Blood Disorders in Infants: Membrane Abnormalities

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Questions and Answers

What is the inheritance pattern of the most common inherited abnormality of the red blood cell membrane?

It is usually transmitted as an autosomal dominant disorder, but can also be autosomal recessive.

Which proteins are partially deficient in the disorder affecting red blood cell membranes?

The disorder results from a partial deficiency of spectrin or ankyrin.

What are the consequences of the membrane defect in red blood cells?

The defect leads to the formation of spherocytes that are poorly deformable and have a shortened life span.

What condition may require phototherapy or exchange transfusions during the neonatal period?

Severe hyperbilirubinemia may require these treatments. Signup and view all the answers

What is a potential consequence of prolonged splenic trapping of spherocytes?

It may lead to splenomegaly and hemolytic anemia. Signup and view all the answers

What happens to hemoglobin (Hb) levels in infants, and why is this significant?

Hemoglobin levels decrease in infants, which is significant as it prevents them from meeting their oxygen demand. Signup and view all the answers

How does the heart compensate for low hemoglobin in infants, and what are the potential outcomes?

The heart compensates by increasing its heart rate, leading to hyperdynamic circulation, which can strain the heart over time. Signup and view all the answers

What remains unchanged with age in a person's blood profile according to the document?

The platelet count remains the same with age. Signup and view all the answers

What are the implications of a hyperdynamic circulation in infants as a compensatory mechanism?

Hyperdynamic circulation may lead to increased workload on the heart, which can result in long-term cardiac issues. Signup and view all the answers

Why is it important to monitor hemoglobin levels in neonates and infants?

Monitoring hemoglobin levels is crucial to ensure that infants can meet their metabolic demands and prevent potential complications. Signup and view all the answers

What can occur if the heart is overloaded due to compensatory mechanisms in infants?

Overloading the heart can lead to heart failure or other serious cardiovascular conditions over time. Signup and view all the answers

What role does the heart play in compensating for anemia in infants?

The heart increases its rate of contraction to enhance blood flow and oxygen delivery in response to anemia. Signup and view all the answers

What are the main causes of decreased RBC production?

Decreased RBC production can be caused by a reduced number of precursors in the bone marrow and increased destruction of RBCs. Signup and view all the answers

List three types of microcytic anemia.

Three types of microcytic anemia are iron deficiency anemia, thalassemias, and lead poisoning. Signup and view all the answers

What is macrocytic anemia and what are two common causes?

Macrocytic anemia is characterized by larger than normal RBCs, commonly caused by vitamin B12 deficiency and folic acid deficiency. Signup and view all the answers

What does an increased reticulocyte count usually indicate?

An increased reticulocyte count typically indicates a response to anemia due to blood loss or increased destruction of RBCs. Signup and view all the answers

Explain the relationship between hypothyroidism and anemia.

Hypothyroidism can lead to normocytic anemia due to impaired production of RBCs. Signup and view all the answers

How does hypersplenism affect RBC survival?

Hypersplenism leads to increased destruction of RBCs, reducing the number that survive to be released into the blood. Signup and view all the answers

What is the significance of the four stages of iron deficiency?

The four stages of iron deficiency outline the progression from normal iron levels to complete iron deficiency anemia. Signup and view all the answers

Describe what is meant by normocytic anemia.

Normocytic anemia is characterized by RBCs that are normal in size but reduced in number. Signup and view all the answers

What are the implications of having iron deficiency without anemia for a significant portion of the population?

Iron deficiency without anemia implies that individuals may have low iron stores, which can lead to fatigue and other health issues if not addressed. Signup and view all the answers

What genetic mutation commonly causes β-thalassemia?

Mutations in the β globin gene on chromosome 11. Signup and view all the answers

What distinguishes β-thalassemia major from minor?

β-thalassemia major is characterized by severe anemia, while minor typically causes mild anemia. Signup and view all the answers

What are symptoms of β-thalassemia major observed in infants?

