Micturitional disturbance and the pontine tegmental lesion: urodynamic and MRI analyses of vascular cases

Lower urinary tract function in patients with pituitary adenoma compressing hypothalamus

BACKGROUND

The micturition reflex is under the tonic influence of suprapontine structures including the anteromedial frontal cortex, basal ganglia, and hypothalamus. However, there have been few reports about the role of the hypothalamus on the lower urinary tract (LUT) function in humans.

OBJECTIVE

To investigate LUT function in patients with pituitary adenomas.

METHODS

Urodynamic studies were carried out in three patients with LUT symptoms who had pituitary adenomas extending upwards to the hypothalamus.

RESULTS

All three male patients (age 28 to 62 years) developed LUT symptoms (urinary urgency and frequency (3); urinary incontinence (3); voiding difficulty and retention (2)) along with weight loss, psychiatric symptoms, unsteady gait, and/or visual disturbances. One had the syndrome of inappropriate secretion of antidiuretic hormone, but none had diabetes insipidus. Two had resection of the tumour and subsequent radiation therapy, but LUT dysfunction persisted. The third patient had partial resection of the tumour to ameliorate hydrocephalus. Urodynamic studies showed detrusor overactivity during the storage phase in all patients; during the voiding phase there was underactive detrusor in two and non-relaxing sphincter in one.

CONCLUSIONS

Hypothalamic lesions can cause severe LUT dysfunction in both the storage and voiding phases of micturition. This may reflect the crucial role of the hypothalamus in regulating micturition in humans.

An fMRI study of the role of suprapontine brain structures in the voluntary voiding control induced by pelvic floor contraction

We have learned that micturition is comprised of two basic phases: storage and emptying; during bladder emptying, the pontine and periaqueductal gray (PAG) micturition center ensures coordinated inhibition of striated sphincter and pelvic floor muscles and relaxation of the internal urethral sphincter while the detrusor muscle contracts. Due to several disorders of the brain and spinal cord, the achieved voluntary control of bladder function can be impaired, and involuntary mechanisms of bladder activation again become evident. However, little has been discovered so far how higher brain centers strictly regulate the intricate process of micturition. The present functional magnetic resonance imaging (fMRI) study attempted to identify brain areas involved in such voluntary control of the micturition reflex by performing functional magnetic resonance imaging during a block design experiment in 12 healthy subjects. The protocol consisted of alternating periods of rest and pelvic muscle contraction during empty-bladder condition (EBC) and full-bladder condition (FBC). Repeated pelvic floor muscle contractions were performed during full bladder to induce a stronger contrast of bladder sensation, desire to void and inhibition of the micturition reflex triggering, since the subjects were asked not to urinate. Empty-bladder conditions were applied as control groups. Activation maps calculated by contrast of subtracting the two different conditions were purposed to disclose these brain areas that are involved during the inhibition of the micturition reflex, in which contrast, the SMA, bilateral putamen, right parietal cortex, right limbic system, and right cerebellum were found activated. The combined activation of basal ganglia, parietal cortex, limbic system, and cerebellum might support the assumption that a complex visceral sensory-motor program is involved during the inhibitory control of the micturition reflex.

Transient postictal urinary retention: presentation of three cases

A transient focal neurologic deficit after epileptic event is a well-known phenomenon. We report for the first time in English literature, three cases of transient urinary retention after seizures. The possible pathophysiologic mechanisms are discussed.

Neurological disorders cerebrovascular disease and parkinsonism

To store and expel urine at appropriate intervals, the lower urinary tract requires extensive input and control from the peripheral autonomic, somatic, and central nervous systems. Neurological disorders, such as cerebrovascular disease and Parkinson's disease, often cause functional disturbances of the lower urinary tract.

