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IgA Nephropathy (Berger's Disease)

Immune Deficiency

Immune Suppression Monitoring

Immune Thrombocytopenia (ITP)

What Is Immune Thrombocytopenia (ITP)? Immune thrombocytopenia (ITP) is an autoimmune condition in which your immune system mistakenly destroys platelets — the blood cells that help your blood clot and stop bleeding. This leads to a lower-than-normal platelet count, which can cause easy bruising, prolonged bleeding, and sometimes spontaneous bleeding into the skin or other tissues. ITP was previously called idiopathic thrombocytopenic purpura, but the name changed once it became clear that the cause is immune-mediated rather than unknown. "Purpura" refers to the purple-colored bruises or spots on the skin that can appear when platelet counts are low. Most people now simply say "immune thrombocytopenia" or "ITP." ITP can affect people of all ages. In children, it often starts suddenly after a viral infection and usually resolves on its own within weeks or months. In adults, it tends to be more chronic, lasting six months or longer, and may require ongoing monitoring and treatment. In short: in children, ITP usually gets better; in adults, it is more likely to be long-term.

Immunodeficiency

Immunoglobulin A (IgA) Deficiency

Here’s a clear, medically accurate, and patient-friendly overview of the health condition Immunoglobulin A (IgA) Deficiency: What Is Immunoglobulin A (IgA) Deficiency? Immunoglobulin A (IgA) Deficiency is a condition in which the body produces little or no IgA, a type of antibody that plays a crucial role in protecting mucosal surfaces such as the mouth, respiratory tract, digestive system, and genitourinary tract. IgA is also present in fluids like saliva, tears, and breast milk. It is the most common primary immunodeficiency, especially in people of European descent, and is often diagnosed during childhood or early adulthood. Why Is IgA Important? IgA helps guard against bacteria, viruses, and toxins that enter the body through mucous membranes. Without enough IgA, the immune system may have a harder time defending these surfaces, making individuals more prone to infections and, in some cases, autoimmune issues. Causes of IgA Deficiency Most cases are genetic, meaning the condition is inherited.

Inclusion Body Myositis

Inclusion Body Myositis (IBM) is a complex and progressive muscle disorder, classified as an inflammatory myopathy, characterized by a combination of inflammation and degenerative changes in muscle tissue. It is distinct among myopathies for its insidious onset and gradual progression, typically affecting individuals over the age of 50, with a higher prevalence in males. IBM's hallmark symptoms include asymmetric muscle weakness and atrophy, predominantly impacting the quadriceps, wrist, and finger flexors, leading to significant disability over time. Unlike other forms of myositis, IBM is often resistant to standard immunosuppressive therapies, posing a challenge in management and treatment. Pathologically, IBM exhibits unique features, including the presence of rimmed vacuoles and inclusion bodies in muscle fibers, indicative of both inflammatory and degenerative processes. The etiology of IBM remains largely unknown, though it is believed to involve a complex interplay of genetic predisposition and environmental factors, potentially triggering autoimmune responses.

Infection (Acute)

Acute infections are sudden-onset illnesses caused by pathogenic microorganisms including bacteria, viruses, fungi, or parasites that invade the body and multiply, triggering an immediate immune response. Common acute infections include respiratory infections (colds, flu, COVID-19, pneumonia, bronchitis), gastrointestinal infections (food poisoning, viral gastroenteritis, bacterial diarrhea), urinary tract infections, skin infections (cellulitis, abscesses, infected wounds), and throat infections (strep throat, tonsillitis). Symptoms vary depending on the type and location of infection but typically include fever, chills, fatigue, body aches, and localized symptoms such as cough, sore throat, abdominal pain, painful urination, or skin redness and warmth. The immune system responds rapidly to acute infections by producing white blood cells and antibodies to fight the invading pathogens, often causing temporary inflammation and elevated infection markers in blood tests.

Infectious Mononucleosis

Infectious Mononucleosis, often referred to as "mono" or the "kissing disease," is a contagious illness primarily caused by the Epstein-Barr Virus (EBV). This infection is widespread and known for its hallmark symptoms of fatigue, sore throat, fever, swollen lymph nodes, and at times, an enlarged spleen. Mono most commonly affects teenagers and young adults, though it can occur at any age. The virus is transmitted through saliva, which is why it earned the nickname "kissing disease," but it can also spread through coughing, sneezing, or sharing utensils with someone who is infected. Upon infection, the symptoms of mono may take 4 to 6 weeks to appear, and the severity and duration of these symptoms can vary greatly from one person to another. Some individuals may experience mild symptoms for only a few weeks, while others may have more severe symptoms that last for months. Fatigue can be particularly persistent, making it hard for those affected to keep up with their usual daily activities.