Infants may present with failure to thrive, pallor, jaundice, and abdominal enlargement. Signup and view all the answers

What is the silent carrier state for β-thalassemia?

In the silent carrier state, individuals are asymptomatic with no significant anemia. Signup and view all the answers

Describe a common diagnostic characteristic of β-thalassemia.

It is characterized by severe microcytic, hypochromic anemia detected early in childhood. Signup and view all the answers

What is a potential physical manifestation of severe anemia due to β-thalassemia?

Severe anemia can cause marked bone changes due to the expansion of marrow space. Signup and view all the answers

What does 'crew cut' or 'hair on end' appearance refer to?

These terms describe characteristic bone changes observed in patients with severe thalassemia. Signup and view all the answers

How does β-thalassemia intermedia present in comparison to β-thalassemia major?

β-thalassemia intermedia presents with mild to moderate anemia, unlike the severe anemia seen in β-thalassemia major. Signup and view all the answers

What type of anemia is commonly associated with β-thalassemia?

β-thalassemia is associated with microcytic and hypochromic anemia. Signup and view all the answers

What role does hemolysis play in thalassemia-related symptoms?

Hemolysis contributes to decreased RBC survival, exacerbating anemia symptoms. Signup and view all the answers

What are the most common manifestations of G6PD deficiency during episodes of hemolysis?

Neonatal jaundice and episodic acute hemolytic anemia are the most common manifestations. Signup and view all the answers

How does the age of red blood cells affect G6PD deficiency?

Older red blood cells are more deficient due to enzyme instability, which leads to earlier degradation. Signup and view all the answers

Which factors can induce episodes of hemolytic anemia in G6PD deficiency?

Infections, certain drugs, and stress can induce episodes of hemolytic anemia. Signup and view all the answers

What is a typical urine finding during a hemolytic episode in G6PD deficiency?

The urine often darkens, resembling 'Coca-Cola' due to hemoglobin and urobilinogen. Signup and view all the answers

Describe the general health of children with G6PD deficiency between hemolytic episodes.

Children with G6PD deficiency are typically asymptomatic and appear normal between episodes. Signup and view all the answers

What are some symptoms associated with hemolytic anemia in G6PD deficiency?

Symptoms include pallor, jaundice, and dark urine. Signup and view all the answers

What laboratory findings are associated with hemolysis in G6PD deficiency?

Laboratory findings may include hemoglobinuria and increased urobilinogen in the urine. Signup and view all the answers

Why are older red cells more affected by G6PD deficiency?

Older red cells have a shorter half-life for the enzyme, leading to increased susceptibility. Signup and view all the answers

What is the significance of stress in G6PD deficiency?

Stress can precipitate hemolytic episodes, worsening the condition. Signup and view all the answers

What is the effect of specific foods like fava beans in G6PD deficiency?

Certain foods like fava beans can trigger hemolytic episodes in susceptible individuals. Signup and view all the answers

What is thalassemia and how does it affect hemoglobin production?

Thalassemia is a group of inherited blood disorders characterized by reduced or absent production of globin chains, leading to impaired hemoglobin synthesis and resulting in anemia. Signup and view all the answers

What are some common symptoms of thalassemia?

Common symptoms include anemia, growth retardation, jaundice, and in severe cases, bone deformities. Signup and view all the answers

What methods are typically used to diagnose thalassemia?

Diagnosis usually involves blood tests to assess hemoglobin levels and indices, hemoglobin electrophoresis, and genetic testing. Signup and view all the answers

How does iron chelation therapy help thalassemia patients?

Iron chelation therapy helps manage iron overload that results from frequent blood transfusions, preventing complications. Signup and view all the answers

Describe the role of blood transfusions in managing severe thalassemia.

Blood transfusions provide necessary red blood cells to alleviate anemia and improve oxygen delivery to tissues. Signup and view all the answers

What can happen if thalassemia is left untreated over time?

