Approach to Anemia

PG CME 2014

Vikram MathewsHaematology DepartmentChristian Medical CollegeVellore

2017

Definition of Anemia

Beutler et al. Blood 2006.

Definition of Anemia

WHO definition of anemia (40 years old)

– Adult male <13g%

– Adult female <12g%

– Adult pregnant female <11g%

Beutler et al. Blood 2006.

Definition of Anemia

Databases analyzed:

Third US National Health and Nutrition Examination Survey [ NHANES-III ]

Scripps-Kaiser database

Definition of Anemia

Beutler et al. Blood 2006.

At Birth

Day 3 1 month

2 months

3 – 6 months

1 yr 2 – 6 yrs

6 – 12 yrs

RBC x 106/dL

6 ± 1 5.3 ±1.3

4.2 ±1.2

3.7 ±0.6

4.7 ±0.6

4.5 ±0.6

4.6 ±0.6

4.6 ±0.6

Hb gm/dL

18 ± 4 18 ± 3 14 ±2.5

11.2 ±1.8

12.6 ±1.5

12.6 ±1.5

12.6 ±1.5

13.5 ±2

MCV fl

110 ±10

105 ±13

104 ±12

95 ±18

76 ± 8 78 ± 6 81 ± 6 86 ± 9

WBC 18,000

± 8000

15000

± 8000

12000

± 7000

10000

± 5000

12000

± 6000

11000

± 5000

10000

± 5000

9000

± 4000

ANC 4000 –14000

(9000)

3000 –5000

(4000)

3000 –9000

(6000)

1000 –5000

(3000)

1000 –6000

(3500)

1000 –7000

(4000)

1500 –8000

(4750)

2000 –8000

(5000)

ALC 3000 –8000

(5500)

2000 -8000

(5000)

3000 –16000

(9500)

4000 –10000

(7000)

4000 –12000

(8000)

3500 –11000

(7250)

6000-9000

(7500)

1000-5000

(3000)

Briefly address:

- Reticulocyte count

- Coulter principle

- Generation of red cell indices

Reticulocyte Count

The reticulocyte count is the key toanswer the question whether it is aproduction problem or a loss problem

Expressed frequently aspercentage of RBC’s

Normal 0.5 – 1.5%(RBC – 5,000,000/mcl)

Absolute 25,000 – 75,000/mcl

Corrected Retic count= Obs/Exp Hb x Retic count

Reticulocyte Count

Normal Hb 12g%RBC count 5,000,000/mclRetic % 1%Absolute Reticulocyte count 50,000/mcl

Severe anemiaHb 6g%RBC count 2,000,000/mclRetic % 2%Absolute Reticulocyte count 40,000/mclCorrected Retic count 6/12 x 2 = 1%

Reticulocyte Count

- Additional correction for prolonged survival in peripheral blood often twice the normal duration of 1 dayhence x 0.5 (Reticulocyte production index)

RPI=Retic% x (Obs / Exp Hb:HCT) x (1/RMT)

- Limitations of reticulocyte count- High CV - Poor inter-laboratory comparison

(reticluocyte maturation time)

The Coulter Principle

Sensing Zone

Red Blood Cell

A red cell passes through RBC aperture

OscilloscopeOhm’s law: Voltage = Current X resistance

HgbHgb MeasurementMeasurementIn Beckman Coulter InstrumentsIn Beckman Coulter Instruments

ADC Signal Processor

HGB Lamp

Hb Cuvette

SampleHGB Sensor &

PRE-AMP

Absorbance= log 10 ( VR / Vs )

Where VR = Reference voltageVs = Sample voltage

Derivation

RED CELL INDICES

MCV (fl)= PCV 0.45 = 90fl Normal range: 81 – 101 fl

RBC count/L 5 x 1012

MCH (pg) = Hb/L 150 = 30pg Normal range: 27 – 32 pg

RBC count/L 5 x 1012

MCHC (g/l) = Hb (g/l) 150 = 33.3g/l Normal range: 31.5 - 34.5 g/l

PCV (%) 45

Reference ranges from Dacie and Lewis Practical Haematology

RED CELL INDICES

MCV (fl)= PCV 0.45 = 90fl Normal range: 81 – 101 fl

RBC count/L 5 x 1012

MCH (pg) = Hb/L 150 = 30pg Normal range: 27 – 32 pg

RBC count/L 5 x 1012

MCHC (g/l) = Hb (g/l) 150 = 33.3g/l Normal range: 31.5 - 34.5 g/l

PCV (%) 45

Reference ranges from Dacie and Lewis Practical Haematology

RBC Distribution Width (RDW)

