Blood Disorders Flashcards
Hemophilia A
Most common X linked disorder
F VIII deficiency
Genes located at tip of X chromosome
Hem A: large gene, intron 22 inversion (flip tip)
Complications: Musculoskeltal bleeds; hemarthrosis, ilipsoas, easy bruising
Life threatening hemorrhage of CNS, airway or GI
Bleeding with circumcision
Dental bleeding, hematuria, soft tissue bleeds
Severe hemophilia with hemoatoma following immunization (should put pressure for 15 mins)
Labs: prolonged PTT,
normal PT and bleeding time
Treatment: give VIII concentrate (evaluate for transmissible diseases)
Desmopressing increases release of VIII and vWF from endothelial cells
Hemophilia B
Most common X linked disorder
F IX deficiency
Genes located at tip of X chromosome
Hem B: smaller gene, missense, dysfunctional or absent protein
Complications: Musculoskeltal bleeds; hemarthrosis, ilipsoas, easy bruising
Life threatening hemorrhage of CNS, airway or GI
Bleeding with circumcision
Dental bleeding, hematuria, soft tissue bleeds
Neonatal hemophilia post circumcision bleed with hematoma dorsum
Labs: prolonged PTT,
normal PT and bleeding time
Treatment: give IX concentrate (evaluate for transmissible diseases)
Von Willebrand Disease
most common bleeding disorder-AD with inocmoplete penetrance
Characterized by mucocutaneous hemorrhages, easy bruising, heavy menses, nose and gingival bleeding
Defect of vW factor
VWF: large mutimeric glycoprotein
Produced and stored in endothelial cells and platelet alpha granules
Gene located on chormosome 12
Functions: tethering protein through platelet glycoprotein Ib
Carrier protein for VIII
Clinical: menorrhagia, epitaxis, easy bruising
Excessive bleeding with trauma-post op, tooth extraction
GI bleeding in severe deficiency
Lab values normal: platelet count, PT,and fibrinogen
Increased BT, Increased PTT due to decreased half life of VIII
Will not aggregate in ristocetin test
Specific tests: VWF Ag assay: ELISA Protein quantification FVIII clotting activity or assay Ristocetin cofactor assay: measures plasma levels of VWF VWF multimers
Treatment: desmopressin stimulates vWF release from endothelium
Hereditary Hemorrhagic telangiectasia
Inherited:
Autosomal dominant
Arteriovenous malformation: nose bleeding, intracrania hemorrohage, GI, pulmonary
Acquired: Senile purpura Vasculitis Henoch-shonlein purpura IgA meditaed, hematuria, joint swelling, abdominal pain, pupuric rash on buttock and extremities renal failure Can be drug induced by steroids
Bernard Soulier
Platelet adhesion disorder
Autosomal Recessive
decreased GP Ib-IX the vWF receptor
Labs: large platelets
Increased BT, decreased platelet count
Mild thrombocytopenia
Decreased ristocetin aggregation
Markers: CD42b/42a
Symptoms: microhemorrhage, mucous membrane bleeding, epistaxis, petechiae, purpura,
Glanzmann’s thrombasthenia
Platelet aggregation disorder
Autosomal recessive
decreased GPIIb-IIIa fribrinogen receptor
Labs: platelet count normal, no response to collagen, epinephrine, thrombin, increased BT
Normal Ristoceitin aggregation, ADP test will not aggregate
Markers: CD41/61
Symptoms: microhemorrhage, mucous membrane bleeding, epistaxis, petechiae, purpura,
Immune thrombocytopenia
immunlogic destruction of platelets in response to unknown stimulus (may be triggered by viral illness)
NO hepatomegaly
Pathogenesis: IgG autoAbs interact with platelet specific Ags-GPIIb-IIIa or Ib/IX on platelets and megakaryocytes
Bind to FC receptor promoting phagocytosis in spleen
Decreased thrombopoietin production
T-cell mediated cytotoxicity
Labs: decreased PC, increased BT
incrased megakaryocytes on BM biopsy
Treatment: steroids
DIC
Triggers: release of Tissue Factor, endothelial damage and cytokine release: TNF, IL-1, 6 and 10
Characteristics: increased thrombin generation
Supressed anticoagulant pathway
Activation of subsequent fibrinolysis (plasmin) releases D dimers
Activation of inflammatory pathway
Causes: Sepsis (gram negative), Trauma, Obstetric complications, acute Pancreatitis, Malignancy, Nephrotic syndrome, Burns
Secondary disease
Death due to organ failure
Pathogenesis: widespread activation of clotting leads to a defieciency in clotting factors creating a bleeding state
Clinical: Bleeding from puncture sites, generalized bleeding, organ failure, gangrene, shock, acidosis
Pathology: fragmented red cells, thrombocytopenia, fibrin deposition in kidneys
Labs: decreased platelet count , PT and PTT prolonged, increased bleeding time, D-dimers increased, Fibrinogen decreased, antithrombin, decreased, protein C decreased
Treatment: treat underlying cause, blood component therapy, Anticoagulants and Antithrombin concentrates
TTP
ADAMTS13 deficiency or inhibition (vWF metalloproteinase)
Unusually large multimers of vWF produced in endothelium, megakaryocyte and stored in Weibel Palade bodies
Binds efficiently to glycoprotein 1b-IX
Pathogenesis: large vWF increased platelet adhesion leading to increased platelet aggregation and thrombosis
Labs: decreased PC, Increased BT
Schistocytes, Increased LDH
Clinical: Thrombocytopenia, microangiopathic hemolytic anemia, neurologic abnormalities, renal failure, fever
Treatment: Plasmaperesis/plasma exchange, Anti CD20, Supportive care, Solirus-eculizumab, steroids
HUS
Normal levels of ADAMTS13
