Chẩn đoán điều trị thiếu máu thiếu sắt trẻ em 2019

IRON DEFICIENCY ANEMIAAnemia with biochemical evidence of iron deficiency based on following laboratory findings: • serum ferritin, • total iron binding capacity TIBC, • transferrin satu

CHẨN ĐOÁN VÀ ĐIỀU TRỊ THIẾU MÁU THIẾU SẮT

TS BS Nguyễn Minh Tuấn Bệnh viện Nhi Đồng 1 Khoa Y – Đại học Quốc gia TPHCM Đơn vị Nghiên cứu Lâm sàng Đại học Oxford

Hội nghị Khoa học Nhi khoa Bệnh viện Nhi Đồng 1

TPHCM, 20-21/9/2019

Defined as an insufficient RBC mass to adequately

deliver oxygen to peripheral tissues.

13.5 (Hct 34%) 9.5 (Hct 28%) 10.5 (Hct 33%) 11.0 (Hct 33%) 11.5 (Hct 34%) 13.0 (Hct 39%) 12.0 (Hct 36%)

IRON DEFICIENCY ANEMIA

Anemia with biochemical evidence of iron

deficiency based on following laboratory findings:

• serum ferritin,

• total iron binding capacity (TIBC),

• transferrin saturation,

• or transferrin receptor

✓ Physical and cognitive performance, and

✓ Unfavorable clinical outcomes

Classification of anemia as a problem

of public health significant

Anemia prevalence

IRON DISTRIBUTION

• Most body iron is present in haemoglobin in

circulating red cells

• The macrophages of the reticuloendotelial

system store iron released from haemoglobin

as ferritin and hemosiderin

• Small loss of iron each day in urine, faeces,

skin and nails and in menstruating females as blood (1-2 mg daily)

IRON ABSORPTION

• Food sources supply: 10 - 25 mg / day

• Absorbed in the brush border of the upper small intestine

– Enhanced by gastric acid

– Inhibited by tannins, systemic inflammation

• Most dietary iron is nonheme form, <5%

bioavailability

• < 10% dietary iron is heme form, >25%

bioavailability

IRON ABSORPTION

Iron absorption from food

Iron Absorption (% of dose)

Veal muscle Hemoglobin Fish muscle Veal liver Ferritin Soy beans Wheat Lettuce Corn Black beans Spinach

Rice

Non-heme iron

Heme iron

• IDA results from prolonged negative iron balance

• Mainly due to following factors:

1 Inadequate iron intake: infancy, inappropriate diet

2 Decreased iron absorption:

3 Increased iron demand or hematopoiesis:

prematurity, low-birth weight, cyanotic congenital heart diseases, polycythemia

4 Increased iron loss: GI bleeding, menorrhagia,

recurrent bleeding of hematologic diseases, etc.

Matthew W et al Am Fam Physician 2013;87(2):98-104

IDA adversely effects:

• Cognitive performance, behavior, and physical

growth of infants, preschool, and school-aged

children

• The immune status and morbidity from infections

of all age groups

• The use of energy sources by muscle and thus the physical capacity and work performance of

adolescents and adults of all age groups

• Increase perinatal risks for mothers and neonates and overall infant mortality during pregnancy

1 Palor: skin, nailbed, conjunctiva

2 Koilonychia (brittle, spoon shaped nails)

3 Atrophic glossitis (atrophy of tongue papilla; making the tongue smooth and shiny)

4 Pica (compulsive eating of nonfood items)

or pagophagia (compulsive eating of ice)

Symptoms and Signs

Dizziness Decreased mental acuity

Irritability Increased intensity of some

cardiac valvular murmurs Weakness

Palpitations

Vertigo

Shortness of breath

Chest pain

Laboratory evaluation

• Complete blood count (CBC), erythrocyte

sedimentation rate (ESR), and peripheral

blood film (PBF)

• Serum Iron profile

• Bone marrow study (if needed)

• Investigations to determine other causes of IDA (e.g fecal occult blood test, colonoscopy, gastroscopy, etc.)

Lưu đồ chẩn đoán thiếu máu

DIFFERENTIAL DIAGNOSIS

Ferritin Serum iron RDW

Thalassemia Raised Raised or

IDA Thalassemia trait Mentzer index

Matthew W et al Am Fam Physician 2013;87(2):98-104

Dosage of oral iron therapy:

4-6mg/kg/d, t.i.d

Forms:

• Tablets, capsules

• Sugar coated & uncoated tablets

• Slow release tabs & chewable tabs

• Drops & syrups—used by children

MANAGEMENT

AVAILABLE PRODUCTS

DiPiro J Anemia In: Pharmacotherapy: A Pathophysiological Approach, 2011

AVAILABLE PRODUCTS

Forms:

• Tablets, capsules

• Sugar coated & uncoated tablets

• Slow release tabs & chewable tabs

• Drops & syrups—used by children

Response to oral therapy

• 12 – 24hrs: restore enzyme, improve appetite andirritability

• 48 – 72hrs: reticulocytes increase, peak after 1 – 2 weeks

• Considered as satisfactory if Hb ↑ by 1 % per day (0.15 g %), with at least 10 % (1.5 g % ) within 3

weeks

Factors influencing iron absorption

Important points to remember

• Elemental iron content and not quantity of

iron compound per unit dose to be considered

• Sustained released preparations expensive

Common side effects

• Gastrointestinal (GI) intolerance

Nausea, vomiting, heartburn, and constipation or diarrhea

➢ Slow release or sustained release preparations may be used

➢ Combination products, e.g Ferro-DDS (ferrous

fumarate/docusate), may be advantageous for certain patient population

• Cause discoloration of stool

• Metallic taste

• Staining of teeth

Parenteral iron therapy

➢ Indications for therapy

• Intolerance to oral route

• Malabsorption

• Long-term nonadherence

• Patient with significant blood loss who refuse transfusion and are intolerant to oral therapy

• Chronic kidney disease (CKD) or malignancy

➢ Currently available formulations include

Dextran, sodium ferric gluconate, iron sucrose, ferumoxytol

➢ Formulations differ in their molecular size, degradation

kinetics, bioavailability, and side effects profile

➢ All preparations carry a risk for anaphylactic reactions

but likely to a lesser extent than iron dextran

Iron supplementation to prevent IDA

TAKE-HOME MESSAGES

➢ IDA is the most common form of anemia

➢ Four main factors contributing to IDA:

• Inadequate iron intake

• Decreased iron absorption

• Increased iron demand or hematopoiesis

• Increased iron loss

➢ Complete patient history, physical exams, and laboratory investigations

➢ Abnormal laboratory investigations: low MCV, serum iron, and ferritin.

➢ Treatment of IDA consists of dietary supplementation and administration

of oral iron preparations.

➢ Complete therapeutic response requires iron supplementation for 3

months after Hct and ferritin levels normalize.