Congenital myopathy is a rare genetic condition that causes muscle weakness and lack of muscle tone, typically present at birth or appearing in early childhood. These inherited disorders affect skeletal muscles throughout the body, with symptoms ranging from mild weakness to severe breathing and feeding difficulties.

Congenital nephrogenic diabetes insipidus is a rare inherited disorder where the kidneys cannot respond properly to a natural hormone, causing the body to produce large amounts of dilute urine and leading to excessive thirst and the risk of severe dehydration.

Congenital pseudarthrosis is a rare bone condition where a fracture fails to heal properly, most commonly affecting the shin bone in young children. Though challenging to treat, modern surgical techniques have transformed outcomes for patients with this condition.

Congenital ureteric anomalies are birth defects affecting the tubes that carry urine from the kidneys to the bladder. These conditions can lead to various complications, including infections, blockages, and kidney damage, but many can be successfully treated with modern surgical techniques.

Conjunctivitis, commonly known as pink eye, is one of the most frequent eye conditions people experience. This inflammation of the clear membrane covering the eye can make your eyes appear pink or red, often with discharge and discomfort, but it rarely threatens your vision.

Allergic conjunctivitis is a common eye condition that affects up to 40% of people at some point in their lives. When your eyes come into contact with allergens like pollen or pet dander, your immune system reacts, causing uncomfortable symptoms like itching, redness, and watering.

Connective tissue disorders are a group of over 200 conditions that affect the tissues holding your body together. These disorders can range from inherited genetic conditions to autoimmune diseases where the body attacks its own tissues, causing inflammation and damage throughout the body.

Constipation is a common problem affecting around 1 in 7 people, causing difficulty or infrequency with bowel movements. While it can significantly impact your quality of life, most cases can be treated with simple changes in diet, fluid intake, and exercise.

Contusion is the medical term for a bruise, one of the most common injuries that can affect anyone, from active children to athletes and older adults, occurring when blood vessels break beneath the skin due to a direct blow or impact.

Corneal dystrophy is a group of rare genetic eye diseases that affect the clear front part of your eye. While some people live without symptoms, others may experience blurred vision, eye pain, or sensitivity to light. There are more than 20 different types, each affecting different layers of the cornea.

Corneal graft failure is the most common reason why corneal transplants stop working, affecting thousands of patients worldwide each year. While the cornea has special properties that usually protect it from rejection, in about one-third of failed grafts, doctors find clear signs that the body’s immune system has attacked the donated tissue.

Despite the cornea’s special protection from the immune system, corneal graft rejection remains the most common cause of transplant failure, with the body’s immune response targeting the donor tissue and threatening the clarity of vision that the transplant was meant to restore.

Coronary artery bypass surgery creates a new path for blood to flow around blocked or narrowed arteries in the heart, helping to restore oxygen-rich blood supply to the heart muscle and reduce the risk of heart attack.

Coronary artery disease is a common heart condition affecting millions of people worldwide, where the arteries supplying blood to the heart become narrowed or blocked, potentially leading to serious complications like heart attacks.

Coronary artery dissection is a tear in the wall of a heart artery that can happen suddenly and without warning, most often affecting younger women who may have no traditional risk factors for heart disease.

Coronary artery occlusion is a partial or complete blockage of the blood vessels that supply your heart with oxygen-rich blood, which can lead to serious complications like a heart attack if left untreated.

Cortical dysplasia is a genetic brain condition where cells in the outer layer of the brain don’t form properly before birth. It is one of the most common causes of epilepsy in children and a frequent cause of seizures that don’t respond well to typical medications. While challenging to treat, surgery and other therapies can offer hope for seizure control.

Corticobasal degeneration is a rare brain disease that causes areas of the brain to shrink and nerve cells to die over time, leading to increasing difficulty with movement, speech, memory, and swallowing.

When cortisol levels in your body become too high or too low, it can lead to serious health problems that affect nearly every part of your body, from your blood pressure and weight to your energy levels and immune system.

A cough is a powerful reflex that helps your body clear the airways of irritants, mucus, and germs, protecting your lungs from infection. While most coughs resolve on their own, understanding what triggers them and how to manage symptoms can bring relief and peace of mind.

