Browse by condition.

Hashimoto's disease

Hashimoto's disease, also known as Hashimoto's thyroiditis, is an autoimmune disorder where the immune system attacks the thyroid gland, leading to chronic inflammation and an underactive thyroid gland, or hypothyroidism. This condition can lead to a wide array of symptoms and significantly impact an individual's quality of life if left untreated. The thyroid, a small gland located at the base of the neck, plays a crucial role in regulating metabolic processes in the body through the release of hormones. When Hashimoto's disease impairs its function, the body's metabolism slows down, leading to symptoms such as fatigue, weight gain, sensitivity to cold, constipation, dry skin, hair loss, muscle weakness, and depression. Additionally, individuals may experience swelling at the front of the neck due to an enlarged thyroid gland, known as a goiter. Diagnosing Hashimoto's disease involves a combination of clinical evaluation, blood tests, and sometimes imaging studies.

Heart Failure

Helicobacter pylori (H. pylori) infection

Helicobacter pylori (H. pylori) infection is a common condition that affects the stomach lining and is a leading cause of peptic ulcers and gastric inflammation (gastritis). This bacteria can be silently lurking in the digestive tract, often without causing symptoms, but it's a major culprit behind stomach pain, bloating, and discomfort. If left untreated, H. pylori infection can lead to more serious health issues, including stomach cancer. It's usually contracted in childhood and can be spread through contaminated food, water, or close contact with an infected person. The good news is that H. pylori infection is treatable with a combination of antibiotics and medications to reduce stomach acid and heal the stomach lining. It's important to seek medical advice if you're experiencing symptoms like persistent stomach discomfort, as early detection and treatment can prevent complications. Understanding H. pylori is the first step towards managing its impact on health, ensuring individuals can lead a healthier, more comfortable life.

Hematuria

Hemochromatosis

Hemochromatosis: Causes, Symptoms, Diagnosis, and Treatment Hemochromatosis is a genetic disorder that leads to iron overload in the body. This excess iron can cause serious damage to vital organs, such as the liver, heart, pancreas, and joints. If left untreated, hemochromatosis can result in conditions like liver disease, diabetes, heart issues, and arthritis. Here’s everything you need to know about this condition, including types, symptoms, diagnosis, treatment, and management tips. What is Hemochromatosis? Hemochromatosis can be thought of as the body absorbing too much iron, like a sponge that can't stop soaking up water. This extra iron is stored in organs, which can eventually lead to significant health problems. Types of Hemochromatosis There are two main types of hemochromatosis: Primary Hemochromatosis (Hereditary) Caused by mutations in the HFE gene, specifically the C282Y and H63D variants. Inherited in an autosomal recessive pattern. Non-HFE types (10-15% of cases) involve mutations in other genes, like HJV and HAMP.

Hemoglobinopathy

Hemolytic Anemia

Hemolytic anemia is a blood disorder that typically happens when your red blood cells break down or die faster than your body can replace them with new blood cells. Hemolytic anemia can develop quickly or slowly, and it can be mild or serious. People may develop hemolytic anemia by inheriting genetic conditions that cause anemia, certain infections and certain medications. Sometimes, people have mild hemolytic anemia symptoms that go away after treatment. Many times, healthcare providers can cure hemolytic anemia after finding out what caused the condition. Left untreated, however, severe hemolytic anemia can cause serious heart trouble. Red blood cells normally live for about 120 days. When they break down or die sooner than that, your bone marrow doesn’t have time to produce enough new red blood cells, leaving you with a low red blood cell count. Other anemia types may occur when: - Injury or illness causes excessive bleeding that drains your red blood cell supply faster than your body can replace it.

Hemophilia A

Hepatitis

Hepatitis A (Acute HAV Infection)

Hepatitis A is an acute viral infection of the liver caused by the hepatitis A virus (HAV). It is one of the most common vaccine-preventable infections worldwide, spread primarily through contaminated food or water or close contact with an infected person. Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease — almost everyone recovers fully, and infection provides lifelong immunity. Illness ranges from very mild or completely asymptomatic — particularly in young children — to a debilitating illness lasting several months in adults. Acute liver failure is rare but possible, particularly in people with pre-existing liver disease or those who are older. How hepatitis A spreads HAV is transmitted by the fecal-oral route — meaning the virus is shed in the stool of infected people and enters a new host through ingestion.

