RBC and Bleeding Disorders VI Flashcards
prothrombin time
PT
extrinsic and common pathways
V, VII, X, PT, fibrinogen
partial thromboplastin time
PTT
intrinsic and common pathways
V, VIII, IX, X, XI, XII, PT, fibrinogen
platelet count
best confirmed by PBS inspection
petechia and purpura in skin or mucous membranes
bleeding disorders caused by vessel wall abnormalities
normal PT, PTT and platelet count
infection causing bleeding disorders with vessel wall abnormalities
meningococcemia
infective endocarditis
rickettsioses
vasculitis and DIC
leukocytoclastic vasculitis
hypersensitivity
with drug rxns
immune complex deposition in vessel walls
scurvy
microvascular bleeding resulting from collagen defect weakening vessel wall
vit C deficiency
ehler danlos syndrome
microvascular bleeding resulting from collagen defect weakening vessel wall
cushing syndrome
excess corticosteroid causes loss of vascular supporting tissue
bleeding disorder
henoch schonlein purpura
systemic immune disorder
purpuric rash, colicky pain, polyarthralgia and acute glomerulonephritis
deposition of immune complexes of IgA throughout body and within glomerular mesangial region
purpuric rash, colicky pain, polyarthralgia and acute glomerulonephritis
henoch schonlein purpura
weber osler rendu syndrome
hereditary hemorrhagic telangiectasia
auto dominant
mutation in genes regulating TGF-beta signaling
dilated, turtous blood vessels with thin walls - serious bleeding
nose, tongue, month, eye, GI bleeds
perivascular amyloidosis
weak blood vessels
bleeding disorder
most common with amyloid light chain
often mucocutaneous petechiae
severe bleeding
hereditary hemorrhagic telangiectasia
-weber osler rendu syndrome
thrombocytopenia
platelets < 100,000
posttraumatic bleeding
20-50,000 platelets
spontaneous bleeding
<20,000 platelets
bleeding from thrombocytopenia
normal PT and PTT
most feared with low platelets
intracranial bleeds
causes of thrombocytopenia
1 decreased platelet production
2 decreased platelet survival
3 sequestration
4 dilution
decreased platelet production
drugs and alcohol
HIV - infect megakaryocytes
decreased platelet survival
immunologic and nonimmunologic
immune thrombocytopenia
deposition of Abs or immune complexes on platelets
fetus thrombocytopenia
alloantibodies
IgG antibodies made in mother can cause thrombocytopenia in fetus
nonimmunologic destruction of platelets
mechanical injury - metal prosthetic heart valves
splenomegaly
platelets can be sequestered
thrombocytopenia occurs
massive transfusions
can lead to dilutional thrombocytopenia
chronic ITP
caused by autoAb mediated destruction of platelets
can be idiopathic or secondary
secondary - SLE, HIV, B cell neoplasms
can be improved by splenectomy - major site of removal of opsonized platelets and removal of source of antoAbs - plasma cells
autoAbs in chronic ITP
against platelet membrane glycoproteins IIb-IIIa, or Ib-IX
IgG class
increased megakaryocytes in BM
seen in chronic ITP
also see large platelets on peripheral blood - megathrombocytes
and normal sized spleen
chronic ITP clinical
adult women < 40yo
boeeding into skin and mucosal surfaces
petechiae - pinpoint
easy bruising, nosebleeds, bleeding from gums, melena, hematuria, excessive menstruation
intracranial bleeds fatal - rare in treated pts
normal PT and PTT
dx of exclusion**
chronic ITP and splenomegaly
probably not primary - idiopathic
look at B cell neoplasm secondary cause
acute ITP
disease of children
equal frequency both sexes
1-2 weeks after viral infection
resolves spontaneously within 6 months
tx of ITP
glucocorticoid
- in chronic
- and in acute if severe
acute ITP without viral prodrome
worse prognosis
drug induced thrombocytopenia
quinine, quinidine, vancomycin
HIT
heparin induced thrombocytopenia
type I - rapidly after start heparin therapy and goes away
type II - 2 weeks after heparin - severe arterial/venous thrombosis
type I HIT
rapidly after start heparin therapy and goes away
type II HIT
2 weeks after heparin - severe arterial/venous thrombosis
Abs for heparin and platelet factor 4
DVT, PE, vascular insufficiency
HIV thrombocytopenia
common heme manifestation of HIV
CD4 and CXCR4 - on megakaryocytes
-HIV receptors
these cells apoptose and don’t produce platelets
thrombotic microangiopathy
includes TTP and HUS
excessive platelet activation - deposit as thrombi in small blood vessels
fever, thrombocytopenia, microangiopathic hemolytic anemia, transient neuro deficits, renal failure
pentad of TTP
TTP vs. HUS
TTP - neuro sx
HUS - no neuro sx
both have normal PT and PTT
microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure, children
HUS
deficiency of ADAMTS13
TTP
tx plasmaphaesis
E.Coli 0157:H7 infection
typical HUS
deficiency of complement factor H, CD46, or factor I
atypical HUS
inhibitors of alternate complement pathways
