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Hb

haemoglobin

HbA1c

An abbreviation for glycated haemoglobin, a measure of how well glucose levels have been controlled over the previous three months or so in a person with diabetes. It is expressed as a percentage.

HCG

human chorionic gonadotrophin

HDL-cholesterol

A substance that mainly exists to carry cholesterol from the circulation to the liver; commonly referred to as 'good cholesterol'.

heart attack

The death of a section of heart muscle caused by an interruption in its blood supply. Also called a myocardial infarction.

heart block

An abnormally slow heart rate arising because of a problem with the electrical conduction system of the heart

heart failure

Failure of the heart to pump adequately.

heavy metals

Metals that can accumulate in the body, with a detrimental effect on health.

Heller's myotomy

Surgery to ease the passage of food contents from the gullet, or oesophagus, to the stomach.

helminths

Worm-like parasites.

hemiplegia

Also called hemiparesis. Paralysis of one side of the body.

Henoch-Schonlein purpura

Inflammation of small blood vessels causing leakage of blood into the skin, joints, kidneys and intestines.

heparin

A substance produced by the body, or given as medication, that reduces the likelihood of the blood to clot, coagulate.

hepatic

Relating to the liver.

hepatitis

Inflammation to the liver with accompanying damage to liver cells.

hepatomegaly

Enlarged liver occuring as a result of any liver disorder.

Herbenden's nodes

Small, fixed bumps on the fingers, usually at the last joint, which are a sign of osteoarthritis.

hereditary haemorrhagic telangiectasia

A genetic disorder, also known as Osler-Weber-Rendu disease, in which there is a tendency to nosebleeds and sometimes bleeding in the intestines or lungs, along with small red spots or spidery lines on the skin due to enlarged capillaries.

hermaphroditism

A condition in which reproductive organs of both sexes are present in the same individual, so a human is born with both ovarian and testicular tissue

hernia

When part of an organ pushes through the wall of the body cavity that normally holds it. Hernias can develop in many different parts of the body.

herpangina

A disease caused by Coxsackie viruses causing painful mouth ulcers.

herpes gestationis

A rare autoimmune disorder that affects women during pregnancy.

Herpes simplex

The virus responsible for cold sores and genital herpes

Herpes zoster

An infection of the nerves supplying certain areas of the skin that is characterised by a painful rash.