anemia Flashcards
what is anemia
-anemia is defined as a reduction in the number of circulating red blood cells, as measured by hemoglobin (Hb) or hematocrit (Hct)
(hematocrit is the percentage of red blood cells in your blood. Hemoglobin is part of your red blood cell. Hemoglobin helps your red blood cells carry oxygen throughout your body so Hb is amount of oxygen-carrying protein in the blood)
what does anemia maily affect that lead to organ damage
• Anemia affects tissue oxygenation; oxygen is needed by all vital tissues for normal function bcz Hb
deliver o2 from the lungs to tissues and get rid of co2 so anemia may lead to organ dysfunc.on.
• Anemia-> low Hb-> low o2 delivery to body
Causes of anemia(general):
- Blood loss anemia
- Decreased production
-Nutritional deficiency anemias-iron
-B12, folate
-Marrow disease, since the BM is the factory (e.g., infiltration with cancer, leukemia, myeloma), malignancy, radiation - Increased destruction: hemolytic anemia
as general rule blood transfusion is not recommended unless either of the following is true:
- The HB concentration <7 g/dL OR
- the patient requires increased oxygen-carrying capacity (e.g.,patient with coronary artery disease or some other cardiopulmonary disease)
clinical features of anemia
- fatigue
- dyspnea
- headache
- palpitation
- tachycardia
- pallor (most noted in the conjunc.va)
- signs and symptoms of the underlying cause:
a. orthostatic lightheadedness, syncope or hypertension if acute bleeding
b. jaundice if hemolytic anemia
c. blood in stool if GI bleeding
what do you look for in diagnosing the cause of anemia
reticulocyte index
-if < 2% not gd bone marrow , check if microcytic, macrocytic , or normocytic anemia
-if the reticulocyte index is >2% indicating an adequate bone marrow response, and differential diagnoses include:
a. acute blood loss
b. hemolysis
If microcytic anemia (MCV<80), the differential diagnosis includes:
TAILS - thalassmia, anemia of chronic disease , IDA, lead poisoning , syderoblastic anemia
I. Iron deficiency anemia- most common cause
II. anemia of chronic disease -iron is present in the body but is not available for hemoglobin synthesis due to iron trapping in macrophages
III. thalassemia -defective synthesis of globin chain
IV. sideroblastic anemia (include a lead poisoning, pyridoxine deficiency, toxic effects of alcohol)- defective synthesis of protoporphyrin leading to iron accumulation in mitochondria
If macrocytic anemia (MCV >100), the differential diagnosis includes:
VITAMINS
• V → Vitamin B12 deficiency
• I → Inherited disorders (congenital anemia, metabolic disorders)
• T → Toxins (alcohol, lead, drugs like methotrexate or zidovudine)
• A → Alcohol & liver disease
• M → Myelodysplastic syndromes (MDS), marrow failure syndromes
• I → Increased reticulocytes (hemolysis, bleeding recovery)
• N → Non-thyroid endocrine disorders (hypothyroidism, adrenal insufficiency)
• S → Sideroblastic anemia
If normocytic anemia ( MCV 80 to 100), differential diagnosis include:
I. Aplastic anemia – bone marrow failure
II. Bone marrow fibrosis
III. bone marrow infiltration
IV. anemia of chronic disease
V. renal failure -decreesed erythropoietin production result in decreased erythropoiesis
what is a conditon in which the hemoglobin content of blood is lower than normal as a result of
deficiency of one or more essential nutrients.
nutritional anemia
why is iron important
Iron is important for heme synthesis in hemoglobin molecules in red cells ( heme = protoporphyrin + iron ) so if no or less iron = no or less heme
what is the diff btwn ferrous (FE2+) and ferric (FE3+)
• Heme Iron = ferrous (Fe2+), from meat, better absorbed (iron content in red meats is higher than in vegetables)
• Non-Heme Iron = ferric (Fe3+), from vegetables & cereal, reduced to Fe2+ by brush border ferrireductase enzyme
• Transported in plasma bound to transferrin.
Most of the iron is found in our RBC but where is iron absorbed?
duodenum upper part of small
intes.ne.
someone had an upper intestine removal and then he was fatigued what is the reason?
IDA
There are two types of iron:
- Ferritin: is the iron that is found in ALL types of cell
- Hemosiderin: is the excess iron that is stored in case of diseases
what is the role of transferrin
- If serum iron has increased ->the protein will be reduced because my cells have enough iron and I don’t need more iron so this protein “transferrin” will be reduced
- If serum iron has reduced -> the protein will be increased because I need more iron to enter the cell so this protein “transferrin” will be increased.
- Serum iron reduced->transferrin increased
Serum iron increased-> transferrin reduced
in elderly patients with irons deficiency anemia, we must rule out
colon cancer ( colon cancer is a common cause of GI bleeding in the elderly)
someone had a gastric bypass surgery, soon after the surgery he is feeling dizzy and fatigue, what is the reason?
iron deficiency anemia, why? simply because he was bleeding after the surgery (blood loss = iron loss, remember the main cause of iron deficiency anemia is bleeding )
causes of IDA
Mnemonic: “LID” (Loss, Intake, Demand/Absorption Issues)
- Blood loss (most common cause) -> from GI or menses ( menstrual blood loss is the most common source, in the absence of menstrual bleeding, GI blood loss is most likely), hookworm (feeds on the blood of the host tissue leading to the loss of iron and protein resulting in anemia, bleeding in the intestine )
- Increased demand (growth or pregnancy) or poor intake
• Dietary deficiency/increased iron requirements, which are primarily seen in the following three age groups:
–>Infants and toddlers: occurs especially if the diet is predominantly human milk , which is low in iron :children in this age group also have an increased requirement for iron due to accelerated growth
–>Adolescents: increased requirements for iron due to rapid growth, adolescent women are particularly at risk due to loss of menstrual blood
–>Pregnant women: pregnancy increased iron requirements - Decreased absorption -> gastrectomy/small bowel disease (celiac, tropical sprue)
why do symptoms occur in IDA
Due to low Hb > low O2
symptoms of IDA
- Anemia > fatigue, pallor ( the most common sign, by looking at the mucus membrane like conjunctiva and buccal ) , SOB ( dyspnea on exertion) , tachycardia ( to compensate the low Hb and low O2)
- Brittle hair and nails
- Atrophic glossitis, angular stomatitis
- Koilonychia ( spooning, flaRened, concave nails)
- Pica (crush ice or scratch the paint on the wall and eat it)
investigations for diagnosis of IDA
• Low hemoglobin (Hb) → Confirms anemia
• Low hematocrit (Hct)
• Low mean corpuscular volume (MCV) → Microcytic anemia (MCV < 80 fL)
• Low mean corpuscular hemoglobin (MCH) → Hypochromic anemia
• High red cell distribution width (RDW) → Suggests iron deficiency
blood film for diagnosis
a. small hypochromic RBCs
b. anisocytosis (size) (RBC unequal in size )
c. poikilocytosis (shape)
tx of IDA
Oral iron supplements (ferrous sulphate/gluconate):
o must be treated for 3 to 6 months before determining response
o Monitor response by increase in re.culocyte followed by increase in Hb 10g/L per week until normal.
o Lack of response could be due to: noncompliance, malabsorption, or ongoing loss ex: menorrhagia)