COVID-19 is a contagious illness caused by a virus called SARS-CoV-2 that emerged in late 2019 and spread globally, affecting millions of people and causing nearly 1.2 million deaths in the United States alone by June 2024.

Craniocerebral injury, also known as traumatic brain injury, affects thousands of people every year when the brain is damaged by an outside force. This injury can range from mild to severe, with effects that may last days, months, or even a lifetime.

Craniopharyngioma is a rare, noncancerous brain tumor that develops near the pituitary gland, a pea-sized structure that controls many important body functions through hormones. Though these tumors grow slowly and don’t spread to other parts of the body, their location makes them serious because they can press on vital brain structures, affecting vision, hormone levels, and overall health.

Craniosynostosis is a birth condition where the bones in a baby’s skull join together too early, before the brain finishes growing. This happens when the flexible seams between skull bones, called sutures, close prematurely. The condition affects about 1 in every 2,000 to 2,500 babies and can change the shape of the head as the brain continues to grow.

A craniotomy is a major brain surgery where a surgeon temporarily removes part of your skull to access and treat problems inside your brain, then carefully replaces the bone before closing the incision.

Crigler-Najjar syndrome is a rare inherited condition where the liver cannot properly break down bilirubin, a substance produced when red blood cells are broken down. This leads to a dangerous buildup in the body that can cause serious brain damage if not treated promptly.

Critical illness refers to life-threatening medical conditions that require intensive care treatment, as well as a specialized type of insurance designed to provide financial support when serious health emergencies strike unexpectedly.

Crohn’s disease is a lifelong inflammatory condition that can affect any part of your digestive system, most commonly the small intestine and colon. While there is no cure, treatments can help control symptoms and allow you to live an active, fulfilling life.

Cryoglobulinaemia is a rare blood vessel condition where abnormal proteins clump together in cold temperatures, potentially blocking blood flow and damaging organs throughout the body, particularly the kidneys and liver.

Cushing’s syndrome is a rare condition that happens when your body has too much of a hormone called cortisol for a long time. This can lead to noticeable changes in your appearance, serious health problems, and emotional challenges. While living with this condition can be difficult, understanding it and getting proper treatment can help you take back control of your health.

Cutaneous calcification occurs when calcium salts build up in the skin and tissue beneath it, forming hard deposits that can range from harmless bumps to painful, disabling lesions that significantly affect daily life.

Cutaneous lupus erythematosus is an autoimmune disease that primarily targets the skin, causing various types of rashes and lesions. While some people experience only skin symptoms, others may develop signs of systemic disease affecting multiple organs. Understanding this condition and its triggers—especially sunlight exposure—is essential for managing symptoms and preventing complications.

Cutaneous sarcoidosis is a skin condition that occurs in up to one third of people with sarcoidosis, a disease that causes tiny clusters of inflammatory cells to form in various organs. Because the skin lesions can appear in many different forms, cutaneous sarcoidosis is known as one of the “great imitators” in dermatology.

Cutaneous T-cell lymphoma is a rare group of blood cancers that primarily affects the skin, often appearing as patches or rashes that can be mistaken for common skin conditions like eczema or psoriasis for years before diagnosis.

When cutaneous T-cell lymphoma returns after treatment, patients face unique challenges that require careful management and support. Understanding what happens when the disease comes back, and what options are available, can help patients and their families navigate this difficult phase of the illness.

When cutaneous T-cell lymphoma does not respond to treatment or returns after a period of improvement, patients and their healthcare teams face new challenges in managing this complex skin condition.

Stage I cutaneous T-cell lymphoma represents early-stage disease where cancer affects less than 10% of the skin, with no involvement of the blood, lymph nodes, or internal organs, offering patients a favorable outlook with many living normal lives for decades.

Cutaneous T-cell lymphoma stage II is a form of blood cancer that primarily affects the skin, with disease that has begun to show changes beyond simple patches or plaques, marking a transition between early and more advanced stages.

Cutibacterium acnes is a bacterium that lives on nearly everyone’s skin, but it can transform from a harmless companion into an opportunistic pathogen, causing infections ranging from common acne to serious complications following surgery and medical device implantation.

