MT3 Flashcards
which bones in adults are generally responsible for hemotopoiesis?
long bones
buffy coat
lies between the layer of plasma and the layer of RBCS when blood is centrifuged. Contains WBCs and platelets
RBCs circulate for ____ days
120
RBCs are recycled in ____
spleen
Hb consists of:
4 heme groups and 4 globins
Hb synthesis requires (4)
iron
vit B12
vit B6
folic acid
Platelets are also called
thrombocytes
Generally speaking, anemia means…
low blood
Hb is below normal levels
anemia may be associated with (3)
hint: 3 forms anemia can take
different appearance of Hb
Reduced number of RBCs
Structural abnormalities in RBCs
Anemia may be a consequence of (3)
decreased hematopoiesis
abnormal hematopoiesis
Increased loss or destruction of RBCs
Anemias due to decreased hematopoiesis resulting from bone marrow failure
Aplastic anemia (bone marrow doesn't work) Myelophthisic anemia (something replacing bone marrow)
Anemias due to decreased hematopoiesis can also be caused by deficiencies in which nutrients?
vit B12, folic acid (megaloblastic anemia)
Protein deficiency
An example of anemia caused by abnormal hematopoiesis
sickle cell anemia (genetic cause)
Anemia can be the result of increased loss and destruction of RBCs.
What are some signs of this? (4)
- bleeding
- intrasplenic sequestration
- immune hemolysis
- infections (malaria)
Aplastic Anemia
- cause
- what happens
- results
- Idiopathic, secondary
- Bone marrow depleted of hematopoietic cells; consists only of fibroblasts, fat cells, scattered lymphocytes
- Leads to anemia, leukopenia, thrombocytopenia.
- Leads to uncontrollable infections, bleeding tendency, chronic fatigue, sleepiness, weakness
Which is the most common form of anemia?
iron deficiency anemia
Iron deficiency anemia
- prevalence
- appearance
- Etiology
- Most common form of anemia
- hypochormic (pale red cells), microcytic (small red cells) anemia
Etiology:
- Increased loss of iron
- inadequate iron intake/absorption
- increased iron requirements
Megaloblastic anemia is caused by:
deficiency of vitamin B12 or folic acid
Megaloblastic anemia caused by vit B12 deficiency occurs due to…
Pernicious anemia
lack of gastric intrinsic factor
atrophic gastritis
Megalobalstic anemia caused by folic acid deficiency occurs due to…
Inadequate intake in diet or malabsorption caused by intestinal disease
Megaloplastic anemia:
What does it lok like
Bone marrow is hypercellular, with numerous megaloblasts
Peripheral blood shows macrocytic anemia.
Neutrophils are hypersegmented (5+ nuclei)
Sickle Cell Anemia etiology
Substitution of glutamic acid for valine
Synthesis of abnormal beta chain of globin.
Most prevalent among african americans
Sickle Cell Anemia results in
- Multiple infarcts in various organs (neuro, sharp pains in bones, sleep, extremities)
- Hyperbilirubinemia, jaundice (bile stones)
- Delayed neuro dev (can be avoided medically)
- Cardiopulmonary insifficiency
- Recurrent infections
Thalassemia
- etiology
- genetic defect in synthesis of HbA resulting in reduced rate of globin chain synthesis.
No abnormal Hb produced. Just a slower rate.
Thalessemia minor vs major
minor - just the thalessemia trait. Heterozygotes with mild, nonspecific symptoms and asymptomatic.
major - homozygots. Severe, serious disease. Develop antibodies.
Beta-thalessemia vs alpha-thalessemia
Reduced sythesis of beta chain vs alpha chain of globin
Thalessemia presentation
- hypochromic (pale RBCs)
- Splenomegaly, heosiderosis, heptomegaly
- Compensatory hyperplasia of BM
- Calvarium ‘crew-cute’ hair
- Hyperbilirubinemia, jaundice
- Chronic and slows growth in children
- Intellectual development impaired
- Cardiorespiratory insufficiency
Hemolytic Anemia is caused by
destruction of RBCs (hemolysis)
Intracorpuscular defects of hemolytic anemia
Defects within the cell.