Untreated thalassemia can lead to serious complications such as organ damage, severe anemia, and life-threatening health issues. Signup and view all the answers

What is the significance of bone marrow transplantation in thalassemia?

Bone marrow transplantation can potentially cure severe thalassemia by replacing defective hemoglobin production with healthy stem cells. Signup and view all the answers

How does the severity of thalassemia vary among individuals?

Severity of thalassemia varies based on the specific globin chain affected and the extent of the deficiency, leading to different clinical presentations. Signup and view all the answers

Why is long-term management important for individuals with thalassemia?

Long-term management is crucial to prevent complications, improve quality of life, and ensure timely interventions. Signup and view all the answers

What are the potential physical manifestations of severe anemia due to β-thalassemia?

Severe anemia in β-thalassemia can lead to physical manifestations such as pallor, skeletal deformities, and growth retardation. Signup and view all the answers

What protein is primarily affected in iron deficiency anemia, leading to reduced oxygen transport?

Hemoglobin is the protein affected. Signup and view all the answers

Identify two dietary sources that can help increase iron intake to treat iron deficiency anemia.

Red meat and leafy green vegetables. Signup and view all the answers

Describe a symptom that may indicate a severe case of G6PD deficiency.

Hemolytic anemia resulting in jaundice. Signup and view all the answers

What are two common triggers for hemolytic anemia in individuals with G6PD deficiency?

Infections and certain medications. Signup and view all the answers

What genetic mutation results in the production of abnormal hemoglobin in sickle cell anemia?

A mutation in the HBB gene causes the production of hemoglobin S (HbS). Signup and view all the answers

What primary complication should be addressed for patients experiencing pain crises in sickle cell anemia?

Pain management must be prioritized. Signup and view all the answers

How can chronic blood loss pose a risk factor for developing iron deficiency anemia?

Chronic blood loss depletes the body's iron stores needed for hemoglobin production. Signup and view all the answers

In G6PD deficiency, what diagnostic test is typically utilized to measure the enzyme's levels?

A blood test measuring G6PD enzyme levels is used. Signup and view all the answers

What preventive measure can reduce the risk of developing iron deficiency anemia?

Maintaining a balanced diet rich in iron. Signup and view all the answers

What role does genetic counseling play for families affected by sickle cell anemia?

Genetic counseling informs families about the condition's prevalence and inheritance patterns. Signup and view all the answers

Study Notes

Anemia in Children

Anemia is defined as a decrease in hemoglobin concentration or red blood cell (RBC) volume below healthy levels.
Cord blood hemoglobin levels: 16.8 g/dL
2-week-old: 16.5 g/dL
3-month-old: 12.09 g/dL
6-month-to-6-year-old: 12.01 g/dL
7-12-year-old: 13.01 g/dL

Clinical presentations of Anemia

General manifestations: pallor, sleepiness, irritability, weakness, decreased exercise tolerance.
Flow murmur: often present in anemia.
Shortness of breath on exertion, tachycardia, cardiac dilation, and high-output heart failure can occur. These stem from increasingly severe anemia, regardless of the underlying cause.
The heart tries to compensate by increasing heart rate (HR) and cardiac output (CO), but this may lead to hyperdynamic circulation and, over time, heart failure.

Classification of Anemia

Morphological classification: based on RBC size (mean corpuscular volume, MCV).
- Microcytic: <70 fL
- Normocytic: 70-90 fL
- Macrocytic: >90 fL
Physiological classification: decreased RBC production or increased destruction.
- Decreased RBC production: ineffective erythropoiesis, failure of erythropoiesis
- Increased destruction: hemolysis (hyper-splenism), bleeding (blood loss)

Types of Anemia

Microcytic anemia: iron deficiency anemia, thalassemias, lead poisoning, anemia of chronic disease, sideroblastic anemia
Normocytic anemia: chronic disease, inflammation, anemia of aplastic, infection, drugs, malignancies, endocrinopathies (hypothyroidism), renal failure, acute bleeding
Macrocytic anemia: vitamin B12 deficiency, folate deficiency, liver disease, hypothyroidism, other disorders (e.g., diamond-blackfan anemia, aplastic anemia, down syndrome)

