We can diagnose cachexy in children whose BMI is <5 percentiles and under 3-rd negative deviation. The aetiology of poor state of nutrition can be: incorrect feeding, frequent infections, congenital defects, improper care or a combination of the previous situations.

Authors present four cachectic patients: two children suffering of trisomy 21, who had associated each one heart malformation: first, a boy, N. S., aged 7 and weighting 12 Kg had Fallot tetralogy and bacterial endocarditis; second, a girl, P. S, 43 months aged, weighting 10 Kg, had ventricular septal defect and acute interstitial pneumonia. The third cachectic patient was a girl aged 8, weighting 13 kg, D. C. with Seckel syndrome, admitted for staphylococcal pneumonia; the fourth is a 11 years girl weighting 12 Kg, P. D. with spastic tetraparesis, microcefaly, diagnosed with severe sepsis.

Only the boy suffering of endocarditis, evaluated to MODS and death; the three girls were discharged healed. Trisomy 21 caused immunodeficiency and cachexy also permitted severe infections. The boy had severe hypoxia, but girls had a normal oxygen saturation. The aetiology of poor state of nutrition was combinated: congenital defects, improper diet, frequent infections, inadequate care (three patients lived in orphanage, a girl had only mother). Pneumonia is frequent in thin children, with birth malformations. Congenital heart defects could been complicated to endocarditis.

Cachexy in malformed children is an important cause of immunodeficiency which leads to severe, sometimes letal infections. Infections produce denutrition and cachexy promotes severe sepsis, especially in parentless children.