Conditions
Diseases and conditions: definition, affected anatomy, causes, symptoms, diagnosis, treatment and prevention.
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Showing all 114 conditions
A
Abdominal aortic aneurysm
An abdominal aortic aneurysm is a bulge in the aorta, the body's main blood vessel, where it runs through the tummy.
ACL 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.
Acne
Acne is a common skin condition in which spots, from a few small ones to deep painful lumps, appear mostly on the face, chest and back.
ADHD (attention deficit hyperactivity disorder)
ADHD is a neurodevelopmental condition that affects attention, activity levels and impulse control.
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.
Angina
Angina is chest pain or discomfort that happens when the heart muscle does not get enough blood.
Anxiety and generalised anxiety disorder
Generalised anxiety disorder (GAD) is a long-term condition in which a person feels worried or anxious about many different things, much of the time.
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.
Atopic eczema
A skin condition that causes dry, itchy skin and comes and goes in flare-ups.
Atrial fibrillation
A common heart rhythm disorder in which the atria quiver chaotically instead of contracting, producing an irregular and often fast pulse.
Autism
A lifelong difference in how a person communicates, behaves and reacts compared with people who are not autistic.
B
Bipolar disorder
Bipolar disorder is a mental health condition that causes extreme mood changes, with high moods (mania or hypomania) and low moods (depression).
Bladder cancer
Bladder cancer is cancer that forms in the tissues of the bladder, the organ that stores urine.
Bone fracture
A break in the continuity of a bone, from a hairline crack to a shattered, displaced or open injury.
Brain tumours
A brain tumour is a growth of abnormal cells in or around the brain, and it may be non-cancerous or cancerous.
Breast cancer
A malignant tumour arising from the cells that line the ducts or lobules of the breast. It may remain within the ducts (in situ) or invade the surrounding…
Bronchitis
Bronchitis is inflammation of the airways in the lungs, usually caused by an infection.
C
Cellulitis
Cellulitis is an infection of the deeper layers of the skin caused by bacteria.
Cervical cancer
A malignant tumour of the cervix, the neck of the uterus, that develops almost always from persistent infection with high-risk types of human papillomavirus…
Chlamydia
A sexually transmitted infection caused by the bacterium Chlamydia trachomatis.
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.
Coeliac disease
Coeliac disease is an autoimmune condition in which the immune system reacts to gluten and damages the lining of the small bowel.
Colorectal (bowel) cancer
A malignant tumour of the colon or rectum, almost always arising from a benign polyp (adenoma) over years.
Conjunctivitis
Inflammation of the conjunctiva, the clear tissue that covers the white of the eye and lines the inside of the eyelids.
Coronary artery disease
Narrowing of the coronary arteries by fatty plaque (atherosclerosis), limiting blood flow to the heart muscle.
COVID-19
COVID-19 is an illness caused by a virus called coronavirus (SARS-CoV-2), with symptoms that overlap with colds and flu.
D
Deep vein thrombosis
A blood clot in a deep vein, most often of the calf or thigh.
Depression
Depression is a low mood that lasts for weeks or months and affects daily life.
Diverticulitis and diverticular disease
Diverticular disease is a condition in which small pouches in the wall of the large intestine cause symptoms, and diverticulitis is when those pouches become…
E
Ear infection (otitis media)
An ear infection is an infection, usually of the middle ear behind the eardrum, that is common in children and often settles without treatment.
Ectopic pregnancy
A pregnancy in which the fertilised egg implants and begins to grow outside the cavity of the uterus, most often in a fallopian tube, where it cannot develop…
Endometriosis
A chronic condition in which tissue similar to the lining of the uterus (the endometrium) grows outside the uterus, most often on the ovaries, the peritoneum…
Enlarged prostate (benign prostatic hyperplasia)
An enlarged prostate is a common condition in which the prostate gland grows larger and can squeeze the urethra, the outlet tube for urine, slowing the flow of…
Epilepsy
A tendency to recurrent, unprovoked seizures: bursts of abnormal synchronised electrical activity in the brain.
