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Anaemia

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Description: Anaemia is a condition characterized by a deficiency of red blood cells or hemoglobin, resulting in a reduced capacity of the blood to carry oxygen.
Type: Anaemia is a condition characterized by a deficiency of red blood cells or hemoglobin. There are several types of anaemia, and the genetic transmission varies depending on the specific type. Here are some examples:

1. **Sickle Cell Anaemia**: This type is inherited in an autosomal recessive pattern. Both parents must carry one copy of the mutated gene (HbS) for a child to be affected.

2. **Thalassemia**: This group of inherited blood disorders is also transmitted in an autosomal recessive manner. It includes α-thalassemia and β-thalassemia, depending on which part of the hemoglobin molecule is affected.

3. **Hereditary Spherocytosis**: This type of anaemia is usually inherited in an autosomal dominant pattern. A single copy of the mutated gene is sufficient to cause the disorder.

4. **G6PD Deficiency**: This type of enzyme deficiency-related anaemia is inherited in an X-linked recessive pattern, meaning it primarily affects males, while females can be carriers.
Signs And Symptoms: A person with anemia may not have any symptoms, depending on the underlying cause, and no symptoms may be noticed, as the anemia is initially mild, and then the symptoms become worse as the anemia worsens. A patient with anemia may report feeling tired, weak, decreased ability to concentrate, and sometimes shortness of breath on exertion. These symptoms are unspecific and none of the symptoms alone or in combination show a good predictive value for the presence of anemia in non-clinical patients.
Symptoms of anemia can come on quickly or slowly. Early on there may be few or no symptoms. If the anemia continues slowly (chronic), the body may adapt and compensate for this change. In this case, no symptoms may appear until the anemia becomes more severe. Symptoms can include feeling tired, weak, dizziness, headaches, intolerance to physical exertion, shortness of breath, difficulty concentrating, irregular or rapid heartbeat, cold hands and feet, cold intolerance, pale or yellow skin, poor appetite, easy bruising and bleeding, and muscle weakness. Anemia that develops quickly, often, has more severe symptoms, including, feeling faint, chest pain, sweating, increased thirst, and confusion. There may be also additional symptoms depending on the underlying cause.In more severe anemia, the body may compensate for the lack of oxygen-carrying capability of the blood by increasing cardiac output. The person may have symptoms related to this, such as palpitations, angina (if pre-existing heart disease is present), intermittent claudication of the legs, and symptoms of heart failure.On examination, the signs exhibited may include pallor (pale skin, mucosa, conjunctiva and nail beds), but this is not a reliable sign. A blue coloration of the sclera may be noticed in some cases of iron-deficiency anemia. There may be signs of specific causes of anemia, e.g. koilonychia (in iron deficiency), jaundice (when anemia results from abnormal break down of red blood cells – in hemolytic anemia), nerve cell damage (vitamin B12 deficiency), bone deformities (found in thalassemia major) or leg ulcers (seen in sickle-cell disease). In severe anemia, there may be signs of a hyperdynamic circulation: tachycardia (a fast heart rate), bounding pulse, flow murmurs, and cardiac ventricular hypertrophy (enlargement). There may be signs of heart failure.
Pica, the consumption of non-food items such as ice, paper, wax, grass, hair or dirt, may be a symptom of iron deficiency; although it occurs often in those who have normal levels of hemoglobin.
Chronic anemia may result in behavioral disturbances in children as a direct result of impaired neurological development in infants, and reduced academic performance in children of school age. Restless legs syndrome is more common in people with iron-deficiency anemia than in the general population.
Prognosis: The prognosis for anemia depends on the underlying cause, type, severity, and the effectiveness of treatment. Generally, if the underlying cause is identified and treated appropriately, many types of anemia can be managed successfully. In cases of iron deficiency anemia, for example, prognosis is often good with iron supplementation and dietary changes. However, if anemia is caused by chronic diseases, genetic disorders, or bone marrow issues, the prognosis might be more complex and requires ongoing management. Regular medical follow-up is crucial to monitor the condition and adjust treatment as needed.
Onset: Anaemia can have a gradual or sudden onset depending on the underlying cause. It develops when there is a deficiency in the number or quality of red blood cells or hemoglobin, affecting the oxygen-carrying capacity of the blood. The onset may be acute in cases like significant blood loss, or chronic in conditions like iron deficiency or chronic diseases.
Prevalence: The prevalence of anemia varies depending on the population and region. Worldwide, anemia affects approximately 24.8% of the global population. It is particularly common among young children and pregnant women, with an estimated prevalence of 47.4% and 41.8%, respectively, in these groups. The prevalence can be higher in low-income regions due to factors such as poor nutrition, high rates of infectious diseases, and limited access to healthcare.
Epidemiology: Anemia affects 27% of the world's population with iron-deficiency anemia accounting for more than 60% of it. A moderate degree of iron-deficiency anemia affected approximately 610 million people worldwide or 8.8% of the population. It is somewhat more common in females (9.9%) than males (7.8%). Mild iron-deficiency anemia affects another 375 million. Severe anaemia is prevalent globally, and especially in sub-Saharan Africa where it is associated with infections including malaria and invasive bacterial infections.
Intractability: Anemia is typically not considered an intractable disease. It is often treatable, especially when the underlying cause is identified and addressed. Common treatments include dietary changes, supplements (such as iron, vitamin B12, or folate), medications, and sometimes procedures or surgeries. Chronic or severe anemia cases may require more intensive management, but many forms of anemia can be effectively managed or even cured with appropriate treatment.
Disease Severity: Anaemia can vary in severity based on the underlying cause and the level of haemoglobin in the blood. It ranges from mild, moderate to severe. Mild anaemia may cause few or no symptoms, while moderate and severe anaemia can lead to significant symptoms such as fatigue, weakness, shortness of breath, and dizziness, possibly requiring medical intervention. The severity is typically determined by blood tests measuring haemoglobin levels and red blood cell counts.
Healthcare Professionals: Disease Ontology ID - DOID:2355
Pathophysiology: Anemia occurs when the number of red blood cells (RBCs) or the hemoglobin concentration within them is lower than normal. This impairs the blood's ability to carry oxygen to tissues, leading to various symptoms.

