S18C232 - Acquired hemolytic anemia Flashcards Preview

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Flashcards in S18C232 - Acquired hemolytic anemia Deck (17)
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1
Q
Tests for hemolysis
A
-hb and Hct decreased
-reticulocyte increased
-peripheral smear - schistocytes from shearing force, spherocytes from extravascular hemolysis
-LDH - elevated
-K may be elevated
-haptoglobin decreased - sign of intravascular hemolysis
-bilirubin increased
2
Q
Immune-mediated acquired hemolytic anemia
A
AUTOIMMUNE
-will have positive DAT
-AIHA ore common in women, assoc with lymphoproliferative, autoimmune or infxs dz

ALLOIMMUNE
-requires exposure to allogeneic RBC and subsequent alloantibody formation, do not react with pts own RBC
-eg. Rh- mom and Rh + baby
-usually requires a prior TFn exposure

DRUG-INDUCED Hemolytic anemia
-tx: steroids
-TFN will aggravate the hemolysis
-catchein, cefotetan, CTX, cephalothin, diclofenac, interferon, levodopa, mefenamic acid, methyldopa, oxaliplatin, Pen G, quinidine, rifampin
3
Q
DDx for DAT positive
A
-AIHA
-hemolytic tfn rxn
-hemolytic dz of newborn
-tranplant
-druge-related
-IVIG
-Rh immunoglobulin therapy
-SCD
-beta-thal
-mulitple myeloma
-hodgkin
-SLE
-HIV
4
Q
Microangiopathic syndromes
A
-microangiopathic hemolytic anemia
-TTP and HUS
-involve platelet aggregation in microvasculature via mediation ofr vWF
-RBC are fragmented during travel through partially occluded arterioles/capillaries
-TTP more common in adults and more prominent neurologic effects
HUS more commin in kids and more specific to renal system
5
Q
TTP
A
-thrombotic thrombocytopenic purpura
-pentad:
1 CNS abnormalities
2 renal pathology
3 fever
4 microangiopathic hemolytic anemia
5 thrombocytopenia
-dx: hemolytic anemia + thrombocytopenia with no other cause
-high mortality rate unless given PlEx
-ddx: malignant HTN, sepsis, SLE, HELLP
6
Q
TTP: pathophys
A
-vWF multimers accumulate due to decreased ADAMTS-13 acitivty, causes platelet aggregation and RBCs are sheared across the microthrombi
-thrombocytopenia
7
Q
TTP: sx
A
-neuro deficits
-coma
-AKI
-ARF
8
Q
TTP vs DIC vs HELLP
A
-TTP has normal coag studies b/c TTP thrombi don't use up fibrin
-HELLP should respond to steroids w/in 24h by an increase in platelets whereas TTP will not, delivery also will not improve TTP
-if TTP treated with PlEx then pregnancy can be carried to term
9
Q
TTP: Tx
A
-daily plasmapheresis (plasma exchange) until platelets normal
-avoid platelet TFN except for life-threatening bleed
10
Q
HUS
A
-microangiopathic hemolytic anemia, acute neprhopathy/fenal failure, thrombocytopenia
-typical: occurs 1w into infxs bloody diarrhea episode with fever (O157:H7), shiga-toxin present (but also shigella, yersinia, c jej, salmonella)
-atypical: difficult to distinguish from TTP, occurs in older children and adults caused by strep or EBV or non-infxs source such as bone marrow transplant
11
Q
HUS: pathophys
A
-toxin absorbed into circulation, affinity for glomerular and renal rubules, microvascular injury causes platelet aggregation, thrombi, microangiopathic hemolytic anemia, ischemia, necrosis
-may also affect pancreatic beta cells leading to hyperglycemia
-onset of HUS is 2-14d after diarrhea develops
12
Q
HUS: Tx
A
-supportive, fluids for renal failure, analgesia,
-NO immodium
-NO Abx - may increase shiga toxin expression and increased risk of HUS
13
Q
Macrovascular hemolysis
A
-prosthetic heart valves
-aortofem bypass
-Ao valve dz
-coarctation
-VAD
-Dx: scheistocytes on smear
-if mild give iron and folate, BB may help
14
Q
Malaria
A
-world's most common cause of hemolytic anemia
-plasmodium lyses RBCs
15
Q
Other infxs causes of hemolysis:
A
-babesia microti/divergens (Babesiosis) from tick bites or blood tfn
-clostridium perfringens (gas gangrene) and direct lysis of RBC via toxins
-leptospirosis - ingestion of contaminted water/food (weil's syndrome)
16
Q
Envenomation and hemolysis
A
-hymenoptera stings (bees) lead to acute tubular necrosis and renal failure, hemolysis, rhabdo, shock
tx with PlEx
-brown recluse spider: hemolysis, tx with steroids
-pit viper (rattlesnakes, copperhead, cottonmouth, bushmaster) cause intravascular RBC hemolysis
-Aus. brown and black snakes, tx with antivenom or PlEx
17
Q
Hemolysis and chemical exposure
A
-arsine gas : rapid massive hemolysis and death, industrial settings,
-naphthalene from moth balls or industrial spills: hemolytic anemia, methemoglobinemia, renal failure