A mother brings her 3-year-old daughter to the Emergency Department because she is having trouble urinating.The child is not feverish.She has otherwise been healthy except for a bout of diarrhea about 10 days ago.Laboratory test results are as follows: $\begin{array}{|l|l|}
\hline\text { TEST } & \text { RESULT } \
\hline \text { RBC } & 4.30 \times 10^{12} / \mathrm{L} \text { (moderate schistocytes }\
&\text { present on peripheral blood smear) }\
\hline \text { WBC } & 5.00 \times 10^{9} / \mathrm{L} \
\hline \text { PLT } & 28 \times 10^{9} / \mathrm{L} \
\hline \text { HGB } & 13.0 \mathrm{~g} / \mathrm{dL} \
\hline \text { HCT } & 39 \% \
\hline \text { MCV } & 89 \mathrm{fl} \
\hline \text { MCH } & 28 \mathrm{pg} \
\hline \text { MCHC } & 33 \% \
\hline \text { BUN } & 85 \mathrm{mg} / \mathrm{dL}(\mathrm{RR}: 8-24 \mathrm{mg} / \mathrm{dL}) \
\hline \text { CREAT } & 3.3 \mathrm{mg} / \mathrm{dL}(\mathrm{RR}: 0.2-1.3 \mathrm{mg} / \mathrm{dL})\
\hline
\end{array}$
Based on the history and the laboratory results, what is the most likely diagnosis?

Question

Quizplus · Accepted Answer

The laboratory results are consistent with hemolytic uremic syndrome (HUS), a condition characterized by hemolytic anemia, thrombocytopenia, and acute kidney injury. The presence of schistocytes on the peripheral blood smear suggests microangiopathic hemolytic anemia, and the low platelet count indicates thrombocytopenia. The elevated BUN and creatinine levels suggest acute kidney injury. The history of recent diarrhea is also consistent with HUS, which can be triggered by infections with certain strains of E. coli, such as E. coli O157:H7. The other answer choices are less likely given the information provided.

A Mother Brings Her 3-Year-Old Daughter to the Emergency Department