CMAP summary
Tuesday, December 1, 2015
10:06 AM
Anemia
Monday, October 26, 2015
8:26 AM
1. What is anemia? What’s its presentation?
 Reduction in total circulating RBC mass
 Presentation (hypoxia):
 Pale conjunctiva and skin
 Weakness, fatigue, dyspnea
 Headache and lightheadedness
 Angina, especially with CAD
2. How is anemia measured?
 Hb, Hct and RBC count (total RBC mass difficult to measure)
 All of these measures are concentration dependent so have problems. Ex – in pregnancy, blood
volume increases making Hb and Hct concentration low even though total amount might be
same. Immediately after gunshot wound and blood loss, Hb and Hct concentration might be
normal even though pt might have lost lots of blood.


What is practical definition of anemia?
Hb<13.5 g/dl for males and Hb<12.5 g/dl for females. (lower for females because of
menstruation)




What are different types of anemia?
Microcytic (MCV – mean corpuscle volume <80) – small RBC
Normocytic (MCV = 80-100) – normal size RBC
Macrocytic (MCV > 100) – big RBC
Microcytic anemia- Fe deficiency
Tuesday, October 27, 2015
9:23 PM
1. What is pathophysiology of microcytic anemia?
 Main problem in microcytic anemia is decreased production of Hb.
 RBC is produced from subsequent division of erythroblast (EB). During Hb deficiency, EB
divides too much. As a result, RBCs become small and microcytic anemia occurs. If erythroblast
doesn’t divide enough, macrocytic anemia occurs.
 Think that by dividing extra, RBC surface area exposed to blood increases and it can carry more
O2 – not correct idea but works for thinking
Fig: microcytic anemia. Normal RBC size is equal to size of nucleus of lymphocyte. Notice that
multiple RBC are smaller than that. Also notice variability in size of RBC and increased pallor in
center of RBC
2. What is hemoglobin made up of?
 Hemoglobin = heme + globin (protein).
 Heme = Iron + protoprophyrin.

What are etiologies of microcytic anemia (Hb deficiency)?




Fe deficiency
Anemia of chronic state- being unable to use Fe. In chronic inflammation, Fe is stored away in
macrophage and can’t be used.
Cideroblastic anemia – protoprophyrin deficiency
Thalessemia – decreased production of globin
Fe deficiency anemia


What is epidemiology Fe deficiency anemia.
Fe deficiency is the most common nutritional deficiency in the world making this the most
common type of anemia (1/3rd of world is deficient in Fe)


Describe digestion and storage of Fe (HY).
Fe is absorbed in duodenum (HY). Protein called FERROPORTEIN plays a key role in Fe
transport from lumen to enterocyte to blood.













TRANSFERRIN transports iron in blood and takes it to liver and bone marrow macrophage for
storage
Stored intracellular iron is bound to FERRITIN
There is no real way to get rid of Iron from body. So absorption by enterocytes is regulated.
(some lost during skin sloughing off and menstruation)
Iron is always bound to something because free Fe generates free radical by fenten reaction.
What are lab measurement for Fe in body?
Serum Fe – measures Fe in blood (most of it is bound to transferretin)
TIBC (total iron binding capacity) – tells total transferritin in blood. Normally, 1 in every 3
transferritin in blood is bound to Fe.
% saturation – % saturation of transferritin by Fe
Serum ferritin – indication of how much Fe is in storage sites
When ferritin↓, TIBC ↑ and vice versa(liver makes more TIBC to search for more Fe)
What are some etiologies of Fe deficiency anemia?
Malabsorption –
 Celiac
 Gastrectomy (HY)– Fe 2+ is absorbed easily (Fe 2 goes INTO the body). Acidic
environment promotes Fe 2 conformation. When stomach is resected, due to lost
acidity, more Fe will be in 3+ and Fe won’t be absorbed well.
Other etiologies are based on blood loss of dietary lack
 Infants – breast feeding (breast milk has no Fe)
 Children – poor diet
 Adults –
 peptic ulcer disease (most common cause in adult males);
 Menorrhagia (too much bleeding during periods) or pregnancy (females).
 Elderly –
 colon polyps/carcinoma (western world);
 hookworm (developing world)






What are stages of iron deficiency anemia?
Depletion of iron storage (low serum ferretin)
Depletion of serum iron
Normocytic anemia (HY) – first there will be few but normal sized RBC
Microcytic, hypochromic anemia (central pallor in RBC is big)
Know that Normocytic anemia is followed by microcytic in Fe deficiency anemia




What are clinical presentation of iron deficiency anemia?
Anemia
Koilonychia (spoon shaped nails)
Pica (psychological drive to eat dirt – perhaps to get Fe)





What are lab findings of Fe deficiency anemia?
Microcytic, hypochromic anemia with ↑RDW (RDW is like standard deviation of size of RBC;
larger the variation in RBC sizes, larger the RDW) – due to transition from normocytic to
microcytic anemia
↓ferritin, ↑TIBC
↓serum iron, ↓%saturation
↑FEP (free erythrocyte protoporphyrin)


Why is there ↑FEP in Fe deficiency anemia?
As Fe is low but protoporphyrin is normal, some protoporphyrin will be unbound to Fe hence
increasing the FEP.

