Hyperthyroidism means that your thyroid gland is functioning at a high or overactive level. The thyroid gland releases a hormone that helps control metabolism – if more hormone is released, your metabolism speeds up. This can cause weight loss without trying, your heart beats hard or fast, and you can feel twitchy, irritable or anxious. You may have difficulty sleeping although you feel very tired, and you might feel sweaty and hot all the time, perhaps wearing scanty clothing when others around you feel cold. Your thyroid gland is a small gland in the front of your neck. In a chain reaction, your brain releases a hormone to prompt the thyroid gland to release a hormone (called thyroid-stimulating hormone or TSH) to produce thyroxine, also called free T4. This is the active substance controlling metabolism.

Hypothermia is a medical emergency. It occurs when your body gets to dangerously low temperatures, below 35°C. This can be life-threatening. At temperatures this low, your vital organs cannot function properly resulting in organ failure or death as your body fails to retain any heat.

Your thyroid gland is a small gland in the front of your neck. It's a chain reaction, where your brain releases a hormone, which prompts the thyroid gland to release a hormone (called thyroid-stimulating hormone or TSH), which then produces thyroxine, also called free T4. This is the active biochemical. Hypothyroidism means that your thyroid gland is underactive, or not making enough thyroid hormone. You get symptoms of a slowed metabolism, which affects how you use and store energy. This can affect the body in many ways: gain weight feel cold all the time feel tired sluggish need to sleep more dry skin hair loss slower in your thinking less able to concentrate feel a bit depressed have a slower or weaker pulse. Hypothyroidism is ten times more common in women than in men and in the UK about 1 in 100 of people have it. It is most common in adult women and becomes more common with increasing age but it can occur at any age and can affect anyone. Fortunately, it is easily fixed once it’s been identified and treatment started, although it can take a month or two for this to take full effect.

Named after the doctor who first described it in 1862, Raynaud's phenomenon – often just called Raynaud’s - is a condition that affects the circulation of blood in certain areas of the body, most often the fingers and toes, usually when exposed to the cold. It can cause the areas to change colour (white, blue and then red in an attack), become painful, numb, and restrict movement. It is a fairly common condition that affects women more than men and the most common type usually develops before the age of 30, sometimes running in families. It can be triggered by various factors like stress, cold weather (the most common trigger), and even excess caffeine. It is not usually a serious condition although it can affect people's quality of life, and sometimes can also be linked to other underlying medical conditions.

A sebaceous cyst is an umbrella term for epidermoid and pilar cysts. It means a fluid-filled sac or lump and either originates from skin cells (epidermoid) or from a hair follicle (pilar). Sebaceous cysts are not harmful and can slowly get bigger over time or can disappear without any treatment. They are non-cancerous, so they will not cause harm or spread to any other part of your body, and they do not usually require treatment. They appear as round, mobile lumps that can feel bouncy and can at times release a white or yellow paste-like substance from the inside of it if there is a break in the lining of the cyst and it is squeezed. We do not recommend squeezing cysts as they can cause inflammation or even infection. Sebaceous cysts are not painful unless they become inflamed or infected.

Acute kidney injury (AKI) means that the kidneys suddenly come under strain and they function less effectively. This can cause toxic waste products to build up in the blood and they change the balance of essential salts like potassium and sodium. It is essential it’s recognised and treated promptly, to ensure the kidneys have a chance to recover without permanent damage. It can prove life-threatening if left untreated. AKI is diagnosed on a blood test, which will show that creatinine, a substance excreted by the kidneys, is raised, indicating the kidneys are not doing their job. Urea may also be raised, eGFR (estimated glomerular filtration rate) may be low, and potassium may be raised. AKI is also known as acute renal failure. The name AKI is misleading in that it doesn’t mean you have received a physical injury or blow as such.

Alzheimer’s disease is the most common form of dementia and mostly affects people over the age of 65 years old. It is believed to be caused by the build-up of abnormal proteins in the brain, reduced levels of neurological chemicals (neurotransmitters) and causes shrinkage of different parts of the brain over time. These lead to problems with memory, language and performing tasks that the person had previously been able to do.

