Bloody Diarrhea, Oliguria, and Thrombocytopenia After Undercooked Beef
A 4-year-old boy, previously well and weighing 16 kg, presents with 5 days of bloody diarrhea and crampy abdominal pain. He ate undercooked hamburger at a fair 6 days ago. He is now lethargic and has passed little urine for 12 hours. Heart rate is 140/min, respiratory rate 32/min, blood pressure 90/55 mm Hg, capillary refill 4 seconds, and temperature 37.8°C. He is pale with dry mucous membranes. Initial investigations show hemoglobin 9.2 g/dL, platelets 48 × 10⁹/L, white cell count 18 × 10⁹/L, creatinine 120 µmol/L, sodium 131 mmol/L, potassium 5.6 mmol/L, bicarbonate 16 mmol/L, and schistocytes on the blood film. Urine output is 0.3 mL/kg/hour. Stool polymerase chain reaction is positive for Escherichia coli O157:H7. The emergency department has ordered ceftriaxone and an antimotility agent. The nurse asks whether these should be given before transfer to the pediatric ward.
1. What is the likely diagnosis, and what immediate management would you prioritize?
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The combination of prodromal bloody diarrhea after undercooked beef, schistocytes, thrombocytopenia, anemia, rising creatinine, and oliguria is characteristic of Shiga toxin–producing E. coli hemolytic uremic syndrome (STEC-HUS). The immediate priorities are volume resuscitation and careful monitoring, not antibiotics. I would give an isotonic crystalloid bolus of 10–20 mL/kg (160–320 mL) for shock and repeat as needed while watching for fluid overload, because poor perfusion worsens renal injury. I would check electrolytes, calcium, blood gas, lactate, blood count, and renal function frequently; treat hyperkalemia with calcium gluconate, insulin–dextrose, and salbutamol if indicated; and avoid potassium-containing fluids. I would insert a urinary catheter to measure output, monitor blood pressure, and involve pediatric nephrology early. The reasoning is that HUS is a toxin-mediated microangiopathy, and supportive care with careful fluid balance is the mainstay while the endothelium recovers.
2. Which therapies should be avoided in this child, and what is the rationale?
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I would avoid ceftriaxone and the antimotility agent that have already been ordered. Antibiotics against STEC may increase release of Shiga toxin from dying bacteria and have been associated with a higher risk of HUS, so they are not indicated for uncomplicated STEC colitis. Antimotility drugs slow transit and can worsen toxin absorption and abdominal distension. I would also avoid nonsteroidal anti-inflammatory drugs because of renal toxicity and bleeding risk. Platelet transfusion is not routinely indicated for thrombocytopenia alone; it should be reserved for active bleeding, a planned invasive procedure, or a very low platelet count with critical bleeding, because transfused platelets are consumed in the microangiopathic process. The reasoning is that none of these therapies shortens the illness, and several can worsen the toxin-mediated injury.
3. What are the indications for renal replacement therapy in this child, and what complications would you monitor for?
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Renal replacement therapy is indicated for anuria or severe oliguria with fluid overload, refractory hyperkalemia, severe metabolic acidosis, uremic encephalopathy or pericarditis, and inability to maintain nutrition or electrolyte balance. This child already has oliguria, acidosis, and hyperkalemia, so nephrology should assess him early even if dialysis is not yet needed. I would monitor for pulmonary edema from fluid overload, hypertension, hyponatremia, hypocalcemia, and bleeding. Neurologically, I would watch for seizures, irritability, or reduced consciousness, which can reflect hyponatremia, uremia, or central nervous system involvement of HUS. I would also monitor the blood count and film for worsening microangiopathic hemolysis. The reasoning is that HUS can deteriorate rapidly over days, and dialysis decisions are based on the trajectory of renal function, fluid balance, and electrolyte safety rather than a single creatinine value.