6a: Haematology in systemic disease Flashcards
What three things must we consider when we think about things influencing patient blood counts
- Cause
- Complications (bc of systemic disease)
- Treatment
What are the causes of reduced erythropoeisis?
- Empty bone marrow unable to respond to stimulus from EPO eg after chemotherapy or toxic insult such as parvovirus infection or in aplastic anaemia
- Marrow infiltrated by cancer cells or fibrous tissue (myelofibrosis) means the normal haemopoietic cells are reduced
- Lack of response to the haemostatic loop – eg in chronic kidney disease the kidney stops making EPO
What is Anaemia of Chronic Disease/inflammation?
Anaemia of chronic disease (also called anaemia of inflammation) is a common cause of anaemia (2nd worldwide after iron deficiency) associated with chronic inflammatory conditions such as rheumatoid arthritis, chronic infections (e.g. tuberculosis) and malignancy
How is RBC production control?
What is anaemia of chronic disease an example of?
Dyserythropoiesis
How does anaemia of chronic disease occur?
- Iron dysregulation: iron not released for use in bone marrow
- The marrow shows a lack of response to erythropoietin
- Reduced lifespan of red cells
What is a functional iron deficiency?
Sufficient iron in the body but not available to the developing erythroid cells
Describe the importance of macrophages in supplying iron
- In bone marrow, erythroid cells develop in islands surrounding a nursing macrophage
- Macrophage takes the iron and gives to RBCs that need it
- Macrophages ‘eat’ old senescent RBCs and recycle iron
- Iron recycling is the main source of iron for new rbc
- Small amount of iron absorbed from gut
What is Hepcidin?
- Degrades ferroportin a protein involved in moving iron out of cells
- Prevents iron release from macrophages
- Prevents iron absorption from gut
What is hepcidin regulated by?
- HFE (hereditary haemochromatosis)
- Transferrin receptor
- Inflammatory cytokines - MOST IMPORTANT
Outline the causes for Anaemia of Chronic Disease/inflammation due to inflammatory cytokines
- Iron dysregulation: iron not released for use in bone marrow
- The marrow shows a lack of response to erythropoietin
- Reduced lifespan of red cells
How does Chronic kidney disease result in anaemia?
- Deficiency of erythropoietin production by the damaged kidneys
- Lower level of erythropoiesis in bone marrow leading to insufficient red cell production and anaemia
- Reduced clearance of hepcidin from blood
- Increased hepcidin production due to inflammatory cytokines
- Reduced lifespan of RBC as a direct effect of uraemia
- Dialysis-damage to rbc and loss due to bleeding
List some investigations for chronic kidney disease
- Often normocytic normochromic or microcytic anaemia
- Normal or high ferritin (iron stores)
- Normal or high Reticulocyte Haemoglobin content (CHr)
- CRP often elevated
How do we treat anaemia of chronic disease?
- Treat underlying condition – need to reduce inflammation and reduce the number of cytokines circulation
- Recombinant human erythropoeitin – can be given if associated renal failure. Only effective in patients with sufficient iron, folate and B12 to support an increase in erythropoiesis
- Vit B12 folate - to ensure and iron stores are adequate
- Transfuse - if all else fails and patient is symptomatic (and sparingly)
Describe the management of the chronic renal failure
Describe how chronic kidney disease can cause uraemia and some consequences of this
- Kidney dysfunction can result in uraemia (increase in urine concentration)
- Can inhibit erythropoiesis
- Reduces the lifespan of existing red blood cells as well as inhibiting platelet function
- Can cause chronic bleeding from the gastrointestinal tract
Discuss why there may low or high platelet count in chronic kidney disease
Low:
- direct effect of uraemia on platelet production
- drugs
- Haemolytic uraemic syndrome
High
- Reactive
- bleeding
- iron deficiency
Discuss why there may low or high RBC count in chronic kidney disease
Low:
- ARF/ACD (acute renal failure)
- Blood loss
- Haematinic causes
High
- Post renal transplant
- Renal tumour
Discuss why there may low or high WBC count in chronic kidney disease
Low:
- Immunosuppression post renal transplant drugs
- Marrow infiltration eg in myeloma
High
- Inflammation
- Connective tissue disease
- Infection
- Drugs: steroids
What is Rheumatoid Arthritis
- Chronic immune mediated inflammatory conditions
- Damage to the synovial joint - Joint inflammation
How is Rheumatoid Arthritis treated?
- Analgesia often NSAIDs
- Corticosteroids
- Chemotherapy
How does Rheumatoid Arthritis cause low haemoglobin?