Iron Deficiency Anemia (IDA)

Most common cause of anemia in children.
15% frequency rate in children.
Causes: increased demand, decreased intake, increased loss.
- Increased demand: growth spurts in children and infants, puberty
- Decreased intake: poor diet (inability to access sufficient nutrients), poor absorption (e.g., intolerance)
- Increased loss: GI bleeding, hemolysis, surgical procedures, worm infestation

Iron Absorption

Enhanced by: orange juice, vitamin C, soy sauce, vinegar
Inhibited by: tea, coffee, milk, phytate

Forms of Iron in the Body

Iron in food: meat, beans, and vegetables
Iron in storage: ferritin (liver, spleen, muscle, bone marrow), hemosiderin (excreted in urine)
Iron in circulation: recycled from hemoglobin breakdown

Clinical Features of Iron Deficiency Anemia

CNS manifestations: apathy, irritability, poor concentration, poor muscle tone, cognitive deficits, poor school performance
Pica (pagophagia): persistent craving and compulsive eating of nonfood substances like ice
Breath-holding spells: in children.

Oral Signs in Iron Deficiency Anemia (IDA)

Koilonychia (spoon-shaped nails)
Atrophic glossitis (beefy red tongue)
Cheilosis (angular stomatitis)
Plummer-Vinson syndrome: triad of IDA, esophageal webs, and dysphagia

Lab Findings in Anemia

Low hemoglobin, low MCV, low MCHC, elevated RDW, microcytic hypochromic red blood cells, anisocytosis with target cells, teardrops, elliptical cells, and fragmented cells
Increased platelets with normal morphology

Treatment of Anemia

Oral iron therapy: 3-6 mg/kg/d, divided doses
Iron therapy results in increased reticulocyte counts within 3-5 days, peaking between 5 and 7 days with increasing hemoglobin levels thereafter)
Iron medication is continued for 8 weeks after blood values are normalized
To restore iron stores

Congenital Hypoplastic Anemia (Diamond-Blackfan Anemia)

Rare congenital bone marrow failure syndrome
Usually becomes symptomatic in early infancy.
More than 90% of cases are recognized within the first year of life.
Characterized by macrocytic anemia, reticulocytopenia, and deficiency or absence of red blood cells (RBC) precursors in an otherwise normal cellular bone marrow.

Associated anomalies in Diamond-Blackfan Anemia

Microcephaly, micrognathia
Triphalangeal thumb, bifid thumb
Heart defects (VSD, ASD, coarctation)
Genitourinary tract anomalies (absence or horseshoe kidney, hypospadia)
Short stature

Diagnosis of Diamond-Blackfan Anemia

Complete blood count: very low number of red blood cells, low hemoglobin
Low retic count
Bone marrow sample (biopsy): few new red blood cells

Treatment of Diamond-Blackfan Anemia

Prednisolone
Androgens
Antithymocyte globulin
Transfusion
Stem cell transplantation

Thalassemias

Heterogenous group of inherited disorders characterized by reduced or absent globin chain synthesis.
Imbalance will leads to ineffective erythropoiesis and shortened RBC lifespan.

