Digestive and Urinary Systems Flashcards

GI System and Elimination

Major Controls in the Digestive Tract and Their Effects

Anorexia, Nausea, Vomiting

• Anorexia and vomiting:
  • Can cause serious complications: dehydration, acidosis, malnutrition.
• Anorexia:
  • Often precedes nausea and vomiting.
• Nausea:
  • Unpleasant subjective feeling.
  • Simulated by distention, irritation, inflammation of digestive tract.
  • Also stimulated by smells, visual images, pain, and chemical toxins and/or drugs.
• Vomiting (emesis):
  • Vomiting center located in the medulla. Coordinates activities involved in vomiting and protects the airway during vomiting.
  • Forceful expulsion of chyme from the stomach, sometimes including bile from the intestine.

Diarrhea

• Excessive frequency of stools, usually of loose or watery consistency.
• May be acute or chronic.
• Frequently occurs with nausea and vomiting when infection or inflammation develops.
• May be accompanied by cramping pain.
• Prolonged diarrhea may lead to dehydration, electrolyte imbalance, acidosis, malnutrition.

Common Types of Diarrhea

• Large-volume diarrhea (secretory or osmotic):
  • Watery stool resulting from increased secretions into the intestine from the plasma.
  • Often related to infection.
  • Limited reabsorption because of reversal of normal carriers for sodium and/or glucose.
• Small-volume diarrhea:
  • Often caused by inflammatory bowel disease.
  • Stool may contain blood, mucus, pus.
  • May be accompanied by abdominal cramps and tenesmus.
• Steatorrhea—“fatty diarrhea”:
  • Frequent bulky, greasy, loose stools with a foul odor.
  • Characteristic of malabsorption syndromes like celiac disease and cystic fibrosis.
  • Fat is usually the first dietary component affected, and its presence interferes with the digestion of other nutrients.
  • The abdomen is often distended.

Blood in Stool

• Blood may occur in normal stools with diarrhea, constipation, tumors, or an inflammatory condition.
• Occult blood:
  • Small hidden amounts, detectable with stool test. May be caused by small bleeding ulcers.
• Melena:
  • Dark-colored, tarry stool. May result from significant bleeding in the upper digestive tract.

Constipation

• Less frequent bowel movements than normal with small hard stools.
• Can be an acute or chronic problem.
• May be caused by decreased peristalsis, leading to increased time for reabsorption of fluid.
• Periods of constipation may alternate with periods of diarrhea.
• Chronic constipation may cause hemorrhoids, anal fissures, or diverticulitis.
• Causes of constipation:
  • Weakness of smooth muscle due to age or illness.
  • Inadequate dietary fiber.
  • Inadequate fluid intake.
  • Failure to respond to the defecation reflex.
  • Immobility.
  • Neurological disorders.
  • Drugs (i.e., opiates).
  • Some antacids, iron medications.
  • Obstructions caused by tumors or strictures.

Drugs Used in GI Disorders

Intestinal (Intestines and Bowel) Obstruction

• Lack of movement of intestinal contents through the intestine, more common in the small intestine.
• Mechanical obstructions:
  • Result from tumors, adhesions, hernias, other tangible obstructions.
• Functional or adynamic obstructions:
  • Result from impairment of peristalsis.
  • Spinal cord injury
  • Paralytic ileus: muscles of the intestines stop moving food through, caused by surgery, inflammation, drugs, or electrolyte imbalance.

Intestinal (Bowel) Obstruction - Risk Factors

• Cancer, especially in the abdomen.
• Crohn’s disease.
• Ulcerative colitis.
• Previous abdominal or pelvic surgery, which may increase the risk of adhesions.
• Radiation therapy.

Intestinal (Bowel) Obstruction - Complications

• Newborns and older adults are at higher risk.
• Effects of obstruction:
  • Increased fluid and gas lead to distention.
  • Distention causes increased peristalsis to force contents past obstruction, leading to colicky pain.
  • Severe vomiting from distention and pain leads to dehydration and electrolyte imbalance.
  • Increased pressure on the intestinal wall causes more fluid to enter the intestine.
  • Decreased blood pressure and hypovolemic shock as fluid shifts into the intestine (third-spacing).
  • Continued pressure on the intestinal wall causes edema, ischemia of the wall, and decreased peristalsis.
  • Prolonged ischemia causes increased permeability and necrosis of the wall.
  • Intestinal bacteria and toxins leak into the blood and the peritoneal cavity (peritonitis).

