Anemia (Taylor) Flashcards
Evaluation of Anemia
Erythron: Circulating RBCs and erythroid marrow (5 day maturation from BFU-E).
• 2L RBCs and 90mL marrow in 70kg male •
Reticulocyte – no nucleus – retains mitochondria, rRNA and hemoglobin synthesis 24-36 hours in circulation • Loss of these organelles in sinusoids of spleen
Mature RBC – 120 day lifespan until marked for destruction. Steady state, daily replacement of 0.83% of erythron (17 mL)
Oxygen Sensing-Hypoxia stimulates erythropoietin synthesis; done in the kidney
Erythropoiesis
Epo is made in the kidney and released in the blood stream then the bone marrow.
Hemoglobin
measured by absorption at 540 nM after cell lysis, the best measure of O2 carrying
RBC count
automated rbc counting when alter electrical conductance through aperture (x109/μL). Cells > 36 femtoliters in size and density of the cell
Hematocrit
volume blood composed of
RBCs. Calculated by RBC x MCV/10 and
reported in %. This is a calculated value!
aka packed cell volume
MCV (mean cell vol)
RBC size measured directly and
reported as a histogram. The mean rbc size is
reported as the mean cellular volume.
• Normocytic, microcytic (<80) or macrocytic (>100)
Mean Cellular Hemoglobin (MCH)
Calculated = hgb/RBC x 10. Few clinical uses.
Mean Cellular Hemoglobin concentration (MCHC)
Calculated = hgb/HCT x 100.
Normal 32-36 g/dL.
- MCHC < 32 = hypochoromic
- MCHC elevated in heretitary spherocytosis
Red cell distribution width (RDW)
Calculated value with normal range = 11.5% - 14.5%.
Reticulocyte count
% of all RBC (normal 0.8-1.5%)
Absolute reticulocyte count
– Relative reticulocyte count x RBC count
– Normal 25,000-90,000/μl
– Examples:
1.1% x 4.96 x106 = 55,000/μl
12.2% x 2.05 x106 = 250,000/μl
Anemia by Etiology
External blood loss – acute or chronic
• Increased destruction (hemolysis) – long
differential including toxin, RBC defect,
extra-erythrocytic damage (antibody, etc.),
splenic destruction
• Decreased production (hypoplastic) –
primary marrow failure, insufficient Epo,
injury (radiation), replacement (malignancy)
Classification of Anemia:
RBC Kinetics and Size 1
Macrocytic = MCV >100 fL
- Microcytic = MCV < 80 fL
- Hypochromic = MCHC < 32 g/dL
Classification of Anemia:
RBC Kinetics and Size 2
Macrocytic, normochromic anemia vs Normocytic, normochromic anemia
Macrocytic, normochromic anemia
– MCV >100 fL
– Megaloblastic (B12 or folate def., chronic AZT)
– Non-megaloblastic (drugs, liver disease,
hypothyroidism) – often with reticulocytosis
• Normocytic, normochromic anemia
– Acute blood loss, acute hemolysis, bone marrow
failure, chronic disease, hypersplenism
Microcytic, hypochromic anemia
MCV < 80 fL; MCHC <32 g/dL
– Iron deficiency
– Lead poisoning
– Thalassemia (can be normochromic)
– Chronic disease
Case 1:
19-year old male admitted hospitalized for an elective cholecystectomy.
- A consultation is requested to evaluate anemia noted with pre-operative testing. “Always been told by physicians has mild anemia”.
- Past medical history: Negative.
- Vitals signs normal. Mild icteric sclerae and palpable mass in the left upper quadrant below the costal margin. Remainder normal
cholecystectomy - hemoglobin is broken down to billirubin and excreted by the gall bladder
LUQ- spleen, destruction of red blood cells
Normocytic Anemia
Case 1 labs
Hemoglobin 11.2 g/dl
- Hematocrit 34%
- WBC 9.0, normal diff
- Platelet count 295,000/ul
- MCV 89 fl
• Absolute reticulocyte count 200,000 (29,500-87,300)
• Blood Smear Polychromasia, microspherocytes
micrspherocytes - HS or something causing hemolysis
normocytic
Case 1: Which of the following tests is most likely to help confirm the diagnosis?
