Hematology Flashcards
1
Q
describe the effect of 4 α genes deleted
A
-
4 genes deleted = lethal in utero (hydrops fetalis)
- γ chains form tetramers (Hb Barts) → extremely high affinity for O2 → no O2 reaches the tissues
2
Q
the best screening test for the condition seen in the image is ____
A
the best screening test for the condition seen in the image is metabisulfite screen which causes cells with HbS to sickle
3
Q
list the blood levels values seen in B12 deficiency
A
- increased homocysteine
- increased methylmalonic acid
- low B12 (with normal folate)
4
Q
___ is the most accurate test for the condition seen in the image, but the downside is ____
A
G6PD assay is the most accurate test for the condition seen in the image, but the downside is may have to wait 2 months b/c reticulocytes produced at time of crisis do NOT reflect the enzyme deficiency – only mature RBcs do
5
Q
___ is the most common form of immunohemolytic anemia, with most antibodies being ____ class
A
warm antibody IHA is the most common form of immunohemolytic anemia, with most antibodies being IgG class
6
Q
describe the etiology of idiopathic form of the condition seen in the image
A
- idiopathic = 65% of cases
- immune-mediated (cellular or T cell) destruction of antigenically altered stem cells
- primary intrinsic stem cell defect
- genetic abnormalities detected in some cases
7
Q
describe lab findings seen in the condition in the image
A
- blood
- ↑ LDH
- ↑ unconjugated bilirubin
- ↑ free Hb
- ↑ reticulocytes
- ↓ haptoglobin (made by liver to bind free Hb)
- urine
- free hemoglobin → hemoglobinuria & hemosiderin → hemosiderinuria → dark urine
8
Q
name causes of malabsorption that can lead to folate deficiency
A
- malabsorption in the jejunum that can be caused by:
- Crohns
- Tropical sprue
- Celiac disease
- Whipples
9
Q
describe the treatment for the condition seen in the image
A
splenectomy & folic acid supplements
will see HJ bodies upon splenectomy
10
Q
describe how malabsorption can lead to B12 deficiency
A
- malabsorption in ileum
- absorption in distal ileum affected by:
- Crohns
- Tropical sprue
- Celiac
- Whipples
- absorption in distal ileum affected by:
11
Q
chronic ___ can lead to B12 deficiency
explain this concept
A
chronic pancreatitis can lead to B12 deficiency
- pancreatic enzymes are needed to cleave R binder from B12 so intrinsic factor can bind to it
12
Q
describe the osmotic fragility test in relation to the condition seen in the image
A
- osmotic fragility test:
- in 65% of patients with HS, RBCs lyse prematurely compared to normal when exposed to increasingly hypotonic solution
13
Q
describe the presentation of the condition seen in the image
A
- asymptomatic until exposed to injurious agent
- 2-3 days after oxidant stressor: acute hemolysis, fever, jaundice, fatigue, dark urine (due to free Hb)
- NO splenomegaly (differential from HS due to being intrinsic)
14
Q
describe the complications of the condition seen in the image
A
- complications:
- CHF
- if they have Plummer Vinson → sq. cell carcinoma of esophagus
- Pica syndrome (psychiatric problem w/ eating dirt, ice)
15
Q
describe the etiology of the condition seen in the image
A
- etiology = intrinsic/genetic defect in RBC membrane proteins
- ankyrin (AD)
- spectrin (AR)
- band 3.1
16
Q
describe the presentation of the condition seen in the image
A
- mild to chronic hemolytic anemia, jaundice, fatigue, dragging sensation in LUQ due to splenomegaly
17
Q
in PNH there is absence of CD__, CD___ and ____ which causes susceptibility to ____
A
in PNH there is absence of CD55, CD59 and C8-binding protein which causes susceptibility to hemolysis
18
Q
cardiac ____ can cause hemolysis due to mechanical RBC damage
A
cardiac prosthetic valves can cause hemolysis due to mechanical RBC damage
19
Q
describe causes of anemia in chronic diseases (3 main groups)
A
- chronic bacterial infections
- lung abscess, endocarditis
- chronic immune disorders
- RA
- malignant tumors
- cancers of lung & breast, lymphoma
20
Q
describe chronic primary immune thrombocytopenia (ITP)
A
- chronic:
- women 20-40
- insidious onset of skin +/- mucosal bleeding
- rarely resolves spontaneously
21
Q
describe the type of anemia seen in the image
A
normocytic anemia with predominant extravascular hemolysis
22
Q
describe the pathogenesis of PNH
A
- PIGA forms an enzyme needed to synthesize GPI
- 3 GPI-linked proteins normally inhibit complement activation on blood cells; absence of CD55, CD59 and C8-binding protein causes susceptibility to hemolysis
23
Q
in diffuse liver disease, there is ___ hypofunction, affecting mainly ____, and the etiology is multifactorial
A
in diffuse liver disease, there is BM hypofunction, affecting mainly RBCs, and the etiology is multifactorial
24
Q
list causes of microangiopathic hemolytic anemia (5)
A
DIC, malignant HTN, SLE, TTP/HUS, disseminated cancer
25
list 2 potential treatments for chronic ITP
* immunosuppression via steroids
* splenectomy
26
describe a diet that is at greater risk of acquiring the condition seen in the image
* **nutritional**: iron from plants (non-heme) & animal (heme = better absorbed)
* vegan more likely to get IDA than B12 def.