Pathophysiology:
1. Reduced RBC Production: This can result from bone marrow disorders, nutritional deficiencies (such as iron, vitamin B12, or folate), chronic diseases, or hormonal imbalances.
2. Increased RBC Destruction: Conditions like hemolytic anemia, autoimmune disorders, and certain infections can cause the premature destruction of RBCs.
3. Blood Loss: Acute or chronic bleeding, such as from gastrointestinal ulcers, heavy menstrual periods, or trauma, can lead to anemia by depleting the body's RBCs.

The decreased oxygen delivery to tissues results in symptoms such as fatigue, weakness, shortness of breath, and pallor.
Carrier Status: Anemia is not a single disorder but a condition characterized by a deficiency in the number or quality of red blood cells or hemoglobin. Carrier status is applicable to certain types of anemia that are inherited, such as sickle cell anemia and thalassemia. In these cases, a person can be a carrier (having one abnormal gene) without showing significant symptoms, but they can pass the gene to their offspring.

For non-inherited types of anemia, such as those caused by nutritional deficiencies (e.g., iron-deficiency anemia), chronic diseases, or other factors, the concept of carrier status does not apply.
Mechanism: Anemia is a condition characterized by a deficiency in the number or quality of red blood cells (RBCs) or hemoglobin, which results in a reduced ability of the blood to carry oxygen to the body's tissues. The mechanisms and molecular mechanisms of anemia can vary based on its type.

### Mechanisms:
1. **Decreased RBC Production**: This can be due to deficiencies in essential nutrients (e.g., iron, vitamin B12, folate), bone marrow disorders (e.g., aplastic anemia), or chronic diseases.
2. **Increased RBC Destruction**: In conditions like hemolytic anemia, RBCs are destroyed prematurely. This can be due to autoimmune reactions, infections, or inherited disorders like sickle cell disease.
3. **Blood Loss**: Chronic or acute blood loss through gastrointestinal bleeding, heavy menstrual periods, or trauma can lead to anemia.
4. **Impaired Hemoglobin Function**: In some anemias, the RBCs are present but dysfunctional (e.g., thalassemia).