Erectile dysfunction
Erectile dysfunction, also called impotence, is being unable to get or keep an erection.
F
Fatty liver disease (MASLD)
A common condition in which fat builds up in the liver, often linked to being overweight.
Fibroids
Benign (non-cancerous) growths of smooth muscle and fibrous tissue that develop in the muscular wall of the uterus, ranging from the size of a pea to a mass…
Fibromyalgia
A long-term condition that causes pain all over the body.
Flu (influenza)
Flu is a respiratory illness caused by influenza viruses.
Food allergy and anaphylaxis
A food allergy is when the immune system overreacts to certain foods, with reactions that range from mild to life-threatening anaphylaxis.
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.
Gender dysphoria (gender incongruence)
The distress that can arise when a person's gender identity differs from the sex they were assigned at birth. The mismatch itself is called gender incongruence…
Genital herpes
Genital herpes is a sexually transmitted infection caused by the herpes simplex virus.
Gestational diabetes
Gestational diabetes is a form of diabetes that starts during pregnancy and typically clears up after the baby is born.
Gonorrhoea
A bacterial sexually transmitted infection caused by Neisseria gonorrhoeae that can affect the genitals, rectum, throat and eyes.
Gout
An inflammatory arthritis caused by deposition of uric acid crystals in joints, triggered when blood urate is persistently high.
H
Hay fever (allergic rhinitis)
Hay fever is an allergic reaction to pollen, also called seasonal allergic rhinitis.
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.
Hepatitis C
Hepatitis C is an infection with a virus that causes inflammation of the liver, which can damage the liver over time.
Hernia
A hernia forms when muscle weakness lets tissue push through.
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).
High cholesterol (hypercholesterolaemia)
High cholesterol, also called hypercholesterolaemia, means there is too much cholesterol in the blood.
HIV
HIV is a virus that attacks the immune system and, with treatment, can be managed as a long-term condition.
Hives (urticaria)
Hives, also called urticaria or nettle rash, is an itchy, raised rash that can appear anywhere on the body.
I
Inflammatory bowel disease
Chronic inflammation of the gut driven by an abnormal immune response: ulcerative colitis affects the colon's lining continuously from the rectum; Crohn's…
Insomnia
A sleep problem in which a person regularly has trouble sleeping, including finding it hard to get to sleep or waking often in the night.
Irritable bowel syndrome (IBS)
A long-term digestive condition with repeated abdominal pain and changes in bowel habit, but no visible damage or disease in the digestive tract.
K
Kidney infection (pyelonephritis)
A kidney infection, also called pyelonephritis, is a urinary tract infection that affects one or both kidneys.
Kidney stones
Hard crystals, most commonly calcium oxalate, that form in the kidney and can pass into and block the ureter.
L
Lactose intolerance
Digestive symptoms such as bloating, diarrhoea and gas that follow eating or drinking foods that contain lactose, the sugar in milk.
Lung cancer
A malignant tumour arising from the lining of the airways or alveoli, divided into non-small-cell (about 85%) and small-cell types.
Lupus
A long-term autoimmune condition in which the immune system attacks healthy tissue, most often causing joint aches, skin rashes and tiredness.
Lymphoma (Hodgkin and non-Hodgkin)
Lymphoma is a cancer of the lymphatic system, and doctors group it into Hodgkin lymphoma and non-Hodgkin lymphoma.
M
Meningitis
Meningitis is an infection of the protective membranes that surround the brain and spinal cord.
Menopause and perimenopause
Menopause is when periods stop altogether, and perimenopause is the stage before this when periods change and symptoms begin.
Migraine
A recurrent headache disorder with attacks of moderate to severe throbbing pain, typically one-sided, lasting 4 to 72 hours, with nausea and sensitivity to…
Miscarriage
The loss of a pregnancy.
