Multiple System Atrophy (MSA) is a rare progressive, fatal neurodegenerative adult-onset disorder whose clinical features include parkinsonism, cerebellar ataxia, cardiovascular dysautonomia and urogenital dysfunction (1).  Urinary incontinence due to an overactive bladder and erectile dysfunction are commonly reported, and may precede the occurrence of motor or cardiovascular autonomic symptoms (2). Progressive incomplete bladder emptying and urinary retention usually develop during the course of disease.  We present six cases where urinary retention was the presenting feature with very little neurological signs, who subsequently developed classical neurological signs of MSA over time.

Between 2012-2018, six patients (mean age 55 years SD 10.3 years , 2 females) presented to a tertiary-level specialist Uro-Neurology unit with urinary retention who subsequently developed classical signs of MSA.

At initial presentation, 1 patient was able to void, and 5 were in urinary retention and catheter-dependent (table).   No cause for urinary retention could be identified during urological investigations, and urodynamics studies showed evidence for detrusor underactivity in 3 patients.  Concentric needle EMG of the anal sphincter performed in 4 to evaluate the sacral root (S2,3,4) innervation was however abnormal.  5 patients had sexual dysfunction and 4 had bowel dysfunction.
Subtle neurological signs were noted at presentation in 5 patients, however these were insufficient to establish a neurological diagnosis. During follow-up, all six patients developed motor and autonomic symptoms/ signs meeting the diagnostic criteria of MSA over a mean period of 3.6 years. Three patients expired (mean duration of illness 8.3 years). Urinary retention was managed by clean intermittent catheterisation initially, however indwelling catheterisation  was required over time as neurological  disability progressed.

At the time of initial presentation, these 6 patients presented predominantly with urinary retention and urological causes such as bladder outflow obstruction were excluded.  Urinary retention in the setting of MSA occurs as a result of neurodegenerative changes affecting regions involved in the neural control of voiding such as the brainstem and sacral spinal cord. There were no signs suggesting brainstem dysfunction at the time of initial presentation.  However the anal sphincter EMG was grossly abnormal, thereby suggesting the lesion to be at the level of the sacral spinal cord.   In the sacral spinal cord, MSA-related degeneration can affect the Onuf’s nucleus and bladder motor neurons and recently, high resolution MRI sequences of the lumbosacral spinal cord have demonstrated atrophy in the grey matter in patients with MSA (3). It is therefore likely that this cohort of patients presenting to urology services for urinary retention had a sacral spinal cord-onset of disease.  They subsequently developed the classical motor and autonomic signs of MSA as the disease pathology spread to other regions in the spinal cord and brainstem.

Urinary retention may be the initial presenting feature of MSA in a subset of patients, and at the time of presentation to urology services may manifest with very little neurological signs.  However the presence of concomitant sexual and bowel dysfunction, and abnormal EMG, betrayed a neurological cause for urinary retention. Based on the pattern of urological and neurological dysfunction, we postulate the onset of this fatal disease to be in the sacral spinal cord in this cohort of patients with MSA.

Gilman, S., et al., Second consensus statement on the diagnosis of multiple system atrophy. Neurology, 2008. 71(9): p. 670-6.
Sakakibara, R., et al., Urinary dysfunction and orthostatic hypotension in multiple system atrophy: which is the more common and earlier manifestation? J Neurol Neurosurg Psychiatry, 2000. 68(1): p. 65-9.
Liechti, M. et al., Assessing changes within the lumbosacral spinal cord in neurological disease: preliminary results of a pilot in vivo MRI study. in International Society for Magnetic Resonance in Medicine 25th Annual Meeting & Exhibition (Intl. Soc. Mag. Reson. Med. 25., 2017).