sudden and rapid blood loss that occurs when a blood vessel is damaged.
occurs when the heart becomes weak and struggles to pump blood around the body efficiently.
flap of tissue in the heart that ensures blood flows in one direction only.
HIV (human immunodeficiency virus) is a virus that damages the cells in the immune system and weakens the ability to fight everyday infections and disease. HIV is transmitted through sexual intercourse, sharing needles and from mother to baby during pregnancy.
a synthetic (artificial) version of the hormone cortisol, usually taken in tablet form, to replace cortisol in the body.
high blood pressure.
low blood pressure.
an operation to remove a woman's womb and ovaries, resulting in the menopause. A partial hysterectomy can be performed where the ovaries are preserved, which does not result in the menopause.
an increased number of cells, leading to an increase in the size of a tissue or organ. For example in congenital adrenal hyperplasia, there is an enlargement of the adrenal glands as they work harder to try to produce the steroid hormone cortisol.
The hypothalamus is a part of the brain that has a vital role in controlling many bodily functions including the release of hormones from the pituitary gland.
Human chorionic gonadotrophin is a reproductive hormone that is essential for establishing and maintaining early pregnancy.
Hashimoto's disease is an autoimmune disease that causes inflammation of the thyroid gland and results in a reduction in thyroid hormone levels.
Hirsutism is the presence of excess male-pattern hair growth in women and is commonly caused by an imbalance of hormones.
Hypercalcaemia is the presence of abnormally high calcium levels in the blood.
Hyperthyroidism is a common condition where the thyroid gland becomes overactive and produces too much thyroid hormone.
Hypocalcaemia refers to low calcium levels in the blood. It is most commonly caused by either vitamin D deficiency or diseases of the parathyroid glands causing low parathyroid hormone (PTH) secretion.
Hyponatraemia means abnormally low levels of sodium (salt) in the bloodstream or a deficiency of sodium in the body.
Hypoparathyroidism is a rare condition characterised by inadequate parathyroid hormone (PTH) secretion from the parathyroid glands, resulting in low calcium levels in the bloodstream.
Hypophosphataemia is the term used to describe low levels of phosphate in the blood. It is most commonly caused by hyperparathyroidism and vitamin D deficiency.
Hypopituitarism is the failure of production of one or more hormones from the pituitary gland.
Hypothyroidism is a condition that develops when the thyroid gland is unable to produce enough thyroid hormones.