Renal Disorders and Urinary Incontinence

Renal Disorders

• Renal disorders can manifest in a variety of ways including psychological, neurological, cardiovascular, gastrointestinal, ophthalmological, pulmonary, integumentary, endocrine/reproductive, hematologic, metabolic, musculoskeletal, and peripheral neuropathy.

Urinary Incontinence (UI)

• Defined as the involuntary leakage of urine
• It is more common among older adults, but not a natural consequence of aging and is considered common, but not normal.
• Urinary Incontinence occurs when bladder pressure exceeds urethral closure pressure, or anything that interferes with the internal or external urethral sphincter control.

Types of Urinary Incontinence

• Stress Incontinence is commonly found in women and is defined as involuntary urine leakage due to sudden increases in intra-abdominal pressure; this can be related to coughing, sneezing, pregnancy, or obesity.
• Overflow Incontinence is commonly found in men; it occurs when the pressure of urine in an overfull bladder overcomes sphincter control and/or weak bladder muscles (detrusor underactivity); symptoms include frequent or continual leakage of small amounts of urine, often throughout the day and night, along with incomplete bladder emptying, with a distended bladder that is usually palpable.
• Functional Incontinence involves the loss of urine due to cognitive, functional, or environmental factors like arthritis, immobility, or dementia, and prevents the person from getting to the bathroom in time.
• Urge Incontinence is common in older adults and involves random leakage of urine triggered by urgency and related to nervous system issues, usually involving detrusor muscle spasms; also known as overactive bladder, and leakage is periodic and may vary in amount.
• Neurogenic Bladder is bladder dysfunction caused by neurological disorders like spinal cord injuries or brain damage; Types of neurogenic bladder are Spastic, Flaccid, Detrusor Muscle Hyperreflexia, and Detrusor Areflexia.
• Overactive Bladder (OAB) typically affects women due to shorter urethra and decreased sphincter tone.

Urinary Tract Obstruction

• Defined as the interference with urine flow anywhere in the urinary tract
• Causes of urinary tract obstruction are either Anatomic (strictures, scarring) or Functional (stones, tumors).

Severity and Long Term Effects

• Severity depends on location, completeness, involvement of one or both upper urinary tracts, duration, and cause.
• Possible long-term effects include Tubular damage (leading to metabolic acidosis and dehydration) or increased risk of infection and renal calculi due to urinary stasis and compromised renal function.

Common causes

• Common causes in older men include benign prostatic hypertrophy or prostatic cancer.
• Common causes in men and women include tumors, inflammation, scarring, stenosis, congenital defects, and renal calculi.

Kidney Stones (Renal Calculi/Nephrolithiasis)

• Definition: Masses of crystals, proteins, or other substances that form within the urinary tract and may cause obstruction.
• The risk of kidney stone recurrence is high, around 5% of women and 12% of men will develop kidney stones, with a 30-50% chance of recurrence within 5 years if underlying causes are not treated.
• Risk factors include inadequate fluid intake, and inactivity.

Urine pH

• A low (acidic) pH increases the risk for uric acid and cysteine stones.
• A high (alkaline) pH increases the risk for calcium phosphate stones.
• A spontaneous passage is possible for stones smaller than 5mm.

Types of Kidney Stones

• Common types of kidney stones are Calcium Phosphate, Calcium Oxalate (Most common, 70-80% of stones), Uric Acid, Cystine and Struvite (Magnesium Ammonium Phosphate).
• Formation of stones occurs when there are excessive amounts of relatively insoluble salts in the filtrate or when insufficient fluid intake leads to concentrated filtrate, causing the precipitation of salts from liquid to solid, and deposits building up and aggregate, eventually forming stones.

Symptoms and Diagnostics

• Symptoms of kidney stones are renal colic which produces severe, wave-like flank pain and radiating pain which may radiate to the pelvic floor and upper thighs.
• Diagnostic tests are Intravenous Pyelogram (IVP), and KUB (Kidney, Ureter, Bladder) X-ray.

Hydronephrosis

• Defined as the Enlargement of the kidneys and/or ureters caused by a blockage in the urinary tract.
• Causes a secondary condition often due to complications of kidney stones (calculi), tumors, scar tissue, or untreated prostatic enlargement; may also be caused by developmental defects in the urinary tract, such as kinking or stenosis of the ureter.

