March Week 4: HUS
You have a 3 year old male who is brought to the ED by his mother when she noted bloody diarrhea earlier in the day. There is no fever, ill contacts, or recent exposures to children with diarrhea. He is noted to be pale. His family had attended a birthday party 7 days prior where the child had consumed hot dogs and hamburgers. He has a low grade fever and on the physical exam, he is alert but fussy, non-toxic appearing. You notice a pale conjunctiva, oral mucosa is most. His heart has a regular rhythm with tachycardia and a grade III/VI vibratory systolic ejection murmur at the left sternal border without radiation. His lungs are clear with good aeration. His abdomen is flat, soft, and non-tender, with the liver edge palpable 3cm below the RCM. The spleen is non-palpable. His genitalia and anus are normal. (no rectal prolapse). His pulses and perfusion are good. There are is no edema, rash, or petechiae.
You order labs:
CBC: WBC 16,000 with 56% segs, 12% bands, 27% lymphs, 3% eos, 2% basos, hemoglobin 8 mg/dL, hematocrit 24.6, platelet count 75,000; peripheral smear shows schistocytes, helmet cells, and polychromasia. Na 133, K 5.9, Cl 96, bicarbonate 16, BUN 45, creatinine 1.3, glucose 145 mg/dL, Ca 7.8, PO4 7.1, uric acid 7.3, and LDH 300. Coagulation studies are normal.
1. What is the likely etiology?
2. What defines D+HUS?
3. What types of blood cells would be most consistent with a diagnosis of HUS in a 3 year old child with bloody diarrhea?
a. Atypical lymphocytes
4. What is the strongest indication for dialysis?
a. Serum sodium of 120
b. Initial bicarbonate of 14
c. Serum BUN 120 mg/dL
d. Initial K of 5.2
e. Anuria for 3 days
5. True/False: The severity of hemolysis correlates with degree of renal failure?
A 3 year old girl presents with signs and symptoms of intussusception which include crampy intermittent abdominal pain, crying with puffy eyes, currant jelly diarrhea, pallor, dehydration and oliguria. Could this patient have HUS? Explain how all of the findings above could be due to HUS instead.
Case/Questions written by Dr. Carolina Salvador, PGY2