Dr Mere Kende, MBBS (UPNG), MMED (Path), MAACB (AUS), MACTM (AUS), MACRRM (AUS)

Lecturer-SMHS

UPNG

Outline

Hemopoiesis in Normal Pregnancy

Anaemia

Iron Deficiency

Folate Deficiency

Aplastic Anemia

Hemolysis

Drug-induced/G6PD

Thalassaemia

Sickle Cell

Hemopoesis in Normal Pregnancy

Hemopoesis in Normal Pregnancy Blood Volume

Increases 20-100% (av . 45-50%)

Rapid 1st tri------plateaus at 30th wks

Large women >small

Singlet>multiple

?Mechanism- Hormonal/aldosterone, increased fetal demand

increased kidney perfusion

prepare for maternal loss e.g., 500-600mls vaginal --1000mls C/s

Changes in RBC/iron Red Cells

Increased 33% ~450mls RBC

Increase is greater with iron supplements

Plasma increase>RBC until end of 2nd trimester

Iron Increase RBC....> increased requirement for iron

No supplement = iron deficiency

Fetus extracts iron from mother

Changes in WBC/PLT White Blood cells Normal 400-5000/mcl

Increased to 2-3x normal or even up to 5-6x

?Mechanism – reduced chemotaxis/adherence in 3rd trimester

–prone to infection

Platelets

Increased production and consumption

Increases in both PGI2 (aggregation inhibitor) & TXA2 (aggregation inducer),

Changes in coagulation factors Clotting factors

Increased viz. Fibrinogen (I) and factor VIII (+++) and Factors (VII, IX, X, XII) +

Factor XIII (fibrin-stabilising factor) decreased 50% towards term

Depressed fibrinolysis

Anemia Significant problem in Pregnancy

Investigate if Hb<11g/L or HCT <33%

Anaemia will worsen from blood loss during birth of child (vaginal/caesarean Section).

Causes Nutritional iron & folate deficiency (common)

Aplastic Anaemia (parvo virus B19)

Drug-induced hemolysis

Iron Deficiency Accounts for 95% of anaemia in pregnancy

Iron requirement increases in pregnancy

Hb (contains 70% of body iron)

Storage iron (ferritin, haemosiderin, RES) ~300mg

Diet supply must meet increased demand by growing foetus

Decreased BM iron (hemosiderin) is early sign of iron deficiency

If severe, can endanger foetal life

Causes of iron deficiency. Deficient diet (children on milk)

Decreased absorption

Increased requirements

Pregnancy

Lactation

Blood loss (common)

Gastrointestinal (PUD/aspirin)

Menstrual

Blood donation

Hemoglobinuria

Iron sequestration

Pulmonary hemosiderosis

Absorption: stomach, duodenum, and upper jejunum.

Diet iron: heme is efficiently absorbed (10–20%) , Nonheme iron less so (1–5%)

Loss ---approximately 1 mg/d—are normally lost through exfoliation of skin and mucosal cells.

Iron requirement in Pregnancy Requirement for iron increases in 2nd trimester

Mother: 500mg (increased RBC & Hb)

Baby: 300mg (growth)

Total over course of pregnancy 800mg

Requires 3.4mg/day or elementary iron >40mg/day

Clinical Findings Pallor

Tachycardia/Palpiations

Tiredness/Easy fatigue

Low Hb (hypochromic microcytic)

If severe Glossitis, stomatitis, koilonykia

may endanger baby

Laboratory Findings Iron Studies:

low iron,

low ferritin,

Elevated TIBC & transferrin

decreased % saturation,

Iron Parameters

Red Cell indices: low MCV, low retics

WbC normal

Elevated soluble transferrin receptor

Blood Film: hypochromic Microcytic

Differential Diagnosis Thalassaemia Trait (normal iron studies, elevated

HbA2)

Chronic Inflammation (can see hypochromia, microcytosis)

