RESUMO
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.