What is blood smear finding in Fe deficiency anemia?


Poikilocytosis (variable shapes), anisocytosis (variable size), cigeratte shaped RBC (classic
finding), tear drop RBC
Microcytic anemia (note RBC smaller than lymphocyte nucleus)



What is treatment of Fe deficiency anemia?
Iron supplement – Ferrous sulfate
Rule out any risk factors (ex – if old people, rule out colon carcinoma)


What is Plummer-Vinson syndrome?
Iron deficiency anemia with esophageal web and atrophic glossitis (smooth tongue due to lack
of white papillae- beefy red appearance)
Microcytic anemia 2 - anemia of chronic disease
Tuesday, October 27, 2015
9:24 PM
Anemia of chronic disease
1. What is epidemiology of anemia of chronic disease (ACD)?
 Most common anemia in hospitalized pt.
2. What is pathophysiology of ACD?
 During acute/chronic inflammation, acute phase proteins are produced. One of them is
Hepcidin. It has 2 functions that results in anemia
 ↓Erythropoietin production
 Increased sequestering of Fe in macrophage. Less transfer of Fe to erythroid precursors
will result in Fe deficiency, which results in anemia.
 Evolutionary advantage of hepcidin is that bacteria need Fe to grow and flourish.




What are lab findings in ACD?
↑ferritin, ↓TIBC
↓serum iron (bone marrow takes Fe from serum as macrophage isn’t giving it), ↓% saturation
↑FEP (free erythrocyte protoporphyrin) (due to low available Fe but normal protoporphyrin,
free protoporphyrin will ↑)


What are stages of ACD?
Normocytic anemia is followed by microcytic anemia (same as Fe deficiency anemia)



What is treatment of ACD?
Treat underlying cause of chronic disease (to reduce hepcidin)
Exogenous erythropoietin (especially helpful in cancer pt)

What are lab difference between Fe deficiency anemia and ACD?
Fe deficiency
anemia
Anemia of
chronic disease
Hemochromatosis Oral contraceptive
pill (OCP)
↓
↓
↑
Transferrin/TIBC ↑
↓
↓
Serum Fe
↑
Ferretin


↓
↑
↑
Transferrin/TIBC change is always opposite of ferretin. Look at ferretin first.
TIBC (total iron binding capacity) is a measure of Transferrin
Sideroblastic anemia (sidero = related to iron)



What is pathophysiology of sideroblastic anemia?
Low synthesis of protoporphyrin is main cause.
If protoporphyrin is deficient, Fe is trapped in mitochondria. As mitochondria surround nucleus,
Fe trapping presents as ringed sideroblasts.
Fig: ringed sideroblasts seen in bone marrow biopsy (purssian blue stain – marks Fe)

What are steps of heme synthesis?

First and last three reactions take place inside mitochondria

What are etiologies of sideorblastic anemia?
Congenital
Acquired
Mutation of ALAS (most common cause of Alcoholism (EtOH is mitochondrial poison that
congenital sideroblastic anemia) - XR
damages protoporphyrin production)
Lead poisioning (denatures ALAD and
ferrocheletase)
Vit B6 deficiency (ALAS requires Vit B6 as
cofactor) – Isoniazid treatment can cause Vit B6
deficiency
10. What are clinical features of lead poisoning leading to sideroblastic anemia?
 Pt at old house with chipped paint at high risk
 Mnemonic LEAD:
 L - Lead lines on gingivae and metaphyses of long bones (aka Burton lines)




E - Erythrocyte basophilic stippling and encephalopathy (lead inhibits rRNA degradation
causing RBCs to retain aggregates of rRNA seen as basophilic stippling)
A - sideroblastic Anemia, Abdominal colic
D - Dimercaprol and EDTA for treatment; Wrist and foot Drop
Succimer used for chelation in kids - sucks to be kid that eats lead
Fig: From right to left - basophilic stippling; Burton lines on gum; metaphysis







What are lab findings in sideroblastic anemia? What's its treatment?
Lab findings based on Fe overload as they can’t attach to portoprophyrin
As Fe increase in erythroblast, cells die due to free radical produced by Fenten reaction. Fe
leaks out and is taken by macrophage.
↑ferritin, ↓TIBC
↑serum Fe, ↑% saturation
Very similar lab findings as hemochromatosis
Treatment:
 Pyrodoxine (B6 - cofactor for ALAS)
Microcytic anemia 3
Tuesday, October 27, 2015
9:26 PM
Thalassemia
1. What are normal globin molecule in hemoglobin?
Hemoglobi abDevelopment
n
subuni subuni al stage
t
t
HbF
a
Υ
Fetal, persists
for 6 moths
after birth
HbA
α
β
Adult
HbA2
α
δ
Adult (“Other
adult”)
2. How does thalassemia lead to microcytic anemia?
 Thalassemia is decreased synthesis of globin chains. It results in reduced hemoglobin which
leads to microcytic anemia. In sickle cell, there's defect in globin chain.