- Structural abnormalities, sickle cells, thalessemia, hereditary spherocytosis
- Infection (malaria)
Extracorpuscular defects in hemolytic anemia
- ANtibodies, infectious agents, mechanical factors
- Autoimmune hemolytic anemia, hemolytic disease of the newborn, transfusion reactions
symptoms of hemolytic anemia
- anemia
- compensatory RBC hyperplasia in BM
- hyperbilirubinemia, jaundice
Immune mediated anemias
Mediated by antibodies that destroy RBCs.
- Autoantigens, alloantigens, neoantigens
- Might be a mismatched blood transfusion, hemolytic disease of the newborn, or autoimmune disease.
Polycythemia vera
What is it?
Primary vs secondary.
Increased number of RBCs
PRIMARY - prolif of hematopoietic stem cells / uncontrolled prod of RBCs
SECONDARY - Increased RBC volume as a result of increased bone marrow caused by increased EPO. Usually caused by prolongued hypoxia (high altitudes)
Polycythemia symptoms
- hypertension
- dark red, or flushed face
- headaches, visual problems, neurologic symptoms
- Splenomegaly
- Hypercellular BM
4 leukocytic disorder
Leukopenia
Leukocytosis
Lymphoma
Leukemia
Leukopenia
Too few WBCs
- Neutropenia: bacterial infections or drugs (closapine)
- Lymphopenia: Some infections
Leukocytosis
Characterized by (1)
Types (4)
Symptoms (2)
- Too many WBCs
- Neutrophilia - bacterial infection
- Eosinophilia - allergies, skin diseases, parasitic infections
- Lymphocytosis - viral infections, chronic infections, some autoimmune
- Splenomegaly lymphadenopathy
Plasma cell myeloma
Malignant disease of plasma cells; lots of antibodies produced.
Leukemias are
Malignant diseases involving WBCs or their precursors in BM.
Two categories of leukemias
Myeloid - neutrophil, eosinophil, basophil
Lymphoid - B or T cells only
Etiology of leukemia
Bone marrow becomes overrun with leukemia cells. More immature blood cells in peripheral blood.
Bone marrow isn’t working properly so RBCs, WBCs, and platelets aren’t made normally.
Leads to anemia, infections, and bleeding/difficulties clotting.
Acute Lymphoblastic Leukemia
- prevalence
- origin
- pathology
- treatment
- prognosis
- Most common leukemia in children
- Almost always B cell origin
- Massive infiltration of bone marrow, peripheral blood, bleeding into skin/internal organs
- Chemo –> 90% cure
- Higher incidence of developing other cancers + social issues from young illness
Acute Myelogenous Leukemia
- origin
- how many abnormal cells?
- prognosis?
- Clonal proliferation of myeloid precursors in BM
- 20% abnormal cells (cytogenic abnormalities)
- Death 6 months after onset without treatment.
Chronic Myelogenous leukemia
- origin
- pathology
- phases
- treatment
- Philadelphia chromosome with BCR-ABL rearrangement
- BM and peripheral blood overrun with neutrophils and their precursors
- (1) chronic phase, (2) accelerated phase, (3) blast cells
- treat with tyrosine kinase inhibitors
Chronic Lymphocytic Leukemia
- origin
- populations
- diagnosis
- Almost exclusively B cells
- Most patients older than 50
- Lymphocytes > 5000/mL for diagnosis
Lymphomas are…
lymphoid cell malignant diseases predominantly involving lymph nodes.
Malignant cells infiltrate lymph nodes, spleen, thymus, or bone marrow. May involve other organs.
Lymphomas generally metastasize to
brain or spleen
Lymphomas - age groups
Can affect any age group.
More common in adults, more aggressive inkids.
Two categories of lymphomas are:
Non-Hodkin’s Lymphoma (B, T, NK cells)
Hodgkin’s Lymphoma (B cells)
Non-Hodgkin’s Lymphomas (generally)
- No benign lymphomas
- Most have B-cell phenotype
- All age groups (more common in adults, more aggressive in children)
- Can spill over into blood and present as leukemia
- Involve lymph nodes, BM, spleen, thymus, but can be of extranodal origin.
Diagnosis of Non-Hodgkin’s Lymphomas
- Light microscopy
- Ancillary techniques: immunochemo, flow cytometry, cytogenic analysis
- Clinical features: lymph node/spleen/liver enlargement, systemic constitutional symptoms (FNW), extranodal tumor spread.
