Reversible blindness secondary to severe diabetic ketoacidosis.

We present a case of sudden-onset reversible blindness secondary to severe diabetic ketoacidosis. The exact mechanism is not fully understood but is postulated to be due to uncoupling of retinal electrical transmission in a severe acidic environment. This report adds to the small number of reported cases of reversible blindness secondary to severe diabetic ketoacidosis and serves to raise awareness of this unusual diagnosis. It should be considered in patients who present with acute-onset reversible bilateral blindness only after other causes are excluded via detailed retinal examination and cranial imaging.

Assessing the utility of the stop dialysate flow method in patients receiving haemodiafiltration.

BACKGROUND: The stop dialysate flow (SDF) method of post-dialysis urea sampling is the most commonly used method in the UK. It can also be used with a published formula to predict 30 min equilibrated urea accurately. The method has not been validated in patients undergoing haemodiafiltration (HDF). Given the increased use of HDF across Europe, we felt it prudent to assess the utility of the SDF method and prediction equation in this modality. METHODS: Fourteen patients from two renal units were studied. Blood samples were taken at 1 min intervals from the arterial side of the dialysis circuit in the first 5 min after HDF had ceased whilst blood circulation continued. A peripheral sample was taken from the contralateral arm immediately after HDF had ceased and a 30 min sample was taken from the arterial needle. These samples were used to assess the utility of 5 min arterial blood urea and the 30 min prediction formula, respectively. RESULTS: Blood urea measured from the arterial circuit at 5 min correlated closely with the contralateral sample taken immediately post-HDF, with no significant difference (6.45+/-2.11 vs 6.52+/-2.19 mmol/l, P = 0.39). The use of 5 min arterial blood urea and prediction formula allowed an accurate prediction of 30 min urea (R2 = 0.96). CONCLUSIONS: The use of the SDF method with a 5 min post-HDF arterial sample is valid in patients receiving HDF. The previously published prediction formula for estimating 30 min urea is also valid using the 5 min post-HDF sample.