Medicine- haem/ onc Flashcards
Best initial test for ?leukemia
CBC with smear showing blast cells
Auer rods are characteriestic of what?
AML subtype M3
Most accurate test for leukemia
BM biopsy with flow cytometry
Who tends to get CLL?
Older people, M>F
What are the characteristic cells of CLL?
Smudge cells (fragile leukemia cells crushed by the slide)
What are Reed Sternberg cells associated with?
Hodgkin lymphoma
What is this?
Dense metaphyseal lines which are associated with lead poisoning
Lead limits in blood
The Centers for Disease Control (US) has set the upper limit for blood lead for adults at 10 µg/dl (10 µg/100 g) and for children at 5 µg/d
Signs of lead poisoning on blood smear
Patients with lead poisoning will often show basophilic stippling (it’s not unique to lead poisoning though). Microcytosis and hypochromia may be present, and reticulocyte counts may be elevated
What does LMWH affect in the coagulation pathway and how do you monitor it?
LMWH does not require routine monitoring because it exerts its effect on factor Xa in the coagulation pathway, which is not tracked by the PT/INR or aPTT
When is Haemoglobin F seen?
Haemoglobin F dominates until about 6 weeks of age
Pattern of inheritance sickle cell anemia
Autosomal recessive
The genetic defect in sickle cell anemia
Chromosome 11
The gene defect is a single nucleotide mutation (GAG codon changing to GTG) of the β-globin gene, which results in glutamic acid (E/Glu) being substituted by valine (V/Val) at position 6 (E6V substitution). Haemoglobin S with this mutation is referred to as HbS, as opposed to the normal adult HbA.
(Note that sickle cell anemia is specific to β-globin)
Diagnosis of sickle cell anemia
- Hb electrophoresis
- Confirm with high-performance liquid chromatography
Over the course of two months, a 62-year-old man developed numbness and a “pins and needles” sensation in his hands, had trouble walking, experienced severe joint pain, began turning yellow, and became progressively short of breath
What’s the most likely diagnosis?
Vitamin B12 deficiency
Characteristics of pernicious anemia
Anemia with bone marrow promegaloblastosis (megaloblastic anemia). Due to the inhibition of DNA synthesis (specifically purines + thymidine).
Gastrointestinal symptoms: alteration in bowel motility, loss of bladder or bowel control.
Neurological symptoms: Sensory or motor (absent reflexes, diminished vibration or soft touch sensation), subacute combined degeneration of spinal cord, or seizures.
Deficiency symptoms in children include: developmental delay, regression, irritability, involuntary movements and hypotonia.
What does this show?
Peripheral blood smear showing hypersegmented neutrophils, characteristic of megaloblastic anemia.
What does megaloblastic anemia result from?
Inhibition of DNA synthesis during red blood cell production.
When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis.
What is the pathological state of megaloblastosis is characterized by?
The pathological state of megaloblastosis is characterized by many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow and also by hypersegmented neutrophils (defined as the presence of neutrophils with six or more lobes or the presence of more than 3% of neutrophils with at least five lobes).
These hypersegmented neutrophils can be detected in the peripheral blood (using a diagnostic smear of a blood sample).
Causes of Vitamin B12 deficiency
- Achlorhydria-induced malabsorption
- Deficient intake
- Deficient intrinsic factor- required for B12 absorption (pernicious anemia or gastrectomy)
- Coeliac disease
- Biological competition for vitamin B12 by diverticulosis, fistula, intestinal anastomosis, or infection by the marine parasite Diphyllobothrium latum (fish tapeworm)
- Selective vitamin B12 malabsorption (congenital—juvenile megaloblastic anemia 1—and drug-induced)
- Chronic pancreatitis
- Ileal resection and bypass
- Nitrous oxide anesthesia (usually requires repeated instances).
How to differentiate between B12 and folate deficiency
A measurement of methylmalonic acid (methylmalonate) can provide an indirect method for partially differentiating Vitamin B12 and folate deficiencies
Megaloblastic anemia blood film
- Decreased RBC count and Hb levels
- Increased MCV, >100 fL and mean corpuscular hemoglobin (MCH)
- Normal mean corpuscular hemoglobin concentration (MCHC, 32–36 g/dL)
- Decreased reticulocyte count due to destruction of fragile and abnormal megaloblastic erythroid precursor.
- The platelet count may be reduced.
- Neutrophil granulocytes may show multisegmented nuclei (“senile neutrophil”). This is thought to be due to decreased production and a compensatory prolonged lifespan for circulating neutrophils, which increase numbers of nuclear segments with age.