Attention deficit hyperactivity disorder, or ADHD, is characterised as children finding it hard to focus on a task or play without getting distracted. They may also act on impulse and make mistakes, they may be forgetful, and they can appear restless or fidgety. This condition is often picked up in children between 3 and 7 years old, but a diagnosis can be made in older children or even adults. It's much more commonly diagnosed in boys, and around 75,000 children are on ADHD medication in the UK, which is the equivalent of a medium-sized town. It can be a tough time for parents and teachers, especially before any diagnosis is made, as behaviours can be disruptive in the classroom and in family life, and your child may be finding it difficult to meet the expectations laid on them, which can feel quite isolating.

An absence seizure is where you lose awareness of what's happening around you for a brief period of time, a few seconds or up to 20 seconds. There may be no obvious visible signs to anyone witnessing, or they may be very subtle, and you don’t usually lose consciousness. It is a type of epilepsy caused by abnormal electrical activity in the brain, and it mostly affects children, typically between the ages of 4 and 14. They don't usually cause any long-term problems, although they can be disruptive to school days because they affect concentration. Most children outgrow them but it’s still possible to have an absence seizure at any age. We don’t know why they happen.

Renal calculi – often more commonly called kidney stones - are crystals formed from the naturally occurring salts in urine that can sometimes clump together to form a solid lump or ‘stone’. They are common, and every year about 2 people in every 1,000 will have kidney stone symptoms. They are more common in men, almost double than women, and in their lifetime, 1 in 8 men and 1 in 16 women will have pain caused by a kidney stone. Kidney stones often do not tend to cause many symptoms if they are stationary in the kidney itself, but the real problems usually occur if they move out from the kidney and travel into the ureter – the tube connecting a kidney to the bladder. If this happens, along with causing severe pain, they can block the ureter, leading to potential infection and difficulty passing urine. They can also carry the risk of preventing the kidneys from working effectively, either in the short term or with more long-term consequences. What do kidney stones feel like? The typical pain associated with kidney stones is felt from the loin to the groin. This is from the side of the back, radiating around to the front lower part of the abdomen. People sometimes feel the pain travelling into the vagina, testicle or tip of the penis, and they may also see blood in their urine. Most people report the pain of kidney stones to be excruciating, coming in waves and spasms to double them over until it passes after a few seconds or minutes before returning again and is often so severe it makes them vomit. The waves of pain happen when your ureter is blocked, but this muscular tube tries to force the stone along it by squeezing. If you have classical-sounding pain, along with blood in your urine, your doctor may arrange a scan to see whether there is any evidence of kidney stones.

Ramsay Hunt syndrome (herpes zoster oticus) is a type of shingles that affects the facial nerve. This causes a number of symptoms, including weakness or paralysis of one side of the face and one-sided hearing loss. It’s caused by varicella-zoster virus (VZV), and implies that you had chickenpox – most likely as a child – and while that illness has cleared, the virus remains dormant in your nerves until it is reactivated. It’s important to get checked out, firstly because this can look very much like a stroke, and secondly because prompt treatment can help this improve more quickly.

Pressure ulcers are also known as bed sores. They occur due to prolonged pressure on a certain area of the body causing injury or damage to the skin and underlying tissue. They often affect bony areas which have thin layers of tissue overlying them such as the lower spine, heels, hips or elbows. But they can develop anywhere. As the chances of developing a pressure sore increase the longer the pressure is applied, so the highest risk comes to those confined to a bed or chair for long periods. Early signs of a pressure ulcer developing are when the area starts to become pink and painful. Later the skin may start to become hardened or warm. If a pressure ulcer is not taken care of at this stage, it can then develop into a break in the skin. Over time this can lead to a wound or blister, that begins to extend into the deeper tissues and finally the muscle. At this stage, it is very painful.