Snapshot A 7-year-old boy recently had several episodes of bloody diarrhea. Desperate, his parents called his primary care physician, who reassured them that the infection is self-limited. Still concerned, his parents bought some diarrhea pills (anti-motility agents). A week later, he presents to the ER with jaundice, abdominal pain, and easy bruising. Lab results come back with low platelet count, anemia, and increased creatinine. A peripheral blood shows schistocytes. He is started on IV hydration. Introduction Syndrome commonly seen in children most commonly caused by Escherichia coli O157:H7 (EHEC) acute diarrhea due to Shiga-like toxin S. pneumoniae infection Shigella spp. Shiga toxin Classic triad thrombocytopenia (first) nonimmune microangiopathic hemolytic anemia (second) acute renal failure (hence, “uremia” in title) (third) Similar to TTP but without fever and neurologic symptoms Pathogenesis toxin damages endothelium microthrombi form at site of damage consumes platelets → thrombocytopenia intravascular mechanical hemolysis → schistocytes decreases renal blood flow → acute renal failure Epidemiology most commonly in children exposed to E. coli raw or undercooked meat unwashed fruits/vegetables animals at petting zoos Risk factors use of antimotility agents in EHEC diarrhea use of antibiotics in EHEC diarrhea Presentation Symptoms prodromal gastrointestinal illness abdominal pain bloody diarrhea nausea vomiting fatigue (anemia) oliguria/anuria (renal failure) Physical exam pallor (anemia) jaundice (hemolysis) petechiae/purpura uncommon hepatosplenomegaly Evaluation Criteria for HUS hemolytic anemia hematocrit < 30% schistocytes (helmet cells) on peripheral smear thrombocytopenia ↑ serum creatinine Normal PT/PTT Negative Coombs test ↑ bleeding time Differential Characteristics DIC ITP TTP HUS Fever No No Yes Yes/No Splenomegaly No No Yes Yes Platelets Low Low Low Low Bleeding time ↑ ↑ ↑ ↑ PT ↑ - - - PTT ↑ - - - Shistocytes Yes No Yes Yes Trauma Yes No No No Treatment Supportive care with fluids to maintain renal perfusion dialysis if acute renal failure unresponsive to fluids Fresh frozen plasma can be used (increases coagulation factor levels) Plasmapheresis or plasma exchange for severe cases Prognosis, Prevention, and Complications Prognosis 3-5% mortality 5% severe sequelae such as end-stage renal failure Prevention prevent EHEC infection avoid raw or undercooked meat avoid antimotility agents or antibiotics Complications chronic kidney disease hypertension heart failure electrolyte abnormalities
QUESTIONS 1 of 2 1 2 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 . = + (M2.HE.4673) A 6-year-old male presents to the emergency room complaining of severe abdominal pain. His mother notes that he has had several episodes of diarrhea for the past week, with vomiting over the past 3 days. The child is on summer vacation and attended a 4th of July barbecue 1 week ago. The patient's vital signs are as follows: T 38.3 C, HR 116, BP 110/75, SpO2 98%. Physical exam is remarkable for diffuse abdominal tenderness without rebound or guarding. CBC shows WBC 9 x10^3/uL, Hgb 10.2 g/dL, Hct 33%, Plt 46 x10^3/uL. Peripheral blood smear yields the following findings (Figure A). The patient's creatinine is found to be elevated at 1.3. What is the underlying cause of this patient's anemia? Review Topic QID: 107021 FIGURES: A 1 Chronic renal disorder 0% (0/18) 2 Gastrointestinal arterio-venous malformation 0% (0/18) 3 Poor dietary nutrition intake 0% (0/18) 4 Inheritance of a beta-globin gene variant 6% (1/18) 5 Toxin-mediated damage to endothelial cells and prothrombotic changes 89% (16/18) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 5 (M2.HE.33) A 6-year-old boy is admitted with a one-week history of diarrhea, which was sometimes bloody and originally began after a birthday party. He has become lethargic and has not been eating or drinking. His vital signs are as follows: T 38.5 C, HR 135, BP 82/54. Physical examination is significant for petechiae on his legs and diffuse abdominal tenderness to palpation. Lab-work shows BUN 72 mg/dL, creatinine 8.1 mg/dL, and platelet count < 10,000. PT and PTT are within normal limits. Which of the following would be expected on a peripheral blood smear? Review Topic QID: 104673 1 Rouleaux formation 0% (0/30) 2 Fragmented red blood cells 83% (25/30) 3 Spur cells 3% (1/30) 4 Giant platelets 3% (1/30) 5 No abnormalities 3% (1/30) M2 Select Answer to see Preferred Response PREFERRED RESPONSE 2