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BACKGROUND:
A simple pubmed search for the term “neurogenic bladder” yields topics including myelomengingocele, spinal cord injury, posterior urethral valves and painful bladder syndrome. Neurogenic bladder (NB) in the literature can be found in various forms: “neuropathic dysfunction,” “neurogenic bladder dysfunction”, and “neurogenic lower urinary tract (LUT) dysfunction.” According to the International Continence Society “neurogenic bladder” is defined as LUT dysfunction due to a disturbance of neurological control mechanisms, in the “presence of neurological pathology only.” In the current ICD-9 coding system, NB occurs in only two codes: 344.61 - cauda equina syndrome with NB, and 596.54 - neurogenic bladder NOS. Since all non-cauda equina NB encompasses one code, we undertook this study to see how this ICD-9 code is used in our institution - namely, if etiologies for NB diagnoses could be determined. Additionally, we sought to determine reasons for admission in children with NB.
METHODS:
Using the PHIS (Pediatric Health Information System) database, we retrospectively reviewed all inpatient visits at our tertiary care center during which the ICD-9 code 596.54 (“NB”) was included as a diagnosis. Since each PHIS visit can include up to 41 ICD-9 diagnoses, we then reviewed all diagnosis codes for each visit, including the admitting or principal diagnosis, to see if the specific etiology of the NB could be determined.
RESULTS:
In total, 304 inpatient visits with the diagnosis of NB (mean length of stay=13days, range=1-288) were identified over a five year period (2009-2014). The majority (97%) of NB codes were secondary diagnoses. The etiology of the NB could only be determined for 62.8% of visits with the most common causes being spina bifida with/without hydrocephalus (30.6%, of total visits), obstructing hydrocephalus NOS (6.6%), encephalitis/myelitis (4.6%), other anomalies of the spine (3.9%), spinal cord injury (1.6%), intraspinal abscess (1.6%), cerebral palsy (1.6%), and brain/spinal tumor (1.3%). For 37.2% of visits with a NB diagnosis, no specific etiology for NB could be determined. Of the 93 children with spina bifida, 28 (30.1%) had VP shunts and 7 of these children (25%) were admitted for shunt related complications. The most common admitting diagnosis was infection (26% total - 6% UTI, 4% sepsis, 2.3% pyelonephritis), followed by post-surgical complications (18%), orthopedic indications (9%), GI disorders (9%), and dehydration (5.7%).
CONCLUSIONS:
Neurogenic bladder is a descriptive diagnosis that does not predict course of disease nor patient prognosis. Coding of NB during inpatient visits is often incomplete with no determinable etiology in over 37% of visits. Given that only two ICD-9 codes include NB, one for NB caused by cauda equine syndrome and the other for all other NB NOS, the documentation of NB in the current ICD-9 system is insufficient and potentially problematic. Since hospital visit information submitted to national databases is often from non-clinicians, the ambiguity behind certain diagnosis codes, such as 596.54, may not be fully understood by those using it. To facilitate better collection of data, new separate codes and delineations for NB with specific etiologies should be included in future ICD coding systems.