What are patients with thalassemia protected against?
Malaria by plasmodium falciparum.




What causes alpha thalassemia? What chromosome is alpha gene located in?
Alpha thalassemia is caused due to gene deletion of alpha chain of hemoglobin.
Normally, 4 alpha alleles are present on chromosome 16 (2 allele per chromosome)
'a in alpha looks like d (deletion); if you rotate b in beta, you get m (mutation).

What are subtypes of alpha thalassemia?
1 alpha allele
deleted

2 alpha allele deleted
Asymptomatic 
patient

Severe anemia
4 alpha allele
deleted - Hb Bart
Hydrops fetalis

Lethal in utero
(hydrops
fetalis)

Cys deletion (deletion of 
both allele on same
chromome) is worse than
trans deletion (deletion of
two allele on different
chromosome) because cys
is associated with
increased risk of severe
thalassemia in offspring
No problem in
fetus (one good
alpha allele takes
care)

Cis deletion classically

seen in Asians (higher rate
of spontaneous abortion
in Asia is partly due to
this)
Trans deletion classically
seen in Africans
When HbA and

HbA2 are formed, B
chain tetramers
(aka HbH) are
formed (4 B
combine due to
bad A)
Gamma chain
tetramers(aka
Hb Barts) are
formed

HbH can be seen 
on electrophoresis
Hb Barts seen
on
electrophoresis



Mild anemia with slightly
increased RBC count
(remember in microcytic
anemia, erythroblast
divides more)
3 alpha allele deleted
- HbH B chain
tetramer

What causes beta thalassemia? What chromosome is beta gene located in?
Beta thalassemia is caused due to mutation of beta chain of hemoglobin. Mutations result in
absent (aka B0) or diminished (aka B+) production of B-globin chain.
Normally, 2 beta alleles are present on chromosome 11 (1 allele per chromosome)

What are subtypes of beta thalassemia?
B/B+
B0/B0

Aka Beta thalassemia minor

Aka Beta thalassemia major

Pt usually asymptomatic with
increased RBC count

Pt has severe anemia few months after birth as
α4 tetramer will form (instead of α2β2)
HbF at birth is temporarily protective (no B in
fetal hemoglobin)


Microcytic, hypochromic RBC and
target cells on blood smear


Hemoglobin electrophoresis findings: 
 Increased HbA2 to 5% (normal
2.5%)- main finding
 Increased HbF to 2% (normal
1%)
 Slightly decreased HbA
Microcytic, hypochromic target cells and
nucleated RBC
Hemoglobin electrophoresis findings:
 No HbA (no B chain)
 Increased HbA2 and HbF


What are target cells?
Normally, hemoglobin is present mainly on edge of RBC giving it biconcave shape with central
pallor. In target cells, there are some hemoglobin in center giving central darkness (like bull's
eye target practice).

MOA- due to reduced hemoglobin in edge of RBC, the membrane in center gets floppy and
some hemoglobin comes to stay there.




What are presentation of beta thalassemia major?
Bad erythropoiesis with severe anemia
Extravascular hemolysis as spleen will phagocytose these RBC
Massive erythroid hyperplasia
o Expansion of hematopoiesis into skull and facial bone marrow - crew cut X-ray of skull
and chipmunk face
o Extramedullary hematopoiesis - hematopoiesis in liver and spleen (hepatosplenomegaly)
o Risk of aplastic crisis with parvovirus B19 (parvovirus affects erythrocyte precursors and
shuts down RBC production. In normal person, shutting down of RBC production for a
week or so won't matter. For pt with beta thalassemia major, they can't afford even a
single day of RBC production loss. They depend on every drop of RBC)
Fig: chipmunk face (left) and crewcut appearance (right) seen in massive erythroid hyperplasia

