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 3 1 2 3 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M2.HE.15.4673) 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? Tested Concept QID: 107021 FIGURES: A Type & Select Correct Answer 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) M 5 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review tested concept (M2.HE.15.33) 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? Tested Concept QID: 104673 Type & Select Correct Answer 1 Rouleaux formation 0% (0/34) 2 Fragmented red blood cells 82% (28/34) 3 Spur cells 3% (1/34) 4 Giant platelets 3% (1/34) 5 No abnormalities 6% (2/34) M 6 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review tested concept