27
describe the complications of the condition seen in the image
* all anemias → LVH → LHF → RHF → CHF
* rapid production of RBCs uses folate → folate def. anemia → megaloblastic anemia
* **increased** **risk** **of aplastic crisis due to Parvovirus B19** (infects normoblasts/erythroid precursors) → reticulocytopenia in chronic hemolytic anemia
* **bilirubin gallstones** → **cholecystitis** *due to supersaturation of bilirubin in bile* → increased chance of precipitation
28
\_\_\_\_ is the leading cause of death in PNH (40% develop \_\_\_\_)
**thrombosis** is the leading cause of death in PNH (40% develop **DVT**)
29
the ____ response can be used to determine B12 deficiency
explain this
the **reticulocyte** **response** can be used to determine B12 deficiency
there would be improvement approx. 5 days after a parenteral B12 injection
30
in the condition seen in the image, ___ is necessary to rule out other causes of pancytopenia
* BM biopsy is necessary to rule out other causes of pancytopenia (acute leukemia, myelodysplastic syndrome)
* BM biopsy
* very hypocellular
* only fat cells, few lymphocytes, plasma cells
31
describe the lab values seen in ACD and IDA
32
50% of patients with warm antibody IHA have predisposing factors, such as \_\_\_, ___ or \_\_\_\_
50% of patients with warm antibody IHA have predisposing factors, such as **autoimmune diseases**, **lymphoma** or **drug reactions**
33
a small number of PNH patients develop ____ or \_\_\_\_\_
a small number of PNH patients develop **acute myeloid leukemia** or **myelodysplastic syndrome**
34
describe the acquired causes of the condition seen in the image (3)
* chemical agents:
* dose-related, predictable
* alkylating agents and antimetabolites (chemotherapeutic agents)
* idiosyncratic
* chloramphenicol, chlorpromazine, phenytoin
* physical agents:
* whole body irradiation
* viral agents:
* hepatitis D and E, CMV, EBV, herpes zoster
35
describe acute primary immune thrombocytopenia (ITP)
* acute:
* children
* post-viral
* abrupt onset
* spontaneous resolution
36
describe the pathogenesis of the condition seen in the image
* ↓ iron → ↓ heme → ↓ Hb → increased cell division → microcytic hypochromic anemia
37
describe the etiology of the major form of the condition seen in the image
* point mutations of chr. 11
* **absent B chain (B° caused by mutation in splicing/chain termination)**
* **diminished B chains (B+ caused by mutation in the promoter region)**
38
describe the image
**G6PD**
as the splenic macrophages pluck out the Heinz bodies inclusions, "bite cells" are produced
39
describe the image
**G6PD**
red cells with precipitates of denatured globin (Heinz bodies) shown by supravital staining
40
list a treatment for hemophilia A and a potential complication
* recombinant FVIII infusions
* 15% develop FVIII antibodies
* also risk of transmission of viral diseases
41
describe the presentation of the condition seen in the image in adults
**sickle cell anemia**
42
\_\_\_ a peptide synthesized in the ___ in response to high levels of iron stores, inhibits iron uptake from ___ mucosal cells into the bloodstream
**hepcidin** a peptide synthesized in the **liver** in response to high levels of iron stores, inhibits iron uptake from **duodenal** mucosal cells into the bloodstream
43
list 2 possible treatments of PNH
* immunosuppression
* bone marrow transplantation
44
describe the type of anemia seen in the condition in the image
**normocytic anemia with predominant intravascular hemolysis** (due to abnormality in HMP shunt)
45
describe the type of anemia that is seen in the image
**normocytic anemia with predominant extravascular hemolysis**
46
if the flow cytometry image shown is normal, what is seen in PNH?
