Causes
Hyperglycemia may be caused by: diabetes, various (non-diabetic) endocrine disorders (insulin resistance and thyroid, adrenal, pancreatic, and pituitary disorders), sepsis and certain infections, intracranial diseases (e.g. encephalitis, brain tumors (especially if near the pituitary gland), brain haemorrhages, and meningitis) (frequently overlooked), convulsions, end-stage terminal disease, prolonged/major surgeries, excessive eating, severe stress, and physical trauma. Endocrine
Chronic, persistent hyperglycaemia is most often a result of diabetes. Several hormones act to increase blood glucose levels and may thus cause hyperglycaemia when present in excess, including: cortisol, catecholamines, growth hormone, glucagon, and thyroid hormones. Hyperglycaemia may thus be seen in: Cushings syndrome, pheochromocytoma, acromegaly, hyperglucagonemia, and hyperthyroidism. Diabetes mellitus
Chronic hyperglycemia that persists even in fasting states is most commonly caused by diabetes mellitus. In fact, chronic hyperglycemia is the defining characteristic of the disease. Intermittent hyperglycemia may be present in prediabetic states. Acute episodes of hyperglycemia without an obvious cause may indicate developing diabetes or a predisposition to the disorder.In diabetes mellitus, hyperglycemia is usually caused by low insulin levels (diabetes mellitus type 1) and/or by resistance to insulin at the cellular level (diabetes mellitus type 2), depending on the type and state of the disease. Low insulin levels and/or insulin resistance prevent the body from converting glucose into glycogen (a starch-like source of energy stored mostly in the liver), which in turn makes it difficult or impossible to remove excess glucose from the blood.
During the course of evaluation of the patient, a bulging out of the left ventricular apex with a hypercontractile base of the left ventricle is often noted. It is the hallmark bulging-out of the apex of the heart with preserved function of the base that earned the syndrome its name takotsubo "octopus trap", in Japan, where it was first described.Stress is the main factor in takotsubo cardiomyopathy, with more than 85% of cases set in motion by either a physically or emotionally stressful event that prefaces the start of symptoms. Examples of emotional stressors include grief from the death of a loved one, fear of public speaking, arguing with a spouse, relationship disagreements, betrayal, and financial problems. Acute asthma, surgery, chemotherapy, and stroke are examples of physical stressors. In a few cases, the stress may be a happy event, such as a wedding, winning a jackpot, a sporting triumph, or a birthday. Risk factors
Stress trigger
Although there have been documented cases of TTS without a triggering stressor, it is widely recognized that TTS is preceded by a stressful event. Case series looking at large groups of patients report that some patients develop takotsubo cardiomyopathy after experiencing emotional stress. Some patients have a preceding clinical stressor (such as a brain injury, asthma attack or exacerbation of a chronic illness) and research has indicated that this type of stress may even occur more often than emotionally stressful triggers. Roughly one-third of patients have no preceding stressful event.