### Molecular Mechanisms:
1. **Iron-Deficiency Anemia**:
- **Heme Synthesis**: Iron is a critical component of heme, the non-protein part of hemoglobin. Deficiency in iron impairs heme synthesis, leading to reduced hemoglobin production.
- **Regulatory Proteins**: Alterations in proteins like hepcidin, which regulates iron homeostasis, can impact iron absorption and mobilization.

2. **Vitamin B12 and Folate Deficiency Anemia**:
- **DNA Synthesis Impairment**: Both vitamins are crucial for DNA synthesis. Deficiency leads to ineffective erythropoiesis (production of RBCs), resulting in the formation of large, immature RBCs (megaloblasts).

3. **Thalassemia**:
- **Globin Gene Mutations**: Mutations in the globin genes (α or β) reduce the production of one of the globin chains of hemoglobin, causing imbalanced chain synthesis and resulting in ineffective erythropoiesis and hemolysis.

4. **Sickle Cell Disease**:
- **Hemoglobin S (HbS) Mutation**: A single nucleotide mutation in the β-globin gene leads to the production of hemoglobin S. Under low-oxygen conditions, HbS polymerizes, causing RBCs to sickle, leading to hemolysis and vaso-occlusive crises.

5. **Hemolytic Anemia**:
- **Autoimmune Mechanisms**: Autoantibodies target RBCs, marking them for destruction by the spleen or activating the complement system.
- **Enzyme Deficiencies**: Conditions like G6PD deficiency impair RBC metabolism, increasing susceptibility to oxidative damage and premature RBC destruction.

Understanding these mechanisms is crucial for diagnosing and treating various forms of anemia effectively.
Treatment: The global market for anemia treatments is estimated at more than USD 23 billion per year and is fast growing because of the rising prevalence and awareness of anemia. The types of anemia treated with drugs are iron-deficiency anemia, thalassemia, aplastic anemia, hemolytic anemia, sickle cell anemia, and pernicious anemia, the most important of them being deficiency and sickle cell anemia with together 60% of market share because of highest prevalence as well as higher treatment costs compared with other types. Treatment for anemia depends on cause and severity. Vitamin supplements given orally (folic acid or vitamin B12) or intramuscularly (vitamin B12) will replace specific deficiencies. Apart from that iron supplements, antibiotics, immunosuppressant, bone marrow stimulants, corticosteroids, gene therapy and iron chelating agents are forms of anemia treatment drugs, with immunosuppressants and corticosteroids accounting for 58% of the market share. A paradigm shift towards gene therapy and monoclonal antibody therapies are observed.
Compassionate Use Treatment: Compassionate use treatment, off-label, or experimental treatments for anemia might include:

1. **Erythropoiesis-Stimulating Agents (ESAs):** These agents, such as erythropoietin or darbepoetin, can be used to stimulate red blood cell production in specific forms of anemia not always approved by regulatory agencies. For instance, they're commonly used in anemia due to chronic kidney disease but might be considered in other severe or refractory cases.

2. **Iron Chelators:** In cases of iron overload, iron chelators like deferoxamine, deferiprone, or deferasirox can be used. These are primarily used in secondary iron overload conditions, like transfusion-dependent anemias, to prevent iron-induced organ damage.

3. **Off-label Use of Glucocorticoids:** Some forms of immune-mediated hemolytic anemia might be treated with glucocorticoids, although this might not be the first-line or approved use for all types of anemia.

4. **Luspatercept:** This is a newer medication that's been approved for certain subtypes of beta-thalassemia and is being investigated for other anemia types.

5. **Gene Therapy:** Experimental protocols, especially for inherited anemias like thalassemia and sickle cell disease, include gene therapy approaches which aim to correct the underlying genetic defect causing the anemia.

6. **Hematopoietic Stem Cell Transplantation:** For some severe congenital anemias or refractory cases, stem cell transplantation might be considered, although it's not routine.

7. **New Pharmacological Agents:** There are various other agents in clinical trials targeting specific pathways involved in erythropoiesis or red cell survival, such as pyruvate kinase activators for pyruvate kinase deficiency or hepcidin modulators in cases of iron metabolism disorders.