47
describe the complications of the condition seen in the image
* **aplastic crisis** → due to Parvovirus B19
* **folic acid deficiency** due to chronic hemolytic anemia
* **bacterial infections** from iron-loving bacteria (Vibrio & Yersinia enterocolytica)
* **bilirubin gallstones**
* **failure to thrive**
48
list causes of decreased production of thrombocytes (thrombocytopenia(
* generalized BM disease
* aplastic anemia
* marrow infiltration
* leukemia, metastatic cancer, granulomatous inflam.
* drug-induced
* ethanol, cytotoxic drugs
* infections
* HIV, measles
* megaloblastic anemia
* myelodysplastic syndromes (MDS)
49
describe blood level values seen in folate deficiency
which value is truly diagnostic of folate def.?
* increased homocysteine
* increased in both, folate and B12 def.
* **decreased** **serum folate**
* **only truly diagnostic test, as other changes could mean B12 def. too**
50
describe how nutrition can lead to folate deficiency
**lack of raw greens (boiling destroys folate)**
most common cause of folate deficiency in older patients
51
describe conditions of chronic blood loss that can lead to the condition seen in the image
* chronic blood loss:
* right-sided colon cancer → occult bleeding
* peptic ulcer by H. pylori → melena
* uterine fibroids → heavy bleeding (menorrhagia)
52
list the most common outcome and complications of the condition seen in the image
self-limiting: complete resolution
* usually self-limiting with complete resolution after hemolytic event
* Hb (as is hemosiderin) is toxic to renal tubules → **acute tubular necrosis → acute renal failure**
53
describe how the Schilling test can be used to determine B12 malabsorption
* Schilling test = inability to absorb an oral dose of B12, measured by urinary excretion of labeled B12
54
describe the type of anemia seen in the image and why it is significant
**microcytic hypochromic anemia**
**most common cause of anemia**
55
list the 5 features found in thrombotic thrombocytopenic purpura (TTP)
* clinical syndrome of:
* fever
* thrombocytopenia
* microangiopathic hemolytic anemia
* transient neurologic deficits
* renal failure
56
describe the most accurate test for diagnosing the condition seen in the image
* most accurate test = BM biopsy w/ Prussian blue (depletion of BM iron stores) → mild erythroid hyperplasia
57
how is HUS different from TTP?
clinically, HUS is like TTP, except HUS has NO neurologic deficits and instead has **prominent acute renal failure**
58
describe the pathogenesis of the condition seen in the image
* pathogenesis: **HbS polymerizes when deoxygenated** → polymers aggregate into needle-like structures → sickle cells
59
describe the etiology of the condition seen in the image and name the 2 types of mutations
* etiology = X-linked recessive
* 2 types of mutations (role against falciparum malaria)
* _G6PD A (African variant)_ = **mild version → only older RBCs are affected**
* _G6PD (Mediterranean variant)_ = **more severe → even younger RBCs are affected**
60
describe how pernicious anemia can lead to B12 deficiency
* pernicious anemia = antibodies destroying intrinsic factor = type II HS
* most common cause in the US
* pernicious anemia → intestinal gastric adenocarcinoma & type I gastric carcinoid
61
name drugs that can lead to folate deficiency
**phenytoin, methotrexate (chemotherapy)**
62
describe diseases that cause malabsorption that can lead to the condition seen in the image
* **malabsorption**: absorption in duodenum affected by **Crohns**, **tropical sprue, celiac** disease and **Whipple**
* iron balance regulated at the level of absorption by hepcidin (inhibits iron uptake from duodenal mucosal cells into the bloodstream)
63
describe the blood investigations found in the major form of the condition seen in the image
* blood:
* ↑ LDH
* ↑ reticulocytes
* ↑ RDW
* ↑ serum iron & ferritin
* ↓ TIBC
64
describe the pathogenesis and presentation of the major form of the condition seen in the image
* no B chains (no HbA which is α2B2), which leads to an increase in HbF (α2γ2) and HbA2 (α2δ2)
* **expansion of hematopoietic marrow in skull** → chipmunk face, frontal bossing & crew-cut appearance due to erythroid hyperplasia in flat bones
