The Spleen Flashcards
What is the red and white pulp made up of? And which components pass through each?
Red - sinuses lined by endothelial macrophages and cords. Red cells.
White - similar structure to lymphoid follicles. White cells and plasma.
Functions of the spleen
- Sequestration and phagocytosis
- Blood pooling (platelets and red cells can be rapidly mobilised during bleeding)
- Extramedullary haemopoiesis
- Immunological function
Hyposplenism causes, blood film
- Lack of functioning splenic tissue
- Splenectomy
- Sickle cell disease, due to multiple infarcts then fibrosis
- Coeliac disease
- Howell Jolly bodies seen in blood film
- Patients at risk of sepsis
Cytopenia and its different forms
- Reduction in the number of blood cells
- Anaemia (red cell)
- Leucopenia (white cell)
- Neutropenia (neutrophil)
- Thrombocytopenia (platelet count)
- Pancytopenia (red cell, white cell, and platelets)
Increase blood cell forms
- Erythrocytosis (red cell)
- Leucocytosis (white cell)
- Neutrophilia (neutrophil)
- Lymphocytosis (lymphocyte)
- Thrombocytosis (platelet count)
What is neutrophil maturation controlled by and what are its effects?
- Granulocyte colony stimulating factor (G-CSF)
- Increases production of neutrophils
- Decreases time to release of mature cells from bone marrow
- Enhances chemotaxis
- Enhances phagocytosis
When does neutrophilia occur?
- Infection
- Inflammation
- Cancer
- Smoking
- Myeloproliferative diseases
- Acute haemorrhage
- Metabolic/endocrine disorders
Neutropenia cell count
< 1.5 x 10^9 /L
Causes of increased use or removal of neutrophils in neutropenia
- Immune destruction
- Sepsis
- Splenic pooling
- Benign ethnic neutropenia
Causes of reduced production of neutrophils
- B12/folate deficiency
- Infiltration of bone marrow by malignancy or fibrosis
- Aplastic anaemia
- Radiation
- Drugs
- Viral infection
- Congenital disorders
Consequences of neutropenia
- Life threatening bacterial and fungal infections
- Mouth ulceration
Monocytosis occurs as a result of:
- Chronic inflammatory conditions
- Chronic infection
- Carcinoma
- Myeloproliferative disorders
Eosinophil functions
- Responsible for dealing with some parasites
- Mediators of allergic response
- Granules contain arginine, phospholipid, enzymes
- Phagocytosis of antigen antibody complexes
- Mediate hypersensitivity reactions
Basophils
- Active in allergic reactions and inflammatory conditions
- Dense granules contain histamine, heparin, hyaluronic acid, serotonin
Lymphocytosis
Reactive: - Viral and bacterial infections - Stress related (MI/cardiac arrest) - Post splenectomy - Smoking Lymphoproliferative - Chronic lymphocytic leukaemia (B cells) - T or NK cell leukaemia - Lymphoma