What is treatment of beta thalassemia major? What's it's complication?
Treatment is chronic blood transfusion; splenectomy for swollen spleen and iron chelation to
prevent secondary hemochromatosis
Macrocytic anemia
1. What is macrocytic anemia? What are it's causes?
 Macrocytic anemia is anemia with MCV (mean corpuscle volume) >100. RBC precursor doesn't
divide much and the RBC end up being big.
 Causes:
o Megaloblastic anemia (anemia with big cells) - disruption in production of DNA
precursors results in quick cytoplasmic development relative to nuclear development:
 Folate deficiency
 Vit B12 deficiency
 Orotic aciduria
 Folate and Vit B12 needed for DNA precursor synthesis
o Alcoholism
o Liver disease, drugs (ex- 5-FU)
Megaloblastic anemia
Vit B12 and Folate deficiency
2. Describe relationship between folate and Vit B12.
 Folate comes to body as methylated tetrahydrofolate (M-THF).
 THF is the active form. M-THF donates it's methyl group to Vit B12. Vit B12 then gives methyl
group to homocysteine. Homocysteine now becomes methionine.




What is presentation of macrocytic anemia due to folate or vit B12 deficiency?
Megaloblastic anemia (impaired division of RBC precursors)
Hypersegmented neutrophil with >5 lobes (normal is 3-5 lobes) (impaired division of
granulocytic precursors)
Megaloblastic changes in rapidly dividing cells (ex - intestinal epithelial cells)
Fig: hypersegmented neutrophils with large RBC (aka macroovalocyte) on the left- classic
finding in megaloblastic anemia



What is difference between megaloblastic anemia and macrocytic anemia that's not
megaloblastic?
In macrocytic anemia that's not megaloblastic, hypersegmented neutrophils and megaloblastic
changes (ex - large intestinal epithelial cells) won't be seen. Large RBC will be seen.
Compare dietary information of folate and vit B12.
Folate
Vit B12
Food
Dark green vegetable and food Animal derived proteins
Absorption
Jejunum
Ileum
Deficiency
Develops in months as body
stores are minimum
Takes years to develop due to large hepatic
storage
Causes of
deficiency



Poor diet (alcoholics, old)
Increased demand
(pregnancy, cancer,
hemolytic anemia)
Folate antagonists
(methotrexate - inhibits
DHFR)






Pernicious anemia (autoimmune
destruction of parietal cells of stomach) most common
Using proton pump inhibitor
Pancreatic insufficiency (Vit B12 won't be
free from R-binder)
Damage to terminal ileum (Chron's,
Diphylloborthium latum)
Vegans (dietary deficiency rare
otherwise)
Compare clinical and lab findings of folate and Vit B12 deficiency.
Folate deficiency
Vit B12 deficiency

Macrocytic RBC and
hypersegmented neutrophils

Macrocytic RBC and hypersegmented neutrophils

Glossitis (inflammation of
tongue - due to less turnover
of tongue cells)

Glossitis

Low serum folate

Low serum vit B12

Increased serum
homocysteine (increases risk
for thrombosis)

Increased serum homocysteine (increases risk for
thrombosis)

Normal methylmalonic acid;
no neuro symptoms

Increased methylmalonic acid in myelin cells which
impairs spinal cord myelinization resulting in subacute
combined degeneration of spinal cord



What are two important reactions that Vit B12 participate in?
DNA precursor synthesis (with folate)
Conversion of methylmalonic acid to succinyl Co. A



Why do we see increased serum homocysteine in folate deficiency?
Normally, dietary folate (M-THF) gives it's methyl group to Vit B12 which in turn gives it to
homocysteine. Homocysteine now becomes methionine.
The reaction won't happen in folate deficiency and we'll see increased serum homocysteine.


Why will methylmalonic acid be increased in Vit B12 deficiency?
Because Vit B12 is necessary to convert methylmalonic acid to succinyl Coenzyme A.




Describe absorbtion of Vit B12 in gut (HY)
R-binder protein from saliva binds to Vit B12. The complex will travel till small bowel. There's
Vit B12 is set free by pancreatic proteases.
The free Vit B12 binds to intrinsic factor secreted by parietal cells of stomach.
This complex will go to ileum and get absorbed there.




What are 3 P's of parietal cell?
Proton pump - they pump proton to stomach to make it acidic
Pink in histology (chief cells appear blue)
Pernicious anemia if they get damaged - makes IF
Orotic aciduria

Defn

Presentation 
Treatment
Inability to convert orotic acid to uridine monophosphate (UMP) that leads
to accumulation of orotic acid (defect in de-novo purine synthesis pathway)
AR inheritence


Megaloblastic anemia in children refractive to folate and vit B12
Failure to thrive, developmental delay
Orotic acid in urine but no hyperammonemia

UMP to pass the mutated enzyme
Nonmegaloblastic macrocytic anemia
Defn


Macrocytic anemia where DNA synthesis is unimpaired
RBC macrocytosis without hypersegmented neutrophils
Causes


