RBC Path Flashcards
Anaemia classification
In notes
Hemolytic anemia’s features & types
Features for all hemolytic anaemias:
① RBC death before 120 days
② increased erythropoietin levels & compensatory increase in erythropoiesis
③ Hb degradation products Accumilation
Normal Hemolysis of RBC occurs in macrophages in spleen, liver, bone marrow. (process triggered by age dependent changes in RBC surface protiens)
Types:
Extravascular & intravascular.
Extravascular hemolysis
Caused by alterations that cause RBC less deformable..
Extreme changes in shape needed for RBC to go through splenic sinusoids
Hence, if RBC less deformable,RBC passage is difficult, RBC sequestration & phagocytosis by macrophages occur.
Anaemia, jaundice and splenomegaly seen
Decrease in haptoglobin ( alpha 2 globulin that binds free Hb& prevents its excretion through urine )
Intravascular hemolysis.
Less common
Caused by mechanical injury (microangiopathic hemolytic anemias- DIC,TTP, HUS ; Cardiac traumatic hemolysis- cardiac valves defect); complement fixation (occurs when abs recognises bind to RBC self (Ag’s) , intracellular parasites, toxic injury.
Anemia, jaundice, hemoglobinuria, hemoglobinemia , hemosiderinuria
As serum haptglobin depletes free hb oxidises to methemoglobin which is brown in color & passes in urine to give brown color.
Renal hemosiderosisis- iron released from Hb accumulate in tubular cells.
Morphology of hemolytic anemia’s.
Erythropoietin cause erythroid differentiation hence increased no of erythroid precursers(normoblasts) in bonemarrow.
Reticulocytes- no increase in peripheral circulation.
Hemosiderosis- phagocytosis of RBC lead to accumulation of iron containing pigment hemosiderin in bone marrow, livers spleen.
Extra-medullary hematopoiesis- in liver, spleen, lymphnodes
Pigmented gallstones
SICKLE CELL DISEASE def
. is common heriditary hemoglobinopathy caused by point mutation in B-globin that promotes polymerisation of deoxygenated Hb leading to RBC destruction, hemolytic anemia, micro vascular occlusion , ischemic tissue damonge.
o HbA(L2B2),HbA2 (a2d2), HbF(a2g2) present in Risc. o point mutation of 6 th codon of beta globin codes tor valine in the place of Glutamic Acid. • This Gives rise toHbS causes physiochem prop’s of disease.
Sickle cell trait in population
① Metabolically active intracellular parasite consume 02 & decrease ph hence conditions favour sickling of RBC, hence macrophages phagocytosis increase and parasite is cleared
② sickling of RBC prevents formation of membrane blebs which contain parasite protein
Absorption of iron
Non heme iron- iron only absorbed in ferrous form
. Ferric to ferrous by duodenal cyt b reductase
.transport across membrane by divalent metal transporter
.inside gut cells ferrous stored as ferritin or
.transported to transferrin by ferroportin
Pathogenesis of fe def anemia
.dec dietary intake
.increase demand
.inc blood loss
.dec absorption
Etiology of fe def anemia
- Inc demand - pregnancy,infants,adolescents,premature infants
- dec intake- low socioeconomic ,anorexia
- dec absorption -,,gastrectomy,achloridia,coeliac disease
- blood loss - gi -hookworm,carcinomas,peptic ulcers,haemorrhoids,oesophageal varices,U.C. Renal-hematuria. Nose -epistaxis. Lungs -haemoptysis
Lab diagnosis of fe def anemia
3 stages:
- Storage iron depletion
- iron defeciant erythropiosis
- frank iron defeciancy anemia
BLOOD SMEAR AND RED CELL INDICES: mild to moderate anemia hb<6.5gm/dl
- hb-fall in conc
- RBC: aniso poikilocytosis, microcytic ,hypochromic {central pallor} -if severe only thin rim of pink staining at periphery , target cells and elliptical cells present
- reticulocyte count : normal or dec
- Absolute values : dec MCV MCH MCHC
- leukocytes:normal
- plt:normal
Etiology of megaloblastic anemia
Vit b12 def :
- Dec diet intake :veg
- dec absorption : 1. Intestinal:ileal resection, crohns,fish tapeworm,tropical sprue
2. gastric:gastrectomy , pernicious anemia
FOLATE def:
Dec intake :alchoholics
Dec absorption :jejunal resection ,crohns, tropical sprue
Excess demand: physio :infants ,pregnancy
Patho :TB, RA
Other cause:
Drugs like methotrexate ,pyrimethamine inhibit DHF reductase
