Basically, it's an approach to a child with edema. You need to rule out other causes of generalized edema as specified by admin. For a more detailed approach: [Approach to a child with edema | Epomedicine][1]
As you begin to get a clue, from the history that the case might be probably of a nephrotic syndrome, you need to ask also the following things:
1. Number of hospital admissions (To see if it's frequent relapse)
2. Relation of the symptoms with steroid use (To see if it's steroid dependent)
3. Recurrent infections, neurologic symptoms, cushingoid symptoms (To rule out complications of disease and steroids)
4. If renal biopsy had been performed previously
5. Any history of insect bite or drug allergies
6. History of any extra immunizations after the diagnosis of disease
7. Blood pressure must be taken carefully and percentile must be calculated
[1]:
http://epomedicine.com/clinical-medicine/approach-to-a-child-with-edema/