It's crucial to know that these treatments may come with significant risks and are prescribed based on a patient’s specific condition, usually under clinical supervision and sometimes as part of a research protocol.
Lifestyle Recommendations: For managing anemia, consider the following lifestyle recommendations:

1. **Dietary Adjustments:**
- Increase intake of iron-rich foods such as lean meats, beans, lentils, fortified cereals, spinach, and other leafy greens.
- Consume vitamin C-rich foods like oranges, strawberries, and bell peppers to enhance iron absorption.
- Avoid or limit foods and beverages that can inhibit iron absorption, such as coffee, tea, and foods high in calcium.

2. **Regular Exercise:**
- Engage in moderate, regular exercise to improve overall health and maintain energy levels. However, consult with a healthcare provider to tailor an exercise program suitable for your condition.

3. **Adequate Rest:**
- Ensure you get enough sleep and rest to help your body recover and cope with fatigue associated with anemia.

4. **Avoid Substances that Can Worsen Anemia:**
- Limit alcohol consumption, as it can interfere with the production of red blood cells.
- Be cautious with medications that may affect your iron levels or red blood cell production.

5. **Hydration:**
- Stay well-hydrated to assist in the proper functioning of your body, including blood circulation.

6. **Regular Medical Check-ups:**
- Keep up with regular appointments with your healthcare provider to monitor your anemia and adjust treatments as needed.

These lifestyle adjustments, along with any prescribed treatments, can help manage anemia more effectively.
Medication: For anemia, common medications include iron supplements (such as ferrous sulfate), vitamin B12 injections or supplements, and folic acid supplements. The specific treatment depends on the type and cause of the anemia.
Repurposable Drugs: Repurposable drugs for anemia are medications initially approved for other conditions that have shown potential in treating anemia. Common examples include:

1. **Metformin**: Typically used for type 2 diabetes, it has shown promise in treating anemia in patients with chronic kidney disease.
2. **Thalidomide**: Used for multiple myeloma and leprosy, it can help in specific types of anemia, such as myelodysplastic syndromes.
3. **Erythropoiesis-stimulating agents (ESAs)**: Originally for chronic kidney disease, they are often repurposed for chemotherapy-induced anemia.
4. **Deferasirox**: Utilized for iron overload conditions, it helps manage anemia associated with thalassemia.

"NAN" usually stands for "not a number," but within a medical context, it might refer to data that is not available or not applicable in the context given.
Metabolites: Anemia is associated with various changes in metabolite levels due to altered metabolic processes. Some key metabolites that can be affected include:

1. **Iron**: Often decreased in iron-deficiency anemia.
2. **Ferritin**: Low levels can indicate iron deficiency, while high levels may be seen in chronic diseases.
3. **Hemoglobin**: Reduced in all forms of anemia.
4. **Folic acid and Vitamin B12**: Decreased in megaloblastic anemia.
5. **Bilirubin**: Elevated in hemolytic anemia due to increased red blood cell breakdown.
6. **Lactate**: Can be increased due to hypoxia and altered cellular respiration.

Nan (nanogram per milliliter, ng/mL) is a unit of measurement often used for very low concentrations of substances in the blood, including some of these metabolites.
Nutraceuticals: Nutraceuticals for anemia commonly include iron supplements, vitamin B12, folic acid, and vitamin C. These supplements help increase red blood cell production and improve the body's ability to absorb iron. Nano-based delivery systems for these nutraceuticals can enhance bioavailability and reduce side effects. Examples include nano-encapsulated iron to prevent gastrointestinal irritation and nano-sized vitamin B12 particles to improve cellular uptake.
Peptides: Anemia is a condition characterized by a deficiency in the number or quality of red blood cells or hemoglobin, which impairs the blood's ability to carry oxygen. Peptides related to anemia are often involved in the regulation of iron metabolism and erythropoiesis (the production of red blood cells). For example, hepcidin is a key peptide hormone that regulates iron absorption and distribution in the body. Nanotechnology approaches, such as the use of nanoparticles, are being explored to improve the delivery of iron supplements and other treatments for anemia, potentially offering more efficient and targeted therapeutic options.