3/11 hematology Flashcards
Pyruvate kinase deficiency (E)
- inheritance pattern?
- whats it causes?
- Autosomal recessive.
- rigid RBCs (lack of ATP) => extravascular hemolysis.
Why do RBCs need:
- NADH
- NADPH
- NADH: reduce naturally occuring MetHb => Hb.
- NADPH: reduce glutathione.
2,3-BPG level in PK deficiency?
- inc. 2,3-BPG
- PK is deficient to the substrates upstream of it will build up, which includes 2,3 BPG.
- This will shift oxy-Hb to the right and O2 will be unloaded easier. So these pts have a hard time carrying oxygen.
HbC defect
- whats the mutation?
- what type of hemolysis?
- Glutamic acid-to-lysine mutation at residue 6 in β-globin.
- extravascular hemolysis.
Whats worse, HbSC or HbSS?
HbSS is worse.
-full sickle cell.
Whats the problem in paroxysmal nocturnal hematuria (PNH)?
- Mutation in PIGA gene.
- Impaired synthesis of GPI anchor needed to flank the decay-accelerating factor that protects RBC/WBC/platelets against complement.
*DAF degrades C3 convertase.
PNH
- inheritance pattern?
- inc. incidence in what disease?
- Acquired mutation in a hematopoietic stem cell.
- Increased incidence of acute leukemias.
PNH
- Coombs + or -?
- Sxs:
- Coombs (-)
- hemolytic anemia, pancytopenia, and venous thrombosis.
*these pts have a history of infection due to the lack of WBCs.
PNH
-why do you get venous thrombosis?
-when platelets are destroyed they release their components into serum which causes a hypercoag. state.
PNH
- Tx:
- CD55 =
- CD59 =
- eculizumab.
- CD55 = DAF
- CD59
glutamic acid => _____ @ residue 6 on beta chain.
- HbC:
- Sickle Cell:
- HbC: lysine
- SS: valine
the O2-dissociation curve shifted to the ____ for Hb-S
RIGHT
Absent spleen
-what happens to platelet & WBC count?
-both increase.
-About one third of all circulating platelets are pooled
in the spleen, and granulocytes are marginated in splenic
sinusoids, so that when the spleen is absent, the WBC and platelet counts increase.
Sickle cell
-common presentation in kids?
dactylitis
Sickle Cell
- most common way it kills adults?
- Tx:
Acute chest syndrome
–occlusionin lungs. Precip by pneumonia.
-Tx: hydroxyurea (inc. HbF).
Do HbC and HbS bind 2,3-BPG considering their beta-chains are mutated?
Yes, they still do.
Warm agglutinin
- which Ab?
- seen in which diseases?
- caused by which drugs?
- IgG
- SLE, CLL
- alpha-methyldopa
Cold agglutinin
- which Ab?
- seen in which diseases?
- caused by which drugs?
-IgM
-CLL, Mycoplasma pneumonia infections, or infectious mononucleosis.
-
Why do you see spherocytes in autoimmune hemolytic anemia?
Spleen will take off the attached IgG or IgM and the piece of membrane its attached to. Too little membrane leads to a spherocyte.
Most important test for autoimmune hemolytic anemia?
Direct Coomb’s test will be (+).
Indirect Coombs test
-aka?
Antibody screen
-screen plasma for Abs
How does CLL cause IgG Autoimmune hemolytic anemia?
-Neoplastic B cells do NOT turn into plasma cells,
so you get a hypogammaglobinemia and most pts
will end up dying via ifx. The ones that do
make immunoglobulin will make them against the pts
own RBCs => autoimmune hemolytic anemia.
Why do you get neutropenia in a severe infection?
Most neutrophils are in tissues and not serum, so you can get a neutropenia.
What are the most vulnerable cells in the body to radiation?
Lymphocytes
Acute intermittent porphyria
- inheritance pattern?
- affected enzyme?
- what builds up?
- auto dom.
- Porphobilinogen deaminase (PORD) (aka uroporphyrinogen 1 synthase).
-Porphobilinogen (and everything upstream = δ-ALA,
coporphobilinogen)
Acute intermittent porphyria
-Sxs:
Symptoms (5 P’s):
- Painful abdomen
- Port wine–colored urine
- Polyneuropathy
- Psychological disturbances
- Precipitated by drugs, alcohol, and starvation
Acute intermittent porphyria
-Tx:
-glucose and heme, which inhibit ALA synthase.
-red urine that darkens on exposure to light or
air = what disease?
Acute intermittent porphyria
-key feature of acute porphyrias are red urine that darken on exposure to light or air due to oxidation of excess PBG.
Porphyria cutanea tarda
- affected enzyme?
- what builds up?
- Sxs:
- Uroporphyrinogen decarboxylase
- Uroporphyrin (tea-colored urine)
- Blistering cutaneous photosensitivity.
Most common porphyria?
Porphyria cutanea tarda
ALAD
-contains which metal cofactor?
Zn
What activates factor 12 (hageman factor)
-first step of which pathway?
SEC
- subendothelial collagen
- intrinsic pathway
What activates factor 7?
-first step of which pathway?
Thromboplastin (aka tissue factor)
-extrinsic pathway
Extrinsic
-PT or PTT?
PT
Intrinsic
- PT or PTT?
- mnemonic?
-Intrinsic has more factors so measured using PTT which has more letters than PT.
Hemophilia A pt not respond to factor 8. What could be the problem?
15% of patients with hemophilia A eventually develop an inhibitor to factor VIII = giving the pt normal plasma (w/factor 8) will not solve the problem.
What drug causes release of vWF & factor 8 from endothelial cells?
DDAVP (desmopressin)
-remember, DDAVP does not have the V1-vasoconstrictive properties as normal ADH.
Bernard-Soulier syndrome
- problem?
- mnemonic?
- genetic Gp1b deficiency.
- Craig (Bernard) is a 1beta male
Glanzmann thrombasthenia
- problem?
- what does blood smear show?
- platelet GpIIb/IIIa deficiency.
- blood smear shows no platelet clumping.
Immune thrombocytopenia
- Abs against what?
- possible trigger?
- labs?
- GpIIb/IIIa
- viral illness
- inc. megakaryocytes on bone marrow biopsy.
Thrombotic thrombocytopenic purpura
- problem?
- leads to what?
- which systems hit the hardest?
- Inhibition or deficiency of ADAMTS 13 (vWF metalloprotease) which degrades vWF multimers.
- lots of platelet microthrombi forming.
-CNS and renal hit the hardest. But mostly CNS (HUS will be mostly renal).
Thrombotic thrombocytopenic purpura
-Tx:
Exchange transfusion and steroids.
Thrombotic thrombocytopenic purpura & HUS
-is coagulation system activated?
NO
Thrombotic thrombocytopenic purpura
- PT time: inc or dec?
- PTT time: inc or dec?
both normal!
-NO activation of coag cascade in TTP or HUS!
HUS
- PT time: inc or dec?
- PTT time: inc or dec?
both normal!
-NO activation of coag cascade in TTP or HUS!
Uremia
-effect on platelets?
-disrupts platelet function: adhesion & aggregation problems.