Firing patterns of micturition-related neurons in the pontine storage centre in cats

The pontine storage centre (PSC) and the pontine micturition centre (PMC) are known to be critical for urinary filling and emptying, respectively. In the present study, firing patterns of 45 neurons in the PSC area where electrical stimulation induced inhibition of the micturition reflex were analyzed in 20 male decerebrated and paralyzed cats. The electrically determined PSC area was widespread in the dorsolateral pontine reticular formation (P0-P4), ventrolateral to the PMC. Four major types of neurons were detected according to urinary storage/micturition cycles: tonic storage neurons (38%), phasic storage neurons (40%), tonic micturition neurons (9%) and phasic micturition neurons (13%). These four types of neurons were intermingled in the PSC. However, the tonic and phasic micturition neurons tended to be located within a limited area (P2-P3). These neurons were further classified into augmenting, constant and decrementing firing patterns. Some increased their firing prior to the storage/micturition phase initiation. Such preceding pattern was more frequently found in the tonic neurons than in the phasic neurons. In conclusion, the PSC neurons with diverse heterogeneous discharge patterns suggest that these neurons may organize a complex neuronal circuitry, which is critical in the neural control of the urinary continence.

Neurological signs are common in patients with urodynamically verified "idiopathic" bladder overactivity

Overactive bladder dysfunction is an expression of defective neuromuscular control of the lower urinary tract. The causes and the way to classify this problem are currently under debate. In some patients the overactive bladder is one sign of a neurological disorder, in so called "idiopathic detrusor instability" the cause is less obvious. That an overactive bladder has a neurogenic cause is a reasonable hypothesis. We made a detailed neurological investigation in 45 patients with idiopathic overactive bladder. Cerebrospinal fluid (CSF) was examined and blood tests for vitamin B(12)and folic acid deficiency were checked, too. In 37 of the 45 patients (82%) pathological signs were observed in the neurological tests. The most common finding was central or peripheral paresis of the legs appearing in 24 patients (53%). Of the 45 patients, eight received a neurological diagnosis, definite or possible MS or dorsal column sensation neuropathy. The results of this study give an indication of the importance of the neurological examination and suggest that neuropathy might not be uncommon in patients with so-called idiopathic detrusor instability. This also invites to reconsideration of the current classification. It is possible that a new classification based on a functional view could provide a better fundament in the search of etiologic and pathogenetic factors and also guide in the selection of the treatment most optimal for the individual patient.

Depletion of corticotrophin-releasing factor neurons in the pontine micturition area in multiple system atrophy

We sought to determine whether the putative pontine micturition center in the human dorsal pons contains corticotrophin-releasing factor (CRF) neurons, and whether these neurons are depleted in patients with multiple system atrophy and bladder dysfunction. Brains were obtained at autopsy from 4 control subjects and 4 patients with clinical diagnosis of multiple system atrophy, confirmed neuropathologically. Serial 50 microm cryostat sections were obtained throughout the rostral half of the pons, and every eighth section was processed for CRF immunocytochemistry (rabbit polyclonal antibody). Consecutive sections were stained for nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) to identify neurons of the laterodorsal tegmental nucleus or for both CRF and NADPH. Locus ceruleus neurons were identified by their neuromelanin content. Abundant CRF immunoreactive neurons were identified in the dorsal pontine tegmentum just ventral to the locus ceruleus. CRF neurons were intermingled with, but distinct from, the NADPH-d-reactive neurons of the laterodorsal tegmental nucleus. In all multiple system atrophy cases, there was a severe depletion of these CRF-immunoreactive neurons (26.6 +/- 3 neurons/section in patients; 73.7 +/- 4 neurons/section in controls). Our results suggest that depletion of CRF neurons in the putative pontine micturition center may contribute to the severe bladder dysfunction that characterizes multiple system atrophy.

Bladder, Bowel, and Sexual Dysfunction in Multiple Sclerosis

The majority of patients with multiple sclerosis (MS) experience genitourinary and bowel dysfunction over the course of their illness. Lower extremity pyramidal signs are excellent predictors of concurrent bladder dysfunction. Constipation is the most common bowel dysfunction, which results from a range of causes including pelvic floor spasticity, decreased gastro-colic reflex, inadequate hydration, medications, immobility, poor physical conditioning, and weak abdominal muscles. Despite the advent of new therapeutic modalities, the physician and patient commonly overlook sexual dysfunction. A detailed history of the patient is crucial to determine the cause of the dysfunction. Fatigue, pain, mood disorders, spasticity, bowel, and bladder dysfunction can all interfere with normal sexual functioning, and these subjects should be explored in detail in order to plan for proper treatment. Integrated treatment plans, often in conjunction with an urologist, can lead to amelioration of symptoms.