Follicular Lymphoma
- prevalence
- characterstics
- Most common lymphoma in USA
- Slow growing
- Presents as long-standing enlargement of lymph nodes, mild constitutional symptoms
Diffuse Large-Cell Lymphomas
- what do the cells look like?
- Prognosis?
- Most aggressive Non-Hodgkin’s Lymphoma
- Tissue infiltrated by large lymphoid cells with irregular nuclear outlines, prominent nucleoli
- Complete remission in 75% of patients
Burkitt’s Lymphoma
- Highly malignant tumor of B-cells
- Extranodal masses more prominent than enlarged lymph nodes
Burkitt’s lymphoma: Endemic ariant
sub-saharan africa, children infected with epstein-barr virus experience mandible and soft tissue involvement
- Sporadic and endimic variants.
Most can be cured
Burkitt’s Lymphoma: Sporadic variant
Children and young adults most affected.
Abdominal masses
Hodgkin’s Lymphoma
- Populations
- histology
- Bimodal age distribution: Peaks at 25 and 55
- REed-Sternberg cells: bilobed nucleus, prominent nucleoli with clear halo
Five types of Hodgkin’s Lymphoma
- Nodular sclerosing
- Lymphocyte predominant
- Lymphocyte rich
- Mixed cellularity
- Lymphocyte depleted.
Hodgkin’s Lymphoma: Clinical Features
- Enlarged lymph nodes
- ## Extranodal involvement, leukemic spread (rare)
Plasma Cell/Multiple Myeloma
- populations
- how it works
- prognosis
- Most patients >45
- Malignant plasma cells proliferate in bone marrow
- Punched-out holes/lytic lesions in calvaria vertebrae
- Hypercalcemia (turn on osteoclast function)
- Renal failure (too much antibody)
- Anemia, leukopenia
- Death <3-4 years after diagnosis
Plasma Cell/Multiple Myeloma:
Diagnosis based on… (4)
- X-rays (lytic lesions)
- Serum electrophoresis (monoclonal spike)
- Bone marrow biopsy (neoplastic plasma)
- Clinical presentation
Edema - what is it (simply)
Too much fluid in tissues
Components of blood
Water
Electrolytes
Cells: RBCs, WBCs, platelets
Proteins: albumin, coagulation proteins, others
Albumin
Maintains oncotic pressure
Made by liver
Important in transportation (steroids, bile salts, FAs etc)
Two main drivers of fluid across capillary walls:
- Capillary Hydrostatic pressure
2. Capillary Oncotic Pressure
Capillary Hydrostatic pressure
pressure from heart pumping and the weight of blood
Capillary oncotic pressure
Albumin normally stays inside the capillary; only water and electrolytes can freely cross.
Typical fluid movement across capillary walls, to tissues and then to lymphatic channels
At first the hydrostatic pressure drives fluid out.
Hydrostatic pressure decreases toward venous side, becomes less than oncotic pressure and fluid is returned to the capillary. Small amounts of fluid enter lymphatic channels
Pericytes
Vascular supportive cells that are on the outside of capillary walls
Flow in the lymphatic system from extremities
Extremities -> lymph nodes -> thorax -> thoracic duct / right lymphatic duct ->venous system
Flow through a lymph node
afferent lymphatic vessel -> subcapsular sinus -> efferent lymphatic vessel
Causes of LOCALIZED edema (3)
- Ischemia
- Infection
- Lymphatic obstruction
How does ischemia cause localized edema?
Irreversible cell injury -> lysed cells release mediators that promote capillary leakage.
Fluid leaves leaky capillaries, overwhelms lymphatics, and accumulates in tissues.
How does infection cause localized edema?
Neutrophils/WBCs release mediators that cause capillaries to get leaky.
Two examples of infection that cause edema
- IMPETIGO
- CROHN’S DISEASE: presents with dilated lymphatics in the ileum because they are trying to drain local edema caused by inflammation there.
How does lymphatic obstruction cause localized edema?
Normally, lymphatic system removed fluid from tissues and eventually drains into thoracic duct/right lymphatic duct to return to venous system.
Blockage or damage of a lymphatic vessel or node with cause edema in the area corresponding to it
Example of localized edema caused by lymphatic obstruction.
Breast Carcinoma Therapy:
- Axillary lymph node dissection (for treatment and/or tumor staging)
- Radiation
- Arm edema results from surgical removal of axillary lymph nodes and radiation of axilla.
