Anemia Flashcards
Anemia also called?
Anemia
Also called: lack of blood 🩸
Definition of Anemia
Anaemia is defined as decreased concentration of haemoglobin for the age and sex of the individual
(i.e. below 13 g/dL in adult males,
12 g/dL in adult females, 11 g/dL in children, and below 13.5 g/dL in the 1st week of life).
Anaemia always has a cause, which must be identified and properly managed.
The cause must be investigated before initiating treatment.
In an emergency, blood samples must be taken for investigations before blood transfusion.
Anemia is a reduction in hemoglobin (Hb) or hematocrit (HCT) or RBC count
•Anemia is not a diagnosis, but a presentation of an underlying condition.
•Whether or not a patient becomes symptomatic depends on the etiology of anemia, the acuity of onset, and the presence of other comorbidities, especially the presence of cardiovascular disease.
•Most patients experience some symptoms related to anemia when the hemoglobin drops below 7.0 g/dL.
Reduction in the volume of RBC’s (hematocrit) or concentration (hemoglobin) when compared to similar values from a reference population.
•Hgb = expression of amount (g/dL).
•Hct = expression of volume (% or decimal fraction).
•RBC = expression of number (#/mm3).
Normal Hemoglobin (Hgb)-specific laboratory cut-offs will differ slightly, but in general, the normal ranges are as follows:
•13.5 to 18.0 g/dL in men
•12.0 to 15.0 g/dL in women
•11.0 to 16.0 g/dL in children
•Varied in pregnancy depending on the trimester, but generally greater than 10.0 g/dL
A condition in which the blood doesn’t have enough healthy red blood cells.
Anaemia results from a lack of red blood cells or dysfunctional red blood cells in the body. This leads to reduced oxygen flow to the body’s organs.
OR
Anaemia is a condition in which the number of red blood cells or the haemoglobin concentration within them is lower than normal.
Aetiology / Causes
Causes
Nutritional micronutrient and vitamin deficiency
y Iron
y Folic acid
y Vitamin B12
Bleeding
y Heavy menstruation
y Haemorrhoids(piles)
y Peptic ulcer
y Infestations e.g. hookworm, bilharzia
y Solid organ malignant tumours e.g. colonic cancer
y Haematological malignancies: e.g. leukaemia
Haemolysis
y Severe malaria
y Sickle cell disease
y G6PDdeficiency
y Hypersplenism
y Autoimmune
y Drugs
Bone Marrow Failure
y Disease infiltration e.g. leukaemia, lymphoma, tuberculosis
y Aplasia – primary or secondary e.g. due to cytotoxics
Chronic Diseases
y Kidney disease
y Tuberculosis
y Hypothyroidism
Autoimmune Disease
y SLE
y Pernicious anaemia
Causes
1) Hypoproliferative Microcytic Anemia (MCV<80 fl)
•Iron deficiency anemia
•Anemia of chronic disease (AOCD)
•Sideroblastic anemia (may be associated with an elevated MCV as well, resulting in a dimorphic cell population)
•Thalassemia
•Lead poisoning
2)Hypoproliferative Normocytic Anemia (MCV 80-100 fL)
•Anemia of chronic disease (AOCD)
•Renal failure
•Aplastic anemia
•Pure red cell aplasia
•Myelofibrosis or myelophthisic processes
•Multiple myeloma
- Macrocytic Anaemia
•Macrocytic anemia can be caused by either a hypoproliferative disorder, hemolysis, or both.
•Thus, it is important to calculate the corrected reticulocyte count when evaluating a patient with macrocytic anemia.
•In hypoproliferative macrocytic anemia, the corrected reticulocyte count is <2%, and the MCV is greater than 100 fl.
•But, if the reticulocyte count is > 2%, hemolytic anemia should be considered
Hypoproliferative Macrocytic Anemia (MCV>100 fL)
•Alcohol
•Liver disease
•Hypothyroidism
•Folate and Vitamin B12 deficiency [3]
•Myelodysplastic syndrome (MDS)
•Drug-induced - Haemolytic Anaemia
•Hemolytic anemia (HA) is divided into extravascular and intravascular causes
•Extravascular hemolysis: red cells are prematurely removed from the circulation by the liver and spleen. This accounts for a majority of cases of HA
•Hemoglobinopathies (sickle cell, thalassemias)
•Enzyemopathies (G6PD deficiency, pyruvate kinase deficiency)
•Membrane defects (hereditary spherocytosis, hereditary elliptocytosis)
•Drug-induced
•Intravascular hemolysis: red cells lyse within the circulation, and is less common.