Neuroprosthetic applications of electrical stimulation

Neural prostheses are a developing technology that use electrical activation of the nervous system to restore function to individuals with neurological impairment. Neural prostheses function by electrical initiation of action potentials in nerve fibers that carry the signal to an endpoint where chemical neurotransmitters are released, either to affect an end organ or another neuron. Thus, in principle, any end organ under neural control is a candidate for neural prosthetic control. Applications have included stimulation in both the sensory and motor systems and range in scope from experimental trials with single individuals to commercially available devices. Outcomes of motor system neural prostheses include restoration of hand grasp and release in quadriplegia, restoration of standing and stepping in paraplegia, restoration of bladder function (continence, micturition) following spinal cord injury, and electrophrenic respiration in high-level quadriplegia. Neural prostheses restore function and provide greater independence to individuals with disability.

Autonomic nervous system disorders in stroke

Disturbances of the autonomic nervous system are common in patients with various cerebrovascular diseases. They are attributed to damage of the central autonomic network, particularly in the frontoparietal cortical areas and in the brain stem, or to a disruption of the autonomic pathways descending from the hypothalamus via the mesencephalon, pons, and medulla to the spinal cord. The most common clinical problems include abnormalities in heart rate and blood pressure regulation, reflecting cardiovascular autonomic dysfunction, and asymmetric sweating with cold hemiplegic limbs, reflecting changes in the sudomotor and vasomotor regulatory systems. Bladder and bowel dysfunction and impotence are also frequent complaints after stroke, but the present knowledge concerning their prevalence and clinical significance is still limited. Cardiovascular autonomic dysfunction, which is mainly related to increased sympathetic activity, is most evident in the acute phase of stroke, whereas other autonomic disorders, such as abnormal sweating, are long-standing or even irreversible. In addition to the well-established sympathetic hyperfunction, abnormalities of the parasympathetic nervous system may also contribute to the autonomic imbalance after stroke. Reliable recognition of autonomic dysfunction using quantitative analysis methods is important, because these disturbances are not only subjectively disabling and uncomfortable, but they may also be prognostically unfavorable. Moreover, quantitative measurements also form the ground for successive treatment of various stroke-related autonomic disorders.

Bladder and urethral pressures evoked by microstimulation of the sacral spinal cord in cats

Experiments were conducted to measure the bladder and urethral pressures evoked by intraspinal microstimulation of the sacral segments (S1-S2) in neurologically intact, chloralose anesthetized adult male cats. The bladder pressure was measured with a superpubic catheter and the urethral pressure was measured simultaneously at the level of the urethral sphincter and at the level of the penis using a two-element micromanometer. Intraspinal stimuli (typically 1 s, 20 Hz, 100 microA, 100 microseconds) were applied with activated iridium microwire electrodes in ipsilateral segments and intersegmental boundaries with a 250 micrometer mediolateral resolution and a 200 micrometer dorsoventral resolution. Increases in bladder pressures were generated by microstimulation in the intermediolateral region, in the lateral and ventrolateral ventral horn, and around the central canal. Simultaneous increases in urethral pressure were evoked by microstimulation in the ventrolateral ventral horn, but not at the other locations. Small reductions in urethral pressure (<10 cm H(2)O) were evoked at locations in the intermediate laminae and around the central canal. The magnitude of these pressure reductions was weakly dependent on the stimulus parameters. Stimulation around the central canal produced bladder contractions with either no change or a reduction in urethral pressure and voiding of small amounts of fluid. These results demonstrate that regions are present in the spinal intact anesthetized cat where microstimulation generates selective contraction of the bladder without increases in urethral pressure and that regions are present where microstimulation generates small reductions in urethral pressure.

Neurological disorders of micturition and their treatment

An overview of the current concepts of the neurological control of the bladder is given, based on laboratory experiments and PET scanning studies in human subjects. This is followed by a description of the various causes of the neurogenic bladder, discussed in a hierarchical order starting with cortical lesions and descending through the basal ganglia and brainstem, spinal cord, conus and cauda equina to disorders of peripheral innervation. Then follows a description of the condition of isolated urinary retention in young women. The article concludes with a review of the methods available for treating neurogenic bladder disorders. These are largely medical but brief mention of appropriate surgical procedures is made.

Micturitional disturbances are associated with impaired breathing control in multiple sclerosis

STUDY OBJECTIVES

To investigate whether the localization of multiple sclerosis (MS), the duration of the disease, and the level of neurologic functioning in patients with MS predispose them to disturbed breathing control.