Two mechanisms by which capillaries can become leaky
- Endothelial cell retraction (in response to chemical mediators; reversible)
- Endothelial cell injury (more sever damage results in endothelial cell necrosis and detachment; not reversible)
Leaky capillaries allow for ______ to escape, and water to follow.
Hint: normally kept within capillaries
albumin
Causes of SYSTEMIC edema
- Heart failure
- Kidney Disease
- Liver failure
Heart failure - what is it (simply)
heart is unable to pump enough blood to adequately perfuse tissues
How does left heart failure result in systemic edema?
Pressure increases in pulmonary veins, building pulmonary hydrostatic pressure. Fluid enters lung tissue (usually at base of lungs).
What is a clinical red flag for systemic edema caused by left heart failure?
Pulmonary edema -> you can hear crackles with a stethascope at base of lungs
How does right heart failure cause systemic edema?
Pressure increases in vena cavae -> hydrostatic pressure increases in systemic capillary bed, causing fluid to enter systemic tissues (usually seen in legs).
Pitting edema
Pressing on skin will leave an indentation. A presentation of systemic edema caused by right heart failure.
Systemic edema caused by heart failure leads to fluid build up in the bottom of lungs and legs. This is due to what?
Gravity
How does kidney disease cause systemic edema?
Normal kidneys don’t allow albumin to cross the glomerular basement membrane.
Diseased kidneys allow albumin to be filtered and released in urine.
Albumin concentration in the blood gets too low, thereby decreasing oncotic pressure. Hydrosatic pressure stays the same, so fluid will not return to the capillaries and will accumulate in tissues.
How does liver failure cause systemic edema?
Liver isn’t producing enough albumin so oncotic pressure in systemic circulation drops. Hydrostatic pressure stays the same so fluid is driven out of capillaries and accumulates in tissues.
Two forms that liver failure can take
Liver failure can be (1) not producing enough albumin, or (2) not producing enough clotting factors.
thrombus
a blood clot
Composed of platelets and fibrin. Entraps RBCs and WBCs.
Thrombo-embolus
a piece of thrombus breaks off and travels elsewhere in the body.
Hypercoagulable state
Condition in which blood clots form very easily
Atrial fibrillation
Disease of the heart where the atria have irregular twitchings.
Hemostasis
= coagulation
The process of thrombus formation at site of blood vessel injury to make bleeding stop.
Three major components that control thrombus formation
Endothelial cells
Platelets
Coagulation cascade
Process of thrombus formation
Damage to endothelium causes platelets to adhere;
Platelets aggregate and form a plug at the site of injury;
Coagulation cascade: Thrombin cleaves fibrinogen into fibrin, which stabilizes the platelet plug;
Platelets and fibrin form thrombus. They form laminations (layers) and trap RBCs.
Where to platelets come from
Megakaryocytes in bone marrow produce platelets and release them into the blood. Platelets are tiny fragements of megokaryocyte cytoplasm.
Pathologic thrombi can be caused by (3)
- Endothelial cell injury
- Poor blood flow
- Hypercoagulable state
Causes of arterial thrombi
- Atherosclerosis - hardening of the arteries; thrombi can form on plaques and then can break off
- Atrial Fibrillation - Uncoordinated chaotic contraction of atria resulting in areas of irregular blood flow (vulnerable for thrombus formation)
How atrial fibrillation causes arterial thrombi
Uncoordinated chaotic contraction of atria resulting in areas of irregular blood flow (vulnerable for thrombus formation)
Thrombi can develop on surface of left atrial appendage. These thrombi can break loose, embolize and cause infarction.
Consequences of arterial thrombi (3)
Myocardial infarction
Cerebral infarction
Kidney infarction
Venous stasis
- what is it?
- where is it most common?
- risk factors?
poor blood flow
- most common in leg veins
- immobilization is a risk factor (long distance air travel, surgery)
Causes of venous thrombi
- Venous stasis
- Cancer (hypercoagulable state)
- Pregnancy
- Inherited thormbophilia
Pregnancy - a cause of venous thrombi?
Pro-coagulent changes with pregnancy are part of preparation for delivery (prevent excess hemorrhaging)
Inherited thrombophilia
Hypercoagulable state that causes venous thrombi;
Genetic abnormalities in coagulation proteins;
Potential thromboembolic consequences of venous thrombi
pulmonary emboli - venous thrombi end up in the lungs when they break. Leads to pleural infarction.
