Chapter 35: Disorders of the Bladder and Lower Urinary Tract

Disorders of the Bladder and Lower Urinary Tract explores the normal physiological control mechanisms and subsequent pathological alterations of the bladder and lower urinary tract, a critical area in human pathophysiology. Normal urine elimination necessitates the coordinated function of the detrusor muscle and the internal and external urethral sphincters, governed by involuntary autonomic pathways (parasympathetic for emptying, sympathetic for storage) and the voluntary somatic nervous system, all integrated across the spinal cord, pontine micturition center, and cerebral cortex. Diagnostic evaluation of these functions includes urodynamic studies, such as cystometry and uroflowmetry, alongside PVR volume checks. Alterations in function begin with lower urinary tract obstruction, often due to prostatic enlargement in men, leading to compensatory bladder hypertrophy, which manifests clinically as urgency and frequency, eventually progressing to destructive changes like trabeculae and diverticula, and ultimately decompensation with urine retention and overflow incontinence. Neurogenic bladder disorders are classified based on the location of the neural lesion: lesions above the sacral cord typically cause spastic bladder (failure to store urine, often with detrusor-sphincter dyssynergia), while lesions at the sacral level result in flaccid bladder (failure to empty urine, such as seen in diabetic neuropathies). The chapter further defines urinary incontinence into subtypes, including stress incontinence (involuntary loss during increased abdominal pressure due to pelvic floor weakness), overactive bladder/urge incontinence (caused by detrusor hyperactivity), overflow incontinence (resulting from chronic overdistention), and functional incontinence (linked to physical or cognitive limitations). Treatment strategies encompass behavioral therapies like Kegel exercises, pharmacologic manipulation of nervous system receptors, catheterization, and surgical intervention. Finally, the discussion addresses bladder cancer, predominantly urothelial carcinoma, identifying painless hematuria as the most common presenting sign, with prognosis and treatment varying based on the tumor’s histologic grade and invasiveness.