CHẨN ĐOÁN VÀ ĐIỀU TRỊ
THIẾU MÁU THIẾU SẮT
TS BS Nguyễn Minh TuấnBệnh viện Nhi Đồng 1
Khoa Y – Đại học Quốc gia TPHCMĐơn vị Nghiên cứu Lâm sàng Đại học Oxford
Hội nghị Khoa học Nhi khoa Bệnh viện Nhi Đồng 1TPHCM, 20-21/9/2019
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
ANEMIA
Defined as an insufficient RBC mass to adequately deliver oxygen to peripheral tissues.
-- Wintrobes
Defined as a decrease in the amount of red blood cells (RBCs) or the amount of hemoglobin in the blood. It can also be defined as a lowered ability of the blood to carry oxygen.
-- Wikipedia
Anemia is defined as a reduction of the total circulating red cell mass below normal limits
-- Robbins
ANEMIATheo Tổ chức Y tế thế giới, gọi là thiếu máu khi lượng hemoglobin (Hb) dưới giới hạn sau đây:
Tuổi / giới tínhHb bình thường
(g/dL)
Thiếu máu
(Hb ≤ giới hạn)
Trẻ sơ sinh (đủ tháng)
Trẻ từ 2 – 6 tháng
Trẻ từ 6 tháng đến 2 tuổi
Trẻ từ 2 – 6 tuổi
Trẻ từ 6 – 12 tuổi
Nam trưởng thành
Nữ trưởng thành (không mang
thai)
13.5 – 18.5
9.5 – 13.5
10.5-13.5
11.0 – 14.4
11.5 – 15.5
13.0 – 17.0
12.0 – 15.0
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
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
EPIDEMIOLOGY
• Globally, anemia affects 1.62 billion people , which corresponds to 24.8% of the population
• IDA occurs across all populations and is associated with
✓ Diminished QOL
✓ Physical and cognitive performance, and
✓ Unfavorable clinical outcomes
Classification of anemia as a problem of public health significant
Anemia prevalence
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
IRON DISTRIBUTION
IRON DISTRIBUTION
• Most body iron is present in haemoglobin in circulating red cells
• The macrophages of the reticuloendotelialsystem store iron released from haemoglobinas 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)
0 5 10 15 20 25
Veal muscle
Hemoglobin
Fish muscle
Veal liver
Ferritin
Soy beans
Wheat
Lettuce
Corn
Black beans
Spinach
Rice
Non-heme
iron
Heme
iron
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
ETIOLOGY
• 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
PROGNOSIS
IDA adversely effects:• Cognitive performance, behavior, and physical
growth of infants, preschool, and school-agedchildren
• 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
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
Preliminary findingsChief ComplaintsFatigue, lassitude, palpitation, and generalized weakness
HistoryChronic blood loss, deficient diet
Clinical Features1. Palor: skin, nailbed, conjunctiva2. 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 SignsSymptoms Signs
Decreased exercise tolerance
Tachycardia
Fatigue Pale appearance (most prominent inconjunctiva)
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
IDA Reduced Reduced Raised
Thalassemia Raised Raised or
Normal
Normal
Chronic disease Raised or
Normal
Reduced Normal
IDA Thalassemia trait
Mentzer index
MCV : RBC
> 13 < 13
Srivastava index
MCH : RBC
> 3,8 < 3,8
Shine and Lal index
(MCV2 x MCH) x 0.01
> 1530 < 1530
MCV – RBC – (Hb x 5) – 3.4 > 0 < 0
Green and King index
(MCV2 x RDW) x Hb x 0.01
> 65 < 65
RDW – CV% > 14,6 < 14,6
RDW index
MCV x RDW : RBC
> 220 < 220
DIFFERENTIAL DIAGNOSIS
Contents
• Definition of iron deficiency anemia
• Epidemiology
• Iron metabolism
• Etiology
• Diagnosis
• Management
Therapeutic goals
Short term
• Resolution of symptoms
• Replenish iron stores
Long term
• Improve quality of life (QOL)
• Prevention of recurrences
• Better growth and development (children)
MANAGEMENT
Treatment options
Pharmacological management
• Oral/parenteral iron therapy
Non-pharmacological
• Blood transfusion
MANAGEMENT
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 expensiveand irrational
• Liquid formulations should be put on back of tongue and swallowed
• Absorption better on empty stomach but sideeffects more
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 (ferrousfumarate/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 includeDextran, 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
𝑙ượ𝑛𝑔 𝑠ắ𝑡 (𝑚𝑔) =𝑡ℎể 𝑡í𝑐ℎ 𝑚á𝑢 × 12,5 − 𝐻𝑏 𝑏𝑛 × 3,4 × 1,2
100
rải ra tiêm bắp hay tĩnh mạch cách ngày hay cách tuần
trong 2-3 tuần, ≤0,1 mg/kg/liều.
Thể tích máu: ml/kg
3,4: 1g Hb cần 3,4mg sắt
1,2: thêm 20% cho sắt dự trữ
Parenteral iron therapy
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.