* **intramedullary hemolysis** → ineffective erythropoeisis b/c α chains are not paired with B chains → **α chains precipitate and form tetramers**
* **extravascular hemolysis**: splenomegaly, fatigue, jaundice, brown discoloration of skin due to iron overload
65
list the 2 acquired platelet function abnormalities
* drugs:
* aspirin and NSAIDs
* uremia
* chronic renal failure
66
describe genetic composition in B-thalassemia minor vs. B thalassemia major
* B-thalassemia minor = (B/B+) = mild asymptomatic anemia
* B-thalassemia major = (B°/B°), (B+/B+), (B+, B°) = severe transfusion-dependenent anemia; abnormal Hb causes occlusions in small blood vessels
67
name conditions where there is an increased demand for folate
increased demand during **pregnancy, cancer, and chronic hemolytic anemia**
68
describe type I and type III vs. type II of von Willebrand disease
I and III = reduced quantity of vWF
II = qualitative (functional) abnormality of vWF
69
PNH is caused by a mutation in \_\_\_\_
PNH is caused by a mutation in **PIGA (X-linked)**
70
describe what is seen on peripheral blood smear of the major form of the condition seen in the image
* PB:
* **target cells**, normoblasts, reticulocytes, anisocytosis, poikilocytosis due to extramedullary hepatopoeisis
71
describe the etiology of the condition seen in the image
* AR point mutation at position 6 of B-globin
* **glutamic acid (polar) replaced by valine (neutral/non-polar) → removes** **biconcavity**
* homozygotes (HbS, HbS) = sickle cell anemia
72
for the condition seen in the image,
younger patients can be treated with \_\_\_\_
while
older patients can be treated with \_\_\_\_
younger patients can be treated with **bone marrow transplant**
while
older patients can be treated with **immunosuppression**
73
most iron is absorbed in the \_\_\_\_
a small fraction enters the blood, but most remains in ___ and is lost by \_\_\_\_
most iron is absorbed in the **duodenum**
a small fraction enters the blood, but most remains in **intestinal cells** and is lost by **intestinal exfoliation**
74
in the condition seen in the image, the most common predisposing factor for episodes is \_\_\_\_
in the condition seen in the image, the most common predisposing factor for episodes **are infections**
NADPH is needed for resp. burst
75
describe the presentation of the condition seen in the image in children
* children:
* **crew-cut appearance** & **chipmunk face** (due to hematopoiesis in skull)
* failure to thrive
* **dactylitis** (swollen hands and feet due to vaso-occlusive infarcts in bones → aseptic necrosis of metacarpal bones)
* spleen (crisis → splenomegaly → **autosplenectomy** due to fibrosis → recurrent encapsulated bacterial infxn = most common cause of death in children)
76
describe 1 α-gene deletion
gene deletions on chr. 16
* 1 gene deleted = asymptomatic
77
describe the cause of sickling and types of crises in the condition seen in the image
* crisis (increased sickling) caused by: **hypoxia**, acidosis, infection, dehydration, hypothermia, HbC (glutamic acid is replaced by lysine)
* types of crises: **painful vaso-occlusive**, hemolytic, splenic sequestration & aplastic crisis
78
describe the treatment for the condition seen in the image
* bone marrow transplant
* hydroxyurea (stimulates HbF, increased NO, decreased platelet aggregation)
* vaccines after splenectomy
* folic acid
79
describe the lab findings in the condition seen in the image
* ↑ reticulocytes (reticulocytosis)
* ↑ LDH
* ↑ MCHC (only condition that has this)
* ↑ RDW
* ↑ unconjugated bilirubin
* ↓ MCH
80
a PB smear in chronic ITP may show large ____ which indicates \_\_\_\_
a PB smear in chronic ITP may show large **platelets** which indicates **rapid BM turnover**
81
the test used for definitive diagnosis of the condition seen in the image is \_\_\_\_
the test used for definitive diagnosis of the condition seen in the image is **hemoglobin electrophoresis (most accurate)**
82
describe the change in SA:V ratio in the condition seen in the image and what it affects
* **decreased SA:V ratio** (spheres) → pack more Hb → **no central pallor** → **increased MCHC** (due to cell becoming more concentrated) & **increase in RDW**
83
in myelophthisic anemia, there is BM replacement by ____ that disturb ___ (often with \_\_\_\_)