Multiple sclerosis (MS)
A lifelong condition in which the immune system mistakenly attacks nerves in the brain and spinal cord.
N
O
Obsessive compulsive disorder (OCD)
Obsessive compulsive disorder (OCD) is a mental health condition in which a person has obsessive thoughts and compulsive behaviours.
Obstructive sleep apnoea
Obstructive sleep apnoea is a condition in which the throat narrows or closes during sleep, so breathing stops and starts again.
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.
Ovarian cancer
A malignant tumour of the ovary or, as is now recognised for many cases of the commonest type, of the adjacent fallopian tube, which spreads early across the…
Overactive thyroid (hyperthyroidism)
Excess thyroid hormone, most often from Graves' disease, in which antibodies stimulate the thyroid to overproduce.
P
Pancreatic cancer
Pancreatic cancer is a cancer that starts in the pancreas, an organ that helps with digestion.
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.
Pelvic organ prolapse
Descent of one or more of the pelvic organs (the bladder, uterus, rectum, small bowel or, after hysterectomy, the top of the vagina) from their normal position…
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.
Peripheral arterial disease
A long-term condition in which the arteries that supply blood to the legs become narrowed or blocked, affecting the blood supply and causing pain in the legs.
Pneumonia
Infection of the alveoli, which fill with fluid and inflammatory cells so that part of the lung cannot exchange gas.
Polycystic ovary syndrome
A common hormonal condition in which the ovaries make more androgens (hormones such as testosterone, which everyone makes, usually in higher amounts in men)…
Post-traumatic stress disorder (PTSD)
A mental health condition that can develop after very stressful, frightening or distressing events.
Pre-eclampsia
Pre-eclampsia is a condition that can develop in pregnancy, with high blood pressure and protein in the urine as its early signs.
Prostate cancer
Prostate cancer is a cancer that starts in the prostate, a small gland in the male reproductive system that sits just below the bladder.
Psoriasis
A long-term inflammatory skin condition in which the immune system is involved, usually showing as raised red patches covered with silvery scales.
Pulmonary embolism
Blockage of a pulmonary artery by a clot that has travelled from a vein, usually in the leg or pelvis.
R
S
Sciatica
Pain, and sometimes tingling, numbness or weakness, in one leg when the sciatic nerve is irritated or compressed.
Sepsis
Life-threatening organ dysfunction caused by a dysregulated body response to infection.
Shingles
Shingles is a painful rash caused by the chickenpox virus becoming active again after lying dormant in the body.
Sinusitis
Sinusitis is inflammation of the sinuses, usually caused by an infection.
Skin cancer
Skin cancer is a group of cancers that start in the skin, divided into melanoma and non-melanoma types.
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
Testicular cancer
Testicular cancer is a cancer that starts in a testicle, one of the two glands in the scrotum.
Thrush (candidiasis)
A common yeast infection caused by Candida, a fungus that normally lives harmlessly on the body, which can affect the mouth, the genitals and the skin.
Thyroid cancer
Thyroid cancer is a cancer that starts in the thyroid gland, a gland in the neck that makes hormones.
Tonsillitis
An infection of the tonsils, most often caused by a virus and sometimes by bacteria, that brings a sore throat, painful swallowing and fever.
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 incontinence
The involuntary leakage of urine, from an occasional dribble on coughing to a complete loss of bladder control, caused by weakness of the pelvic floor and…
Urinary tract infection
Bacterial infection of the bladder (cystitis) or, when it ascends, the kidney (pyelonephritis), usually by gut bacteria such as Escherichia coli.
V
Vertigo and balance problems
Vertigo is the feeling that you, or the world around you, is moving or spinning, and it is often caused by a problem in the inner ear.
Vitamin B12 and folate deficiency anaemia
A lack of vitamin B12 or folate that affects the body's ability to make fully working red blood cells.
Vitamin D deficiency
A shortage of vitamin D in the body, which can weaken bones and muscles over time.