A. Hemoglobin Electrophoresis
B. Osmotic Fragility Test
C. Direct and Indirect Antiglobulin (Coombs) test (autoimmunity)
D. Bone Marrow Aspiration and Biopsy (cancer maybe)
B. Osmotic Fragility Test
Hereditary spherocytosis
Normocytic anemia classifications
DETERMINE IF ADEQUATE BONE MARROW RESPONSE RELATIVE TO DEGREE OF ANEMIA
(ABSOLUTE RETICULOCYTE COUNT OF > OR = 100K)
normal BM
myelophistic anemia
absence space and fat globules
aplastic anemia
NORMOCYTIC ANEMIA:
WITH ADEQUATE RESPONSE
choice with reticulocytosis
acute blood loss or hemolysis
methylene blue stain: residual RNA
POLYCHROMASIA: INCREASED
RETICULOCYTES ON PERIPHERAL
SMEAR
NORMOCYTIC ANEMIA: HEMOLYSIS: extravascular
NORMOCYTIC ANEMIA: HEMOLYSIS
Intravascular
COMPLEMENT FIXATION
Example: PNH or paroxysmal
nocturnal hemoglobinuria. Acquired
somatic mutation in PIGA gene = no
GPI-linked membrane proteins like
CD55 (DAF or decay accelerating
factor). Complement fixation and
intense intravascular hemoloysis.
MECHANICAL FIXATION
EXOGENOUS TOXIC FACTORS
HB PRODUCTS IN BLOODSTREAM
Heme ring to biliverdin to bilirubin
extravascular vs intravascular hemolysis
NORMOCYTIC ANEMIA: CLASSIFICATION
WITH RETICULOCYTOSIS
Case 2:
42-year-old female with Systemic Lupus
Erythematosus (SLE) presents with fatigue
•Has been on Anti-TNF therapy and doing well
from lupus standpoint. However, she has
recently experienced worsening fatigue.
•Vital signs normal. Face and conjunctiva are
both jaundiced; she has a fading butterfly
rash on her face. The spleen is palpable on
deep inspiration.
HEMOGLOBIN 7.8 G/dL
- HEMATOCRIT 27%
- MCV 95 FL
- WBC COUNT 4.5, NORMAL DIFF
- PLATELET COUNT 450,000 /UL
- ABSOLUTE RETICULOCYTE 170,000 (29-87)
- ESR 25 MM/HR
- LDH 400 U/L (140-280)
- T. BILIRUBIN 3.5 MG/DL ((0.1-1.0)
- I. BILIRUBIN 3.0 MG/DL
Normocytic anemia
elevated reticulocyte count
LDH - some type of hemolysis is going on
neutrophils and spherocytes present= hemolysis
CASE #2
• WHICH OF THE FOLLOWING IS THE BEST
INTREPRETATION OF THE DATA?