Infertility (Female)

Female infertility is defined as the inability to achieve a clinical pregnancy after 12 months of regular unprotected sexual intercourse in women under 35, or after 6 months in women 35 and older. It is one of the most common reproductive health conditions globally, affecting approximately 1 in 6 couples — and in roughly 40–50% of cases where a couple cannot conceive, a female factor is identified as the primary or contributing cause. Infertility is not a single disease but a clinical outcome with many possible underlying causes — spanning ovulatory dysfunction, structural abnormalities of the reproductive tract, endocrine disorders, immunological factors, and age-related decline in egg quality and ovarian reserve. In approximately 10–15% of cases, no identifiable cause is found despite thorough investigation — a category termed unexplained infertility. Understanding the cause is the essential first step in treatment.

Infertility (Male)

Male infertility is defined as the inability to achieve a clinical pregnancy after 12 months of regular unprotected sexual intercourse, where a male factor is identified as the primary or contributing cause. It is a major component of reproductive health, contributing to approximately 40–50% of infertility cases in couples — either as an isolated factor or in combination with female factors. Male infertility is not a single condition but a clinical outcome with multiple underlying causes. These include abnormalities in sperm production, function, or transport, as well as hormonal imbalances, genetic conditions, structural abnormalities, and environmental or lifestyle factors. In a subset of men (approximately 10–15%), no clear cause is identified despite comprehensive evaluation — termed unexplained male infertility. A structured diagnostic approach — centered on semen analysis, hormonal testing, and targeted imaging or genetic evaluation — allows most causes to be identified and significantly improves the likelihood of successful treatment.

Inflammation

Inflammation is the body's natural immune response to injury, infection, or irritation, characterized by redness, warmth, swelling, pain, and sometimes loss of function in the affected area. Acute inflammation typically develops rapidly and resolves within days to weeks once the triggering cause is removed, such as inflammation from a sprained ankle, surgical incision, or short-term infection. Chronic inflammation persists for months or years and can result from ongoing conditions like rheumatoid arthritis, inflammatory bowel disease (Crohn's disease or ulcerative colitis), psoriasis, or autoimmune disorders where the immune system mistakenly attacks healthy tissue. Systemic inflammation affects the entire body rather than a localized area and can be triggered by severe trauma, major surgery, burns, pancreatitis, or systemic inflammatory response syndrome (SIRS). Common symptoms of significant inflammation include fever, fatigue, body aches, loss of appetite, and elevated inflammatory markers in blood tests such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

Inflammatory Bowel Disease (IBD)

Inflammatory Bowel Disease (IBD) is a term primarily used to describe two chronic conditions that cause inflammation in the gastrointestinal (GI) tract: Crohn's Disease and Ulcerative Colitis. Both are characterized by an abnormal response of the body's immune system. In IBD, the immune system mistakenly attacks the GI tract, leading to inflammation. The exact cause of this immune response is not fully understood, but it is believed to involve a complex interplay of genetic, environmental, and microbial factors. Crohn's Disease can affect any part of the GI tract, from the mouth to the anus, but most commonly affects the end of the small bowel (the ileum) and the beginning of the colon. It can affect the entire thickness of the bowel wall. In contrast, Ulcerative Colitis is limited to the colon and rectum and usually only affects the innermost lining of the bowel wall. Ulcerative Colitis (UC) is a chronic condition affecting the colon and rectum, marked by inflammation and ulceration of the colon's lining.

Inflammatory Myopathies

Influenza

Insulin Resistance

Insulin Resistance: Causes, Symptoms, and Its Role in Diabetes and Metabolic Syndrome Insulin Resistance (IR) is a growing health concern worldwide, playing a major role in the development of type 2 diabetes, obesity, and metabolic syndrome. This article explains what insulin resistance is, why it happens, and how it affects your body’s metabolism and overall health. What is Insulin Resistance? Insulin is a hormone produced by the beta cells of the pancreas, responsible for regulating blood sugar (glucose) levels. After eating, the pancreas secretes insulin to help move glucose from the bloodstream into the body’s cells, where it is used for energy production. Insulin resistance occurs when the body’s cells—especially muscle cells and fat (adipose) cells—become less responsive to insulin. This condition blocks or reduces the ability of cells to absorb glucose efficiently, leading to elevated blood sugar levels and forcing the pancreas to produce even more insulin to compensate.

Interstitial Cystitis

Interstitial cystitis (IC), also called bladder pain syndrome (BPS), is a chronic condition characterised by persistent bladder pain or discomfort, urinary urgency, and frequency in the absence of a confirmed bacterial infection. Although the exact cause is not fully understood, several mechanisms have been identified and guide current treatments. IC/BPS primarily affects women but can occur in anyone. Symptoms range from mild to severely debilitating and significantly impact quality of life. It is a diagnosis of exclusion — other causes of bladder symptoms must be ruled out first. Even though test results may appear normal, the pain and urinary symptoms are real and can be very disruptive. Symptoms Symptoms vary considerably between individuals and often come in flares, with good days and bad days. They can worsen around menstruation, after certain foods or drinks, during stress, or following sexual activity.

