A 6 years old girl child. She has a problem sudden of weight loss, her birth weight was 1 kg, normal delivery. She goes for physiotherapy treatment for a developmental delay but the child is active, normal behaviour, speech. She goes for schooling as a normal child, body looks normal.
She is always suffering from cold. There is a sudden weight loss, it reduces to 5 kg and again weight improves to 10 or 12 kg. What is the diagnosis and management?