E-coli O157:H7 and Shigella produce Shiga toxin (verotoxin) stimulating cells to produce ULM
Follows acute diarrhea
Non-epidemic is a complement factor H defect
Clinical: Microangiopathic hemolytic anemia, Thrombocytopenia, renal failure, fever
Occurs in children
Treatment: antibiotics
Vitamin K deficiency
Vit. K dependent factors=II, VII, IX and X, proteins C and S
Causes: hemorrhagic disease of the newborn, warfarin, malbsorption, biliary obstruction, congenital deficiency
Lab: increased PT and PTT
Normal bleeding time
Treatment: oral Vita K or IV/IM
All babies are born with low vitamin K-prophylactically treat
Venous Thrombosis
Venous blood flow is propelled by muscle activity and affected by gravity
Tissue Factor Pathway Inhibitor, Protein C and S, Antithrombin II and III provide a balance to rapidly formed clots required for hemostasis without promoting systemic activation
Factors reduce opportunity for thrombus formation and obstrucction of venous flow
Risks: immobility, mechanical obstruction, hyperviscocity (dehydraion, polycythemia, diuretics, Tissue damage, surgeries
Contributing factors: pothrombin 20210A, Factor V Leiden, Dysfribrnoenemia, Antithrombin III deficiency, Protein C deficiency, Protein S deficiency
Diagnosis: edema, cyanosis of extremities
Imaging: doppler ultrasound venogram
Complication: propagation of clot release of fragments into the venous flow to be deposited in the filtering vasculature of the lung -pulmonary emboli can be a lethal complication
treatment: Anticoagulants, fibronolytic agents, circulation enhancement
Arterial Thrombosis
less subject to statsis and activation of plasma clotting proteases
Damage to endothelium plays major role in arterial thrombosis
Disruption of endothelium associated with diabetes, smoking, plaque formation, narrowing of arterial lumen and finally obstruction of flow
Destruction of endothelium allows for platelets to bind vWF and eliminates protective effects of attached glycosaminoglycan molecules (heparan) which complex with Antithrombin to circulating Thrombin
Symptoms: Extremities cold, painful, weak or absent pulse
Diagnosis: Doppler Ultrasound, arteriogram, CT scan
Risk factors: smoking, diabetes, hypertension, dyslipidemia, cardiac arrhythmia, obesity, Age, family history
Embolism obstruct vessels with small lumens
Atrial fibrillation associated with arterial thromboembolism
Iron Deficiency Anemia
Four causes: Chronic blood loss, Increased requirements, Malabsorption, Poor diet
Produces hypochromic microcytic anemia
No stain on Prussian blue stains
Chronically causes koilonychia, alopecia, atrophic changes of tongue, and gastric mucosa, Pica, Fissures and ulcerations on corners of mouth
Labs: Hg decreased, hematocrit decreased, serum iron low, ferritin low, total plasma iron capaciy high, transferrin saturation low
Plummer Vinson Syndrome
Associated with iron deficiency
Microcytic hypochromic anemia
Esophageal webs (can’t swallow)
Atrophic glossitis
Sideroblastic Anemia
Causes microcytic, hypochromic anemia
Iron fails to combine with prootoporphyrin
Iron remains in mitochondria-stain using Prussian blue stain-ringed sideroblast
Can be due to X linked defect in ALA synthase
Can be due to alcohol, lead, isoniazid (Vit B6 deficiency, B6 a cofactor for protopophyrin synthesis), copper deficiency, or myelodysplasia
Labs: increased ferritin, decreased transferrin binding capacity, increased serum iron, and increased % saturation of transferrin
Treatment is pyridoxine
Anemia of Chronic Disease
Most common form of anemia in hospitals
Impaired RBC production due to systemic inflammation
Lab findings: MCV normal, Serum iron low, total iron binding capacity low, abundant iron in macrophages, increased ferritin
IL-6 increases hepatic production of hepcidin
Hepcidin released from liver binds ferroportin on intestinal mucosal cells and macrophages inhibiting iron transport leading to decreasd release of iron from macrophages
Low erythropoietin levels
Treat underlying disease
B12 deficiency anemia
Megaloblastic anemia
Impairment of DNA synthesis leads to ineffective hematopoiesis
Nucleated RBCs in BM wait for nucleus to develop and die (LDH and unconjugated bilirubin elevated)
Histology: Neutorphils show nuclear hypersegmentation
Megaloblastic changes in all stages of erythroid development-giant metamyelocytes and bands form
Pathogenesis: Generally Ab prevent binding of intrinsic factor to Vitamin B12 complex to ileal receptor insufficient intake (vegans), malabsorption (Crohns), Diphyllobothrium latum (fish tapeworm), proton pump inhibitors
Symptoms: Fundic gland atrophy, glandular epithelium replaced by goblet cells (metaplasia increases risk of gastric carcinoma), atrophic glossitis (tongue shiny and beefy), Demyelination of dorsal and lateral spinal tracts (hyperreflexia and + babinski sign), peripheral neuroapthy with sensorimotor dysfunction, dementia
Diagnosis:Elevated homocysteine levels (thrombosis and atherosclerosis) and methlymalonic acid (myelin synthesis abnormalities)
Treatment: high dose vit B12 cures anemia (dramatic increase in reticulocytes right away then slow increase in hemoglobin and erythrocytes) not neurological symptoms
Treating with folate worsens symptoms by decreasing unmethylated cobalamin available for methylamalony-CoA processing