Differentiating nonthyroidal illness syndrome from central hypothyroidism in the acutely ill hospitalized patient

Central hypothyroidism - a neglected thyroid disorder

Central hypothyroidism is a rare and heterogeneous disorder that is characterized by a defect in thyroid hormone secretion in an otherwise normal thyroid gland due to insufficient stimulation by TSH. The disease results from the abnormal function of the pituitary gland, the hypothalamus, or both. Moreover, central hypothyroidism can be isolated or combined with other pituitary hormone deficiencies, which are mostly acquired and are rarely congenital. The clinical manifestations of central hypothyroidism are usually milder than those observed in primary hypothyroidism. Obtaining a positive diagnosis for central hypothyroidism can be difficult from both a clinical and a biochemical perspective. The diagnosis of central hypothyroidism is based on low circulating levels of free T₄ in the presence of low to normal TSH concentrations. The correct diagnosis of both acquired (also termed sporadic) and congenital (also termed genetic) central hypothyroidism can be hindered by methodological interference in free T₄ or TSH measurements; routine utilization of total T₄ or T₃ measurements; concurrent systemic illness that is characterized by low levels of free T₄ and normal TSH concentrations; the use of the sole TSH-reflex strategy, which is the measurement of the sole level of TSH, without free T₄, if levels of TSH are in the normal range; and the diagnosis of congenital hypothyroidism based on TSH analysis without the concomitant measurement of serum levels of T₄. In this Review, we discuss current knowledge of the causes of central hypothyroidism, emphasizing possible pitfalls in the diagnosis and treatment of this disorder.

[Prevalence of Hypothyroidism in Major Psychiatric Disorders in Hospitalised Patients in Montserrat Hospital During the period March to October 2010]

INTRODUCTION

Hypothyroidism results from inadequate production of thyroid hormone. It is known that there is a relationship between the major psychiatric disorders and hypothyroidism.

OBJECTIVE

To determine the prevalence of hypothyroidism in patients admitted due to major psychiatric disorders in Montserrat Hospital during the period from March to October 2010.

MATERIAL AND METHODS

A descriptive cross-sectional study was conducted on 105 patients admitted to Montserrat Hospital with a primary diagnosis of major psychiatric disorder (major depression, bipolar affective disorder, generalised panic disorder, panic disorder, mixed anxiety-depressive disorder, and schizophrenia) in the aforementioned period. Thyroid Stimulating Hormone (TSH) was performed to assess the evidence of hypothyroidism.

RESULTS

The overall prevalence of hypothyroidism was found to be 10.5% (95% CI; 5%-16%). It was 12.5% in anxiety disorder, 11.1% in depressive disorder, with a lower prevalence of 10.3% for bipolar disorder, and 9.9% for schizophrenia.

CONCLUSIONS

The overall prevalence of hypothyroidism was found to be less than in the general population, which is between 4.64% and 18.5%, and hypothyroidism was found in disorders other than depression.

Ischemic stroke functional outcomes are independently associated with C-reactive protein concentrations and cognitive outcomes with triiodothyronine concentrations: a pilot study

Elevated concentrations of C-reactive protein (CRP) and decreased concentrations of triiodothyronine (T3) were shown to predict poor outcomes in patients with stroke. However, the prognostic value of CRP and T3 has not been studied simultaneously in relation to stroke functional and cognitive outcomes despite of close interaction between inflammatory markers and thyroid function. We evaluated the association of thyroid hormone and CRP concentrations with immediate outcomes after ischemic stroke. Eighty-eight ischemic stroke patients on admission to the stroke unit were evaluated for clinical stroke severity (Scandinavian stroke scale or SSS) and concentrations of thyroid-stimulating hormone, free thyroxin, free T3, and CRP. Functional outcome (modified Rankin scale) and cognitive outcome (Mini mental state examination) were evaluated at discharge. Greater ln CRP concentrations (r = -0.35, p = 0.001), but not thyroid hormone concentrations, correlated with score on the SSS. In univariate analyses lower free T3 concentrations and higher CRP concentrations were associated with poor functional and poor cognitive outcomes. After adjustment for clinical stroke severity, higher CRP concentrations (β = 0.18, p = 0.04) remained associated with worse functional outcome and lower free T3 concentrations with worse cognitive outcome (β = 0.23, p = 0.03). In sum, clinical stroke severity is associated with elevated CRP concentration. Higher CRP concentration is independently associated with worse functional outcomes and lower free T3 concentration with worse cognitive outcomes at discharge. T3 and CRP can be important biomarkers in patients with acute ischemic stroke.