Alcoholism
Liver disease


Hypothyroidism
Reticulocytosis
Normocytic anemia
Wednesday, October 28, 2015
10:10 AM
1. What is normocytic anemia? What are two types based on etiology?
 Normocytic anemia is decreased RBC mass with normal-sized RBC (MCV - 80-100 µm3)
 Types:
 Peripheral destruction of RBC (will have reticulocyte >3%)
 Extravascular hemolysis (RBC destroyed by liver, spleen and lymph)
 Intravascular hemolysis (RBC destroyed within blood vessel)
 Underproduction of RBC (no increased reticulocytes)
2. What are reticulocytes?
 They are young RBC released from bone marrow to replace dead RBC
 Seen as large cells with bluish cytoplasm (due to RNA) on blood smear
 Normally, 1-2% of RBC die every day and are replaced by reticulocytes.
3. How can reticulocyte be falsely elevated in anemia? How is reticulocyte count corrected?
 Reticulocytes are measured as percent of total RBC. In anemia, total RBC goes down. It will
elevating the percent of reticulocytes.
 It’s corrected by multiplying reticulocyte percent x hematocrit/45.
Total RBC Total
Reticulocyte
% of reticulocyte
Normal
pt
100
(given)
2 (given)
2%
Anemic
pt
50 (given) 2(given)
4%
HCT
Corrected
reticulocyte
23 (given)
4 x 23/50 = 2%
In this example, if we only look at % of reticulocyte, it looks as if bone marrow is normal. But
from corrected reticulocyte, we know that anemic pt’s bone marrow is not producing adequate
reticulocytes.
4. How can reticulocyte count differentiate cause of anemia?
If corrected reticulocyte >3%
If corrected reticulocyte <3%
Good marrow response (suggest peripheral
destruction as cause of anemia)
Poor marrow response (suggest
underproduction of RBC as cause of anemia)
Extravascular vs intravascular hemolysis
1. What is extravascular hemolysis? What happens to broken down RBC?
 Hemolysis done by reticuloendothelial system (macrophage in liver, spleen and lymph nodes)
 Globin is broken to AA; Iron is recycled
 Protoporphyrin is converted to unconjugated bilirubin which is carried by albumin to liver (its
fat soluble). It’s conjugated in liver and excreted to bile.
2. What are lab and clinical finding of extravascular hemolysis?
 Anemia with splenomegaly
 Jaundice due to unconjugated bilirubin (too much bilirubin to be conjugated by liver)
 High risk for bilirubin gallstones
 Marrow hyperplasia with corrected reticulocyte >3%
3. What happens in intravascular hemolysis? What's the presentation?
 RBC is destroyed in blood vessels. Unlike macrophage breaking down hemoglobin to bilirubin,
hemoglobin simply leaks out to blood.
 Hemoglobin is carried by haptoglobin. Haptoglobin is not present a lot. So, pt will quickly have
hemoglobinemia and hemoglobinuria (hemoglobin water soluble)
 Hemosiderinuria after few days (HY) - hemoglobin in urine is picked up by renal tubular cells.
Iron is recycled back and stored as hemosiderin. Renal tubular cells slough off (just like skin
cells) and hemosiderin will be seen in urine.
 Presentation:
Immediate

Decreased serum haptoglobin 

Hemoglobinemia

Hemoglobinuria
After few days
Hemosiderinuria
Normocytic anemia with mainly extravascular hemolysis
Wednesday, October 28, 2015
10:45 AM
Hereditary spherocytosis
1. What is hereditary spherocytosis? What are the mutations?
 In the disease, tethering proteins that attach RBC cytoskeleton to RBC membrane are mutated.
RBC membrane blebs and are lost over time. RBC becomes more spherical.
 Most common mutations are in proteins - ankyrin, spectrin, or band 3.
2. What are clinical and lab findings?
 See spherocytes - RBC becomes round instead of disc shaped (loss of central pallor)
 High RDW (some cells have lost tons of membrane and some only a little bit)
 high mean corpuscular hemoglobin concentration (MCHC) - high concentration of hemoglobin
as cells are getting small
 Extravascular hemolysis findings
o Anemia - spherocytes can't move through splenic sinusoids well and are eaten by
splenic macrophages (this is main problem) - having spherocytes isn't bad
o Splenomegaly (overworked spleen)
o Jaundice with unconjugated bilirubin, high risk for bilirubin gallstones
Fig: spherocytes with high RDW (note variability in RBC sizes and loss of central pallor)
3. What is one feared complication?
 Increased risk of aplastic crisis with parvovirus B19 infection of erythroid precursors
4. How is diagnosis of hereditary spherocytosis made?
 Osmotic fragility test - cells bursts in hypotonic solution very easily because cell doesn't have
much membrane to expand out
5. What's it's treatment?
 Splenectomy (having spherocytes isn't problem, spleen eating them is problem)
 Anemia resolves but spherocytes persist and Howell-Jolly bodies are seen
6. What's Howell-Jolly bodies?
 Some RBC's are impefectly made with little nucleus or nuclear material left. It's job of spleen to
take them out or kill the defective RBC. Howell-Jolly bodies are RBC with nuclear remnant. It
indicates splenic dysfunction
Fig: Howel Jolly bodies
Sickle cell disease
1. What causes sickle cell anemia?
 It’s caused due to mutation in B chain of hemoglobin that changes glutamic acid (hydrophilic)
to valine (hydrophobic). Think GingiVa - from Glutamic acid to Valine
 Disease is due to homozygous recessive mutation. Haterozygotes are protected against
plasmodium falciparum malaria