A. The hemolysis is predominately intravascular.
B. The bone marrow is not responding to the anemia.
C. Direct Coombs testing should be positive.
D. Urine hemoglobin testing should be positive.
D. Urine hemoglobin testing should be positive. (Combs positive)
DIAGNOSIS: WARM AUTOIMMUNE HEMOLYTIC ANEMIA
ASSOCIATED WITH LUPUS
• EXTRAVASCULAR PROCESS
NORMOCYTIC ANEMIA: EXTRINSIC
IMMUNE: AIHA
Warm antibody type
- Active at 37C (body temp)
- IgG and RARELY complement
- Monospecific Coombs’ test
- Primary (Idiopathic)
- Secondary
- Lymphoma/CLL
- Autoimmune disorders
(LUPUS)
• Drugs
NORMOCYTIC ANEMIA: HEMOLYSIS
EXTRINSIC DEFECTS: NON-IMMUNE
TTP= cleaving vWF factor by metalloproteinase
MICROANGIOPATHIC ANEMIA
NORMCYTIC ANEMIA: HEMOLYSIS
intrinsic RBC defects
MEMBRANE:
- HEREDITARY SPHEROCYTOSIS
- HEREDITARY ELLIPTOCYTOSIS
- PNH
HEMOGLOBIN:
- SICKLE CELL ANEMIA
- THALASSEMIAS
- UNSTABLE HEMOGLOBINS
ENZYME DEFECTS:
-G6PD DEFICIENCY (CHECK
LEVELS BETWEEN ATTACKS)
-PRYVATE KINASE DEFICIENCY
NORMOCYTIC ANEMIA: INTRINSIC
HEMOLYSIS: MEMBRANE DEFECTS
HER. SPHEROCYTOSIS and HER. ELLIPTOCYTOSIS
Diagnostic tests: osmotic fragility test
Hereditary spherocytosis frequent pigment gallstones
Her. spherocytosis
Her. Elliptocytosis
ENORMOCYTIC ANEMIA: INTRINSIC
HEMOLYSIS: MEMBRANE DEFECTS
Extravascular hemolysis: Kupffer cells phagocytose rbcs in the spleen
and liver.
CASE #3
•28-year-old male with sickle cell disease
present to ER with abdominal pain, chest
pain, and shortness of breath (SOB).
- His dyspnea evolved over 36 hours after a visit with his kids.
- History of 2 ER visits per year
- He takes Hydroxyurea intermittently.
VITALS SIGNS: PULSE: 116, B/P: 138/76 and
resp rate: 18 and T: 38.3
- Pulse oximeter: 85% on room air; 90% on 4L of O2
- Lungs: Inspiratory crackles in RML.
- Spleen is not palpable
- Rest of exam normal
HEMOGLOBIN 7.9 G/DL
- HEMATOCRIT 25%
- MCV 80 FL
- WBC 16.0 (70% PMNs; 15% LYM)
- PLATELET 490,000
- CXR: RML INFILTRATE -
- SpO2 = 60% on room air
some type of pneumonia
Case 3
Howell Jolly body = nuclear remnants, normally removed by the spleen
CASE #3
• WHICH OF THE FOLLOWING SHOULD YOU ORDER?
A. HYDROXYUREA
B. ERYTHROCYTE EXCHANGE TRANSFUSION
C. PLASMA EXCHANGE
D. ANTICOAGULATION WITH UNFRACTIONATED HEPARIN
E. AGGRESSIVE IV HYDRATION
ANSWER: B. ERYTHROCYTE EXCHANGE TRANSFUSION
- DIAGNOSIS: Sickle cell anemia ACUTE CHEST SYNDROME
- When do you do acute exchange transfusion?
- Acute Chest Syndrome
- Acute Stroke
- NOT FOR AN UNCOMPLICATED PAIN CRISIS – transfusion has no
role in uncomplicated pain crisis unless severe anemia!
SICKLE CELL DISEASE VS TRAIT
SICKLE CELL DISEASE
• BOTH ALLELES FOR β-GLOBIN
GENE MUTATED (SS)
- LOW HGB (anemia): 8-10
- SICKLING WITH HEMOLYSIS 6
MONTHS OF AGE ONWARDS
due to decline in HbF
• VASO-OCCULSION (pain)
SICKLE CELL TRAIT
• ONE SICKLE β-GLOBIN CHAIN
MUTATED (AS)
- <50% HbS
- NOT ANEMIC (normal Hb)
- NO SICKLED CELLS
- RARELY SYMPTOMATIC
- Risk w severe hypoxia,etc.