Interstitial Lung Disease

Interstitial Nephritis

Interstitial nephritis is inflammation of the kidney tubules and the supporting tissue surrounding them (the interstitium) — the tiny filters and structural framework that allow the kidneys to function. This inflammation impairs the kidneys' ability to filter waste and regulate fluid and electrolytes. Acute interstitial nephritis (AIN) develops over days to weeks, while chronic interstitial nephritis (CIN) progresses slowly over months to years. Drug-induced AIN is the most common form and accounts for a significant proportion of unexplained acute kidney injury. Types Acute interstitial nephritis (AIN): Develops over days to weeks, most commonly as an immune reaction to a medication. Kidney function can decline rapidly but is often reversible if the cause is identified and removed promptly — the sooner, the better. Chronic interstitial nephritis (CIN): Develops gradually, often without obvious symptoms until kidney function is significantly reduced. Because CIN progresses silently, it is often only detected through blood or urine tests.

Intestinal Permeability

Intestinal Yeast Overgrowth

Intrahepatic cholestasis of pregnancy (ICP)

Intrahepatic Cholestasis of Pregnancy (ICP), also known as obstetric cholestasis, is a liver disorder that can occur during pregnancy. This condition affects the normal flow of bile, the digestive fluid produced by the liver, causing bile acids to build up in the liver and eventually enter the bloodstream. This buildup can lead to a variety of symptoms, most notably itching, particularly on the hands and feet, which can be more severe at night and can significantly impact a pregnant woman's quality of life. Understanding ICP is crucial for expecting mothers and their families, as it not only affects maternal comfort but can also have implications for fetal well-being. ICP typically presents in the second or third trimester of pregnancy and is characterized by its most common symptom: intense itching without a rash. Other possible symptoms include jaundice (a yellowing of the skin and eyes), dark urine, light-colored stools, and fatigue. The exact cause of ICP is not fully understood, but it is believed to involve genetic, hormonal, and environmental factors.

Iron Deficiency (without anemia)

Key Takeaways Iron deficiency without anemia is the earliest stage of iron deficiency, where iron stores are low but hemoglobin remains normal Ferritin is the most important marker — low levels indicate depleted iron stores even if CBC is normal Common symptoms include fatigue, brain fog, reduced endurance, hair loss, and restless legs Most cases are caused by low intake, poor absorption, increased demand, or chronic blood loss The condition is very common, especially in women of childbearing age, athletes, and individuals with chronic disease Without treatment, it can progress to iron deficiency anemia What Is Iron Deficiency Without Anemia? Iron deficiency without anemia, also called non-anemic iron deficiency or iron depletion, is a condition where the body's iron stores are depleted but hemoglobin levels remain within the normal range. This represents the earliest stage of iron deficiency, occurring before red blood cell production becomes significantly impaired.

Iron Overload

Iron-Deficiency Anemia

Deficiency anemia is a widespread health issue affecting millions globally, significantly diminishing quality of life through its extensive symptoms. This type of deficiency anemia results from the body's lack of enough iron to manufacture hemoglobin, the crucial protein in red blood cells essential for oxygen transportation and its ability to carry oxygen. As a result, deficiency anemia can lead to symptoms such as fatigue, weakness, and shortness of breath, drastically impacting daily functions and overall well-being. The prevalence of deficiency anemia underscores the importance of addressing this health concern, as deficiency anemia can severely affect an individual's capacity to perform daily tasks and their ability to efficiently carry oxygen throughout the body. Recognizing and treating deficiency anemia early is vital to improving life quality, as untreated deficiency anemia can lead to severe complications.

Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome (IBS) is a common disorder affecting the large intestine, characterized by a range of symptoms including abdominal pain, bloating, gas, and altered bowel habits like constipation, diarrhea, or a mix of both. Its exact cause remains unclear, but factors like muscle contractions in the intestine, nervous system abnormalities, inflammation in the intestines, severe infections, or changes in gut bacteria are thought to play a role. IBS is a chronic condition, but many people manage symptoms through diet, lifestyle changes, and stress management. The diagnosis of IBS typically involves ruling out other conditions, as there's no definitive test for it. Treatment focuses on symptom relief and can include dietary adjustments, such as increasing fiber intake or eliminating trigger foods, and medications to control muscle spasms, diarrhea, or constipation. Psychological therapies like cognitive-behavioral therapy or counseling can also be beneficial, as stress can worsen IBS symptoms.

Ischemic Colitis