Pathophysiology and Symptoms

• Prolonged interference with urine outflow causes back pressure, resulting in urine accumulation and dilation of the affected area, or in the kidney, continued urine buildup causes tissue necrosis due to pressure and compression of blood vessels.
• Symptoms are often asymptomatic with mild flank pain developing due to renal capsule distension, or infection may develop.
• Doctors diagnose using Ultrasonography, radionucleotide imaging, CT scan, or IVP.
• If untreated, bilateral hydronephrosis can lead to chronic renal failure.

Overactive Bladder Syndrome (OAB)

• OAB has symptoms of urgency with or without urge incontinence, can be associated with increased urinary frequency and nocturia, and Detrusor muscle over-reactivity and poor coordination between bladder contraction and external sphincter control.
• OAB may lead to urinary retention with overflow incontinence, affects millions of individuals, significantly impacting quality of life and contributing to social isolation, and in the elderly, is correlatedwith an increased risk of falls and urinary tract infections (UTIs).

Urinary Tract Infections (UTIs)

• UTIs have a prevalence of Approximately 6 million Americans affected annually.
• Causative infections may be due to Urine serving as an excellent medium for microbial growth as most UTIs are ascending, with bacteria traveling from the perineal area to the bladder and up to the kidneys caused by Common causative organism: Escherichia coli (E. coli), a resident of the intestinal flora.

Risk factors and Protection mechanisms

• Risk factors are Women with their shorter and wider urethra, proximity to the anus, and frequent irritation from sexual activity, baths, or feminine hygiene products in addition to older men with prostatic hypertrophy and urinary retention and congenital abnormalities in children.
• Protective mechanisms include Urination (washes out bacteria, and fluid intake is essential), acidic urine pH and the vesicoureteral junction (help prevent ascending bacteria), and men have a lower risk due to longer urethras.

Symptoms and Treatments

• Symptoms of UTIs are dysuria (painful urination), urgency, frequency, nocturia, suprapubic and low back pain, and confusion in elderly patients.
• UTIs are marked by cloudy urine with an unusual odor.
• During diagnosis, it must be discovered if there is bacteriuria, pyuria, and microscopic hematuria through a urinalysis.
• Treatment for UTIs typically utilizes antibiotics specific to the causative organism.

Interstitial Cystitis (IC)

• IC is defined as a chronic, painful disease of the bladder characterized by urgency, frequency, and pain in the bladder or pelvis.
• Prevalence: Affects 3-8 million women and 1-4 million men annually.
• Causes are unknown, but likely multifactorial, in some cases Hypersensitivity of the lower urinary tract or the result of Changes in mast cells in the bladder muscle or mucosal layers.

Symptoms and Treatment

• Presents symptoms of urinary pain that is not attributable to other causes like a UTI or Kidney failure in addition to a sense of urgency and high frequency of urination, as well as pain in the bladder or pelvis.
• IC has no single treatment consistently relieves symptoms, though various therapies, including nutrition and drug therapy, may be effective, tricyclic antidepressants may reduce burning and urinary frequency, and pentosan polysulfate sodium (Elmiron) is the only oral agent approved to treat IC symptoms and relieves bladder pain.
• Antibiotic therapy does not provide relief for IC and surgery is rarely needed.

Infection of the Kidney

• Most commonly caused by bacterial infection, but fungi, protozoa, or viruses can also infect the kidney, which can extend from the ureter into the kidney, causing inflammation; purulent exudate fills the kidney, and abscesses or necrosis can form.

Risk factors and Symptoms

• Risk factors include kidney stones, reflux, pregnancy, neurogenic bladder, instrumentation (catheters), and female sexual trauma.
• presents as Acute onset with fever, chills, flank or groin pain, frequency, hematuria, dysuria, costal-vertebral tenderness.
• Treatment includes antibiotics, increased fluid intake, and follow-up in 4-6 weeks.

Chronic Pyelonephritis

• Chronic kidney infection leads to inflammation and fibrosis (scarring) and can result in loss of renal function and renal atrophy (shrinkage); it can be often caused by significant anatomical abnormalities or recurring upper urinary tract infections, eventually progressing to end-stage renal disease (ESRD).

Glomerulonephritis (Inflammation of the Glomeruli)

• Associated with kidney infections, nephrotoxic drugs, immune system problems, and systemic diseases.
• Acute Poststreptococcal Glomerulonephritis develops 1-6 weeks after strep infection (tonsils, pharynx, or skin), causing antibodies as a reaction which triggers inflammation and injury to the glomerular filtration membrane. This results in altered permeability, causing proteins and RBCs to escape in the urine.