Normal ValuesAs CV 12.8±1.2%As SD 42.5±3.5fl

Anemia results in decrease in oxygen carrying capacity

Symptoms depend on:

Degree of anemiaRate of fall in hemoglobinCapacity to compensate

Increase cardiac outputTachycardiaIncreased stroke volumePeripheral resistance

Change in O2 dissociation curve – 2,3 DPGOther co-morbid conditions

Clinical Features

Clinical Features of Anemia

TIREDNESS / EXERTIONAL DYSPNOEA

PALPITATIONS

HEADACHE

PALLOR

TACHYCARDIA

HYPERPNOEA

HYPERDYNAMIC CIRCULATION

FEVER

FEATURES OF HYPOXIA

History: - DURATION OF SYMPTOMS- ONSET & PROGRESSION- BLOOD LOSS IF ANY

TRANSFUSIONS - FREQUENCY- DATE OF LAST TRANSFUSION

- OTHER TREATMENT RECEIVED- EXPOSURE TO DRUGS AND CHEMICALS- DEVELOPMENTAL HISTORY IN CHILDREN- FAMILY HISTORY- OTHER ASSOCIATED SYMPTOMS IF ANY

- INFECTIONS- BLEEDING- OTHER SYSTEMS REVIEW

1. Reticulocyte count in diagnosis of anemia

Decreased production

Increased peripheral destruction

Classification of Anemia based on red cell size

Microcytic Normocytic Macrocytic

2. Morphology approach – based on alteration of red cell size best indicated by the MCV along with the reticulocyte response

Microcytic Hypochromic Anemia

IRON STORES

LOW/ ABSENT

NORMAL / INCREASEDIRON DEFICIENCY- S.Iron /TIBC- S.Ferritin- BM Iron Stores

LOOK FOR CAUSE

1. THALASSEMIA α / β- Hb A2/F- HbH Stain- Globin Chain Analysis

2. HEMOGLOBINOPATHY(Few)- Hb Electrophoresis

3. SIDEROBLASTIC ANEMIA- Siderocytes- Sideroblasts4. ‘CHRONIC DISEASE’

- Diagnosis of Exclusion

Increased lossHemorrhage

GI tractKidneyUterusOther

Decreased intakeIncreased regq-mnt

NutritionalPregnancyLactationOther

Iron deficiency

Causes of GI Blood Loss

ESOPHAGEAL WEB

VARICES, REFLUXCARCINOMA ULCER, CARCINOMA

LEIOMYOMAGASTRITIS

DUODENALULCER

POLYPS, MECKEL’SAV MALFORMATION

HAEMORRHOIDS

CARCINOMAULCERATIVE COLITIS

AMOEBIASISCARCINOMATUBERCULOSISCHRON’S

Normal

Iron deficiency

Low MCVSerum FeS Ferritin

Thalassemia minor

Serum Iron : 32 115 +/- 50 mgm/dL

Iron Binding : 312 330 +/-30 mgm/dL

Capacity

% Saturation : 10.2% 35 +/- 15%

Serum Ferritin: 4 M - 30-300 ng/ml

F - 15-150 ng/ml

Thalassemia / haemoglobinapthy: - appropriate clinical setting- low MCV- low RDW- normal / increased ferritin

Peripheral smear

Hb electrophoresis

HPLC

Mutation analysis

Anemia of Chronic Disease:

Acute infections

Chronic infections

Tuberculosis

Infective endocarditis

Chronic urinary tract infection

Chronic fungal infection

Chronic inflammatory disorders Osteoarthritis Rheumatoid disease Collagen vascular disease Polymyalgia rheumatica Acute and chronic hepatitis Decubitus ulcer

Malignancy Metastatic carcinoma Hematologic malignancies Leukemia Lymphoma Myeloma

