Hi Sudha, After going through your fathers case there there is possibility of underlying chronic kidney disease (CKD) as he is on some medicines for his raised urea and creatinine level (you have not mentioned his range of urea, creatinine levels over past 7 years before current rise). As you have mentioned on 26th Dec he developed fever with chills and swelling over left leg there is possibility of left leg cellulitis (infection) which may responsible for further deterioration of kidney function called as Acute Kidney Injury (AKI) this might be due to 1) Infection its self. 2) Low Blood Pressure caused by infection which leads to decreased blood supply to kidney and deterioration of kidney function. 3) Dehydration. In case of AKI there might be need for hemodialysis as in you father s case. Need for Haemodialysis depends on- 1) Amount of Urine production daily. 2) Serum electrolyte mainly Potassium. 3) Serum Creatinine level. 4) Arterial Blood Gas (ABG) analysis which denote degree of acid accumaulation in blood. 5) Signs of water retention like breathing difficulty(as in your father), swelling over body, puffiness of face. In most of the cases after control of disease responsible for rapid deterioration of kidney function (left leg cellulitis as in your father case) there might be improvement in kidney function. There is persistent deterioration of kidney function in your father s case may be due to- 1) Single kidney. 2) Underlying CKD (may be advansing). 3) Delayed recovery of cellulitis. 4) Persistent hypotension (low blood pressure) Presence of comorbid conditions like diabetes, high blood pressure, cholesterol problem usually associated with deterioration of kidney function.