in myelophthisic anemia, there is BM replacement by **abnormal infiltrates** that disturb **normal architecture** (often with **fibrosis**)
84
in the condition seen in the image, ___ can deliver O2 normally but ___ recognizes them as foreign
in the condition seen in the image, **spherocytes** can deliver O2 normally but **the spleen** recognizes them as foreign → **_chronic extravascular hemolysis_**
85
cold antibody hemolytic anemia is mainly caused by ___ antibodies at ___ temperatures
**cold antibody hemolytic anemia** is mainly caused by **IgM** antibodies at **cold** temperatures
IgM = pentamer, so able to interact more and don't need heating up to cause agglutination
86
there is a common association between PNH and \_\_\_\_
and ___ can also be a problem
there is a common association between PNH and **aplastic anemia**
and **iron deficiency** can also be a problem
87
describe the pathogenesis of the condition seen in the image
* pathogenesis:
* reduced RBC membrane stability → loss of small fragments during normal shearing stresses in the blood circulation → spherocytosis to accommodate → **unable to traverse the splenic sinusoids** → phagocytosis and destruction by splenic macrophages → splenomegaly usually seen due to functional hypertrophy
88
describe what is seen in blood serum levels in the condition seen in the image
* blood:
* ↑ reticulocytes
* ↑ LDH
* ↑ unconjugated bilirubin
* ↑ free Hb (dark urine)
* ↓ haptoglobin
89
describe the diagnosis of the major form of the condition seen in the image
* diagnostic: Hb electrophoresis → no A band b/c no B chain, prominent F and normal/slightly elevated A2
90
list clinical features of PNH
* clinical features:
* **intravascular hemolysis**: chronic low-grade hemolysis
* **thrombosis**: platelet dysfunction → prothrombotic state
91
describe the presentation of B12 deficiency
* presentation:
* fatigue
* atrophic glossitis
* cheliosis
* **neurological symptoms**
* **decreased vibration & proprioception due to subacute combined degeneration of dorsal column due to methylmalonic acid**
92
list the stages of the condition seen in the image
* stages:
* storage iron depleted: ↓ ferritin; increased TIBC
* serum iron depleted: ↓ serum iron; ↓ % transferrin sat.
* normocytic anemia: bone marrow makes FEWER, NORMAL RBCs
* microcytic, hypochromic anemia: bone marrow makes smaller and fewer RBCs
93
describe what is seen on PB smear of the condition seen in the image
* PB: anisopoikilocytosis (pencil cells), hypochromic microcytic cells and ↑ platelets
94
describe the type of anemia seen in the condition in the image
**hypochromic microcytic anemia with extravascular hemolysis**
95
a BM biopsy in chronic ITP would show increased \_\_\_\_
a BM biopsy in chronic ITP would show **increased megakaryocytes**
96
describe the peripheral blood smear in the condition seen in the image
* PB:
* pancytopenia
* normochromic normocytic anemia
* very low reticulocyte count
97
describe laboratory findings in PNH
* hemoglobinuria, hemosiderinuria
* older lab tests:
* sucrose hemolysis test (screening)
* Ham's acid hemolysis test
* flow cytometry:
* absence of CD55, CD59 on WBCs
* Flaer test
98
in chronic renal failure, there is decreased production of \_\_\_\_\_
in chronic renal failure, there is decreased production of **erythropoietin**
99
describe the image
hereditary spherocytosis
note the **anisocytosis** and **several hyperchromic** spherocytes
**Howell-Jolly bodies** (small nuclear remnants) are also present in the red cells of this asplenic patient (seen on the right)
100
list the 4 causes of iron deficiency
which is the most common in the Western world?
1. dietary deficiency
2. impaired absorption
3. increased requirements
4. chronic blood loss
* commonest cause of iron def. in the Western world
* where iron def. anemia is due to chronic GI blood loss until proven otherwise
101
describe the effect of 2 α genes deleted
* 2 genes deleted = miild anemia w/ increased RBC count
* cis deletion = increased risk of severe thalassemia in offspring
102
describe what is seen and what it is caused by
**schistocytes** are seen which can be caused by **microangiopathic hemolysis**
103
why is thrombosis seen in PNH?