Proteinenergy malnutrition

Serum Iron and IBC

NORMAL IRON IRON ANAEMIA OFDEFICIENCY OVERLOAD CHRONIC DISEASE

SE

RU

M I

RO

N

Differentiating from iron deficiency anemia

- Important since ACD does not respond to iron supplements

- Peripheral smear- History

Bone marrow

Hereditary Spherocytosis Sickle cell anemia

MAHA

Aplastic Bone Marrow

Heinz Bodies- G6PD deficiency- Other enzymopathies- Thalassemia

AIHA - AUTOAGGLUTINATION

Leukemia Bone Marrow

Vitamin B12Total Body content –2-5 mgRDA-5-7 mcg/dayTakes 3-4 years to deplete stores

Folic AcidTotal Body content- 5-10 mgRDA- 50 mcgStores can be rapidly depleted.

Folate Deficiency

Decreased Intake

Pancreatic diseaseIncreased RequirementGrowthPregnancyLactationHaemolysis

Metabolic BlockPyrimethamineMethotrexate

Diseases of the smallintestineMal-absorptionBacterial overgrowth

B12 Deficiency

Decreased IntakePure vegetarians

GastrectomyPernicious anemia

Diseases of theterminal ileum

TC II deficiency

Metabolic Block

Megaloblastic Anaemia

Clinical Features

Anaemia with icterus

Macrocytosis, hypersegmented neutrophils, pancytopaenia

Raised indirect bilirubin, LDH

Hypercellular marrow with megaloblastic changes

Pathophysiology of megaloblastic anemia

1.B12 and folate deficiencies result in defective DNA synthesis .

2.This results in an abnormal cell maturation process

3.Megaloblastic cells die in the bone marrow. (apoptosis through p53)

Laboratory evaluation

Suspect when MCV raised

LDH raised

Raised Indirect Bilirubin

Peripheral smear Macrocytosis

Hypersegmented neutrophils

Pancytopenia

Bone Marrow examination

Serum B12 assay

Serum and red cell folate assays

Serum B12 and Folate

Reference ranges Serum B12: 100-700 pg/mL Serum Folate: 3-16 ng/mL

Lower limit for B12 deficiency not well defined

In untreated patients with folate deficiency levels are usually <1.0 ng/mL

Other tests may be needed in borderline cases Serum methyl malonic acid Serum homocysteine

MMA and tHcys are now considered GOLD STD for diagnosis of Vitamin B12 Deficiency.(98% and 96% sensitivity respectively- Savage- Am J Med 1994)

These tests are used in patients with-(1) Borderline Cobalamin and Folate Deficiency.

(2) In conditions which increase or decrease levels.

(3) Both Cbl and Folate are low( MMA= Cbl def)

(4) When there are low Serum levels.

Approach to a Patient with Hemolytic Anemia

Clinical Signs of hemolysis

Chronic long standing from childhood

– Skeletal Abnormalities» Frontal Bossing

» Maxillary prominence

» Harrison’s sulcus

» Genu valgum

Jaundice with acholuric urine

Hepatosplenomegaly

Chronic leg ulcers

Laboratory indices of hemolysis

Raised reticulocyte count, polychromasia

Raised serum bilirubin – indirect fraction

Increased urine urobilinogen

Raised LDH

Intravascular hemolysis– Urine hemoglobin

– Plasma hemoglobin

– Decreased serum haptoglobin

– Methhemalbumin

HEMOLYTIC ANEMIA

COOMBS TEST

IMMUNENON IMMUNE

+ -

WARM Antibody

COLD Antibody

CONGENITAL ACQUIRED

Primary idiopathicSecondary

LymphoproliferConnective tissueDrugsHaptenImmune complex

Primary idiopathicSecondary

LymphoproliferInfectionsMycoplasmaInf Mono

PCHSyphillisPost viral

HemoglobinopathyThal majorHb E disease

EnzymopathyG6PD def

MembranopathyHer spherocytosis

PNH

MAHA

Venoms

Infections

Drugs / Chemicals

Laboratory tests required to establish the cause of hemolysis

Congenital

– Blood Picture

– Sickle prep, Hb H prep, Electrophoresis/HPLC

– Osmotic fragility

– Unstable Hb, Heinz body

– G6PD, PK

Acquired

– Coomb’s test

– Tests for PNH

With a rational approach it is possible to determine the cause of anemia and then plan appropriate treatment