Neonatal hypotonia: is it a diagnostic challenge?

INTRODUCTION

Hypotonia is a frequent sign of disease in newborns. However, it's a nonspecific clinical finding: may be the presentation form of a systemic or neurological disease.

AIMS

To study the main causes of neonatal hypotonia as well as to evaluate the diagnostic accuracy of the anamnesis and physical examination of the hypotonic newborn.

PATIENTS AND METHODS

A 22-year retrospective study of hypotonic neonates admitted to the Neonatal Intensive Care Unit was conducted. It was performed an initial blind classification of hypotonia's type (central-CH, peripheral-PH or undetermined hypotonia) based on the clinical history and the recorded data of physical examination.

RESULTS

91 infants were included. 42 (46.2%) had prenatal history abnormalities: polyhydramnios (28.6%), intrauterine growth restriction (21.4%) and pelvic presentation (19.0%). 53 (58.2%) required resuscitation at birth. The main associated symptoms were respiratory distress (65.9%), feeding difficulties (36.5%) and decreased spontaneous movements (22.4%). The final diagnosis was reached in 64 newborns (70.3%): 81.3% with CH, 18.7% with PH. The positive predictive value of the initial classification was 97.9% in CH and 66.7% in PH group. The mortality rate was 8.8% and it was higher in PH group (58.3% vs 1.3%).

CONCLUSIONS

Neonatal hypotonia can be associated to an extensive list of disorders. A detailed clinical history associated to a careful neurological evaluation present a high diagnostic predictive value that should guide the etiological investigation.