Normal Hemoglobin (Hb) in Adults

Hb A: 2α, 2β (more than 95%)
Hb F: 2α, 2γ (less than 2.5%)
Hb A2: 2α, 2δ (2-3.4%)

Beta-Thalassemia Major

Characterized by severe microcytic, hypochromic anemia
Detected early in childhood (after 6 months)
Infants fail to thrive
Pallor, variable jaundice, abdominal enlargement, hepatosplenomegaly.
Marked bone changes (due to expansion of marrow space for increased erythropoiesis).
Characteristic changes in skull, long bones and hand bones (crew-cut skull)

Sickle Cell Disease (SCD)

Inherited red blood cell disorder
Normal RBCs are round, move through small tubes to deliver oxygen
Abnormal HbS polymerizes, forms rigid fibers, distorts RBCs into sickle shapes when deoxygenated
Consequences: reduced RBC deformability, hemolysis, vaso-occlusion, ischemia and inflammation

Sickle Cell Anemia: Pathophysiology

Molecular basis; substitution of valine for glutamic acid on beta-globin chain
Consequences: reduced RBC deformability, hemolysis, vaso-occlusion, ischemia and inflammation.
Chronic hemolytic anemia.
Sickle cells adhere to endothelial cells and can activate inflammatory pathways, leading to tissue damage and organ dysfunction

Clinical Features of Pain Crisis

Sudden onset of severe deep pain (bones, joints, chest, back, and abdomen)
Pain lasting hours to days
Accompanying symptoms: swelling, tenderness, fever (if infection is present), tachycardia
Common sites: dactylitis, long bones (femur, humerus), ribs, and sternum
Recurrent Crises: chronic pain, organ damage, and avascular necrosis.

G6PD Deficiency

Deficiency of G6PD is the most common red cell enzyme defect leading to hemolytic anemia.
X-linked recessive inheritance; high frequency in certain populations (African, Mediterranean, and Asian ancestry).
Hundreds of G6PD variants are characterized.

G6PD Deficiency: Clinical Presentations

Neonatal jaundice and episodic acute hemolytic anemia, often induced by infections, certain drugs (including fava beans), or other stressors
Episodes of hemolysis are associated with pallor, jaundice, hemoglobinuria and sometimes cardiovascular compromise
Children are asymptomatic between episodes of hemolysis.
Dark-colored urine ("coca- cola colored urine") is a typical sign

G6PD Deficiency: Triggering Agents

Medications: antibacterial (sulfonamides, trimethoprim, sulfamethoxazole, nalidixic acid, chloramphenicol, nitrofurantoin), antimalarials (primaquine, pamaquine, chloroquine, quinacrine)
Chemicals: phenacetin, vitamin K analogs, methylene blue, probenecid, acetylsalicylic acid, phenazopyridine, phenylhydrazine, benzene, naphthalene
Illness: diabetic acidosis

G6PD Deficiency: Diagnosis

Fall in hemoglobin and hematocrit
Free hemoglobin in plasma and urine
Heinz bodies: precipitated hemoglobin within red blood cells
Reticulocytosis: increased number of reticulocytes (immature red blood cells)

G6PD Deficiency: Prevention and Treatment

Prevention of hemolysis is essential.
Supportive care (e.g., blood transfusions) may be necessary in severe cases or when Hb is <7 g/dL.
Discontinuing the causative oxidant agent is crucial for recovery.

Hereditary Spherocytosis

Common inherited abnormality of the red blood cell (RBC) membrane.
Usually transmitted as an autosomal dominant or less commonly autosomal recessive disorder.
25% of patients have no previous family history.
De-novo mutations or undetected mild disease in parents

Hereditary Spherocytosis: Clinical Presentations

Neonatal period: hyperbilirubinemia, potentially severe enough to require phototherapy or exchange transfusions.
Features of anemia: splenomegaly

Hereditary Spherocytosis: Lab Findings

Normochromic, normocytic anemia
Hb maintained 6-9 gm/dL
Spherocytosis (spherical red blood cells)
Reticulocytosis elevated reticulocytes)

Hereditary Spherocytosis: Treatment

Splenectomy: removal of spleen to relieve anemia symptoms

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Description

This quiz explores the inheritance patterns and consequences of red blood cell membrane defects in infants. It covers critical topics such as hemoglobin levels, splenic trapping of spherocytes, and the implications of hyperdynamic circulation for neonatal health. Understand the importance of monitoring hemoglobin levels and the heart's compensatory mechanisms in these scenarios.