Snapshot An 11-month-old Caucasian boy presents to the emergency department for severe fatigue. His symptoms progressively worsened to the point where he is unresponsive. On physical exam, the patient has a flat nasal bridge and triphalangeal thumbs. Laboratory testing is significant for an isolated macrocytic anemia, reticulocytopenia, and increased HbF. Genetic testing is pursued, which demonstrates a ribosomopathy. Introduction Clinical definition isolated anemia and reticulocytopenia due to a pure red cell aplasia (PRCA) Etiology may be due to congenital (e.g., Diamond-Blackfan anemia) or acquired (e.g., transient erythroblastopenia, paraneoplastic syndromes, and parvovirus B19 infection) causes Pure Red Cell Aplasia Cause Clinical Findings Laboratory Findings Treatment Diamond-Blackfan anemia (DBA) Typically occurs in infancy Congenital abnormalities growth retardation craniofacial abnormalities e.g., hypertelorism and a flat nasal bridge thumb abnormalities e.g., triphalangeal thumbs Predisposition to cancer acute myelogenous leukemia myelodysplastic syndrome Etiology congenital impairments affecting ribosome synthesis Macrocytic, normochromic, and non-megaloblastic anemia Reticulocytopenia Increased HbF Corticosteroids and blood transfusions Hematopoietic cell transplantation in patients unresponsive to steroids Transient erythroblastopenia of childhood (TEC) Transient/temporary red cell aplasia DBA is chronic The child is otherwise healthy Etiology unknown Normocytic anemia at the time of diagnosis Reticulocytopenia Patients typically recover 1-2 months without treatment RBC transfusions may be needed for disabling symptoms Parvovirus B19 Patients with an underlying hemolytic process may experience an aplastic crisis with parvovirus B19 infection e.g., sickle cell anemia, hereditary spherocytosis, and pyruvate kinase deficiency Etiology temporary cessation of RBC production with a viral infection of erythroid progenitors via a P-antigen receptor Proerythroblasts and absent erythroid precursors may be seen in the bone marrow Otherwise healthy children do not require treatment Patients with an underlying hemolytic process receive RBC transfusions for symptomatic anemia Paraneoplastic syndrome Hemoglobin decline in a patient who has not had a transfusion and previously responded to erythropoietin Etiology underlying malignancy can result in the production of anti-erythropoietin antibodies malignancies thymoma myelodysplastic syndromes Bone marrow aspirate severe erythroid hypoplasia very little RBC precursors Present anti-erythropoietin antibodies Transfusions for symptomatic anemia Discontinue recombinant erythropoietin (EPO) products Immunosuppression ?
QUESTIONS 1 of 1 1 Previous Next Lab Values Blood Hematologic Cerebrospinal Sweat, Urine, and BMI Blood, Plasma, Serum Reference Range ALT 8-20 U/L Amylase, serum 25-125 U/L AST 8-20 U/L Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL Calcium, serum (Ca2+) 8.4-10.2 mg/dL Cholesterol, serum Rec: < 200 mg/dL Cortisol, serum 0800 h: 5-23 μg/dL //1600 h: 3-15 μg/dL 2000 h: ≤ 50% of 0800 h Creatine kinase, serum Male: 25-90 U/LFemale: 10-70 U/L Creatinine, serum 0.6-1.2 mg/dL Electrolytes, serum Sodium (Na+) 136-145 mEq/L Chloride (Cl-) 95-105 mEq/L Potassium (K+) 3.5-5.0 mEq/L Bicarbonate (HCO3-) 22-28 mEq/L Magnesium (Mg2+) 1.5-2.0 mEq/L Estriol, total, serum (in pregnancy) 24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL 28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL Ferritin, serum Male: 15-200 ng/mLFemale: 12-150 ng/mL Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL Female: premenopause: 4-30 mIU/mL midcycle peak: 10-90 mIU/mL postmenopause: 40-250 pH 7.35-7.45 PCO2 33-45 mmHg PO2 75-105 mmHg Glucose, serum Fasting: 70-110 mg/dL2-h postprandial:<120 mg/dL Growth hormone - arginine stimulation Fasting: <5 ng/mLProvocative stimuli: > 7ng/mL Immunoglobulins, serum IgA 76-390 mg/dL IgE 0-380 IU/mL IgG 650-1500 