Clinical Anatomy of the Urinary System PDF

Clinical Anatomy of the Urinary System Dr Michael Schachtel Presented on 24/08/2018 Learning Objectives Basic anatomy of the kidney and bladder and their relations Innervation of the urinary system, particularly the bladder and control of micturition Understand the anatomical basis for urinary incon...

Clinical Anatomy of the Urinary System Dr Michael Schachtel Presented on 24/08/2018 Learning Objectives Basic anatomy of the kidney and bladder and their relations Innervation of the urinary system, particularly the bladder and control of micturition Understand the anatomical basis for urinary incontinence, particularly neurogenic bladder and its different presentations Basic anatomy of the ureter and anatomical relevance of urolithiasis Kidneys Posterior abdominal wall, retroperitoneal T12-L3 RETROPERITONEUM L1 - trans-pyloric kidney hilum moves max 2cm on resp. R) lower than L) Well cushioned structure Renal hilum – vein, artery, pelvis / ureter liver ant. to post. quite solid renal capsule adherent adherent to hilum limit infectious spread loose connective tissue holds keep kidney fixed R kidney lower liver Kidneys – Important Relations Anterior Posterior Rib 12 Rib 11 diaphragm/pleural cavity aim lower to avoid pneumothroax adrenal at top transversus abdominus retroperitoneal superior subcostal n. t12 Tail of pancreas hepatic flexure medially splenic flexure iliohypogastric n. quadratus loumorum inferior ilioinguinal n. psoas major duodenum is retroperitoneal Kidneys – Innervation Vagus Sympathetic – abdominopelvic splanchnic nerves (T10-L1) Parasympathetic – vagus (CNX) Visceral afferents – follow sympathetics Renal nerve plexus long pre-ganglion ANS Innervation of Abdominal Organs from sympathetic chain *useful during GIT short post-ganglion Bladder Pelvic organ, most anterior 500mL capacity Superior surface covered by peritoneum pushes up on abdominal cavity palpate above pubis if dilated Walls comprised mostly of detrusor muscle (SM) stretches Mucosa in folds, except in trigone Ureters enter at superior angle of trigone in an oblique path back flow through bladder ?function prevent functional Internal urethral orifice – thickened SM in neck of bladder Detrusor areflexia anatomical involuntary Bladder – Innervation Sympathetic – lumbar splanchnic nerves (T12-L2) (-) Detrusor, (+) Int urethral sphincter bladder relaxation Parasympathetic – pelvic splanchnic nerves (S2-S4) (+) Detrusor, (-) Int urethral sphincter Visceral afferents Pelvic splanchnic nerves trigger bladder contraction Distension – follow parasympathetic Pain (inferior) – follow parasympathetic Pain (superior) – follow sympathetic Hypogastric plexus Vesical (pelvic) plexus detrusor sphincter-dyssynergia Pudendal nerve Somatic – pudendal nerve (S2-S4) (+/-) Ext urethral sphincter voluntary Bladder – Innervation Sympathetic – lumbar splanchnic nerves (T12-L2) (-) Detrusor, (+) Int urethral sphincter Parasympathetic – pelvic splanchnic nerves (S2-S4) (+) Detrusor, (-) Int urethral sphincter Visceral afferents Distension – follow parasympathetic Pain (inferior) – follow parasympathetic Pain (superior) – follow sympathetic Hypogastric plexus Vesical (pelvic) plexus main nerve of perineum sensation from external genitalia and skin around anus and perineum damage - lose sensation and faecal incontinence Somatic – pudendal nerve (S2-S4) (+/-) Ext urethral sphincter nerve block The “Pelvic Pain Line” separates organs in contact with peritoneum and those not exception - large intestine where pelvic pain line is in middle of sigmoid colon *useful during GIT sigmoid Control of Urination ( -) Filling phase Spinal reflex (+) Sympathetic (-) Parasympathetic (+) Somatic Bladder Pa < Urethral Pa relaxed Delaying voiding Higher brain centres → PMC inhibited Aids above (+) 4 inhibited Voiding phase Spinal reflex + higher brain centres → PMC activated (+) Parasympathetic (-) Sympathetic (-) Somatic Bladder Pa > Urethral Pa Involuntary process in infants (no PMC) Urinary Incontinence = Involuntary leakage of urine 3 main types: Stress Leak small volumes with increased abdo pressure (cough, laugh, exercise) Weak pelvic floor Urge Urgency, frequency, nocturia, small volumes Overactive bladder Overflow (secondary to retention) Leak small volumes, distended