PATHOPHYSIOLOGY OF SCD
SICKLE CELL DISEASE
CLINICAL MANIFESTATIONS
- CHRONIC HEMOLYTIC ANEMIA
- LIFESPAN OF RBC IS 20 DAYS VS. 120 DAYS
- EXTRAVASCULAR >>>>>>>> INTRAVASCULAR
- OCCULUSION SMALL VESSELS
- TRAPPING SICKLED CELLS
- DELAYED CIRCULATION TIME
- EXPOSURE TO LOWER OXYGEN STATES
- PAIN DUE TO HYPOXIA
SCD:THERAPY PRINCIPLES
- THERAPY
- PREVENTING INFECTIONS (ANTIBIOCTIC
PROPHYLAXIS IN CHILDREN,
PNEUMOCOCCAL VACCINATIONS)
•PREVENTING SICKLING EPISODES (STAY
HYDRATED; AVOID STRESS)
- ANALGESIA FOR ACUTE PAINFUL CRISES
- INCREASING HbF WITH HYDROXYUREA
FDA approved therapies for SCD
L-Glutamine (Endari) – precursor for NAD –
an rbc antioxidant. Reduces pain, increases
hemoglobin.
•Voxelotor (Oxbryta) – small molecule that
shifts P50 curve (oxy-hemoglobin saturation
curve) to the LEFT like HbF. INCREASES
Hb but no effect on pain.
•Crizanlizumab (Adakveo) - monoclonal
antibody blocking post-vaso-occlusion
inflammation (blocks P-selectin). ↓ pain 50%.
experimental SCD therapies
HLA matched sibling donor stem cell
transplant
•Lentivirus mediated gene therapy (insert
modified HbA into stem cells ex vivo followed
by transplant). Recombinant HbA modified
with anti-sickling mutations (axial and lateral sickle β contact sites from M1 lecture)
•CRISPR/CAS9 gene editing/mutation of
BCL11A to increase HbF (BCL11A repressor
of HbF synthesis)
NOT ON TEST
EVALUATION ALGORITHM:
NORMOCYTIC ANEMIA
CASE #4
• 46-year-old female with progressive numbness.
Initially, she has tingling of her toes and now she
has decreased sensation to the level of her thighs
and has trouble buttoning her shirts.
• Physical exam: Objective decreased sensation
greatest in the lower extremities with markedly
diminished proprioception.
• Labs: Hgb 9.5 g/dl, Hct 27%, MCV 113, WBC 3600,
Platelets 398,000
microcytic anemia
small lymphocyte
Huge red blood cells
CASE #4
• THE NEXT MOST APPROPRIATE TESTS IN THIS
PATIENT WOULD BE:
A. Serum folic acid, AST, ALT, and TSH
B. Bone marrow biopsy to look for dysplasis and ringed sideroblasts
C. Flourescent in situ hybridization (FISH) for BCRABL on the peripheral blood (Philadelphia chromosome)
D. Serum Vitamin B12 and Folic acid, plasma homocysteine and methylmalonic acid
D. Serum Vitamin B12 and Folic acid, plasma homocysteine and methylmalonic acid
Serum Vitamin B12 and Folic acid, plasma homocysteine and methylmalonic acid
- Diagnosis: Megaloblastic anemia (likely B12 deficiency)
- Etiology: pernicious anemia (anti-parietal antibodies and no intrinsic factor made to absorb
B12 in terminal ileum); gastric bypass surgery (no IF in gut); GI surgery (resection terminal ileum)
MACROCYTIC ANEMIA:
MEGALOBLASTIC
has to do with cell cycle arrest
MACROCYTIC ANEMIA: CLASSIFICATION
Testing for B12 and folate deficiency
in b12 methylmalonic acid is elevated and in folate the methylmalonic acid will be normal or low
homocysteine is elevated in both
megaloblastic anemia
MACROCYTIC ANEMIA:
CLASSIFICATION
MACROCYTIC ANEMIA
LIVER DISEASE
Target cells + echinocytes
HYPOTHYROIDISM
Round macrocytes and other cells
liver disease- microcytic anemia
microcytic anemia
hypothyroidism
MACROCYTIC ANEMIA ALGORITHM
CASE #5
•58-year-old female with active rheumatoid
arthritis, presents with fatigue and joint pain
•She is taking Prednisone 10 mg daily and
weekly Methotrexate
• Vital signs are normal. Conjunctiva are pale and active synovitis affecting both knees.