DESIGN

Case-control study.

SETTING

Outpatient pneumology department of a university hospital.

PATIENTS

Twenty-three MS patients and 51 healthy control subjects.

MEASUREMENTS AND RESULTS

Resting mouth occlusion pressure at 0.1 s after onset of inspiratory effort (P0.1) was measured during the hypercapnic response (HCR) and the hypoxic response (HR) in all subjects. The Kurtzke expanded disability status scale and the functional system score were used to describe the level of neurologic functioning of the MS patients. Predictors of HCR and HR were assessed by multiple regression analysis. Low maximal inspiratory pressure (MIP) values correlated with low resting P0.1 values (r = 0.44; p = 0.05), although in neuromuscular diseases, high resting P0.1 values are usually found to compensate for low MIPs. Detrusor-sphincter dyssynergia (DSD) was the only predictor for lower ventilatory HCR (p = 0.006; r2 = 0.52), lower P0.1 HCR (p = 0.004; r2 = 0.47), lower ventilatory HR (p = 0.04; r2 = 0.28), and lower P0.1 HR (p = 0.04; r2 = 0.10); low MIPs and pyramidal tract involvement had no role.

CONCLUSIONS

(1) Impaired control of breathing in some MS patients is related mainly to central defects. (2) DSD is the most important predictor of disturbed ventilatory control, presumably because the micturition and pneumotaxic center are closely related and located in the rostral pons. (3) No relationship with the duration of the MS disease could be demonstrated, which can be explained by the variable course of MS itself.

Pontine regulation of pelvic viscera: pharmacological target for pelvic visceral dysfunctions

The pathophysiology and pharmacological targets of disorders of the bladder and colon have focused predominantly on the periphery. However, these viscera are regulated by the CNS, which, in turn, must integrate their functions with compatible behaviours. This review focuses on the role of the pontine micturition centre, Barrington's nucleus, as a key to this integration. Through its efferent network this pontine centre links parasympathetic preganglionic neurones with forebrain-projecting nuclei, providing an anatomical substrate for coregulation of pelvic visceral and forebrain activity. Disorders characterized by multiple pelvic visceral symptoms and comorbidity with psychiatric disorders (for example functional bowel disorders) might have their roots in dysfunctions of this circuit, which could provide a novel target for pharmacological treatment.

Identification of the spinal neural network involved in coordination of micturition in the male cat

In these studies, we used the expression of Fos protein to identify cells within the spinal cord that regulate micturition in male cats. The immediate early gene c-fos that encodes the Fos protein can be induced rapidly and transiently in neurons by increased electrical activity. Animals were anesthetized with alpha-chloralose, and received one of four stimulus protocols: electrical stimulation of the pelvic nerve, electrical stimulation of the pudendal nerve, a period of isometric micturition (induced by ligating the proximal urethra and infusing saline into the bladder), or electrical stimulation of Barrington's nucleus. After the period of stimulation, the animals were perfused and neurons expressing Fos-like immunoreactivity (FLI) were visualized with immunocytochemical methods. Stimulation with each protocol resulted in a substantially larger number of neurons expressing FLI than in operated but unstimulated controls, which exhibited few Fos-positive neurons localized to the superficial dorsal horn. In animals undergoing isometric micturition or stimulation of Barrington's nucleus, neurons exhibiting FLI were found bilaterally in the sacral (S1-S3) spinal cord and were localized to the lateral portion of the superficial dorsal horn (laminae I and II), in the intermediolateral region (lateral laminae V-VII), and around the central canal (lamina X and medial laminae V-VII). The intermediolateral region appeared to contain two populations of cells exhibiting FLI: a group of large multipolar cells and a group of small round cells. Few Fos-immunoreactive nuclei were observed in the medial portion of the superficial dorsal horn, and FLI was not observed in ventral horn neurons. Electrical stimulation of the pudendal or pelvic nerves resulted in fewer numbers of cells exhibiting FLI, with a less widespread spatial distribution. These results identify spinal neurons that are active during the micturition cycle, and demonstrate that a behaviorally relevant stimulus (isometric micturition) generated more widespread and greater intensity of Fos expression than repetitive electrical stimulation of the component peripheral nerves.