bladder, large residual volumes Weak contractions / blocked outlet + Functional – unable to get to bathroom due to mental / physical reasons + Mixed / weak bladder contractions Clinical Case 1 65 year old F B/G: 5 children, on regular steroid Rx for Rheumatoid Arthritis Able to urinate normally but has a small amount of leakage of urine when coughing, laughing and sometimes when walking What type of incontinence and why? stress steroid contributing to incontinence irritation of bladder influence on water retention Detrusor areflexia Neurogenic Bladder = Bladder dysfunction due to a primary nervous system pathology (ie. lesion anywhere in voiding reflex: peripheral nerve ↔ SC ↔ brainstem/cerebrum) 3 main types: Detrusor hyperreflexia (DH) Detrusor-sphincter dyssynergia (DSD) Detrusor areflexia (DA) Pathology may have ≥1 of these, and thus can produce either a primary incontinence (urge, stress, overflow) or a mixed picture Investigations Urinalysis, renal function, bladder scan / PV residual volume, urodynamics, cystoscopy Detrusor Hyperreflexia (+) CEREBRUM/BRAINSTEM Lesion – supra-pontine Spinal reflex intact ↓ cerebral inhibitory signals to PMC → activation ++ = Detrusor overactive (hyperreflexia) + coordinated external urethral sphincter activity Sx: Urge incontinence Eg. Stroke (post-shock phase), brain tumor, head trauma, Parkinsons, hydrocephalus, CP Rx: bladder training, medication, surgery Anticholinergics (oxybutynin) / antispasmodics - relax detrusor TCA (amitriptyline) Detrusor sphincter-dyssyner Detrusor-Sphincter Dyssynergia (+) SPINAL CORD Lesion – pons ↔ sacral spinal cord Spinal reflex intact Nil communication to/from PMC + higher brain centres = Detrusor overactive (hyperreflexia) +/- coordinated external urethral sphincter activity pontine micturition centre Sx: Mixture urge incontinence +/- retention/overflow Can have DSD-DH (more commonly) or isolated DSD Eg. Spinal cord trauma (post-shock phase), tumors, ischaemia, MS, spina bifida Rx: medication (anticholinergics), intermittent / continuous IDC, surgery Detrusor Areflexia (+) SACRAL CORD / PERIPHERAL NERVE Lesion Spinal reflex affected – afferent (sensory) and/or efferent (motor) nerve issue = Unable to sense full bladder +/- detrusor underactive (areflexia) Generally ext sphincter control preserved (unless pudendal nerve damaged) Sx: Urinary retention / overflow incontinence Eg. DM, iatrogenic injury (ie. surgery), pelvic trauma, lumbar disc herniation, GBS Also in shock phase / flaccid paralysis of stroke (days-weeks) / spinal cord injury (mths-yrs) Rx: intermittent / continuous IDC, surgery (urinary diversion - urostomy) Clinical Case 2 (+) 60 year old M B/G: T2DM for last 20 years, poorly controlled, obese Has developed worsening loss of sensation and urge to void despite fluid intake ++, difficult to pass urine Will often leak urine on occasion, generally feels abdomen distended Bladder scan - 600mLs What type of neurogenic bladder? Detrusor areflexia Where is the lesion? sacral cord lesion Clinical Case 3 (+) 50 year old F Progressively worsening loss of sensation of bilateral legs, and spastic weakness in muscle groups. Weight loss ++ Now noticed that developed issues urinating – often has intense urge to pass urine but will be unable to, other times will leak small amounts, feels incomplete emptying when voiding What type of neurogenic bladder? detrusor sphincter-dyssynergia Where is the lesion? pons-sacral spinal cord Ureter Connect kidney → bladder Retroperitoneal muscular tubes 3 natural constrictions – PUJ, pelvic brim, VUJ Innervation Sympathetic – abdominopelvic splanchnic nerves (T11-L1/2) Parasympathetic – vagus (CNX) Visceral afferents – follow sympathetics Clinical Case 4 32 year old M Presents to ED with sudden onset 9/10 L) flank pain, radiating to groin, colicky in nature Associated nausea/vomiting, nil urinary Sx Writhing to find comfortable position Vitals stable, O/E unremarkable, abdo SNT Ix? Dx? Rx? References Moore’s Essential Clinical Anatomy 5th Edition Gray’s Anatomy for Students 2nd Edition Marieb’s Human Anatomy and Physiology 8th Edition Ganong’s Review of Medical Physiology 23rd Edition Last’s Anatomy 9th Edition Gill, B. Neurogenic Bladder. Medscape (2017). Accessed via: http://emedicine.medscape.com/article/453539-overview