HEMOGLOBIN 9.0 G/DL
- HEMATOCRIT 30%
- MCV 80
- WBC 11,500 WITH 80% NEUTROPHILS
- PLATELET 500,000/UL
- ESR 50 MM/HR
- ERYTHROPOIETIN 15 MU/ML (0-19)
normocytic macrocytic anemia
CASE #5
• WHICH OF THE FOLLOWING LABORATORY FINDINGS ARE
CONSISTENT WITH THIS CONDITION?
A. Elevated hepcidin, elevated ferritin, elevated TIBC, elevated
serum iron
B. Elevated hepcidin, elevated ferritin, decreased TIBC, elevated serum iron
C. Decreased hepcidin, elevated ferritin, decreased TIBC, elevated serum iron
D. Elevated hepcidin, elevated ferritin, decreased TIBC, normalserum iron
Elevated hepcidin, elevated ferritin, decreased TIBC, normal serum iron
- Answer: D
- Clinical Diagnosis: Anemia of Chronic Disease
MICROCYTIC ANEMIA: HEMOGLOBIN
SYNTHESIS DEFECT
Hemoglobin Ontology
Adult hemoglobin:
- A: α2β2
- F: α2ϒ2
- A2: α2δ2
- β-Thalassemia
- Increased HbA2 and F
- β-globin: Chromosome 11
- α-globin: Chromosome 16
microcytic anemia
β-Thalassemia
β-Thalassemia Minor (β/β0 or β/β+)
- Single gene defect
- Trait (heterozygote)
- Microcytosis
- Asymptomatic but mild anemia
β-Thalassemia Intermedia (β+/β+)
- 2 genes abnormal
- Anemic: No transfusion needed
β-Thalassemia Major (β0/β0 or β+/β0)
- 2 abnormal genes
- Severe anemia (extramedullary
hematopoiesis; Hb 2-3 gm/dL)
•Transfusion dependent (monthly)
a-THALASSEMIA
- Normal:
- 4 a globin genes
- Abnormal:
- 0-3 alpha globin genes
- Small DNA deletions (meiotic crossover events)
- Large DNA deletions (Southeast Asian)
- Less common point mutations (Hb Constant
Spring)
Hemoglobin Electrophoresis: NORMAL Diagnosis: DNA Testing for mutation
a-THALASSEMIA DNA DELETIONS
- Small DNA deletions: Remove 1 a gene
- 3.7 kb deletion, rightward (z box); ( - a3.7)
- 4.2 kb deletion, leftward (x box); ( - a4.2)
- Nonreciprocal homologous recombination
event: -a / aa and aaa / aa
a-THALASSEMIA DNA DELETIONS- large
Large DNA deletions:
- Remove 2 a genes, gives rise to a0 phenotype
- Southeast Asian variant (SEA; D20 kb), deletions
common in Asia only
Genotypes in red are only observed in Southeast Asia (why?) – Cis 2 gene
deletion alleles only seen in Asia
a-thallassemia
- 29% of African Americans are silent carriers
- 1-2 % of African Americans have a-thal trait
- Note again that only 1 gene deletion alleles are
observed in Africa (so no HbH or hydrops in Africa)
IRON STUDIES IN MICROCYTIC
ANEMIA
IRON DEFICIENCY ANEMIA
LOW FERRITIN
- HIGH EPO
- HIGH TIBC
- LOW SERUM IRON
- What is the cause? Typically chronic blood loss or inadequate
dietary intake.
• Common causes of chronic blood loss: GI bleeding (colon cancer),
menorrhagia (females), poor diet (children ~4-5 years of age)
ANEMIA OF CHRONIC DISEASE
HYPOPROLIFERATIVE ANEMIA
- ELEVATED INFLAMMATORY MARKERS
- MOST COMMON CAUSES OF ANEMIA
AMONG HOSPITALIZED PATIENTS
MICROCYTIC ANEMIA ALGORITHM
See self study slides