- Anisocytosis (increased variation in RBC size) and poikilocytosis (abnormally shaped RBCs).
- Macrocytes (larger than normal RBCs) are present.
- Ovalocytes (oval-shaped RBCs) are present.
- Howell-Jolly bodies (chromosomal remnant) also present.
Intrinsic causes of hemolytic anemia
Defects of red blood cell membrane production (hereditary spherocytosis and hereditary elliptocytosis).
Defects in Hb production (thalassemia, sickle-cell disease and congenital dyserythropoietic anemia).
Defective red cell metabolism (glucose-6-phosphate dehydrogenase deficiency and pyruvate kinase deficiency).
Paroxysmal nocturnal hemoglobinuria (PNH) (Marchiafava-Micheli syndrome)- a rare, acquired, potentially life-threatening disease of the blood characterized by complement-induced intravascular hemolytic anemia.
How do schistocytes form?
Schistocyte formation occurs as a result of mechanical destruction (fragmentation hemolysis) of a normal red blood cell
Describe the direct and indirect Coombs test
Coombs test, aka antiglobulin test (AGT) is either of two blood tests used in immunohematology. They are the direct and indirect Coombs tests. The direct Coombs test detects antibodies that are stuck to the surface of RBCs and is useful in diagnosing autoimmune hemolytic anemia. The indirect Coombs detects unbound antibodies to RBCs that are floating freely in the blood. This test can be done to diagnose reactions to a blood transfusion.
Abnormality on electrophoresis in beta thalassemia
The expected pattern on hemoglobin electrophoresis in people with beta-thalassemia is an increased level of hemoglobin A2 and slightly increased hemoglobin F
Management of beta thalassemia
Long-term transfusion therapy to maintain the patient’s hemoglobin level above 9-10 g/dL (normal levels are 13.8 for males, and 12.1 for females)
Iron chelation to reduce iron overload (Deferasirox)
The 5 features of thrombotic thrombocytopenic purpura
Microangiopathic hemolytic anemia
Thrombocytopenic purpura
Neurologic abnormalities (changes in mental state)
Fever
Renal disease (check creatinine)
You have to start treatment when the factors in bold are present
Detection of microangiopathic hemolytic anemia in TTP
Identify schistocytes on peripheral blood smear
Other abnormalities include elevated indirect bilirubin, increased LDH, low haptoglobin, increased reticulocyte count
What is diphyllobothrium latum doing in a deck of haematology cards?
It is a fish tapeworm that causes vitamin B12 deficiency and megaloblastic anemia.
I don’t make this shit up, it was on Canada QBank
What happend to clotting parameters and LFTs in TTP?
They are normal
What is elevated methylmalonic acid associated with?
B12 deficiency
What’s the most characterisitc lab finding in hemolytic anemia?
Reticulocytosis
Diagnostic test for hereditary spherocytosis
Osmotic fragility test
What are poikilocytes associated with?
Iron deficiency anemia and myelofibrosis
What’s the treatment of choice for TTP?
Plasmapheresis with FFP- this has reduced mortality from 90% to about 10%
What’s the likely cause of a man of 23 being found with a prolonged aPTT and all other clotting parameters normal? Even if there is no bleeding history or family history?
Hemophilia A
The severity is variable and there isn’t always a known family history
What are the possible causes of microcytic anemia with low serum iron?
Iron deficiency or chronic disease
Assess bone marrow iron stores to differentiate
High levels of HbA2 suggest what?
Beta thalassemia trait
Low reticulocyte count in an elderly person with a chronic disease suggests what?
Anemia of chronic disease
Give people on Warfarin having massive GI bleeds what?
FFP
Don’t give what to people with TTP?
Platelets. They form platelet thrombi which can lead to end organ damage
Elderly man with hypochromic, microcytic anemia and is aymptomatic- what investigations?
Colonoscopy
Causes of microcytic anemia (4)
Iron LAST
Iron deficiency
Lead poisoning
Anemia of chronic disease
Sideroblastic anemia
Thalassemia
Microcytic anemia with low serum iron, low ferritin, and raised TIBC
Iron deficiency anemia
Virus associated with aplastic anemia in pts with sickle cell anemia
Parvovirus B19
What is a low serum ferritin diagnostic for?
Iron deficiency anemia
What are these cells?
Sideroblasts
Nucleated erythroblasts (precursors to mature red blood cells) with granules of iron accumulated in the mitochondria surrounding the nucleus. Normally, sideroblasts are present in the bone marrow, and enter the circulation after maturing into a normal erythrocyte.
Clotting paramaters in DIC: D-Dimers, PT, aPTT, Bleeding time
All increased