Phenotype
Hemoglobin composition
Sickle cell disease (homozygous mutation)
90% HbS, 8% HbF, 2%HbA2, no HbA
Trait (one mutated and one normal B chain)
55% HbA, 43% HbS, 2% HbA2
HbS – sickle cell hemoglobin (in α2β2 protein, both copies of β are mutated)
2. What is pathogenesis of sickle cell anemia?
 HbS polymerizes when deoxygenated (reversible). The polymers accumulate into needle
shaped structures and make RBC sickle cell.
 Sickling and de-sickling damages membrane leading to both intravascular and extravascular
hemolysis (spleen eats damaged RBC); sickled RBC cause vaso-occlusion; massive erythroid
hyperplasia to replace RBC.
 Sickling increases with hypoxemia, dehydration and acidosis.
 HbF protects against sickling. Kids protected for first few months of life.
3. What's treatment of sickle cell disease?
 Hydroxyurea - it increases level of HbF. It protects against sickling
4. What are presentations of sickle cell disease?
 Extravascular hemolysis – RBCs being sickle shaped and non-sickle cell repeatedly damages
membranes. Reticuloendothelial system removes these damaged RBC.
o Anemia
o Jaundice with unconjugated hyperbilirubinemia
o Increased risk for bilirubin gallstones
 Intravascular hemolysis – due to membrane damage
o Decreased haptoglobin
o Hemoglobinemia, hemoglobinuria
o Hemosiderinuria after few days
o Target cells - hemoglobin leaks out due to membrane damage and extra membrane
produces target cells
 Massive erythroid hyperplasia (to compensate hemolysis and anemia):
o Hematopoiesis in skull and facial bones (crewcut on X-ray and chipmunk face)
o Extramedullary hematopoiesis (in liver, giving hepatomegaly - pt don't have spleen so
don't get splenomegaly)
o Risk of aplastic crisis with parvo B19 infection

Fig: chipmunk face (left) and crewcut appearance (right) seen in massive erythroid
hyperplasia
Extensive sickling leads to vaso-occlusion
5. What are some physical findings in sickle cell disease due to vaso-occlusion?
 All findings based on infraction





Dactylitis – due to vasoocclusive infaracts in bones – common in infants
Autosplenectomy – shrunken, fibrotic and calcified spleen
o Increased risk of encapsulated organism infection (staph aureus, strep pneumo,
haemophilus influenza)
o Salmonella paratyphi osteomyelitis (encapsulated) - most common cause of
osteomyelitis is staph aureus; in sickle cell, it's salmonella.
o Howel-Jolly bodies on blood smear - nucleated RBC
Acute chest syndrome (vaso-occlusion of pulmonary microcirculation)
o Often precipitated by pneumonia
o Presents with chest pain, SOB, lung infiltrates
Pain crisis
Renal papillary necrosis – presents as gross hematuria and proteinuria
Fig: vaso-occlusive complications of sickle cell disease - from left to right - autosplenectomy small calcified spleen; renal papillary necrosis; dactilytis; Howel-Jolly bodies
6. What’s the most common cause of death in sickle cell patients?
Kids
Hemophilus influenza infection
Adults
Acute chest syndrome
7. What is sickle cell trait?
 Haterozygote carriers of sickle cell mutation have sickle cell trait. They have one mutated and
one normal beta chain.
 HbS (both beta chain mutated) makes <50% of total hemoglobin because HbA is slightly more
efficiently made than HbS
8. What are presentations of sickle cell trait?
 Generally asymptomatic as RBC with <50% HbS don’t sickle
 Renal medulla problems:
o Due to extreme hypoxia and hypertonicity in medulla, sickling occurs.
o Presents as microscopic hematuria and decreased ability to concentrate urine due to
microinfraction of medulla.
9. What are lab findings in sickle cell disease and trait?
Sickle cell disease
Sickle cell trait
Sickle cell and target cells seen in blood
smear
Don’t see sickle cell or target cells
Metabisulfite screen +ve (cells with any
Metabisulfite screen +ve
amount of HbS are sickled by the screen)

