Lower urinary tract dysfunction in children with cerebral palsy and it’s correlation with bladder wall thickness with non-invasive ultrasound

Children with cerebral palsy (CP) have been reported to have a high prevalence of lower urinary tract dysfunctions (LUTD) like urgency, urge incontinence, and recurrent urinary tract infections (UTI), which range from 30% to more than 60%. The common reasons attributable are central nervous system abnormalities, impaired cognitive and communication abilities, and reduced mobility.^[1] Most children with CP eventually attain complete bladder control, but at an age later than unaffected children. Damage to the upper urinary tract and issues like vesico-urethral reflux and hydroureteronephrosis are not commonly reported, and kidneys are usually found to be normal on ultrasonic imaging.^[2]

Urodynamic study (UDS) has been considered as the gold standard for diagnosing bladder dysfunction in various neurological disorders, including in children with CP. Although it has been reportedly performed in children with spina bifida at an early age as 1st year of life, the challenges in the pediatric population remain in reporting various filling and voiding events during the procedure. Empirical treatment with behavioral, supportive, and pharmacotherapy is an option used by most of the treating clinicians in the absence of the UDS procedure in very young children.

Some non-invasive methods, like measuring post-void residual volume (PVR) of urine and bladder wall thickness by ultrasound imaging, can be used to assess the neurogenic bladder dysfunction. Patients with detrusor overactivity and poor bladder compliance have been reported to have chronic/ recurrent UTI and other symptoms of bladder dysfunction.^[3,4]

Kakoti et al. have authored an original article in this issue discussing their research work.^[5] The authors conducted a study with children with CP who reported to the department with complaints of recurrent UTI and other symptoms of neurogenic bladder dysfunction. They recruited 41 such patients with CP and age and sex matched healthy children with a median age of 8 years in both groups and conducted a comparative study. Considering the obvious difficulties in conducting UDS in these children with CP, they decided to use the non-invasive methods for dysfunction assessment. Dysfunctional voiding symptom score (DVSS) was used to compare urinary complaints between children with CP and healthy controls. But the primary objective of the study was to assess the average bladder wall thickness (aBWT) in children with CP with urinary symptoms, using ultrasound, and comparing the same with healthy controls. The authors hypothesized that children with CP would have a thicker bladder wall compared to controls, as suggested by some previous studies. They also measured the PVR in both groups and compared them.

The results of the study showed that the children with CP had a significantly thicker bladder wall as compared to healthy controls. Moreover, 12% of the children with CP were found to have an abnormally thickened bladder wall (≥ 3mm). The post-void residual urine was significantly higher in children with CP, statistically, but it was found to be insignificant in both groups. Children with CP scored significantly high on DVSS scores as compared to controls, denoting considerable storage and voiding bladder dysfunction. The authors found a moderate positive correlation between DVSS score and associated bladder wall thickness in children with CP.

Other significant findings of the study were the near-universal presence of constipation in children with CP and its correlation with urinary dysfunction (high DVSS scores), which has also been reported in the literature. They also reported a significant correlation between gross motor function classification system (GMFCS) levels and LUTDs.

Non-invasive methods are practical solutions, especially in the pediatric CP population with LUTD in the early first decade of life. Kakoti et al recommend a screening algorithm using the DVSS scale during routine clinical visits by these children.^[5] This should be followed by a non-invasive ultrasound to assess aBWT and PVR. Children with height aBWT and DVSS scores can be referred for specialized intervention, including UDS, wherever feasible.