SHOCK
Circulatory failure that results in poor tissue perfusion resulting in cellular hypoxia
Three types of circulatory failure (shock)
- Cardiogenic shock
- Hypovolemic shock
- Septic shock
Cardiogenic shock
Eg: myocardial infarction, other heart pathology
Tissues aren’t getting enough blood because of heart pump failure.
Hypovolemic Shock
Eg: Trauma (blood loss)
Tissues aren’t getting enough blood because there is not enough blood volume.
Septic Shock
Shock associated with systemic inflammatory response, usually infection;
Systemic inflam response causes vasodilation. Tissues don’t get enough blood because peripheral blood vessels are markedly dilated.
Complications of shock (2)
- Acute respiratory distress syndrome
2. Disseminated intravascular coagulation
Acute Respiratory Distress syndrome
A common complication of shock;
Damage to pulmonary capillary endothelium and alveolar epithelium causes edema to enter alveoli;
Damage secondary to many things;
Other causes: aspiration, pancreatitis, smoke/toxic gas inhalation;
ACUTE phase - alveolar edema;
Later phases - progression to hyaline membranes and thickened alveolar walls. Resolve to normal function.
Disseminated Intravascular Coagulation
Complication of shock;
Caused by excessive activation of coagulation and formation of thombi in microvasculature of the body;
Causes consumption of coagulation factors and platelets, which can then lead to bleeding in other parts of the body (brain, kidneys, GIT etc);
Bones in adults
206
12% body weight
10% replaced annually
Periosteum
outer layer of bone
cortical bone
outer bone layer
thick, strong
Medullary bone
Inner bone layer
reticular, lace-like, not as strong
Epiphysis
end of a long bone
associated with cartilage cap and joint
Metaphysis
contains the growth plate; changes radically during growth
Diaphysis
Central portion of long bone
The two kinds of bone formation
Endochondral ossification
Intramembranous ossification
Endochondral ossification
- Begins in the Reserve Zone.
- Chrondrocytes proliferate in the Proliferative Zone
- Hypertrophy Zone - condrocytes hypertrophy and die, leaving spaces for blood and osteoblasts to move in.
- Mineralization Zone.
- Medullary Bone.
Functions of bones (4)
Support muscles / facilitate movement;
Protect organs;
Site of BM (hematopoiesis);
Storage of Ca and phosphate;
Vitamin D controls…
Increased Ca absorption by intestine;
Resorption of Ca by kidney;
Storage of Ca and phosphate;
What can cause a vitamin D deficiency?
Lack of exposure to sunlight;
Inadequate intake;
Abnormal intestinal absorption;
Osteopenia (osteomalacia)
Decreased mineralization (calcification of bones)
- Bones are soft, pliable
- Increased fractures
- Rickets (in children)
Rickets
Decreased ossification of new bone in growth plates with failure to grow, bone deformities, fractures
Osteoporosis
- What is it?
- What is the effect?
- What causes it? Primary vs Secondary
- Reduction of bone mass. Cortical and medullary bone are lost.
- Fracture risk increases (commonly in vertebrae, hips, distal radius)
Often multifactorial
- PRIMARY: Idiopathic (older age, menopause, lifestyle, low initial bone mass are risk factors)
- SECONDARY: Due to an identifiable cause (hormone imbalance, dietary insufficiency, drugs, tumours, immobilization)
Complete fracture
through entire thickness of bone
Incomplete fracture
Partial thickness of bone affected
Simple fracture
just one fracture
Comminuted fracture
multiple fractures
Closed fracture
skin is intact
Compound fracture
skin has been broken (more likely to be infected)
Complicated fracture
infected fracture
Pathologic fracture
Due to abnormal bone (osteoporosis, tumour)
The process of fracture healing
- HEMORRHAGE: Blood fill the gap left by fracture, and clots
- GRANULATION TISSUE: Inflam cells, fibroblasts, and new capillaries use blood clot framework to ingrow
- Soft tissue is transformed into WOVEN BONE
- As bone matures, and is subject to physical stress / weight-bearing, remodeling occurs
Granulation Tissue
Blood clot with invasion of new vessels and inflammatory cells. This is the second stage of fracture healing.