Hepatitis B (Acute)

Hepatitis B (Chronic)

Hepatocellular carcinoma

Hereditary Angioedema (HAE) Type I

What is Hereditary Angioedema (HAE) Type I? Hereditary Angioedema (HAE) Type I is a rare, inherited genetic disorder that causes recurrent episodes of severe swelling (angioedema) in various parts of the body. These episodes most commonly affect the face, lips, throat, abdomen, limbs, and genitals. Swelling can be painful, unpredictable, and, in some cases, life-threatening—especially when it involves the airways. HAE affects approximately 1 in 50,000 people worldwide. Type I is the most common form, accounting for about 85% of all HAE cases. The disorder is inherited in an autosomal dominant manner, meaning a child has a 50% chance of inheriting the condition if one parent is affected. What Causes HAE Type I? HAE Type I is caused by a genetic mutation that leads to low levels of a protein called C1 esterase inhibitor (C1-INH). This protein helps regulate inflammation by controlling the complement system and the production of bradykinin—a chemical that increases blood vessel permeability and causes fluid to leak into surrounding tissues.

Hereditary Complement Deficiency

Hereditary Hemochromatosis

Hereditary Spherocytosis

Herpes Simplex Virus Infection

Herpes simplex virus (HSV) infection is a widespread condition caused by two closely related viruses: HSV-1 and HSV-2. HSV-1 commonly causes oral herpes (cold sores), while HSV-2 typically causes genital herpes, although both types can infect either location. After initial infection, HSV establishes latency in nerve cells and remains in the body for life. Periodic reactivation can lead to recurrent symptoms or asymptomatic viral shedding. Most people with HSV infection experience: No symptoms Mild, occasional outbreaks Unrecognized infection When symptoms occur, they may include blisters, ulcers, tingling sensations, and localized pain. HSV is transmitted through direct skin-to-skin or mucosal contact. It is most contagious during active outbreaks but can still spread without visible symptoms. Diagnosis is typically made through: PCR testing of active lesions Type-specific IgG antibody testing (for past exposure) Management focuses on symptom control and reducing transmission risk. Antiviral medications are effective and widely used.

Herpes Simplex Virus Type 1 (HSV-1)

Herpes Simplex Virus Type 2 (HSV-2) infection

Hirsutism

Hirsutism is a health condition characterized by the growth of excessive or unwanted hair on a woman's face, chest, and back, following a pattern of male hair distribution. This condition is more than a cosmetic concern; it can signify underlying health issues, often linked to an imbalance of male hormones, known as androgens. Common in women, hirsutism is frequently associated with conditions like polycystic ovary syndrome (PCOS), which can affect hormonal balance and lead to other symptoms such as irregular menstrual cycles, acne, and obesity. Diagnosing hirsutism involves a comprehensive evaluation, including a detailed medical history to understand any underlying causes or contributing factors such as medication use or genetic predisposition. Physicians may conduct physical examinations to assess hair growth patterns and use blood tests to measure hormone levels, helping to identify or rule out specific conditions like PCOS, adrenal gland disorders, or other hormonal imbalances.

HIV/AIDS

Hodgkin Lymphoma

Homocystinuria

Hormonal Imbalance

Hormone Replacement Therapy (Monitoring)

Hormone Replacement Therapy (HRT) monitoring refers to the structured evaluation of hormone levels, symptom response, and safety markers in individuals receiving exogenous hormones — most commonly estrogen, progesterone, and/or testosterone. It is an essential component of care to ensure that therapy is both effective (symptom control) and safe (minimizing long-term risk). HRT is widely used in multiple clinical contexts, including menopause management, hypogonadism in men, gender-affirming care, and certain endocrine disorders. Because exogenous hormones alter the body’s natural regulatory systems, ongoing monitoring is required to optimize dosing, avoid under- or over-treatment, and detect potential adverse effects early. A structured monitoring approach — combining lab testing, clinical symptoms, and individualized targets — allows for precise, personalized hormone management over time.

Hypereosinophilic Syndrome

Hyperinsulinemia

Hyperlipidemia / High Cholesterol

Hyperlipidemia, commonly known as high cholesterol, is a condition characterized by elevated levels of lipids (fats) in the blood, including cholesterol and triglycerides. Cholesterol exists in several forms: low-density lipoprotein (LDL or "bad" cholesterol) which deposits in artery walls and contributes to plaque buildup, high-density lipoprotein (HDL or "good" cholesterol) which helps remove excess cholesterol from the bloodstream, and very low-density lipoprotein (VLDL) which carries triglycerides. High cholesterol typically causes no symptoms and is often discovered only through routine blood tests, though severely elevated levels can sometimes cause physical signs such as yellowish deposits around the eyes (xanthelasma) or on tendons (xanthomas). The condition develops due to a combination of genetic factors (familial hypercholesterolemia), diet high in saturated fats and trans fats, obesity, lack of physical activity, smoking, diabetes, hypothyroidism, and certain medications.

