6. Spleen and WBC's Flashcards
What is the function of white pulp?
Immune function -similar to lymphoid follicles.
WBC pass through
What is the structure and function of red pulp?
Sinuses lined by endothelial macrophages, RBC pass through and old or damaged cells are removed.
Why are weight loss and a feeling of abdominal fullness signs of splenomegaly?
As spleen enlarges, it presses on the stomach and causes a feeling of abdominal fullness.
What are the 4 main functions of the spleen in adults?
- Sequesters and phagocytosis of old/abnormal red cells
- Blood pooling - secondary reserve in bleeding
- Extramedullary haematopoiesis - if marrow fails
- Immunological - T cells and B cells
What are some causes of splenomegaly?
- Back pressure - portal hypertension in liver cirrhosis
- Over-working red pulp - haemolytic anaemia
- Over-working white pulp - infection
- Infiltration of abnormal cells - cancer
- Infiltrated by other material
Which infection causes massive splenomegaly, why?
Malaria. It infects red blood cells, so increased red pulp workload as well as T and B cell proliferation.
What type of anaemia causes hypospenism?
Sickle cell anaemia, as it leads to blocked microvasculature and infarction of the spleen.
What would you expect to see on a blood film in a patient with hyposplenism?
Howel-Jolly bodies (dark purple dots) which are DNA remnants
If a neutrophil has >5 lobes, what could this indicate?
Vitamin B12 deficiency
What controls neutrophil maturation?
G-CSF
Which immature neutrophil is the only one you should see in peripheral circulation?
Band cells (non-lobed)
Under what conditions would you see less mature neutrophils such as myelocytes in the peripheral circulation?
Sepsis - neutropenic so bone marrow released cells prematurely.
What can you administer to patients with severe neutropenia after sepsis or chemotherapy?
G-CSF
What does G-CSF do?
Increases neutrophil production
Accelerates release of mature cells from bone marrow
Enhances chemotaxis
Enhances phagocytosis of pathogens
What are causes of neutropenia?
Immune destruction
Sepsis
Chemotherapy
Splenic pooling
What would the presence of Howell-Jolly bodies in circulating red blood cells be a sign of?
Damaged or absent spleen because a healthy spleen would normally remove this type of defective red blood cell.
What single term is used to describe the condition of low red blood cells, low white blood cells and low platelets?
Pancytopenia
What can cause pancytopenia?
Hypersplenism - pooling of the blood in an enlarged spleen
What are the complications associated with splenomegaly?
Rupture and haemorrhage
Infarction - wedge shaped
What are some common causes of neutrophilia?
Infection (bacterial) Tissue damage - post op Acute inflammation Cancer - enhanced cytokines Drugs - steroids Smoking Acute haemorrhage
What are some causes of neutropenia due to increased removal or use?
Splenic pooling
Immune destruction
Sepsis
What are some causes of neutropenia due to decreased production?
B12/folate deficiency Infiltration of bone marrow by malignancy or fibrosis Aplastic anaemia Radiation Drugs - chemotherapy Viral infections
What are the consequences of neutropenia?
Severe life threatening bacterial infection/fungal infection
Mucosal ulceration
What are some causes of monocytosis?
Chronic inflammatory diseases -RA, SLE, Crohn’s,UC
Chronic infection - TB
Carcinoma
Myeloproliferative disorders
What is the function of eosinophils?
Mediate allergic responses and hypersensitivity reactions - e.g asthma, skin inflammation
Release granules containing arginine, phospholipid and enzymes
Parasitic infections
When might eosinophilia occur?
Hodgkin’s lymphoma
ALL, AML
Myeloproliferative conditions
What is the function of basophils?
Allergic reactions and inflammatory conditions
Granules contain - histamine, heparin, hyaluronic acid, serotonin
When might you see basophilia?
Immediate hypersensitivity reactions
UC, RA
Myeloproliferative diseases
What are reactive causes of lymphocytosis?
Viral infections Bacterial infections Stress related-MI Post splenectomy Smoking
What are some malignant causes of lymphocytosis?
Lymphoma
Chronic lymphocyte leukaemia
What are the symptoms of pancytopenia?
Anaemia - fatigue, dizziness, chest pain, shortness of breath
Thrombocytopenia - bleeding, bruising
Neutropenia - infection, ulcers, fever