Sideroblastic Anaemia

Complications Heart: Angina/CHF

Plummer-Vinson syndrome

Prevention Iron supplements in pregnancy (at least 60-80mg/day

elemental iron daily

Treatment Oral iron –Ferrous Sulphate 300mg (60mg

elementary iron -> 10% absorbed) tds

Hb increased by 3-5g/L/week if responding

Continue 3 months after Hb is normal to replenish stores

Iron salt Amount Contents of Ferrous iron

Ferrous fumarate 200mg 65

Ferrous gluconate 300mg 35

Ferrous succinate 100mg 35

Ferrous sulphate 300mg 60

Ferrous sulphate, dried 200mg 65

Only marginal differences between Fe++ salts

Choices depend on cost and side effects

Treatment dose is t.d.s versus daily prophylaxis dose

Some combined with vitamin C or folate (fefol)- cost?

Fefol 150mg ferrous sulphate (47mg iron) / 500mcg folate

Fefol is inadequate to treat megaloblastic anaemia

Parental Iron Different Forms available

Iron dextran (ferric-OH + dextran)—IV/IM injection

Iron sorbitol (ferric- OH +sorbitol)-IV/IM injection

Iron sucrose (ferric –OH + sucrose)-deep IM injection

Reserved for unsuccessful oral iron treatment

Response similar to oral dose

Risk of Anaphylaxis (small test dose initially)

Folate in Pregnancy/Megaloblastic Anaemia

Folate (+ vit B12) is required for DNA synthesis in Red cell maturation

It is essential for the growth and division of all body cells for healing processes.

It aids protein metabolism

Helps prevent premature greying

Lack of folate is associated with LBW and Neural Tube Defect.

Valuable sources Deep FGLV such as spinach, lettuce, brewers yeast,

mushrooms , nuts, peanuts and

liver.

Incidence on BM studies 25-60% (depends on population studied)

Inadequate dietary folate in pregnancy

Demand for folate increased in Pregnancy

Minimum requirement: 50mcg/day

Requirement increases to 800mcg in pregnancy

Folic Acid Deficiency Anaemia Demand is greater with multiple pregnancy and

multigravid

Megalobalstic picture in pregnancy always implies folate deficiency

Megaloblastic picture may be concealed by iron deficiency or thalassaemia

May recur in subsequent pregnancy

Other causes of folate deficiency Impaired absorption

OCP

Antibiotics (bactrim/septrin)

Anticonvulsants (phenytoin/barbiturates)

Malabsorption syndromes

Increased requirement

Hemolysis

Hemoglobinopathies

Malaria infection

Alcohol use

Clinical Findings Non specific

Anorexia

Nausea & vomiting

Diarrhoea

UTI is common

Purpura (occasionally)

Sore mouth & tongue is rare

Pallor is not marked

Other symptoms serious skin disorders

Loss of hair

impaired circulation

Fatigue

Mental depression.

Laboratory tests Blood Film

hypersegmented neutrophils (5 lobes)

Bone Marrow - megaloblastic change

Ovalo- macrocytosis Anisocytosis Poikilocytosis Low reticulocytes, +/-nucleated red cels Pancytopenia (only if severe)

High MCV >100fl

A red blood cell folate level of less than 150 ng/mL is diagnostic

Serum vitamin B12 (deficiency extremely rare in pregnancy)

Iron studies: normal.

Therapy Prevention: folate supplements in pregnancy

Treatment: 1-5mg/day continued several weeks post-partum to replace body stores

Prognosis-good with folate replacement

70% of patients with megaloblastic anaemia also need iron replacement.

Hemolysis

Intrinsic

Membrane

Hereditary

Sperecytosis/ Ovalocytosis

Enzyme

G6PD Deficiency

PK Deficiency

Hemoglobinopathies

Thalassemia

Unstable Hb

Sickle Cell

Hemolysis Extrinsic

Ab -mediated

Coomb’s +ve autoimmune, ABO/Rh-related, Drug Induced,

Cold Agglutinins,

T-antigen activation

Microangiopathy

HUS

TTP

DIC

Post-heart valve

Infections

Malaria

Severe Sepsis

General Features of Hemolysis General exam: Jaundice, Pallor, dark urine

Other physical findings Spleen may be

enlarged; bossing of skull in severe congenital cases

Hemoglobin: From normal to severely reduced

MCV, MCH Usually increased

Reticulocytes Increased (% & absolute nos.)

