Diagnosis and management of treatment-refractory hypothyroidism: an expert consensus report

There is a frequently encountered subset of hypothyroid patients who are refractory to standard thyroid hormone replacement treatment and require unexpectedly high doses of levothyroxine. In addition to clinical situations where hypothyroid patients are non-compliant, or where there is the possibility of excipient-induced disease exacerbation (gluten/celiac disease), therapeutic failure may be due to impaired absorption of the administered drug. The common approach to managing patients with unusual thyroxine needs is to escalate the dose of levothyroxine until targeted TSH levels are achieved. This approach can increase the risk for prolonged exposure to supratherapeutic doses of levothyroxine, which increase the chances of adverse outcomes. Repeated adjustments of levothyroxine can also escalate the costs of treatment, as frequent office visits and laboratory tests are required to determine and maintain the desired dose. Clinicians should take a systematic approach to managing patients whom they suspect of having treatment-refractory hypothyroidism. This may include searching for, and adjusting, occult medical conditions and/or other factors that may affect the absorption of levothyroxine, before up-titrating the dose of traditional levothyroxine therapy. Depending on the underlying pathology, another approach that may be considered is to try alternative formulations of levothyroxine that are less susceptible to intolerance issues related to excipients, or, in some cases, to malabsorption. The early discovery of these factors via a thoughtful patient work-up may avoid unnecessary thyroid medication adjustments and their consequences for both patients and clinicians

Thyroxine treatment with softgel capsule formulation. Usefulness in hypothyroid patients without malabsorption

Background: Levothyroxine sodium (LT4) is the therapy of choice for hypothyroidism. In the last decade, new LT4 formulations, such as liquid and softgel capsules, became available. Even if some evidence has been reached in the efficacy of liquid LT4 in patients with suboptimal TSH on tablet LT4, the usefulness of softgel LT4 has been rarely studied. This study aimed at evaluating the effect of switching from tablet to softgel LT4 patients without increased need for LT4. TSH was used as proxy of LT4 bioavailability and effectiveness. Methods: During the period from April to August 2017, 19 patients on tablet LT4 treatment for hypothyroidism, mostly due to autoimmune thyroiditis, were enrolled. Subjects with causes of malabsorption or increased requirement of LT4 were previously excluded. Patients finally included were asked to switch from tablet to softgel LT4 formulation at unchanged dose and ingestion fashion (30 min before breakfast). TSH was measured with chemiluminescence immunoassays. results: According to exclusion and inclusion criteria, 19 patients were finally selected. One of these had headache 4 days later and come back to tablet LT4, and 18 of them (16W/2M; mean age = 55 years; BMI 22.7 kg/m2) completed the study. They were treated with a median LT4 dose of 88 μg/day and showed a median TSH value of 3.33 mIU/L. The rate of cases with TSH ≤ 4.0 mIU/L was 61.1% (11/18 cases). When patients were re-evaluated after 3 months of softgel LT4, we observed that TSH reached levels under 4.0 mIU/L in 16/18 (88.9%) patients, TSH was lower in 11 cases, and in 6 out of 7 patients with pre-switch TSH values over the normal range. Overall, TSH values on softgel LT4 (median 1.90 mIU/L) was significantly lower from that observed during tablet LT4 (p = 0.0039). conclusion: These data show that hypothyroid patients with no proven malabsorption may have an improved TSH following 3 months from the switch from tablet to softgel LT4 preparation at unchanged dose