platelets are also missing GPI (and therefore CD55, CD59) and are susceptible to complement-mediated killing
## Footnote
**the destroyed platelets release cytoplasmic contents into circulation, causing thrombosis**
104
list the 4 categories of thrombocytopenia
1. decreased platelet production
2. decreased platelet survival
3. sequestration (splenic)
4. dilutional
105
describe type III von Willebrand disease
* type III = severe deficiency/lack of vWF
* affects Factor VIII stability int he plasma so the patient may clinically present like Hemophilia A (increased PTT)
106
list the laboratory findings in chronic ITP
* decreased platelets
* increased bleeding time
* autoantibodies against platelet membrane glycoproteins
107
myelophthisic anemia can be caused by ____ & ____ and there is a ____ blood picture
myelophthisic anemia can be caused by **metastatic cancer** & **granulomatous inflammation** and there is a **leukoerythroblastic** blood picture
108
in the condition seen in the image, there is an increased risk of aplastic crisis due to \_\_\_\_
in the condition seen in the image, there is an increased risk of **aplastic crisis** due to **Parvovirus B19** which infects **normoblasts/erythroid precursors**
109
describe what is seen on PB smear in folate deficiency
* hypersegmented neutrophils (\>5 lobes)
* increased MCV
* decreased reticulocytes
* normal ferritin, TIBC
110
describe blood level values seen in anemia of chronic disease
* decreased serum iron
* decreased TIBC
* increased serum ferritin
* normal or increased iron stores in BM
* EPO levels inappropriately low
111
describe the blood values in the condition seen in the image
* blood:
* ↓ iron & ferritin
* ↑ TIBC
* ↑ platelets
* ↑ free erythrocyte protoporphyrin
112
spontaneous remission of the condition seen in the image is uncommon in adults, but in children a ____ is more likely with a full recovery
spontaneous remission of the condition seen in the image is uncommon in adults, but in children a **viral etiology** is more likely with a full recovery
113
the most common cause of death in the major form of the condition seen in the image is \_\_\_\_
the most common cause of death in the major form of the condition seen in the image is **heart failure due to 2**° **hemochromatosis (due to increased blood transfusions)**
114
describe nutritional deficiencies that can lead to B12 deficiency
* nutritional: B12 found in dairy products & meat, therefore vegans can develop B12 deficiency
115
describe the presentation of the condition seen in the image
* presentation:
* asymptomatic
* weakness
* pallor
* koilonychia (spooning of fingernails), ↓ reticulocytes due to no iron, ↓ MCV, ↓ MHC, ↓ MCHC, ↑ RDW
116
describe how Plummer Vinson syndrome can lead to the condition seen in the image
* PVS triad:
* IDA
* esophageal webs
* atrophic glossitis
117
describe type I and II von Willebrand disease
* type I = 70% of all cases of vWD, with **mild, mostly mucosal bleeding**
* type II = 25% of vWD with **mild to moderate bleeding**
118
describe the pathogenesis of the condition seen in the image
* pathogenesis: abnormal enzymes are misfolded
* ↓ G6PDH → ↓ NADPH → ↓ GSH → oxidative injury by H2O2 → **intravascular hemolysis**
* oxidative stressors = fava beans, infections/antibiotics, antimalarial & sulfa drugs
* mechanism: **oxidation of SH groups** on globin chains of Hb → **Hb precipitates as Heinz bodies** → damage to RBC membrane → **intravascular hemolysis (predominantly)**
119
\_\_\_ is the most common cause of death in adults with the condition seen in the image
**acute chest syndrome: necrotizing pneumonia due to vaso-occlusion of pulm. arteries** is the most common cause of death in adults
120
describe the lab findings in hemophilia A
**factor VIII deficiency**
* normal platelets, BT, PT
* **prolonged PTT**
121
describe the impaired iron utilization and decreased RBC production seen in anemia of chronic disease
* decreased transfer of iron from the BM storage pool (macrophages) to RBC precursors, which is caused by hepcidin
* increased hepcidin production in chronic inflammatory states
* decreased erythropoiesis with inappropriately low erythropoietin
122
describe the complications of the condition seen in the image
* prone to small vessel thrombosis → infarct
* sickled cells are "sticky" due to increased expression of adhesion molecules on their surface
* **pooling of blood in the spleen aka sequestration crisis** → rapid splenic enlargement and entrapment of sickled RBCs → **hypovolemia** → reticulocytosis present in peripheral blood → infarct → splenic fibrosis → **autosplenectomy** **→ HJ bodies**
123
describe the effect of 3 α genes deleted
* 3 genes deleted = severe anemia
* B chains form tetramers (HbH) → high affinity for O2 → severe tissue hypoxia
* HbH is prone to oxidation → precipitated inclusions in older RBCs → extravascular hemolysis