Bilirubin Increased (mostly unconjugated)

LDH Increased (up to 10X normal with intravascular hemolysis)

Haptoglobin Reduced to absent

Other laboratory abnormalities; increased AST

Increased urine/stool urobilinogen

Increased Urine Haemoglobin (Hemoglobinuria)

No bilirubinuria

Increased serum Hb (haemoglobinaemia)

Increased Bone Marrow Activity Macrocytes (retics & sometimes nucleated RBCs)

Polychromasia

erythroid hyperplasia.

Once a HA is suspected, specific tests will usually be required for a definitive diagnosis of the specific type of HA.

Autoimmune Hemolytic Disease

Mechanism of antibody-mediated immune destruction of red cells

Used to diagnose AIHA.

Coomb's reagent Is a rabbit IgM antibody raised against human IgG or human complement.

Direct Coomb's test -

mix the patient's red blood cells with the Coomb's reagent Positive Agglutination Presence of antibody on the red blood cell surface.

Indirect Coomb's test

Mixing the patient's serum with a panel of type O red blood cells. Incubate test serum and panel O red blood cells, Add Coomb's reagent Positive Agglutination Presence of free antibody in the patient's serum.

Coomb’s antiglobulin test

Drug-Induced Hemolysis Decreased G6PD activity in 1/3 of patients in 3rd

trimester

Increased risk of hemolysis

Over-exposure of G6PD deficiency fetus to sulphonamides commonly prescribed for UTI – risk of fetal hemolysis

Pregnant mother can be screened for G6PD status

G6PD Deficient Hemolytic Anemia

Hereditary enzyme defect

Decreased ability of RBC to withstand oxidative stress-----episodic hemolytic anemia

Oxidized hemoglobin ----denatures -----Heinz bodies (precipitants).

Heinz bodies ----------membrane damage --------- removal of these cells by the spleen.

Hexose Mono phosphate Pathway

Genetic Considerations G6PD gene is X-linked,

Males have only one G6PD gene (i.e., they are hemizygous for this gene),

Females, having two G6PD genes, can be normal, deficient (homozygous), or intermediate (heterozygous).

As a result of the phenomenon of X-chromosome inactivation, heterozygous females are genetic mosaics, with a highly variable ratio of G6PD-normal to G6PD-deficient cells and an equally variable degree of clinical expression;

Some heterozygotes can be just as affected as hemizygous males.

Gene defect: -mutations in the coding region of the G6PD gene.

Almost all of the 140 different mutations known are single (missense )point mutations, entailing single amino acid replacements in the 514 amino acid G6PD protein.

G6PD activity decreases with age of RBC so aging cells are more susceptible hemolysis

Clinical Findings G6PD deficiency is an X-linked recessive disorder –

mainly affects males

USA: 10–15% of American black males.

Female: carriers are rarely affected—only when an unusually high percentage of cells producing the normal enzyme is inactivated

Symptoms and Signs Asymptomatic .

Hemolysis occurs as a result of oxidative stress on the red blood cells, generated either by infection or exposure to certain drugs.

Common drugs initiating hemolysis include dapsone, primaquine, quinidine, quinine, sulfonamides, and nitrofurantoin.

Typically, a hemolytic attack starts with malaise, weakness, and abdominal or lumbar pain.

After an interval of several hours to 2–3 days,

patient develops jaundice

often dark urine (hemoglobinuria)

Most serious threat is acute renal failure (exceedingly rare in children).