- Anaemia of chronic disease
- Blood loss due to NSAIDs or corticosteroids > erosions in stomach > bleeding > reduced iron to support > reduced erythropoesis
- Haematinic
- Immune dysfunction: AB production against RBCsa
Why may WBC count be high for rheumatoid arthritis?
- Infection: steroid could increase susceptibility to infections
- Associated inflammation
- Drug reactions
Why may the WBC count be low for individuals with rheumatoid arthritis?
- Drugs e.g. methotrexate and not taking their folic acid. Methotrexate interferes with folic acid cycle
- Immune – associated with folate deficiency
Explain why the platelet count may be low or high for rheumatoid arthritis?
High platelet count
- Reactive
- Bleeding – increase in platelet count
- Iron deficiency
Low platelet count
- Drugs autoimmune splenomegaly (Felty’s)……
- Immune dysfunction leading to disruption of their platelets
What is Felty’s syndrome?
Triad of rheumatoid arthritis, splenomegaly and thrombocytopenia
What is neutropenia?
- Occurs secondary to splenomegaly
- Peripheral destruction of neutrophils, and failure of bone marrow to produce neutrophils
- High level of G-CSF, insensitivity of myeloid cells to cytokines
How do changes in the blood flow in the liver cause anaeamia of chronic disease?
Liver disease has many associated blood changes
Increases portal hypertension:
How do changes in portal hypertension occur in chronic liver disease?
- Increase in resistance bc the blood is not flowing through v well
- Increase in blood resistance from gut
- Backup of blood
- Enlarged spleen
How does portal hypertension cause splenomagaly?
- Causes splenomagaly
- Leading to sequestration of cells
- Because they are spending longer in spleen, more change for: Overactive removal of the cells
Describe the effects of esophageal and gastric varices in chronic liver disease
- Portal hypertension also leads to esophageal and gastric varices (back up of blood)
- Can have little bleeds chronic bleeds or massive bleeds
- Clotting factors are produced in the liver – more susceptible to bleeding
- Causes blood loss
- Endothelial dysfunction
- Thrombocytopenia
- Defective platelet function - platelets don’t work as well as they should do due to
What is Zeive’s syndrome?
- Acute haemolytic anaemia
- Associated with the changes in lipid in the cell membrane for patients with liver disease
- This alters the shape of the cells > leading to macrocytosis, target cells and can lead to haemolysis
Describe how Thrombocytopaenia in Liver disease arises
- Liver produces thrombopoetin
- Impaired production as thrombopoietin is made in the liver
- Splenic pooling - because of splenogomagaly
- Increased destruction - platelets don’t work properly
Describe the three other main haematological features of liver disease?
- Alcohol excess - toxic to bone marrow cells; secondary malnutrition (folic acid deficiency)
- Hepatitis - because of bone marrow failure
- Immune - immune mediated anaemia
Explain why low/ high WBC count arises from liver disease
Low
- Impaired production (iron or folate deficiency, alcohol toxicity)
- Splenic pooling
- Increased destruction
High: steroids
Explain why low/ high WBC count arises from liver disease
Low
- Impaired production (iron or folate deficiency, alcohol toxicity)
- Splenic pooling
- Increased destruction
High: steroids
Explain why low/ high platelet counts arise from liver disease
Low
- Impaired production (iron or folate deficiency, alcohol toxicity)
- Splenic pooling
- Increased destruction
High:
- Bleeding
How do post operative changes cause anaemia?
- Following major surgery patients often have a mild thrombocytosis or neutrophilia which should settle.
- Anaemia can be present due to blood loss or dilution
Describe how post operative changes would affect RBC, WBC and platelet counts
RBC
- Low - Bleeding
- High - Dehydration
WBC
- Low - infection/ sepsis; high: sepsis
Platelet count
- High: Bleeding, Infection, Reactive
- Low: Medication (heparin); sepsis; DIV
Give some examples of anaemia of chronic disease
- Chronic kidney disease/ chronic renal failure
- Rheumatoid arthritis
- Liver disease
- Post op reactive changes
- Infection
Outline some haematological changes associated with infection?
What term would be used to describe a blood film where Granulocyte precursors and nucleated RBCs are present?
Leucoerythroblastic film
Describe the effects of ureaemia in kidney dysfunction
Kidney dysfunction can result in uraemia (as they can’t excrete urea as efficiently) an increase in urea concentration in blood acts to inhibit erythropoiesis and reduces the lifespan of existing red blood cells as well as inhibiting platelet function, which can cause chronic bleeding from the gastrointestinal tract.
