Dr Mahak Bhasin, Dr Sajith Keshavan, Dr Jayakumar, Department of Pediatrics, AIMS, Kochi
Six year old female ba born at term via normal vaginal delivery with birth weight of 3.2kgs to primi mother.
History of reduced perception of fetal movements noted during the third trimester but the mother was reassured.
Uneventful post natal period.
At 3 months child received vaccinations when the mother noticed paucity of movements of lower limbs with floppiness.
She was taken to her local hospital where she was treated with IVIG therapy for acute inflammatory demyelinating neuropathy (AIDP)
The child however continued to have progression of weakness with the mother now also noticing decreased tone and reduced movements in upper limbs also
On examination, she has wide spaced teeth, bell shaped chest, distended abdomen, with a pithed frog posture. Power in distal muscle groups of upper limbs is 2/5 and 1/5 in proximal muscle groups of upper limbs and 1/5 in lower limbs. Tone is significantly decreased. Reflexes are 1+ at best in all 4 limbs.
At 1.5 years old, child could sit with support.
At 1.5 years old, she was admitted in PICU for an LRTI and was started on heated humidified high flow nasal cannula therapy ( HHHFNC) support.
She was also started on Risdilpam.
At 3.5 years old, she was again admitted for an LRTI in the PICU. Child was intubated and was on ventilatory support for 10 days.
At 3.6 years old, she was again admitted for an LRTI in the ward and required face mask.
At 5 years old, child was admitted for bilateral lower lobe collapse and E. coli positive UTI. She was thus discharged on night time BiPAP support.
At 6 years old, child could roll over on her own. She could no longer sit with support. She could feed herself a biscuit but could not comb her hair or dress herself. She could write alphabets and was being homeschooled.
Differential diaganosis of a floppy ba
– Atonic Cerebral Palsy
– Spinal Muscular Atrophy (SMA)
– Peripheral neuropathy
– Muscular Dystrophy
– Myotonic Dystrophy
– Down Syndrome
– Prader-Willi Syndrome
– Birth Asphyxia
– Maternal Substance Abuse
Child is a k/c/o Spinal Muscular Atrophy Type 2 with WES showing SMN gene
Spinal muscular atrophy is a degenerative disorder of motor neurons beginning in fetal life and progressing through infancy and childhood caused due to homozygous deletion in the survival motor neuron 1 gene on chromosome 5q13.
It is divided into 3 types.
SMA Type 1 patients have an onset at <6 months old. The disease is severe with most children succumbing to death 2 years old. They are never able to sit.
In SMA Type 2, onset is between 6 and 18 months old, patients can sit inpendently but can never walk.
In SMA Type 3, onset is after 18 months old and patients can even walk independently though they may lose the ability over time.
Management
Disease-Modifying Therapies
Zolgensma (AVXS-101): Gene therapy, administered via intravenous infusion, replacing the faulty SMN1 gene.
Spinraza (nusinersen): Antisense oligonucleotide therapy, administered via spinal injection, increasing SMN protein production.
Evrysdi (risdiplam): Small molecule therapy, taken orally, increasing SMN protein production.
Supportive Care
1. Physical therapy: Maintaining muscle strength and mobility.
2. Occupational therapy: Enhancing daily functioning.
3. Speech therapy: Improving communication.
4. Respiratory care: Managing breathing difficulties.
5. Nutrition support: Ensuring adequate nutrition.
Emerging Therapies
1. Gene editing (CRISPR/Cas9): Experimental gene editing technology.
2. Stem cell therapy: Investigational treatment for regenerating motor neurons.
3. New antisense oligonucleotides: Additional RNA-targeting therapies.