•PNH
•AIHA
•Transfusion reactions
•MAHA
•DIC
•Infections
•Snake bites/venomOR
This most common type of anemia is caused by a shortage of iron in your body. Your bone marrow needs iron to make hemoglobin. Without adequate iron, your body can’t produce enough hemoglobin for red blood cells. Without iron supplementation, this type of anemia occurs in many pregnant women.
Although many parts of the body help make red blood cells, most of the work is done in the bone marrow. Bone marrow is the soft tissue in the center of bones that helps form all blood cells.
Healthy red blood cells last between 90 and 120 days. Parts of your body then remove old blood cells. A hormone called erythropoietin (epo) made in your kidneys signals your bone marrow to make more red blood cells.
Hemoglobin is the oxygen-carrying protein inside red blood cells. It gives red blood cells their color. People with anemia do not have enough hemoglobin.
The body needs certain vitamins, minerals, and nutrients to make enough red blood cells. Iron, vitamin B12, and folic acid are three of the most important ones. The body may not have enough of these nutrients due to:
Changes in the lining of the stomach or intestines that affect how well nutrients are absorbed (for example, celiac disease)
Poor diet
Surgery that removes part of the stomach or intestines
Possible causes of anemia include:
Iron deficiency
Vitamin B12 deficiency
Folate deficiency
Certain medicines
Destruction of red blood cells earlier than normal (which may be caused by immune system problems)
Long-term (chronic) diseases such as chronic kidney disease, cancer, ulcerative colitis, or rheumatoid arthritis
Some forms of anemia, such as thalassemia or sickle cell anemia, which can be inherited
Pregnancy
Problems with bone marrow such as lymphoma, leukemia, myelodysplasia, multiple myeloma, or aplastic anemia
Slow blood loss (for example, from heavy menstrual periods or stomach ulcers)
Sudden heavy blood loss
Mechanism of Anaemia
Types of Anemia
Mechanisms of anemia
Blood loss
•Acute- hemorrhage, surgery, trauma, menorrhagia
•Chronic- heavy menstrual bleeding, chronic gastrointestinal blood losses [6] (in the setting of hookworm infestation, ulcers, etc.), urinary losses (BPH, renal carcinoma, schistosomiasis)
Hemolytic anemia
•Acquired- immune-mediated, infection, microangiopathic, blood transfusion-related, and secondary to hypersplenism
•Hereditary- enzymopathies, disorders of hemoglobin (sickle cell), defects in red blood cell metabolism (G6PD deficiency, pyruvate kinase deficiency), defects in red blood cell membrane production (hereditary spherocytosis and elliptocytosis)
Deficient/defective erythropoiesis (hypoproliferative anaemia)
•Microcytic
•Normocytic, normochromic
•Macrocytic
Hypoproliferative anemias are divided by the mean corpuscular volume into microcytic anemia (MCV<80 fl), normocytic anemia (MCV 80-100 fl), and macrocytic anemia (MCV>100 fl).
Different types of anemia include:
Anemia due to vitamin B12 deficiency
Anemia due to folate (folic acid) deficiency
Anemia due to iron deficiency
Anemia of chronic disease
Hemolytic anemia
Idiopathic aplastic anemia
Megaloblastic anemia
Pernicious anemia
Sickle cell anemia
Thalassemia
- Iron deficiency anemia is the most common type of anemia.
History and Physical examination
Symptoms
Symptoms
y Easy fatigability
y Dizziness
y Shortness of breath on exertion y Palpitations
y Fresh blood in stools
y Black tarry stools (malaena)
y Haematuria
y Cola-like urine
Signs
y Pale mucous membranes and palms
y Angular stomatitis
y “Spoon shaped” and ridged finger and toe nails y Spleen, liver and lymph nodes may be palpable y Signs of heart failure (in severe anaemia)
y Jaundice (in haemolysis)
y Petechiae and purpura (bone marrow failure)
y Hyperpigmentation of palms and soles of feet
History and Physical
•A thorough history and physical must be performed.
•Some important questions to obtain in a history:
•Obvious bleeding- per rectum or heavy menstrual bleeding, black tarry stools, hemorrhoids
•Thorough dietary history
•Consumption of nonfood substances
•Bulky or fatty stools with foul odor to suggest malabsorption
•Thorough surgical history, with a concentration on abdominal and gastric surgeries
•Family history of hemoglobinopathies, cancer, bleeding disorders
•Careful attention to the medications taken daily
Symptoms of anemia
Classically depends on the rate of blood loss. Symptoms usually include the following:
•Weakness
•Tiredness
•Lethargy
•Restless legs
•Shortness of breath, especially on exertion, near syncope
•Chest pain and reduced exercise tolerance- with more severe anemia
•Pica- desire to eat unusual and nondietary substances
•Mild anemia may otherwise be asymptomatic
Signs of anemia
•Skin may be cool to touch
•Tachypnea
•Hypotension (orthostatic)
•Pallor of the conjunctiva
•Jaundice- elevated bilirubin is seen in several hemoglobinopathies, liver diseases and other forms of hemolysis
•Lymphadenopathy: suggestive of lymphoma or leukemia
•Glossitis (inflammation of the tongue) and cheilitis (swollen patches on the corners of the mouth): iron/folate deficiency, alcoholism, pernicious anemia.
