Red Cell Disorders

Question 1

Features in blood film of Hered sphero

Answer 1

Mild to moderate anemia
Reticulocytosis
Increased mean corpuscular hemoglobin concentration (MCHC)
Spherocytes on the peripheral blood smear
Hyperbilirubinemia
Abnormal results on the incubated osmotic fragility test

Question 2

Hereditary spherocytosis (HS)

Answer 2

A familial hemolytic disorder associated with a variety of mutations that lead to defects in red blood cell (RBC) membrane proteins.
major complications of HS are aplastic or megaloblastic crisis, hemolytic crisis, and cholecystitis and cholelithiasis.

Question 3

Causes of microcytic anaemia

Answer 3

Fe def
Thalassaemia
Sideroblastic anaemia
lead poisoning
Chronic disease

Question 4

Causes of microcytic anaemia

Answer 4

Spurious - newborn, reticulocytosis, RCC agglutination
Drugs: azathioprine, hydroxyurea
B12/folate def, Pyridoxine B6 def, Thiamine B1
Fanconi’s anaemia
Hypothyroidism
Myelodysplasia
Liver disease

Question 5

Cause of sickle cell disease/anaemia

Answer 5

Point mutation of B globin chr 11
AR
Glutamine (acidic) to valine (neut) = HbS
Stable when oxygenated, shifts curve to right (offloads easily)
When deoxygenation: K efflux, incr cell density, polymerises with other Hb - sickles
Reduced polyp with HbF
Incr polym with HbC, D, O Arab
Reduced elasticity, vasculocclusive disease
Cytokines from granulocytes bad prognostic

Question 6

Causes for abnormal immune function in sickle cell

Answer 6

Deficiency in alternative complement pathway serum opsonins to pneumococci
Increased suscept to encapsulated org
Functional asplenia by 5
Parvovirus B19 unique threat as impairs reticulocytosis
Increased risk osteomyelitis in sickle cell especially by salmonella and staph aureus