Early detection of biochemically occult autonomous thyroid nodules

Objective: Autonomously functioning thyroid areas may be associated with subclinical or overt hyperthyroidism, but may exist even in the presence of normal TSH. This study was aimed at comparing the rate of autonomously functioning areas and their cardiac sequelae in patients with nodular goitre studied with the usual and a novel approach. Design and methods: In total 490 adult outpatients with thyroid nodular goitre, living in a mild iodine-deficient area, were selected in our referral centre for thyroid diseases from 2009 to 2014 on the basis of a suspicion of thyroid functional autonomy. They were divided in three groups according to a non-conventional approach (excessive response to thyroxine treatment: group 1) or conventional approach (low/normal TSH with clinical suspicion or low TSH: groups 2 and 3). All patients of the study with the suspicion of thyroid functional autonomy underwent thyroid scan with radioactive iodine (I131) uptake (RAIU). Results: The percentage of confirmed thyroid functional autonomy was 319/490, being significantly higher in group 3 than in groups 1 and 2 (81.5 vs 64.7 vs 52.6%; chi-square P < 0.0001). However, the diagnosis with non-conventional approach was made at a significant earlier age (P < 0.0001). Cardiac arrhythmias as well as atrial fibrillation were similarly detected by conventional and non-conventional approaches (chi-square test: P = 0.2537; P = 0.8425). Conclusions: The hyper-responsiveness to thyroxine treatment should induce the suspicion of thyroid functional autonomy at an early stage, allowing to detect autonomous functioning areas in apparently euthyroid patients

Hypothyroidism and nephrotic syndrome: why, when and how to treat

Hypothyroidism, characterised by low/normal free thyroxine (FT4) and free tri-iodothyronine (FT3) with elevated thyroid-stimulating hormone (TSH), is a well-known complication of nephrotic syndrome (NS). This is a common feature of primary and secondary glomerular diseases and comprises loss of protein in the urine and increased urinary excretion of thyroid hormones and thyroxine-binding globulin. With a normal thyroid reserve, this scenario is associated with the development of subclinical hypothyroidism, with a slight increase in TSH and normal free fractions. However, with a low thyroid reserve the transition toward overt hypothyroidism is almost inevitable, affecting morbidity and mortality. As T4 replacement is a cheap and well-established treatment to achieve a stable hormone status in different types of thyroid deficiency, it is essential to recognise and appropriately treat this condition. In this article we summarise the evidence on this nephro-endocrine disorder in humans and focus on diagnostic and therapeutic strategies

Hashimoto's thyroiditis and autoimmune gastritis

The term "thyrogastric syndrome" defines the association between autoimmune thyroid disease and chronic autoimmune gastritis (CAG), and it was first described in the early 1960s. More recently, this association has been included in polyglandular autoimmune syndrome type IIIb, in which autoimmune thyroiditis represents the pivotal disorder. Hashimoto's thyroiditis (HT) is the most frequent autoimmune disease, and it has been reported to be associated with gastric disorders in 10-40% of patients while about 40% of patients with autoimmune gastritis also present HT. Some intriguing similarities have been described about the pathogenic mechanism of these two disorders, involving a complex interaction among genetic, embryological, immunologic, and environmental factors. CAG is characterized by a partial or total disappearance of parietal cells implying the impairment of both hydrochloric acid and intrinsic factor production. The clinical outcome of this gastric damage is the occurrence of a hypochlorhydric-dependent iron-deficient anemia, followed by pernicious anemia concomitant with the progression to a severe gastric atrophy. Malabsorption of levothyroxine may occur as well. We have briefly summarized in this minireview the most recent achievements on this peculiar association of diseases that, in the last years, have been increasingly diagnosed

Association of coeliac disease and thyroid disorders

A case study is presented. This involves a woman who presented with features of hyperthyroidism, which were refractory to conventional therapy. She was eventually diagnosed to have co-existing coeliac disease and eventually improved on a diet excluding gluten. A discussion exploring the association between gluten-enetropathy and thyroid dysfunction follows.peer-reviewe

Pituitary hyperplasia mimicking macroadenoma associated with primary hypothyroidism in a patient with selective L-thyroxine malabsorption

We present the case of a 29-year-old woman who developed a severe hypothyroidism induced by a thyroxine malabsorption and a secondary pituitary hyperplasia. We performed thyroxine absorption tests to diagnose the malabsorption and to evaluate the best therapeutic intervention. Once assessed a correct therapy lowering TSH, we observed the regression of pituitary mass confirming our diagnosis of secondary pituitary hyperplasia. We suggest to evaluate any possible reason for thyroxine malabsorption and to consider the hypothesis of pituitary hyperplasia in the presence of pituitary mass together with overt hypothyroidism