Examination 🧐:
Abdominal exam
•Splenomegaly: hemolysis, lymphoma, leukemia, myelofibrosis
•Hepatomegaly: alcohol, myelofibrosis
•Scar from gastrectomy: decreased absorptive surface with the loss of the terminal ileum leads to vitamin B12 deficiency
•Scar from cholecystectomy: Cholesterol and pigmented gallstones are commonly seen in sickle cell anemia are hereditary spherocytosis
Cardiovascular
•Tachycardia
•Systolic flow murmur
•Severe anemia may lead to high output heart failure
OR
Symptoms
You may have no symptoms if the anemia is mild or if the problem develops slowly. Symptoms that may occur first include:
Feeling weak or tired more often than usual, or with exercise
Headaches
Problems concentrating or thinking
Irritability
Loss of appetite
Numbness and tingling of hands and feet
If the anemia gets worse, symptoms may include:
Blue color to the whites of the eyes
Brittle nails
Desire to eat ice or other non-food things (pica syndrome)
Lightheadedness when you stand up
Pale skin color
Shortness of breath with mild activity or even at rest
Sore or inflamed tongue
Mouth ulcers
Abnormal or increased menstrual bleeding in females
Loss of sexual desire in men
Diagnostic investigations
Investigations
Complete blood count
y FBC
y Reticulocyte count and blood film comment
y Sickling test and HB electrophoresis if indicated
y Blood film for malaria parasites
y Kidney function tests
y Serum iron, Vitamin B12 and folate levels
y Direct Coomb’s test
y Stool for hookworm ova
y Stool for occult blood
y Urine for schistosoma ova
y Specialized tests depending on the suspected cause e.g. bone
marrow examination, antinuclear antibody (ANA) test, upper and lower GI endoscopy
Complete blood count (CBC) including differential
•Calculate the corrected reticulocyte count = percent reticulocytes x (patient’s HCT/normal HCT)
•For normal HCT, use 45% in men and 40% in women
•If result > 2, this suggests hemolysis or acute blood loss, while results < 2 suggests hypoproliferation.
After calculating the reticulocyte count, check the MCV.
MCV (<80 fl)
•Iron deficiency- decreased serum iron, percent saturation of iron, with increased total iron-binding capacity (TIBC), transferrin levels, and soluble transferrin receptor
•Lead poisoning- basophilic stippling on the peripheral blood smear, ringed sideroblasts in bone marrow, elevated lead levels
•Thalassemia- RBC count may be normal/high, low MCV, target cells, and basophilic stippling are on peripheral smear. Alpha thalassemia is differentiated from beta-thalassemia by a normal Hgb electrophoresis in alpha thalassemia. Elevated Hgb A2/HgbF is seen in the beta-thalassemia trait.
•MCV (90-100fl)
•Renal failure: BUN/Creatinine
•Aplastic anemia- ask for drug exposure, check for infections (EBV, hepatitis, CMV, HIV), test for hematologic malignancies and paroxysmal nocturnal hemoglobinuria (PNH)
•Myelofibrosis/myelophthisis- check bone marrow biopsy
•Multiple myeloma- serum and urine electrophoresis
MCV (>100 fl)
•B12/folate levels- B12 and folate deficiency can be differentiated by an elevated methylmalonic and homocysteine level in B12 deficiency and only an elevated homocysteine level in folate deficiency. Methylmalonic levels are relatively normal.
•MDS- hyposegmented PMNs on peripheral smear, bone marrow biopsy
•Hypothyroidism- TSH, free T4
•Liver disease- check liver function
•Alcohol- assess alcohol intake
•Drugs
•Steps to evaluate for hemolytic anemia
•Confirm the presence of hemolysis- elevated LDH, corrected reticulocyte count >2%, elevated indirect bilirubin
•Examine the peripheral blood smear
•Spherocytes: immune hemolytic anemia (Direct antiglobulin test DAT+) vs. hereditary spherocytosis (DAT-)
•Bite cells: G6PD deficiency
•Target cells: hemoglobinopathy or liver disease
•Schistocytes: TTP/HUS, DIC, prosthetic valve, malignant HTN
•Acanthocytes: liver disease
•Parasitic inclusions: malaria, babesiosis, bartonellosis
•Other investigations that might be warranted include:
•esophagogastroduodenoscopy for the determination of an upper GI bleed,
•colonoscopy for the determination of a lower GI bleed,
•imaging studies if malignancy, or internal hemorrhage is suspected.