Hyperoxaluria

Hyperoxaluria is a complex health condition characterized by an excessive excretion of oxalate in the urine. Oxalate is a natural chemical found in the body, and it's also present in certain foods. When too much oxalate is present in the urine, it can lead to kidney stones and other kidney diseases. This condition can occur on its own (primary hyperoxaluria) or as a result of another disease or dietary factors (secondary hyperoxaluria). Primary hyperoxaluria is a rare, inherited condition caused by a genetic mutation that leads to the overproduction of oxalate by the liver. It is further divided into three types: Type 1, Type 2, and Type 3, each resulting from different genetic mutations affecting specific enzymes. Type 1 is the most common and severe form, potentially leading to kidney failure at a young age if left untreated.

Hyperparathyroidism

Hyperparathyroidism is a condition where the parathyroid glands in the neck produce too much parathyroid hormone (PTH), which regulates calcium levels in the body. It's mainly classified into two types: primary and secondary. Primary hyperparathyroidism, more common, occurs when one or more of the parathyroid glands become overactive, often due to a benign tumor, leading to high calcium levels in the blood. This can cause symptoms like fatigue, bone pain, kidney stones, and mood changes. Secondary hyperparathyroidism, typically caused by chronic kidney disease or vitamin D deficiency, happens when the body's low calcium levels trigger the parathyroid glands to produce more PTH. In both types, diagnosis involves blood tests to check calcium and PTH levels, and sometimes imaging tests to examine the glands. Treatment depends on the cause and severity, ranging from regular monitoring to surgery for removing overactive glands in primary hyperparathyroidism or addressing the underlying cause in secondary hyperparathyroidism.

Hyperprolactinemia

Hyperprolactinemia: Causes, Symptoms, Diagnosis, and Treatment Hyperprolactinemia is a condition characterized by abnormally high levels of prolactin in the blood. Prolactin is a hormone produced by the pituitary gland, primarily responsible for stimulating breast milk production after childbirth. However, elevated prolactin levels can occur in both men and women who are not pregnant or breastfeeding, leading to various health issues. Causes The most common causes of hyperprolactinemia include: Pituitary tumors (prolactinomas) 1, 4 Certain medications, such as those for high blood pressure, depression, and nausea 1, 6 Hypothyroidism 5 Chronic kidney or liver conditions 4 Chest wall injuries or irritation 4 Symptoms Symptoms of hyperprolactinemia can vary between men and women: In women: Menstrual irregularities or absence of periods 1, 2 Infertility 2, 4 Galactorrhea (milk production when not pregnant or breastfeeding) 1, 4 Decreased libido 4 Vaginal dryness 1 In men: Decreased libido 4 Erectile dysfunction 4 Infertility 4 Gynecomastia (enlarged breast tissue) 4 Reduced body hair and

Hypertension (High Blood Pressure)

Hypertension, commonly known as high blood pressure, is a chronic medical condition in which the force of blood against artery walls is consistently elevated, potentially causing damage to blood vessels and organs over time. Blood pressure is measured in millimeters of mercury (mmHg) and recorded as two numbers: systolic pressure (the higher number, measuring pressure when the heart beats) over diastolic pressure (the lower number, measuring pressure when the heart rests between beats). Normal blood pressure is defined as less than 120/80 mmHg, while hypertension is diagnosed when readings consistently measure 130/80 mmHg or higher. The condition is often called the "silent killer" because it typically produces no symptoms until it has caused significant damage, though some people may experience headaches, shortness of breath, nosebleeds, or dizziness with severely elevated blood pressure.