Cystic fibrosis is a genetic condition that causes thick, sticky mucus to build up in the body, affecting the lungs, digestive system, and other organs. While there is no cure yet, advances in treatment have dramatically improved life expectancy, with many people now living into their 50s, 60s, and beyond.

Cystic fibrosis affects much more than just the lungs. The thick, sticky mucus caused by a faulty protein creates serious problems throughout the digestive system, particularly in the pancreas and intestines, leading to difficulties with nutrition and growth that require lifelong management.

Cystic fibrosis is a genetic disease that causes thick, sticky mucus to build up in the lungs and other organs, leading to breathing difficulties and frequent infections that require lifelong management and care.

Cytokine release syndrome is a serious inflammatory response that happens when your immune system releases too many signaling proteins into your bloodstream, causing widespread inflammation that can damage organs and tissues throughout the body.

Cytomegalovirus is a common virus that stays in the body for life once you’re infected. While most healthy people never know they have it, the virus can cause serious problems for pregnant women, newborns, and those with weakened immune systems.

Deafness is the complete loss of hearing that affects millions of people worldwide. While most hearing loss is permanent and cannot be reversed, understanding its causes, recognizing its signs, and exploring available treatments can significantly improve quality of life and communication abilities.

When hearing loss affects both ears, it creates unique challenges in daily life—from following conversations in noisy environments to safely navigating the world around you. Understanding this condition and exploring treatment options can help restore connection and improve quality of life.

Sensorineural hearing loss occurs when the delicate structures of the inner ear or the nerve pathways that carry sound to the brain are damaged, affecting your ability to hear soft sounds and making even loud sounds seem muffled or unclear.

Hearing loss caused by trauma can happen suddenly or develop over time, affecting people’s ability to hear, communicate, and connect with others. Understanding the different types of traumatic hearing loss and their impacts can help individuals seek appropriate care and support.

When a baby dies within the first 28 days of life, families face one of the most difficult experiences imaginable. Understanding what neonatal death means, its causes, and the support available can help families navigate this profound loss.

Decreased appetite is when you don’t feel hungry or lose the desire to eat, and it can happen suddenly or develop gradually over time. This common symptom can stem from physical changes, emotional factors, underlying health conditions, or medication side effects.

Dedifferentiated liposarcoma is a rare and fast-growing cancer that develops from well-differentiated liposarcoma, most commonly affecting adults over 50 and requiring specialized treatment and long-term monitoring.

Deep vein thrombosis is a serious condition where a blood clot forms in a deep vein, most commonly in the leg. While it can cause pain and swelling, sometimes there are no symptoms at all. The real danger lies in the clot breaking free and traveling to the lungs, which can be life-threatening.

Surgery increases your risk of developing dangerous blood clots in your veins, a condition that requires immediate attention and careful prevention to protect your health and recovery.

Delayed graft function is a common complication after kidney transplantation where the newly transplanted kidney does not start working immediately, often requiring dialysis treatment in the first week after surgery.

Delirium is a serious and sudden change in mental abilities that can develop within hours or days, causing confusion, disorientation, and changes in behavior. While it is more common in older adults, especially those in hospitals, it can affect anyone at any age and requires immediate medical attention.

Dementia is not a single disease, but rather a group of symptoms affecting memory, thinking, and the ability to perform daily activities that worsens over time.

Alzheimer’s disease is the most common cause of dementia, accounting for 60-80% of all dementia cases. This progressive brain condition gradually damages memory, thinking, and the ability to perform everyday tasks, affecting millions of older adults worldwide.

Alzheimer’s disease is the most common form of dementia, a condition that slowly destroys memory and thinking skills. While there is no cure, treatments exist to help manage symptoms and slow the disease’s progression, offering hope for improving quality of life for millions of people affected worldwide.

People with Alzheimer’s disease may experience delusions—false beliefs that feel completely real to them—along with suspicion and paranoia. These symptoms can be frightening and distressing for both the person living with the disease and their caregivers, often creating difficult challenges in daily life.

Dementia with Lewy bodies is a complex brain disorder caused by abnormal protein deposits that affects thinking, movement, behavior, and sleep. It is one of the most common types of dementia, yet many people have never heard of it.