Conditions
Diseases and conditions: definition, affected anatomy, causes, symptoms, diagnosis, treatment and prevention.
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A
Alzheimer's disease
The commonest cause of dementia: a progressive loss of memory and thinking ability caused by the build-up of amyloid plaques and tau tangles and the death of…
Anaemia
A haemoglobin concentration below normal (roughly under 130 g/L in men and 120 g/L in women), reducing the blood's capacity to carry oxygen.
Anterior cruciate ligament injury
A sprain or tear of the anterior cruciate ligament, the band inside the knee that stops the tibia sliding forward on the femur and controls rotation.
Appendicitis
Acute inflammation of the appendix, usually because its opening into the caecum is blocked.
Asthma
A chronic inflammatory disease of the airways causing reversible narrowing, with episodes of wheeze, breathlessness, chest tightness and cough.
Atrial fibrillation
A common heart rhythm disorder in which the atria quiver chaotically instead of contracting, producing an irregular and often fast pulse.
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C
Chronic kidney disease
Persistent reduction in kidney function (a filtration rate below 60 ml/min) or evidence of kidney damage such as protein in the urine, for more than three…
Chronic obstructive pulmonary disease (COPD)
Progressive, largely irreversible airflow obstruction caused by damage to the airways (chronic bronchitis) and destruction of alveoli (emphysema), almost…
Cirrhosis
Scarring of the liver from long-term damage, in which nodules of regenerating cells are surrounded by fibrous bands that distort blood flow and impair function.
Colorectal (bowel) cancer
A malignant tumour of the colon or rectum, almost always arising from a benign polyp (adenoma) over years.
Coronary artery disease
Narrowing of the coronary arteries by fatty plaque (atherosclerosis), limiting blood flow to the heart muscle.
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G
Gallstones
Hard deposits, usually of cholesterol, that form in the gallbladder when bile becomes supersaturated.
Gastro-oesophageal reflux disease
Reflux of stomach acid into the oesophagus often enough to cause symptoms or damage the lining.
Gout
An inflammatory arthritis caused by deposition of uric acid crystals in joints, triggered when blood urate is persistently high.
H
Heart attack (myocardial infarction)
Death of heart muscle because a coronary artery is suddenly blocked, usually by a clot forming on a ruptured plaque.
Heart failure
A syndrome in which the heart cannot pump enough blood to meet the body's needs, or can do so only at raised filling pressures.
Herniated (slipped) disc
Protrusion of the soft nucleus of an intervertebral disc through its fibrous outer ring, most often at the lower lumbar levels, which can press on a nerve root.
High blood pressure (hypertension)
Persistently raised arterial pressure, usually defined as 140/90 mmHg or more in the clinic (135/85 on home readings).
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O
Osteoarthritis
The commonest joint disease: progressive loss of articular cartilage with changes in the underlying bone, causing pain and stiffness, most often in the knees,…
Osteoporosis
Loss of bone mass and deterioration of bone architecture that makes bones fragile and prone to fracture after minimal trauma.
Overactive thyroid (hyperthyroidism)
Excess thyroid hormone, most often from Graves' disease, in which antibodies stimulate the thyroid to overproduce.
P
Pancreatitis
Inflammation of the pancreas, acute when its own enzymes are activated inside the gland, chronic when repeated injury leads to scarring and loss of function.
Parkinson's disease
A progressive disorder in which dopamine-producing neurons in the substantia nigra of the midbrain are lost, causing slowness, stiffness and tremor.
Peptic ulcer
A break in the lining of the stomach or duodenum that extends through the mucosa, caused by acid acting on a weakened defence.
Pneumonia
Infection of the alveoli, which fill with fluid and inflammatory cells so that part of the lung cannot exchange gas.
Pulmonary embolism
Blockage of a pulmonary artery by a clot that has travelled from a vein, usually in the leg or pelvis.
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Sepsis
Life-threatening organ dysfunction caused by a dysregulated body response to infection.
Stroke
Sudden loss of brain function because blood supply to part of the brain is interrupted, by a blocked artery (ischaemic, 85%) or a bleed (haemorrhagic).
T
Type 1 diabetes
An autoimmune disease in which the insulin-producing beta cells of the pancreas are destroyed, so the body cannot regulate blood glucose without injected…
Type 2 diabetes
A metabolic disease in which the body's cells respond poorly to insulin (insulin resistance) and the pancreas gradually fails to compensate, leaving blood…
U
Underactive thyroid (hypothyroidism)
Insufficient thyroid hormone, most often because the immune system destroys the thyroid gland, slowing the body's metabolism.
Urinary tract infection
Bacterial infection of the bladder (cystitis) or, when it ascends, the kidney (pyelonephritis), usually by gut bacteria such as Escherichia coli.