Hyperthyroidism

Hypertriglyceridemia

Hypoalbuminemia

Hypoalbuminemia—low levels of albumin in the blood—is one of the most common reasons for reduced total protein on a blood test. It can reflect problems with the liver, kidneys, nutrition, or chronic inflammation, and often appears before any obvious symptoms develop. Albumin is the main protein in the bloodstream, produced by the liver. It helps maintain fluid balance, transports hormones and medications, and plays a key role in overall metabolic function. As albumin levels drop, the body loses some of its ability to keep fluid within blood vessels, leading to fluid buildup in tissues and other systemic effects. What Causes Low Albumin Levels? Hypoalbuminemia can result from several underlying mechanisms: Reduced production (liver-related): Chronic liver disease (e.g., cirrhosis) Acute liver injury Increased loss: Kidney disease (e.g., nephrotic syndrome) Protein-losing enteropathy Inflammatory bowel disease Severe burns or skin loss Inflammation and illness: Chronic inflammation or infection Critical illness or trauma Poor intake or absorption: Malnutrition Malabsorption syndromes

Hypochlorhydria (Low Stomach Acid)

Hypochromic Anemia

Hypogammaglobulinemia

Hypogammaglobulinemia is an immune system disorder characterized by low levels of immunoglobulins (antibodies) in the blood. This deficiency weakens the body's ability to fight infections. Causes of Hypogammaglobulinemia Hypogammaglobulinemia can be classified as either primary (genetic) or secondary (acquired): Primary Causes Common Variable Immunodeficiency (CVID) X-linked Agammaglobulinemia (XLA) Severe Combined Immunodeficiency (SCID) Wiskott-Aldrich Syndrome Secondary Causes Blood Cancers (e.g., chronic lymphocytic leukemia, lymphoma) HIV Infection Medications (e.g., corticosteroids, chemotherapy drugs) Malnutrition Protein-losing Conditions Symptoms The primary symptom of hypogammaglobulinemia is an increased vulnerability to infections.

Hypogonadism

Hypogonadism: Causes, Symptoms, Diagnosis, and Treatment Introduction to Hypogonadism Hypogonadism is a condition in which the body's sex glands—testes in men and ovaries in women—produce little to no sex hormones. In men, this results in a deficiency of testosterone, crucial for developing male characteristics, libido, and sperm production. In women, it leads to insufficient estrogen and progesterone, vital for regulating menstruation and fertility. This condition can occur at any age and significantly impacts both physical and emotional well-being. Beyond reproductive health, hypogonadism affects overall health, influencing muscle mass, bone density, energy levels, and mental health. Understanding its causes, symptoms, and treatment options is essential for effective management. Types of Hypogonadism Hypogonadism is categorized into two primary types: primary hypogonadism and secondary hypogonadism, each with distinct causes. Primary Hypogonadism This type occurs when the sex glands themselves malfunction due to injury, disease, or congenital issues.

Hyponatremia

Hypophosphatasia

Hypopituitarism

Hypothalamic Amenorrhea

Hypothalamic amenorrhea (HA) is the absence of menstrual periods caused by suppression of the hypothalamic-pituitary-ovarian (HPO) axis — the hormonal signaling chain that governs the menstrual cycle. It is one of the most common causes of secondary amenorrhea (absence of periods in a woman who has previously menstruated) in reproductive-age women, accounting for approximately 30–35% of cases. Unlike conditions where the ovaries themselves fail (as in premature ovarian insufficiency), hypothalamic amenorrhea is a functional disorder — the ovaries are structurally intact and capable of normal function, but the brain has effectively switched off the reproductive system in response to perceived threat. The hypothalamus interprets chronic energy deficit, excessive exercise, psychological stress, or a combination of these as conditions too dangerous for reproduction, and suppresses the hormonal signals that initiate ovulation. This makes HA both highly reversible — the reproductive axis can be fully restored in most women — and a window into the body's broader physiological stress state.

Hypothyroidism

Overview Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormones to meet the body’s needs. Thyroid hormones—primarily thyroxine (T4) and triiodothyronine (T3)—play a critical role in regulating metabolism, energy production, temperature control, heart function, and brain health. Hypothyroidism is commonly identified through an elevated Thyroid-Stimulating Hormone (TSH) level on blood testing and is one of the most frequent endocrine disorders worldwide. What the Thyroid Does The thyroid is a small, butterfly-shaped gland located at the front of the neck. It produces hormones that influence nearly every organ system, including: Metabolic rate and energy expenditure Body temperature regulation Heart rate and cardiovascular function Digestion and gut motility Brain function and mood Growth, fertility, and pregnancy health When thyroid hormone levels are too low, many of these systems slow down. Causes of Hypothyroidism Hypothyroidism can develop for several reasons.

Hypoxemia