A 23 years old male presented to the accident and emergency with repeated nausea and vomiting for one week. He denies any symptoms before the last week. He has a background of type 1 Diabetes mellitus and he is on insulin treatment since he was 8 years old.He also started to feel numbness and weakness in his right foot. His GP tried with him Domperidone and PPI with no effect. He has no fever, no diarrhea.But he noted that he did not pass any urine the last 2 days.
On examination: He was pale, Bp: 170/100 mmHg, pulse 75 bpm, Temperature 37.3. He looked dehydrated .There was purpuric rash over both feet and distal both legs. He had impaired sesation over his right foot and weakness in dorsiflexion.
Bloods sent to the laboratory and came back as follow:
Na 139 mmol/l
K 6.7 mmol/l
B. Urea 35 mmol/l
S. Cr 750 umol/l
Base Excess -15
S. Bicarbonate 9 mmol/l
HB 95 g/l
Oesinophils 0.03 x 109 Cells/l
ESR 90 (1ST Hour)
ANA Positive (1/40)
US KUB : Bilateral atrophied small kidneys
Virology requested as preparation for dialysis
What is the most likely cause of his renal failure?