Primary hypothyroidism in a child simulating a prolactin-secreting adenoma

Menorrhagia as main presentation sign of severe hypothyroidism in a pediatric patient: a case report

Background

The relative high frequency of menstrual irregularities in the first two–three years after menarche may lead to the risk of underestimation of associated pathological conditions, which are always to be accurately researched with careful examination and anamnesis. The association between menstrual irregularities and hypothyroidism is described in literature but the available data are scarce and mainly based on adult case series. It is described that low plasma levels of thyroid hormone can shift the hemostatic system towards a hypocoagulable and hyperfibrinolytic state and seem to lead to an increased bleeding risk.

Case presentation

This case report describes the case of a thirteen years old girl who presented to our Emergency Department complaining of menorrhagia for the last fifteen days, leading to severe anemia. The objective examination revealed clinical signs of hypothyroidism and a severe short stature, lower than mid-parental height, with stunting of growth and a significant bone age delay. Blood exams and thyroid ultrasound were consistent with the diagnosis of severe hypothyroidism in autoimmune thyroiditis with acquired von Willebrand syndrome, growth hormone deficiency. Magnetic resonance showed pituitary functional hyperplasia.

The substitutive therapy with levothyroxine led to the resolution of heavy bleeding after five days and following normalization of coagulative parameters and pituitary hyperplasia.

Conclusions

Hypothyroidism usually presents with unspecific symptoms, with consequent risk of diagnostic delay. It can influence the coagulation system and it seems to be associated to increased risk of menstrual irregularities.

We underline the importance of a regular follow up of the pubertal development, including height measurements, thyroid palpation and menstrual anamnesis to intercept red flags findings for hypothyroidism.

Pituitary Macroadenoma and Severe Hypothyroidism: The Link between Brain Imaging and Thyroid Function

In case of primary hypothyroidism, reactive pituitary hyperplasia can manifest as pituitary (pseudo) macroadenoma. We report the case of a 12-year-old boy who was evaluated for impaired growth velocity and increased body weight. Because of low insulin-like growth factor 1 levels and poor response to the growth hormone stimulation test, brain magnetic resonance imaging was performed and a pituitary macroadenoma was found. Treatment with levothyroxine was started, and thyroid function was evaluated approximately every 40 days to titrate the dosage. After few months of therapy, the size of the macroadenoma decreased and growth hormone secretion normalized. The pituitary returned to normal size in approximately 5 years. The boy went through puberty spontaneously and reached a normal adult height. In a patient affected by primary hypothyroidism, reactive pituitary hyperplasia can cause growth hormone deficiency; however, growth hormone secretion usually normalizes after starting levothyroxine treatment. Pituitary macroadenoma can be difficult to distinguish from severe pituitary hyperplasia; however, pituitary macroadenomas are rare in childhood, and our clinical case underlines how the hormonal evaluation is essential to achieve a correct diagnosis and prevent unnecessary surgery in a context of pituitary mass.

Pituitary hyperplasia in childhood primary hypothyroidism: a review

INTRODUCTION

Pituitary hyperplasia following primary hypothyroidism in pediatric age group population is considered rare with reports of unnecessary neurosurgical intervention for this medically treatable condition. Given the paucity of information on this topic, it is timely to provide clinicians with a comprehensive summary of available research.

METHODS

A search of published studies in Pubmed, PsychInfo and Cochrane Database with the terms "pituitary hyperplasia" or "pituitary hypertrophy" and "hypothyroidism" was performed and the results filtered for English language, pediatric (0-18 years) population and CT or MRI confirmed findings. 55 studies met the inclusion criteria. Data for a total of 110 patients with pituitary hyperplasia following primary hypothyroidism were extracted. The study population included 29 males and 81 females (M: F= 0.35:1). Patient age varied from 3 weeks to 18 years with a mean age of 10.22 years.

RESULTS

The most common clinical presentations included growth retardation, constipation and features of myxedema which were present in 78, 36 and 18 percent of children included in our review. Neuroimaging showed the mean (SD) pituitary height being 13.48 mm (4.72 mm). All of the patients achieved resolution of their pituitary mass and clinical as well as biochemical abnormalities 1 to 26 months after initiation of thyroid hormone replacement therapy, with an average time interval of 7.22 months. Our review has tried to delve in the pathophysiology as well as clinical, biochemical and radiological aspects of pediatric pituitary hyperplasia secondary to primary hypothyroidism and provide recommendations for treatment and follow-up. This may help anyone concerned gain a substantial knowledge on this topic.

Primary hypothyroidism with growth failure and pituitary pseudotumor in a 13-year-old female: a case report

Introduction

Primary hypothyroidism is a well-known cause of poor linear growth in children. A rare finding with profound or long-standing disease is anterior pituitary enlargement (pituitary pseudotumor). This case highlights this uncommon finding, discusses clinical situations in which gradual dose escalation of levothyroxine may be advisable and reviews adjuvant therapies that have been previously attempted to improve final height in the setting of profound hypothyroidism.

Case presentation

We report the case of a 13-year-old Hispanic girl initially evaluated for poor linear growth and delayed puberty, and found to have pituitary enlargement secondary to profound primary hypothyroidism. Treatment with progressive doses of levothyroxine normalized her symptoms and led to complete resolution of her pituitary findings, but she then rapidly progressed through puberty, achieving an adult height of only 142cm, significantly below her calculated mid-parental height.

Conclusions

In cases of severe primary hypothyroidism with prolonged elevation of thyroid-stimulating hormone and pituitary pseudotumor, gradual replacement of thyroid hormone with slowly escalating doses of levothyroxine may be beneficial to prevent complications of therapy. Early recognition and treatment of hypothyroidism during childhood is essential for normal growth, as final height is invariably compromised in children with prolonged disease. Additional study is needed to determine the potential beneficial effects of gonadotropin-releasing hormone agonist and recombinant human growth hormone treatment in this setting.

Transdifferentiation of pituitary thyrotrophs to lactothyrotrophs in primary hypothyroidism: case report

Primary hypothyroidism causes adenohypophysial hyperplasia via stimulation by hypothalamic thyrotropin-releasing hormone (TRH). The effect was long thought to simply result in thyroid-stimulating hormone (TSH) and prolactin (PRL) cell hyperplasia, an increase in TSH and PRL blood levels with resultant pituitary enlargement, often mimicking adenoma. Recently, it was shown that transformation of growth hormone (GH) cells into TSH cells takes place in both clinical and experimental primary hypothyroidism. Such shifts from one cell to another with a concomitant change in hormone production are termed "transdifferentiation" and involve the gradual acquisition of morphologic features of thyrotrophs ("somatothyrotrophs"). We recently encountered a unique case of pituitary hyperplasia in a 40-year-old female with primary hypothyroidism wherein increased TSH production was by way of PRL cell recruitment. The resultant "lactothyrotrophs" maintained TSH cell morphology (cellular elongation and prominence of PAS-positive lysosomes) but expressed immunoreactivity for both hormones. No co-expression of GH was noted nor was thyroidectomy cells seen. This form of transdifferentiation has not previously been described.