Urinary retention due to an isolated sacral root injury caused by sacral fracture

STUDY DESIGN

A case report.

SETTING

Urodynamic laboratory in a university hospital, Chiba, Japan.

CASE REPORT

A young woman who suffered from urinary retention following a skiing accident. A sacral X-ray (lateral view) revealed an S2-3 sacral fracture. The patient gradually regained the ability to urinate. At 3 months after the accident, she still suffered difficult urination, although her neurological findings were normal. A urodynamic study showed an acontractile detrusor and a neurogenic sphincter electromyogram (EMG), together indicative of isolated sacral nerve injury.

CONCLUSIONS

It was postulated that the S2-3 sacral fracture had led to bilateral traction of the S2-3 nerve roots, producing transient bladder paralysis (parasympathetic fibers) and incomplete sphincter paresis (somatic fibers). Sacral fracture is also of high clinical suspicion for urinary retention in frail elderly people, because it can result from simple falls.

When is Onuf's nucleus involved in multiple system atrophy? A sphincter electromyography study

BACKGROUND

External anal sphincter (EAS) electromyography (EMG) abnormalities can distinguish multiple system atrophy (MSA) from Parkinson's disease in the first five years after disease onset. However, the prevalence of the abnormalities in the early stages of MSA is unknown.

OBJECTIVES

To present EAS-EMG data in the various stages of MSA.

METHODS

84 patients with "probable" MSA were recruited (42 men, 42 women; mean age 62 years (range 47 to 78); mean disease duration 3.2 years (0.5 to 8.0; <1 year in 25%); 50 cerebellar form (MSA-C), 34 parkinsonian form (MSA-P)). EAS motor unit potential (MUP) analysis and EMG cystometry were carried out in all patients.

RESULTS

The overall prevalence of neurogenic change of the EAS MUP was 62%-52% in the first year after disease onset, increasing to 83% by the fifth year (p<0.05); it also increased with severity of gait disturbance (p<0.05), storage and voiding disorders, and detrusor sphincter dyssynergy (NS). The neurogenic change was not correlated with sex, age, MSA-P/C, postural hypotension, constipation, erectile dysfunction in men, underactive or acontractile detrusor, or detrusor overactivity. In 17 incontinent patients without detrusor overactivity or low compliance, urinary incontinence was more severe in those with neurogenic change than in those without (p<0.05).

CONCLUSIONS

Involvement of Onuf's nucleus in MSA is time dependent. Before the fifth year of illness, the prevalence of neurogenic change does not seem to be high, so a negative result cannot exclude the diagnosis of MSA.

Human cystinuria-related transporter: localization and functional characterization

BACKGROUND

Cystinuria has been proposed to be an inherited defect of apical membrane transport systems for cystine and basic amino acids in renal proximal tubules. Although the mutations of the recently identified transporter BAT1/b(0,+)AT have been related to nontype I cystinuria, the function and localization of human BAT1 (hBAT1)/b(0,+)AT have not been well characterized.

METHODS

The cDNA encoding hBAT1 was isolated from human kidney. Fluorescence in situ hybridization was performed to map the hBAT1 gene on human chromosomes. Tissue distribution and localization of expression were examined by Northern blot and immunohistochemical analyses. hBAT1 cDNA was transfected to COS-7 cells with rBAT cDNA, and the uptake and efflux of 14C-labeled amino acids were measured to determine the functional properties. The roles of protein kinase-dependent phosphorylation were investigated using inhibitors or activators of protein kinases.

RESULTS

The hBAT1 gene was mapped to 19q12-13.1 on the human chromosome, which is the locus of nontype I cystinuria. hBAT1 message was expressed predominantly in kidney. hBAT1 protein was localized in the apical membrane of proximal tubules in human kidney. When expressed in COS-7 cells with a type II membrane glycoprotein rBAT (related to b(0,+)-amino acid transporter), hBAT1 exhibited the transport activity with the properties of amino acid transport system b(0,+), which transported cystine as well as basic and neutral amino acids presumably via a substrate exchange mechanism. BAT1-mediated transport was reduced by the protein kinase A activator and enhanced by the tyrosine kinase inhibitor.

CONCLUSIONS

hBAT1 exhibited the properties expected for a transporter subserving the high-affinity cystine transport system in renal proximal tubules. The hBAT1 gene was mapped to the locus of nontype I cystinuria, confirming the involvement of hBAT1 in cystinuria.