Snapshot A 25-year-old woman presents to the emergency room for painful joints. She has had pain in her bilateral hands and wrists for the past few days. She also had a low-grade fever and mild upper respiratory symptoms. She is 14-weeks pregnant and has had good prenatal care. She works as a kindergarten teacher. On physical exam, the joint in her hands are slightly swollen and tender. A fetal ultrasound shows hydrops fetalis. Introduction Classification parvovirus B19 non-enveloped, linear, single-stranded DNA virus causes a variety of diseases aplastic crisis in patients with red blood cell disorders pure red blood cell aplasia in adults rheumatoid arthritis-like symptom in adults erythema infectiosum (fifth disease) in children hydrops fetalis in fetuses if pregnant women are infected transmission via respiratory droplets Epidemiology incidence highest in winter and spring demographics children > adults risk factors sickle cell disease thalassemia hereditary spherocytosis close proximity to others (e.g., school or daycare centers) Pathogenesis infects red blood cells through the P antigen viral replication in bone marrow causes the death of erythroid progenitor cells causes hydrops fetalis in fetuses due to severe fetal anemia Presentation Symptoms prodrome with flu-like symptom hydrops fetalis and fetal death in pregnant women polyarthropathy small joints (e.g., hands) Physical exam erythema infectiosum first rash appears as slapped cheeks subsequent rash is an erythematous maculopapular rash on the trunk and limbs, which may appear reticular or lacy Studies Labs parvovirus-specific immunoglobulin M detection of parvovirus on polymerase chain reaction anemia Making the diagnosis based on clinical presentation may be confirmed with laboratory studies Differential Measles distinguishing factors confluent maculopapular rash without slapped cheeks rash Koplik spots on buccal mucosa Rubella distinguishing factor non-confluent maculopapular rash that spreads from face to body Treatment Management approach mainstay of treatment is supportive care Conservative supportive care indication all patients modalities analgesics hydration Medical non-steroidal anti-inflammatory drugs indication polyarthropathy Complications Myocarditis Behcet syndrome Aplastic crisis
QUESTIONS 1 of 5 1 2 3 4 5 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 . = + Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (M1.MC.14.201) A 17-month-old male is brought to your office by his mother for evaluation of a rash. Four days ago, the child experienced low-grade fever, irritability, and rhinorrhea. Physical examination is notable for the rash seen in Figure A. To which viral family does the most likely etiologic agent belong? Review Topic | Tested Concept QID: 106228 FIGURES: A Type & Select Correct Answer 1 Hepadnavirus 0% (0/22) 2 Herpesvirus 23% (5/22) 3 Parvovirus 68% (15/22) 4 Togavirus 0% (0/22) 5 Picornavirus 5% (1/22) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (M1.MC.13.10) A 9-year-old male presents to your office with an indurated rash on his face. You diagnose erythema infectiosum. Which of the following is characteristic of the virus causing this patient's disease? Review Topic | Tested Concept QID: 101469 Type & Select Correct Answer 1 Enveloped virus with double-stranded DNA 18% (53/300) 2 Enveloped virus with single-stranded DNA 19% (58/300) 3 Enveloped virus with single-stranded RNA 11% (32/300) 4 Non-enveloped virus with double-stranded DNA 11% (32/300) 5 Non-enveloped virus with single-stranded DNA 39% (118/300) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5