The Spleen, WBCs, Cytopenia Flashcards
Describe the role of the spleen
Secondary reserve of blood,
sequestrian, phagocytosis,
extrameduallary haemopoiesis,
immunological function (T, B cells)
What are the causes for splenomegaly
most commonly malaria = spleen over working (immune response/RBC removal – anaemic).
Cancer = infiltration of abnormal cells (e.g. CLL – expansion of white cell nodules).
Granulomas present (sarcoidosis, TB).
Back pressure = portal hypertension.
Outline palpating the spleen
Should never be able to palpate.
Start at the RIF (right iliac fossa), feel for spleen edge, move towards your hand on inspiration, feel splenic notch, measure in cm
What is hypersplenism?
Dilutional effect = blood in the spleen for a longer amount of time = pancytopenia or thrombocytopenia
What is the clinical significance of splenomegaly
Compressed stomach,
rupture (very dangerous),
trauma = haematoma around spleen,
infarction of infarct spleen tissue due to small capillary damage ~ asplenic
What is the clinical significance of hyposplenism
Lack of functioning splenic tissue
Cause = splenectomy, sickle cell disease (infarcts then fibrosis), coeliac disease.
VERY high risk of sepsis
What 3 MO are important to vaccine against in a patient who is hyposplenic?
Pneumococcus,
Haemophilus influenzae,
Meningococcus
Describe the common causes of leucocytosis
Increase in WBCs = infection
Outline the common causes of leucopenia
Low WBC count = acute viral infect, chemo, radiation, aplastic anaemia
What does multi lobes neutrophils signify?
B12 def
Describe the common causes and clinical significance of neutropenia
Low neutrophil count
immune destruction, viral infection, sepsis, splenic pooling, reduced prod (B12/folate def, cancer, aplastic anaemia, radiation, drugs)
What is the most common cause of neutropenia by reduced prod?
Viral infection
What are the clinical consequences of neutropenia?
Severe life threatening bacterial infect, fungal infection, mucosal ulceration
What are the causes of neutrophilia?
High neutrophil count = bact infection, tissue damage, cancer, steroids, acute haemorrhage, myoproliferative disease, high G-CSF (cytokine), smoking
Describe lymphocytosis
High lymphocyte count = viral infect, bacterial infect, stress, post splenectomy, smoking, CLL, lymphoma (cell spill out of infiltrated bone marrow)
Outline eosinophilia
Increased eosinophils = allergy, drugs, parasites, leukaemia
What is pancytopenia?
Lowering of all cells = reduced prod (B12/folate def, malignancy, marrow fibrosis, aplastic anaemia, radiation, drugs, viruses) OR increased removal (haemophagocytosis)
Outline the differential diagnosis in a patient with a raised haemoglobin concentration
Smoking, live at higher altitudes, poor lung function, EPO doping, increased RBC prod
What are the clinical/lab features that help distinguish polycythaemia vera from other causes of a high [Hb]?
= neoplasm of bone marrow
high RBCs/WBCs/platelets. Low EPO. Itching (abnormal histamine release), red/blue skin, headaches, erthromelalgia = peripheral pain by increased platelets/tiny clots
In a centrifuged blood sample where would you find the highest conc of neutrophils?
Buffy coat
How many femtolitres are in a L?
10^15
Which artery supplies the spleen?
Splenic artery
What would the presence of Howell-Jolly bodies indicate?
A damaged spleen
These cell contain DNA remains which have normally been expelled = damaged spleen not removing abnormal RBCs