mg/dL IgM 40-345 mg/dL Iron 50-170 μg/dL Lactate dehydrogenase, serum 45-90 U/L Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL Female: follicular phase: 5-30 mIU/mL midcycle: 75-150 mIU/mL postmenopause 30-200 mIU/mL Osmolality, serum 275-295 mOsmol/kd H2O Parathyroid hormone, serume, N-terminal 230-630 pg/mL Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L Phosphorus (inorganic), serum 3.0-4.5 mg/dL Prolactin, serum (hPRL) < 20 ng/mL Proteins, serum Total (recumbent) 6.0-7.8 g/dL Albumin 3.5-5.5 g/dL Globulin 2.3-3.5 g/dL Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h Thyroxine (T4), serum 5-12 μg/dL Triglycerides, serum 35-160 mg/dL Triiodothyronine (T3), serum (RIA) 115-190 ng/dL Triiodothyronine (T3) resin uptake 25%-35% Urea nitrogen, serum 7-18 mg/dL Uric acid, serum 3.0-8.2 mg/dL Hematologic Reference Range Bleeding time 2-7 minutes Erythrocyte count Male: 4.3-5.9 million/mm3Female: 3.5-5.5 million mm3 Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/hFemale: 0-20 mm/h Hematocrit Male: 41%-53%Female: 36%-46% Hemoglobin A1c ≤ 6 % Hemoglobin, blood Male: 13.5-17.5 g/dLFemale: 12.0-16.0 g/dL Hemoglobin, plasma 1-4 mg/dL Leukocyte count and differential Leukocyte count 4,500-11,000/mm3 Segmented neutrophils 54%-62% Bands 3%-5% Eosinophils 1%-3% Basophils 0%-0.75% Lymphocytes 25%-33% Monocytes 3%-7% Mean corpuscular hemoglobin 25.4-34.6 pg/cell Mean corpuscular hemoglobin concentration 31%-36% Hb/cell Mean corpuscular volume 80-100 μm3 Partial thromboplastin time (activated) 25-40 seconds Platelet count 150,000-400,000/mm3 Prothrombin time 11-15 seconds Reticulocyte count 0.5%-1.5% of red cells Thrombin time < 2 seconds deviation from control Volume Plasma Male: 25-43 mL/kgFemale: 28-45 mL/kg Red cell Male: 20-36 mL/kgFemale: 19-31 mL/kg Cerebrospinal Fluid Reference Range Cell count 0-5/mm3 Chloride 118-132 mEq/L Gamma globulin 3%-12% total proteins Glucose 40-70 mg/dL Pressure 70-180 mm H2O Proteins, total < 40 mg/dL Sweat Reference Range Chloride 0-35 mmol/L Urine Calcium 100-300 mg/24 h Chloride Varies with intake Creatinine clearance Male: 97-137 mL/minFemale: 88-128 mL/min Estriol, total (in pregnancy) 30 wks 6-18 mg/24 h 35 wks 9-28 mg/24 h 40 wks 13-42 mg/24 h 17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 hFemale: 2.0-8.0 mg/24 h 17-Ketosteroids, total Male: 8-20 mg/24 hFemale: 6-15 mg/24 h Osmolality 50-1400 mOsmol/kg H2O Oxalate 8-40 μg/mL Potassium Varies with diet Proteins, total < 150 mg/24 h Sodium Varies with diet Uric acid Varies with diet Body Mass Index (BMI) Adult: 19-25 kg/m2 Calculator ( ) xy AC 7 8 9 ÷ 4 5 6 × 1 2 3 - 0 . = + (M1.HE.4754) A 35-year-old male presents to his primary care physician complaining of a one-month history of progressively worsening fatigue. He sought medical attention because this has affected his ability to complete his work as a graduate student. As a child, he was hospitalized for hemolytic uremic syndrome. His past medical history is also notable for diabetes mellitus and obesity. He takes metformin and glyburide. He does not smoke and drinks alcohol occasionally. His family history is notable for chronic lymphocytic leukemia in his paternal uncle and stroke in his father. His temperature is 99.9°F (37.7°C), blood pressure is 100/70 mmHg, pulse is 110/min, and respirations are 18/min. Physical examination reveals diffuse pallor. Hematologic labs are shown below:Hemoglobin: 8.9 g/dLHematocrit: 24%Leukocyte count: 7,500 cells/mm^3 with normal differentialPlatelet count: 180,000/mm^3Mean corpuscular volume: 85 µm^3Reticulocyte count: 0.4%Head and neck imaging is negative for neck masses. The pathogen associated with this patient’s condition is also known to cause which of the following? Review Topic QID: 108939 1 Kaposi’s sarcoma 10% (22/226) 2 Erythema infectiosum 30% (67/226) 3 Mononucleosis 35% (80/226) 4 Croup 4% (8/226) 5 Myocarditis 17% (38/226) M1 Select Answer to see Preferred Response PREFERRED RESPONSE 2