Janice said: Since her blood urea : creatinine ratio is less than 1:20, i would suspect a chronic renal failure.. (If creatinine is more than 320, then i would suspect an acute onset.) and her electrolytes are within normal range suggests a compensated state.. However, I would not rush into dialysis at this point of state.. Rather, I would optimize her blood pressure which would further insult her kidney function..
Janice, I do not think we can differentiate ARF from CRF by the level of serum creatinine alone. The difference between ARF and CRF is really a clinical distinction. Chronic renal failure can be defined as diminished renal function for more than 3 months. Therefore if I see a patient for the first time with the above urea and creatinine values, I would look to see whether she has any clinical condition (dehydration, drug intake, features of acute glomerulonephritis, a systemic disease that damages the kidney or diminishes renal perfusion) that can be the cause of acute renal failure. If nothing is there, then I will assume it is chronic renal failure. The urea: creatinine ratio, in my opinion, is one way of distinguishing between pre-renal acute kidney injury and other causes of kidney damage. It is not a reliable way of distinguishing the different forms of parenchymal renal injury.
There are some conditions in every patient with renal failure - acute or chronic - that, if present, should tell you that the patient needs immediate dialysis. Does anyone know what these conditions are?