Pernicious Anaemia and Haemolytic anaemia Flashcards
B12 deficiency
can be caused by insufficient dietary intake or pernicious anaemia / coeliac / malabsorption / bacterial overgrowth of bowel
COCP and pregnancy and metformin lower your b12 levels
what is the pathophysiology of pernicious anaemia
parietal cells of the stomach produce intrinsic factor which is needed for the absorption of vitamin b12 and iluem.
perinicious anaemia is an autoimmune condtioin where antibodies are created against the parietal cells or intrinsic factor thus preventing the absorption of vitamin b12
symptoms of b12 deficiency
(neurological)
Peripheral neuropathy with numbness or paraesthesia (pins and needles)
Loss of vibration sense or proprioception
Visual changes
Mood or cognitive changes
investigation for pernicious anaemia
auto antibodies
- intrinsic factor
- gastric parietal cell antibody (less helpful)
management of pernicious anaemia
if due to a dietary deficiency then oral replacement of vitamin b12 with cyanocobalamin
if due to pernicious anaemia than usually oral intake would be inadequate as the problem is due to absorption.
1mg of IM hydroxocobalamin 3 times weekly for 2 weeks then every 3 months apart.
more intense regimes- 1mg every other day until symptoms improve.
if folate deficiency then treat b12 first because treating folic acid when they have a b12 deficiency can lead to subacute combined degeneration of the cord?
What is haemolytic anaemia?
Destruction of RBC (haemolysis) leading to anaemia
lots of inherited conditions that can cause RBC to be more fragile and vulnerable to breaking down
lots of acquired condition that cause the increased break down of RBC
inherited haemolytic anaemia
Hereditary Spherocytosis Hereditary Elliptocytosis Thalassaemia Sickle Cell Anaemia G6PD Deficiency
acquired haemolytic anaemia
Autoimmune haemolytic anaemia Alloimmune haemolytic anaemia (transfusions reactions and haemolytic disease of newborn) Paroxysmal nocturnal haemoglobinuria Microangiopathic haemolytic anaemia Prosthetic valve related haemolysis
clinical features of haemolytic anaemia
anaemia (reduced RBC circulating)
splenomegaly (spleen is filled with destroyed RBC)
jaundice (bilirubin is released during the destruction of RBC)
investigations of haemolytic anaemia
Full blood count shows a normocytic anaemia
Blood film shows schistocytes (fragments of red blood cells)
Direct Coombs test is positive in autoimmune haemolytic anaemia
inherited haemolytic anaemia: hereditary spherocytosis
most common in northern europeans
autosomal dominant
RBC are fragile so easily break down when passing through the spleen
clinical features: jaundice gall stones splenomegaly aplastic crissi in the presence of parvovirus FHx
investigations
spherocytes on blood film
MCHC raised
reticulocytes
tx: folate and splenectomy
cholecystectomy of gallstones
inherited haemolytic anaemia: hereditary elliptocytosis
similar to hereditary spherocytosis
RBC are ellipse shaped
autosomal dominant
same presentation and mx as hereditary spherocytosis.
inherited haemolytic anaemia: G6PD deficiency
defect in the RBC enzyme G6PD
more common in Mediterranean and African patients
X linked recessive
‘Crisis’ are triggered by infections, medications (e.g antimalarial primaquine, Ciprofloxacin, sulfonylureas, sulfasalazine, fava beans (broad beans)
clinical features: jaundice (neonatal period) gall stones anaemia splenomegaly
investigate:
Heinz bodies on blood film
G6PD enzyme assay
autoimmune haemolytic anaemia
antibodies are created against the patient’s RBC
two types based on the temperature the antibodies function at.
- warm type: common. haemolysis occurs at normal or above temperatures. idiopathic
- cold type / cold agglutinin disease. at temp lower than 10’C the antibodies against RBC agglutinate and destroy. usually secondary to other conditions- lymphoma, leukaemia, SLE, myocplasma, EBV, CMV, HIV.
management of autoimmune haemolytic anaemia
Blood transfusions
Prednisolone (steroids)
Rituximab (a monoclonal antibody against B cells)
Splenectomy
alloimmune haemolytic anaemia
occurs when there are foreign RBC circulating in bloodstream (which patients immune system destroys) OR foreign ANTIBODY circulating which attacks the patients RBC
- transfusion reaction
- haemolytic disease of the newborn
haemolytic disease of the newborn
antibodies cross the placenta from the mother to fetus
maternal antibodies target the antigen on the RBC of the fetus
haemolytic transfusion reaction
RBC is transfused into the patient. the immune system produces antibodies against antigens on the foreign RBC. creates an immune response which leads to the destruction of the RBC
paroxysmal nocturnal haemoglobinuria
rare condition
specific genetic mutation in haematopoetic stem cells in the bone marrow occurs.
this leads to a loss of proteins on RBC which usually inhibits the complement cascade so now there is activation of he complement cascade- destruction of RBC
red urine- HB and haemosiderin
anaemia
predisposed to thrombosis
smooth muslce dystonia
tx:
ecluzimab
bone marrow transplantation
microangiopathic haemolytic anaemia (MAHA)
small blood vessels have structural abnormalities which cause haemolysis of the red blood cells as they pass through.
mesh inside the small blood vessels shredding the RBC. usually secondary to:
Haemolytic Uraemic Syndrome (HUS)
Disseminated Intravascular Coagulation (DIC)
Thrombotic Thrombocytopenia Purpura (TTP)
Systemic Lupus Erythematosus (SLE)
Cancer
prosthetic valve haemolysis
a complication of a prosthetic heart valve
bioprosthetic and metallic
the turbulence around the valve causes a collision of RBC = break down
mx: Monitoring Oral iron Blood transfusion if severe Revision surgery may be required in severe cases
risk of giving hb when really needed it b12
bone marow is full of cells when there is b12 deficiency. when you correct it and give b12, all the cells which could not make start releasing loads of hb they start maturing
EPO was still being produced
pancytopenia is typical in severe b12. b12 deficiency affects RBC then platelets then WBC.
remove lots of blood
jaundice in b12
lots of rbc but cannot mature because of b12 so they break down into bilirubin = yellowing. unconjugated bilirubin.
