antibodies. Pregnancy During the first trimester thyroxine is supplied exclusively by the mother.
Some studies have suggested that if symptoms are present then treatment with thyroxine will resolve them. Common clinical features of hypothyroidism include: Depression and fatigue. Hyperlipidaemia and hyperhomocysteinaemia Goitre Coarse hair Cold intolerance.
(C) Prevention of interference: adding immunoglobulin (Ig) G forms unlabelled sandwiches, which are not detected by the assay. Abbreviations: Fl, fluorescein labeled anti TSH sheep monoclonal antibodies. I I125labelled anti TSH mouse monoclonal antibodies.
One mechanism by which these antibodies cause interference with TSH assays is by immunoglobulin aggregation (Figure 1) (4). The prevalence of heterophile antibodies in the general population is between 0.2 and 15, which can be encountered in various ways such as chemotherapeutic agents, vaccines and environmental and occupational exposure (1).
A fairly large and still growing number of medications, supplements and even food items can alter the fraction of an ingested dose that is absorbed. 3,4 The ingestion of one or more of these items at or near the time of dosing with thyroxine can substantially change the dose requirement in an individual patient, especially.
Controversy remains regarding the treatment of non-pregnant adult patients with serum TSH 10 mIU/L: in this subgroup, treatment should be considered in symptomatic patients, patients with infertility, and patients with goitre or positive anti-thyroid peroxidase (TPO) antibodies.
Hence, clinically discordant values of TSH and Free T4 should trigger further investigation to exclude laboratory error, maintaining a close liaison between clinicians and laboratory personnel (6). Table 1: Thyroid function tests months prior to endocrinology evaluation.