Pallor (Paleness)
Kim Smith-Whitley
INTRODUCTION
Pallor (paleness) results from a decreased amount of circulating hemoglobin or vasoconstriction of dermal blood vessels. Causes can be classified as hematologic or nonhematologic.
DIFFERENTIAL DIAGNOSIS LISTHematologic Causes
Increased Red Blood Cell (RBC)
Destruction—see Chapter 40, “Hemolysis”
Isoimmune or alloimmune hemolytic anemia (hemolytic disease of the newborn)
Autoimmune hemolytic anemia
RBC membrane defects
RBC enzyme defects
Qualitative hemoglobin disorders
Quantitative hemoglobin disorders
Microangiopathic hemolytic anemia
Drugs
Toxins
Infections
Bone Marrow Failure
Transient erythroblastopenia of childhood
Aplastic crisis with underlying congenital hemolytic anemia
Diamond–Blackfan anemia
Anemia associated with systemic illness
Drug-related anemia
Infection
Aplastic anemia—idiopathic or secondary to drugs, chemicals, viruses, radiation, pregnancy
Transient bone marrow suppression—caused by viral or bacterial infection, drugs, pregnancy, radiation
Fanconi anemia
Dyskeratosis congenita
Pure red cell aplasia
Congenital dyserythropoietic anemia
Pregnancy
Bone Marrow Infiltration
Leukemia or neoplasm metastatic to bone marrow
Infection
Osteopetrosis
Histiocytosis
Myelofibrosis
Storage diseases
Nutritional Deficiencies
Iron deficiency
Folate deficiency
Vitamin B12 deficiency
Blood Loss
Hemorrhage
Bleeding disorder
Nonhematologic Causes
Infectious Causes
Bacterial process leading to shock, anemia, or both
Toxic Causes
Lead poisoning
Neoplastic Causes
Pheochromocytoma
Traumatic Causes
Head trauma resulting in a closed head injury or cerebral hemorrhage
Congenital Causes
Constitutional skin color
Metabolic or Genetic Causes
Hypoglycemia
Inflammatory Causes
Atopic dermatitis
Other chronic systemic diseases
Miscellaneous Causes
Shock
Skin edema (myxedema, as in thyroid disease)
Uremia
Cystic fibrosis
Seizures
Syncope
Lack of sun exposure
DIFFERENTIAL DIAGNOSIS DISCUSSION
Blood Loss
Etiology
Blood loss, acute and chronic, is one of the most common causes of anemia in the pediatric patient. Chronic blood loss may be caused by gastrointestinal bleeding, excessive menstrual bleeding, or a bleeding disorder characterized by frequent bleeding episodes.
Clinical Features
Patients with chronic blood loss may present with pallor, usually noted by an observer who has not seen the child recently. Chronic blood loss may be difficult to recognize because the hemoglobin level diminishes slowly.
Evaluation
Initial laboratory studies should include a complete blood count (CBC), blood type and cross-match, prothrombin time, and partial thromboplastin time. In a patient with anemia secondary to chronic blood loss, a peripheral smear shows hypochromic, microcytic RBCs from iron deficiency. In a patient with acute blood loss, it shows normocytic, normochromic RBCs.
Treatment
If bleeding is massive or life threatening, intravenous access should be established, active bleeding controlled, and type O-negative, uncross-matched packed RBCs should be transfused. Rarely, in the previously transfused, alloimmunized child, minor blood group antigen incompatibility results in severe delayed hemolytic transfusion reactions following the administration of Onegative uncross-matched packed cells.
Iron-Deficiency Anemia
HINT: Nutritional deficiencies may be caused by decreased oral intake, increased requirements, decreased absorption, or ineffective transport or metabolism of the element. The specific deficiency should be determined as well as the underlying cause to provide optimal treatment.Etiology
Iron deficiency, which is the most common cause of anemia in childhood, can occur at any age, although children between 6 and 36 months of age and girls between 11 and 17 years of age are at increased risk. Iron deficiency in childhood is caused by rapid growth in the presence of inadequate dietary intake, chronic or massive blood loss, or poor gut absorption. Infants with iron deficiency, usually have a history of consuming large amounts of cow’s milk and other food substances low in iron.
HINT: Iron deficiency is less common in breast-fed infants. Although the iron content of breast milk is lower than that of a formula based on cow’s milk, iron absorption is improved.
HINT: Pica may be a symptom of iron deficiency or a risk factor for iron deficiency. Children who eat dirt should be evaluated for lead poisoning.Clinical Features
Children with severe iron deficiency are commonly pale, irritable, and have little appetite. In addition to signs of anemia, spooning of the nails, angular stomatitis, and splenomegaly may be present.
Laboratory Evaluation
The degree of iron deficiency can be estimated by the abnormalities found on laboratory studies. The following laboratory abnormalities occur progressively: decreased serum ferritin, decreased serum iron, increased microcytosis, and decreased hemoglobin with a normal or decreased reticulocyte count. The RBC distribution width (index) is increased. The platelet count may be markedly increased. The peripheral blood smear shows hypochromic, microcytic RBCs with increased variation in RBC size (anisocytosis) and shape (poikilocytosis). Increased numbers of elliptocytes and ovalocytes may be noted.
Treatment
Treatment of iron deficiency includes iron supplementation, as well as treatment of the underlying cause with nutritional counseling when appropriate. Oral iron replacement is achieved with ferrous sulfate (3 to 6 mg/kg/day of elemental iron in two or three divided doses). Although absorption is better on an empty stomach, gastric irritation is lessened if the iron is given with meals.
In patients with severe anemia, the hematologic response to ferrous sulfate administration can be documented by obtaining a reticulocyte count within 7 to 10 days. The reticulocyte count increases earlier than the hemoglobin level, which may not reach a normal level until 2 months after starting iron therapy, depending on the degree of anemia.
Many physicians believe that because iron deficiency is so common, the healthy child or adolescent with a microcytic, hypochromic anemia is appropriately managed using a trial of iron supplementation without additional laboratory evaluation. If a patient is managed this way, close follow-up should be provided. If the microcytic anemia persists, a comprehensive evaluation for other causes (e.g., thalassemia, anemia of chronic disease, chronic blood loss, sideroblastic anemia) should be performed.
Megaloblastic Anemias
Etiology
Megaloblastic anemias are often caused by folate and vitamin B12 deficiencies, which result in abnormal DNA synthesis. Folate deficiency in the United States is primarily caused by malabsorption of folate, increased RBC turnover, and drugs. Vitamin B12 deficiency may be caused by malabsorption or pernicious anemia, a rare disease caused by an inability to secrete the intrinsic factor required for normal vitamin B12 absorption.
Evaluation
Megaloblastic anemias are characterized by macrocytic RBCs and a mean corpuscularvolume (MCV) value >95 fL. The reticulocyte count is low, and in advanced cases pancytopenia may exist. Analysis of a bone marrow aspirate and biopsy shows dyssynchrony between nuclear and cytoplasmic maturation with increased cellularity.
Serum folate may be decreased, but measurement of RBC folate levels provides a more accurate picture of chronic folate deficiency. In pernicious anemia, serum vitamin B12 levels are reduced and intrinsic factor antibodies may be positive.
Therapy
Therapy includes supplemental folate or vitamin B12 administration, as well as treatment of the underlying cause of the deficiency.
Transient Erythroblastopenia of Childhood
Clinical Features
Transient erythroblastopenia of childhood is characterized by the acute onset of anemia in a previously healthy child between 6 months and 4 years of age. There may be a history of a viral prodrome. The physical examination is normal except for signs of anemia.
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