Laboratory Test Peripheral blood film

Bite cells/immature re cells/henz bodies

Reticulocyte count; increased

Haptoglobulin/LDH/AST/bilirubin

Low Haptoglobulin and increased LDH/AST/unconj Bil

Urinalysis: urobilinogen/bilirubin/Hb

High urobilinogen & hemoglobin; no bilirubin

G6PD assay: qualitative /quantitative test

Heinz Bodies:

A classic test, is supravital staining with methyl violet (rarely done now)

Reveals the presence of Heinz bodies,

precipitates of denatured hemoglobin

Regarded as a signature of oxidative damage to red cells

Once the threat of acute anemia is over, and in the absence of comorbidity, full recovery from acute HA associated with G6PD deficiency is the rule.

Peripheral Blood Smear

Treatment Treat Anemia/Infection

Avoid offending drug/oxidant

Thalassemia/Sickle Cell Anaemia Hemoglobinopathies

Genetic mutation in alpha or beta -globin chains

Family history present

Clinically:

Anaemia/chronic hemolysis

Symptomatic Trait

Hypochromic microcytosis film

Risk of enhanced sickling of red cells during hypoventilation eg during General anaesthesia

Multi-organ symptoms with SC disease

Eg MSS pain and lung, CNS, renal or heart infarct or retinal vein thrombus

Effects on Pregnancy Effects on Mother

Anaemia

Iron/folate deficiency

Risk of infection

Heart failure

Effects on Foetus

Stilbirth

LBW/IUGR/preterm

Laboratory Diagnosis Blood Film-hypochromic, microcytosis, bizzare cell

FBE-Anaemia

Normal/increased iron status

Hb Electrophoresis

DNA studies

Beta Thalassemia syndromes.

-Globin Genes Hb A Hb A2 Hb F

Normal Homozygous 97–99% 1–3% < 1%

T. Major Homozygous 0 0-10% 4–10% 90–96%

T. Minor Heterozygous 80–95% 4–8% 1–5%

Hemoglobin distribution in sickle cell syndromes.

Genotype Clinical DX Hb A Hb S Hb A2 Hb F

AA Normal 97–99% 0 % 1–2% < 1%

AS Sickle Trait 60% 40% 1–2% < 1%

SS SC Anemia 0% 86–98% 1–3% 5–15% S-T SC-Thalassemia 0-20% 70–80% 3–5% 10–20% AS, -Th Sickle trait 70–75% 25–30% 1–2% < 1%

Management Symptomatic

Transfusion

Prenatal Diagnosis (DNA studies) and counselling

Aplastic Anaemia Rapid Development of anaemia

Bone Marrow failure (idiopathic/infection)

Pancytopenia and hypocellular BM

Increased risk of infection

Pregnancy Complications:

FDIU/stillbirths

Prematurity

maternal death

Spontaneusly resolve post-patum

May recur in subsequent pregnancies

Pancytopenia.

No abnormal cells seen.

Hypocellular bone marrow

Causes "Idiopathic" (probably autoimmune) -MAJORITY

Chemotherapy

Radiotherapy

Toxins: benzene, toluene, insecticides

Drugs: chloramphenicol, phenylbutazone, gold salts, sulfonamides, phenytoin, carbamazepine, quinacrine, tolbutamide

Posthepatitis Pregnancy

Paroxysmal nocturnal hemoglobinuria

Congenital (rare)

Systemic lupus erythematosus (rare)

Clinical Findings

Anemia (low RBCs)

weakness and fatigue,

Neutropenia (low neurtrophils)

vulnerability to bacterial infections

Thromtocytopenia (low platelets)

mucosal and skin bleeding.

Pallor, purpura, and petechiae .

hepatosplenomegaly & lymphadenopathy

No bone tenderness

Laboratory Findings

Pancytopenia.

one or two cell lines may be reduced.

always associated with decreased reticulocytes.

Anemia may be severe

Normal Red blood cell morphology.

Neutrophils and platelets are reduced in number, and no immature or abnormal forms are seen.

Bone Marrow Biopsy Hypocellular BM

Only scant amounts of normal hematopoietic progenitors.

No abnormal cells are seen

Laboratory Features Pancytopenia

No abnormal cells seen

Hypocellular BM

References 1. Emedecine.medscape.com

2. Current Obstetrics & Gynaecology, Diagnosis & Treatment, International 9th Edition