Title : Epidemiological profile of patients with spinal muscular atrophy at a children hospital in south of Brazil
Abstract:
Introduction: Spinal muscular atrophies (SMA), prevalence of 1.5:100.000, recessive inheritance, neuromuscular diseases with anterior medullary horn degeneration, are caused by mutations in the survival of motor neuron protein, represented by SMN1 and SMN2 genes, supporting the motor neurons in the medulla and brainstem. They’re classified according to symptomatic onset age and maximum motor function acquired. Actually, the only approved pharmacological treatment is intrathecal nusinersena.
Method: The research objective – observational, transversal and retrospective – objective is to trace the epidemiological profile of the patients, correlating to risk and protective factors for morbimortality and patients using nusinersena. The selected children have a clinical and genetic diagnosis (n = 36), the data collected refer to the period from January 2010 to December 2018, 2 children who died during the period and 1 without genetic confirmation were excluded. The statistical strategy used was through Excel and SPSS v.22.O program, using chi-square test with values of p <0.05. The variables collected were onset age, identification, family history, health plan type, school life, diagnosis, urgent and elective hospitalizations, surgeries and other information of clinical follow-up .
Results: The mean age is 7.5 years (range 1-21.9), 48.5% female and 51.5% male. SMA type 1, 2 and 3 presented 21.2%, 66.7% and 12.2%, respectively, and there were not patients with type 0 and IV. The diagnosis occurred in the first life year in 45%, 42.4% between the 1-4 and 12.1% from 4-15y. Family history was present at 21.2%. The initial symptoms were
hypotonia (33.3%), muscle weakness (42.4%) and delayed neuropsychomotor development (51.5%), the latter reported by parents (54.5%), muscle weakness (88%), frequent hospitalizations (18%), orthoses (18%), gastrointestinal symptoms (9%), pain (18%) and difficulty gaining weight (18%). The need of hospital admission is 80% and 45.5% needed ICU. 15% remained more than 30 days (30% with more than 30 days of ICU). The most prevalent emergencies are pulmonary infections (66.7%), respiratory insufficiency (27.3%), extrapulmonary infections (24.2%) and feeding difficulties (48.5%). Elective hospitalizations for surgeries (51.5%): gastrostomy (24.2%), tracheostomy (15.2%) and orthopedic surgeries (20%). The feeding is oral (66.7%), gastrostomy (30%), nasoenteric (3%), and only 60.6% with adequate weight. Only 21% under treatment, 3 patients took 6m-1y to start treatment and 2 patients waited more than 1y. The reasons of small plot with nusinersena are very advanced disease (6%), study with oral drug (3%), judicial waiting for approval (57.6%) and 12.1% had previous surgery for spinal arthrodesis. A neurologist and a physiotherapist (100%), orthopedist (54%), pulmonologist (27%), occupational therapist (24%), nutritionist (15%), gastroenterologist 12%) and pediatric surgeon (9%) were the professionals of multidisciplinary team. Patients enrolled in education were 57.5%, the majority (45.5%) being in a special school. Discussion: In our study, the most prevalent SMA was type II. They have 2 SMN2 copies (63.5%), 3 (33.3%) or 4 (3%) related to the prognosis. Those with 2 copies have hypotonia as the first symptom (63%), hospitalizations (37%), pneumonia (54%), respiratory failure (45.5%), respirator use (72%), tracheostomy (45.5%), gastrostomy (64%) and GMFSC V (54.5%).
Conclusion: These data confirm, as a disease of high morbimortality, the ensurance of performing adequate genetic tests and have the copies of the SMN 2 counted for prognostic purposes.
