Endocrine diseases are caused by structural changes of endocrine gland or by functional damage which express with higher or decrease of hormonal production. Symptoms in patient could be induced by local changes of organ structure, for example its enlargement or structural changes or are induced by excess or absence of hormones. Therefore it is important to realize that hormonal products influence also function of non endocrine organs and symptoms of patient could mimic disease of another system, e.g. gastrointestinal. In case of hyperthyreoidism patients could have diarrhea or grow slim, by hypothyroidism they have constipation or put on weight.