Symptoms and Chronic Glomerulonephritis

• Glomerulonephritis presents Symptoms of Generalized edema, hypertension, oliguria, hematuria, and proteinuria while fluid retention occurs due to decreased glomerular filtration, leading to hypertension.
• Chronic Glomerulonephritis develops slowly over time, characterized by proteinuria, hematuria, and the gradual accumulation of uremia, can progress to ESRD over several years.

Nephrotic Syndrome

• Defined as characterized by excretion of ≥3.5g of protein in urine per day compared to normal (<0.15g), is caused by glomerular injury, leading to increased permeability to plasma proteins (proteinuria), resulting in low plasma albumin and edema.

Edema and Complications

• The mechanism of edema is Decreased plasma oncotic pressure which stimulates hepatic lipoprotein synthesis, causing hyperlipidemia characterized by Increased lipid levels with fatty casts appearing in urine.
• Complications of nephrotic syndrome include impaired immune response, increasing infection risk.

Acute Kidney Injury (AKI)

• Encompasses any deterioration in kidney function, ranging from slight to severe impairment and characterized by rapid loss of kidney function with or without decreased urine output, and leads to progressive increases in blood urea nitrogen (BUN), creatinine, and potassium levels.
• High mortality, especially in ICU patients (up to 80%).

Classifications of AKI

• Renal Injury: Decrease in renal function.
• Renal Failure: Requires dialysis, serum creatinine becomes increasingly higher and GFR decreases more.
• End-Stage Renal Failure (ESRF): Complete loss of kidney function for >3 months, requiring dialysis or transplant.
• Complications of ESRF include Azotemia where BUN and creatinine are heightened, uremia where waste products accumulate in blood leading to fatigue, N&V, pruritus, and neurological issues, and severe uremia leads to urea crystals on skin.

Acute Renal Failure (AKI) Causes

• Prerenal Causes (Reduced systemic circulation, hypotension, shock, impaired blood flow).
• Intrarenal Causes (Direct damage to kidney tissue, Prolonged ischemia, nephrotoxins).
• Postrenal Causes are mechanical obstructions in urine outflow caused by BPH, bladder outlet issues, ureteral obstruction.

Considerations for AKI

• Nephrotoxic Drugs includes some classes of antibiotics can impair kidney function and lead to elevated creatinine levels, but this is often reversible.
• Acute Tubular Necrosis (ATN) is the most common intrarenal cause of AKI in hospitalized patients.
• Severe kidney ischemia disrupts the basement membrane and destroys the tubular epithelium.
• Can be reversed if the basement membrane is not destroyed and the tubular epithelium regenerates, but is enhanced by dehydration, advanced age, renal insufficiency, and diabetes.

Pathophysiology and Phases of AKI

• Hypotension associated with hypovolemia causes ischemia and an inflammatory response where free radicals cause cell swelling, injury, and necrosis, leading to intrarenal vasoconstriction.
• Oliguric Phase typically lasts for 10-14 days and presents with a decrease in urine output in addition to Fluid Volume Imbalance marked by retention of fluids due to reduced urine output.
• Diuretic Phase is a period of increased urine output of 1-3 L/day due to osmotic diuresis and comes complications fluid such as volume depletion and hypotension.
• Recovery Phase involves Glomerular Filtration Rate (GFR) increase and BUN and serum creatinine levels decrease and can take up to 12 months to stabilize.

Chronic Kidney Disease (CKD)

• Defined as gradual, irreversible destruction of the kidneys over time
• Bilateral pyelonephritis, congenital polycystic kidney disease and systemic disorders like hypertension or diabetes can be causes of CKD.
• Gradual loss of nephrons, often asymptomatic until advanced because kidneys have considerable reserve function.

Renal Failure and Mortality

• Death is related to hypervolemia or hyperkalemia.
• Renal Cell Carcinoma (RCC) is an Adenocarcinoma and most common renal neoplasm.
• Risk factors include cigarette smoking, obesity, and uncontrolled hypertension.
• It is often asymptomatic during early stages and in late stages is marked by painless hematuria, dull aching flank pain, a palpable mass, unexplained weight loss, anemia, or erythrocytosis, and is more common in men and smokers but rare in individuals under 45 years old.

Bladder Cancer

• Bladder cancer is transitional cell carcinoma and defined most often with gross, painless hematuria without a UTI or other cause.
• Bladder cancer is more common in males over 60 years and smokers.