•If a menstruating woman has heavy vaginal bleeding, evaluate the presence of fibroids with a pelvic ultrasound.
OR
Exams and Tests
The provider will perform a physical examination, and may find:
A heart murmur
Low blood pressure, especially when you stand up
Slight fever
Pale skin
Rapid heart rate
Some types of anemia may cause other findings on a physical exam.
Blood tests used to diagnose some common types of anemia may include:
Blood levels of iron, vitamin B12, folic acid, and other vitamins and minerals
Complete blood count
Reticulocyte count
Other tests may be done to find medical problems that can cause anemia.
Management/ Treatment
Also view STG page 64
Treatment / Management
•Management depends primarily on treating the underlying cause of anemia.
•Anemia due to acute blood loss- Treat with IV fluids, crossmatched packed red blood cells, oxygen.
•Always remember to obtain at least two large-bore IV lines for the administration of fluid and blood products.
•Maintain hemoglobin of > 7 g/dL in a majority of patients.
•Those with cardiovascular disease require a higher hemoglobin goal of > 8 g/dL.
•Anemia due to nutritional deficiencies:
•Oral/IV iron, B12, and folate.
•Oral supplementation of iron is by far the most common method of iron repletion. The dose of iron administered depends on the patient’s age, calculated iron deficit, the rate of correction required, and the ability to tolerate side effects.
•The most common side effects include metallic taste and gastrointestinal side effects such as constipation and black tarry stools. For such individuals, they are advised to take oral iron every other day, in order to aid in improved GI absorption.
•The hemoglobin will usually normalize in 6-8 weeks, with an increase in reticulocyte count in just 7-10 days.
•IV iron may be beneficial in patients requiring a rapid increase in levels. Patients with acute and ongoing blood loss or patients with intolerable side effects are candidates for IV iron.
•Anemia due to defects in the bone marrow and stem cells: Conditions such as aplastic anemia require bone marrow transplantation.
•Anemia due to chronic disease: Anemia in the setting of renal failure, responds to erythropoietin. Autoimmune and rheumatological conditions causing anemia require treatment of the underlying disease.
Anemia due to increased red blood cell destruction:
•Hemolytic anemia due to medications requires the removal of the offending drug.
•Persistent hemolytic anemia requires splenectomy.
•Hemoglobinopathies such as sickle anemia require blood transfusions, exchange transfusions, and even hydroxyurea to decrease the incidence of sickling.
•DIC, which is characterized by uncontrolled coagulation and thrombosis, requires the removal of the offending stimulus. Patients with life-threatening bleeding require the use of antifibrinolytic agents.
OR
Treatment
Treatment should be directed at the cause of the anemia, and may include:
Blood transfusions
Corticosteroids or other medicines that suppress the immune system
Erythropoietin, a medicine that helps your bone marrow make more blood cells
Supplements of iron, vitamin B12, folic acid, or other vitamins and minerals
Complications
Complications
•Anemia, if undiagnosed or left untreated for a prolonged period of time can lead to multiorgan failure and can even death.
•Pregnant women with anemia can go into premature labor and give birth to babies with low birth weight
•Anemia during pregnancy also increases the risk of anemia in the baby and increased blood loss during pregnancy.
Complications are more predominant in the older population due to multiple comorbidities
•The cardiovascular system is the most commonly affected in chronic anemia. Myocardial infarction, angina, and high output heart failure are common complications. Other cardiac complications include the development of arrhythmias and cardiac hypertrophy.
•Severe iron deficiency is associated with restless leg syndrome and esophageal webs.
•Severe anemia from a young age may lead to impaired neurological development in the form of cognitive, mental, and developmental delays. These complications are unlikely to be amenable to medical management.
OR
Possible Complications
Severe anemia can cause low oxygen levels in vital organs such as the heart, and can lead to heart failure.
Consultations
Consultations
•Gastroenterologist if a gastrointestinal bleed is suspected
•Nephrologist if anemia of chronic disease in the setting of renal failure is suspected
•Hematologist if a bone marrow disorder is suspected
•Gynecologist if intractable menorrhagia is suspected
•Cardiologist if severe anemia leads to angina, myocardial infarction, heart failure, or arrhythmias
Take Note
Take Note
•Always send blood films in patients with an unclear etiology of anemia.
•Start haematinics early (iron, B12, and folate).
•Inform patients of the side effects of iron therapy, including constipation and black, tarry stools.
•Consider screening for sickle cell and thalassemia in patients with unexplained anemia or with a family history of these diseases.
•Vitamin C aids iron absorption, so coadministration of vitamin C with iron, or encouraging the patients to take iron supplements with orange juice, will aid therapy.