Confirm amount and presence of HbS with Hb electrophoresis
Sickle cell disease
90% HbS, 8% HbF, 2% HbA2, no HbA
Trait
55% HbA, 43% HbS, 2% HbA2
Hemoglobin C
1. What is hemoglobin C?
 Hemoglobin C is formed due to mutation in Beta chain of hemoglobin (autosomal recessive).
 Glutamic acid is changed to lysine (lyCne for hemoglobin C) - think Gingiva - Glutamic acid to
lyCine as gingiva is C shaped)
 Less common than sickle cell disease
2. What is presentation of hemoglobin C?
 Mild anemia due to predominant extravascular hemolysis
 HbC crystals on blood smear (HY)
Fig: HbC crystals characteristic of hemoglobin C (the rods)
Pyruvate kinase deficiency
Pathophys 

Blood
smear
RBC depend on glycolysis to synthesize ATP
Bad pyruvate kinase means ATP deficiency that affects lots of processes in
RBC

Echinocytosis (echino means hedgehog or sea urchin) - also see this in
hyperlipidemia, uremia, hemolytic anemia, hypomagnesemia,
hypophosphatemia etc

Contrast Echinocytosis which looks similar to acanthocytosis
Fig: acanthocytosis - see in hyperlipidemia or liver damage due to RBC
membrane damage
Normocytic anemia with mainly intravascular hemolysis
Wednesday, October 28, 2015
7:04 PM
Paroxymal nocturnal hemoglobinuria (PNH)
1. How do cells in blood protect themselves from complement system?


DAF (decay accelerating factor) and MIRL (membrane inhibitor of reactive lysis) are present in
RBC, WBC and platelets. They block complement fixation in RBC. DAF decays C3 convertase.
Protein called GPI (glycosylphophatidylinositol) anchors MIRL and DAF to cells.
2. What causes paroxysmal nocturnal hemoglobinuria?
 It's acquired (not congenital mutation) defect in myeloid stem cell so that GPI is absent in
myeloid stem cells. Complement fixation lyses RBC, WBC and platelets
3. What is presentation of PNH?
 Symptoms are seen paroxysmally at night because breathing becomes swallow and mild
acidosis activates complement at night.
 Dark urine early morning
 Hemoglobinura, hemoglobinemia
 Hemosiderinura seen few days after hemolysis (after tubular cells slough off)
 Thrombosis - due to release of clotting factors from lysed platelets
4. What is main cause of death in PNH?
 Thrombosis of hepatic, portal or cerebral veins - due to release of clotting factors from lysed
platelets
5. What are complications of PNH?


Fe deficiency anemia (due to chronic loss of Hb in urine)
Acute myeloid leukemia (10% of patients)
6. How is diagnosis of PNH made?
 Screening - Sucrose test
 Confirmatory test - acidified serum test or flow cytometry to test lack DAF (aka CD55) on RBC
Glucose-6-Phosphatase dehydrogenase (G6PD) deficiency - aka favism
1. What is G6PD deficiency? What's it's pathophysiology
 X linked recessive disorder (see in men) that results in low half-life of G6PD.
 G6PD is first enzyme in pentose phosphate pathway and is required to make NADPH. NADPH is
important to reduce oxidative stress.
 G6PD deficiency presents as increased oxidative stress including hemolytic anemia.
2. What are two major variants of G6PD deficiency?
African variant
Mediterranean variant

Mildly reduced half-life of G6PD

Markedly reduced half-life of G6PD

Mild intravascular hemolysis with
oxidative stress

High intravascular hemolysis with
oxidative stress
3. What protective role does being carrier of G6PD deficiency have?
 Protection against falciparum malaria
4. What's histology finding of G6PD deficiency anemia?
 Heinz bodies - precipitation of Hb due to oxidative stress
 Bite cells - Caused due to removal of Heinz bodies from RBC by macrophage
5. What are some causes of oxidative stress?
 Sulfa drugs
 Antimalarial drugs
 Fava beans
6. What's presentation of G6PD deficiency anemia?
 Hemoglobinuria and back pain (hemoglobin is nephrotoxic) hours after exposure to oxidative
stress
7. What is diagnosis of G6PD deficiency?
 Screening - Heinz preparation - need to see heinz body
 Confirm - enzymatic studies (don’t do it during acute phase because RBC lacking G6PD are
already dead).
Immune hemolytic anemia (IHA)
1. What causes immune hemolytic anemia?
 IgG or IgM mediated destruction of RBC.
2. Differentiate between IgG vs IgM mediated IHA.
IgG mediated IHA
IgM mediated IHA

Hemolysis is usually extravascular - tagged RBC are eaten 
Hemolysis is usually
extravascular- tagged RBC
are eaten

Warm agglutination - IgG binds to RBC in warm temp
(central parts of body).
Splenic macrophage phagocytose tagged RBC leading to
formation of spherocytes (when RBC are eaten only
halfway, remaining RBC makes sphere)

