PBL 4: Three Tired Ladies

Question 1

Define angular glossitis?

Answer 1

Inflamed tongue and depapillation of dorsal surface

Question 2

Define angular stomatitis?

Answer 2

Inflammation of edges of mouth

Question 3

Define hydroxocobalamin?

Answer 3

Dietary supplement of vitamin B12 to treat pernicious anaemia

Question 4

What is erythropoiesis?

Answer 4

The formation and life cycle of RBCs

Question 5

Where does erythropoiesis occur before birth?

Answer 5

• mesoblastic = nucleated RBCs 3 weeks, yolk sac cell wall and placenta mesothelium
• hepatic = 6 weeks, liver and spleen
• myeloid = 3 months, bone

Question 6

Where does erythropoiesis occur after birth?

Answer 6

• birth to 5yrs = all bone marrow
• 5 years to 20/25 = marrow of long bones
• 25 years onwards = marrow of membranous long bones

Question 7

What controls erythropoiesis?

Answer 7

Erythropoietin - EPO
produced by the fibroblast interstitial cells of kidney around the P.C.T
Not subject to changes in oxygen due to exercise or blood pressure and only haemoglobin
Regulates RBCs according to Hb oxygen saturation

Question 8

What are the stages of erythropoiesis?

Answer 8

Haematopoietic stem cell gets converted into a proerythroblast

• nucleus shrinks, condenses, cytoplasm fuses with haemoglobin, nucleus gets expelled = reticulocyte
• matures into erythrocyte and squeezes into and squeezes into capillary through pores

Question 9

How do erythrocytes squeeze into capillaries?

Answer 9

Diapedesis

Question 10

How does iron get taken up?

Answer 10

• enterocytes on duodenum absorb Fe2+ via ferroportins
• ferric reductase converts Fe2+ -> Fe3+
• transferrin takes up Fe3+ and transports into erythroblasts via endocytosis
• transferrin can also release Fe3+ to ferritin or haemoglobin
• empty transferrin transported back to cell surface and released

Question 11

What is ferritin?

Answer 11

Large hollow polyprotein

Stores Fe3+

Question 12

How are erythrocytes destroyed by the spleen?

Answer 12

• senescent RBCs detected by spleen as shape is deformed and rigid
• spleen capillaries trap them and engulf (osmotic lysis)
• haem group removed by haemoxygenase
• transferrin collects iron to take to liver -> bone marrow for Hb use

Question 13

How is bilirubin excreted and from what?

Answer 13

• Haem group removed from RBCs = biliverdin (green)
• Biliverdin reductase converts biliverdin into yellow bilirubin (conjugated to albumin)
• goes to the liver where glucuronic acid unconjugates it and increases its solubility
• Bile bacteria converts bilirubin into urobilinogen
• ends up in feces and 10% in liver and recycled in venous blood

Question 14

What is anaemia?

Answer 14

Low haemoglobin levels for that age and gender

Question 15

What should the normal haemoglobin levels be?

Answer 15

• > 11.5g/dl for females

- >13.5g/dl for males

Question 16

How do you diagnose anaemia?

Answer 16

1) full blood count (look for low RBCs)
2) blood film
3) serum ferritin (low)
4) serum iron total iron binding capacity should be low

Question 17

What are the normal physiological responses to anaemia?

Answer 17

• heart rate and SV increase = CO increase via SNS
• redistribution to tissues with greater blood and oxygen demand (heart and brain)
• oxygen-haemoglobin curve shifts to the right as you have less oxygen so lower affinity for haemoglobin for oxygen and higher partial pressure = more unloading
• increase in EPO production
• acute anaemia causes vasoconstriction but if it is chronic it will reduce vascular resistance
• kidneys retain salt and water to increase intravascular volume and preserve cerebral blood flow and decrease renal flow

Question 18

What type of anaemia did each lady have and why?

Answer 18

1 - low Hb, low MCV, normal WBC, normal platelet, normal reticulocytes, microcytic = microcytic iron deficiency anaemia (old, normal diet, constipation, GI bleeding, atrophic glossitis and angular stomatitis)
2- low Hb, high MCV, low WBC, low platelets, high reticulocytes, macrocytic = macrocytic anaemia (normal diet, neurological symptoms so cannot be folate deficiency, pernicious as diet is normal)
3 - low Hb, normal MCV, normal WBC, normal platelets, low reticulocytes, normocytic (middle aged, haemodialysis due to CKD = EPO not functional) = normocytic anaemic due to CKD

Question 19

What should the treatment be for each patient?

Answer 19

1 - microcytic iron deficiency due to GI bleeding = iron supplements/iron transfusion
2 - macrocytic due to pernicious anaemia = intramuscular B12 injection every 3 months for life
3 - normocytic due to CKD = EPO IV or subcutaneous injections/erythropoiesis stimulating agents or renal transplant

Question 20

What are the normal haemoglobin levels?

Answer 20

Females - >11.5g/dl

Males - >13.5g/dl

Question 21

How is the haemoglobin oxygen curve affected?

Answer 21

• shift to the right because you have increased unloading and increased 2,3-DPG