Cold agglutination - IgM
binds to RBC in cold temp
(extremities).
RBC can inactivate
complement, but C3b acts
as opsonin for splenic
macrophages - see
spherocytes







Associated with:

Lupus - pt have anti-blood Ab
CLL (chronic lymphocytic lukemia) - cause hemolytic
anemia
drugs (classically penicillin and cephalosporins) - drug
induces autoantibody production or Ab can bind to drugRBC complex
Associated with:
 Mycoplasma
pneumoniae (cold
agglutination test)
 infectious
mononucleosis (+ve
haterophile
agglutination - Ab
made against sheep
blood)
 CLL
Treatment
 Stop offending drug
 Steroids
 IVIG (distract spleen)
 Splenectomy - spleen is the one that eats RBC
3. How do you diagnose IHA?
Direct coombs test
Indirect coombs test

Confirms presence of Ab or complement
coated RBC

Confirm presence of anti-RBC Ab in
patient's blood

When anti-IgG or anti-complement Ab are
added to pt RBC, agglutination occurs only if
RBC are already coated with IgG or
complement

Anti IgG and test RBC(normal RBC) are
mixed in patient serum (agglutination
occurs only if serum Ab are present)

Most important test for IHA
Microangiopathic hemolytic anemia
1. What is microangiopathic hemolytic anemia (hemolysis in small blood vessel)?
 It's hemolysis that occurs due to vascular pathology (usually something in blood vessel breaks
the RBC)
2. What are some etiologies?
 Presence of microthrombi
o TTP- thrombotic thrombocytopenic purpura
o HU- hemolytic uremic syndrome
o DIC
o HELLP - hemolysis elevated liver enzyme and low platelet
 Prosthetic heart valves - crush RBC
 Aortic stenosis - crush RBC
3. What is blood smear finding?
 Schistocytes (broken RBC) - aka helmet cells
Fig - schistocytes (helmet cells) - has mostly two acute angle and loss of about 50% of RBC;
contrast bite cells that have usually >2 acute angles and almost entire volume of RBC is
present.
Malaria
1. How does malaria cause anemia?
 Plasmodium infects and replicates in RBC. RBC ruptures as merozoites (a stage in their lifecycle)
are released
 Spleen also consumes infected RBC causing some extravascular hemolysis
Erythroblastosis fetalis

Maternal IgG crossing placenta and attacking fetal RBC (ex - Rh -ve mother
carrying two consecutive Rh +ve babies)
Present 
See extramedullary hematopoiesis (ex - in liver) because RBC are damaged
Defn
Normocytic anemia due to underproduction
Wednesday, October 28, 2015
8:24 PM
1. What is anemia due to underproduction?
 It's anemia caused due to low RBC production by bone marrow.
 Characterized by low corrected reticulocyte (<3%)
3. What are some etiologies of anemia due to underproduction?
 Renal failure - decreased erythropoietin production by peritubular interstitial cells
 Anything that causes microcytic and macrocytic anemia
 Damage to bone marrow precursor cells - ex parvovirus B19
4. Describe how parvovirus B19 infection leads to anemia.
 Parvovirus B19 infects progenitor RBC and temporarily halts erythropoiesis.
 It causes significant anemia in setting of preexisting marrow stress (ex - sickle cell)
 Treatment is supportive (infection is self-limited)
Aplastic anemia
1. What is aplastic anemia?
 Aplastic anemia is damage to hematopoietic stem cell resulting in pancytopenia (anemia,
leukopenia, thrombocytopenia)
2. What are etiologies of aplastic anemia?
 Etiologies:
o Drugs or chemicals, radiation
o Viral infection - parvo B19, HIV, EBV, HCV
o Autoimmune damage
o Fanconi anemia (inherited DNA repair defect that causes bone marrow failure) - high risk
of leukemia later
3. What are biopsy finding in aplastic anemia?
 Empty fatty marrow
Fig: Aplastic anemia (left) vs normal bone marrow on right. Note the depletion of marrow and
replacement by fat globules on left.
4. What's treatment for aplastic anemia?
 Immunosuppression for cases with abnormal T cell activation
 Stop causative drugs
 Blood transfusion and marrow stimulating factors (erythropoietin, GM-CSF, G-CSF)
 May need bone marrow transplant
Myelophthisic process
1. What are melophthisic process?
 Pathologic processes that replace bone marrow (ex - cancer)
 Hematopoiesis is impaired resulting in pancytopenia
Lymphoid tissue anatomy
Saturday, December 5, 2015
2:57 PM
1. Spleen
 PALS (periarteriolar lymphatic sheath) - has T cells (drink tea with pals) - in white pulp
 Germinal center - has B cells - in white pulp