Upper GI Disorders

• GERD
• Peptic Ulcers
• Gastritis

Other GI Disorders

• Cholelithiasis
• Bowel Obstruction
• Pancreatitis
• Appendicitis

Inflammatory Bowel Disease: Ulcerative Colitis and Crohn’s Disease

• Autoimmune diseases.
• Ulcerative Colitis:
  • Ulcerations of colonic mucosa.
  • Only affects the large intestine (colon/rectum).
  • Risks: 10-40 years old, smoking, family history, autoimmune factors.
• Crohn’s Disease:
  • Skip lesions, affecting all layers of the GI tract.
  • Can occur from mouth to anus.
  • Fissures leading to deep tunnels.
  • Sporadic throughout the GI tract.
• Exacerbations:
  • Bleeding, leading to anemia.
  • Diarrhea, cramping, pain.
  • Dehydration.
  • Weight loss.
  • Fluid and electrolyte imbalances.
  • Food intolerance.

Risk Factors for Liver Disease

• Heavy alcohol use.
• Obesity.
• Type 2 diabetes.
• Tattoos or body piercings.
• Injecting drugs using shared needles.
• Blood transfusion before 1992.
• Exposure to other people's blood and body fluids.
• Unprotected sex.
• Exposure to certain chemicals or toxins.
• Family history of liver disease.

Liver Infection: Hepatitis

• Viral Hepatitis: Inflammation of the liver, resulting in necrosis.
  • Types A, B, C, D, E.
    • A: Acute but self-limiting; fecal-oral transmission (stool to hand); contaminated water, food, or shellfish; vaccine available.
    • B: Blood, body fluids/STI transmission; tattoos and body piercing; vaccine available.
    • C: Blood transmission; leads to liver failure; antivirals can treat.
• Stages of Hepatitis:
  • Prodromal stage: 2 weeks after exposure; flu-like symptoms, fatigue, anorexia; contagious.
  • Icteral stage: 4 weeks after exposure; jaundice, dark urine, tender and enlarged liver.
  • Recovery stage: 6-8 weeks after exposure; symptoms decrease; liver stays enlarged.

Liver Failure: Cirrhosis

• Cirrhosis: Fibrotic liver disease resulting in destruction of the liver.
  • Risks: Alcohol, hepatitis, hepatotoxic drugs or toxic materials.
  • Signs and symptoms:
    • Chronic: Jaundice, ascites, enlarged liver, encephalopathy, edema, malnutrition.
• Acute Liver Failure: Severe liver necrosis.
  • Cells will regenerate, no existing liver disease.
  • Signs and symptoms: Same as cirrhosis, but with rapid progression.
  • Risks: Hepatotoxic drugs.

Portal Hypertension

• Elevated blood pressure in the portal venous system, caused by scar tissue in the liver (due to cirrhosis) compressing the blood vessels.
  1. Liver becomes fibrotic due to cirrhosis.
  2. Scar tissue prevents blood from passing through the liver.
  3. Pressure increases.
  4. Blood flow is reduced.
  5. Some blood is pushed backwards.
• Pressure backs up to the esophagus.
• Veins can’t accommodate the extra fluid, and pockets form in the esophagus called varices.
• Esophageal varices can burst, leading to hematemesis.

Signs and Symptoms of Liver Disease

• Effects of portal hypertension:
  • Esophageal varices.
  • Splenomegaly.
  • Ascites.
  • Dilated abdominal veins.
  • Gastropathy and melena.
  • Rectal varices (hemorrhoids).
• Effects of liver cell failure:
  • Brain fog.
  • Jaundice.
  • Fetor hepaticus (corpse-like breath).
  • Spider nevi.
  • Gynecomastia.
  • Ascites.
  • Loss of sexual hair.
  • Testicular atrophy.
  • Liver “flap” (coarse hand tremor).
  • Bleeding tendency.
  • Anemia.
  • Ankle edema.
• Labs for liver inflammation: AST (aspartate transaminase), ALT (alanine transaminase).

Urinary System and Elimination

Altered Urinary Elimination Lab Tests

• Risk factors for altered urinary elimination:
  • Altered cognition
  • Impaired mobility
  • Obesity
  • Smoking
  • Enlarged prostate
  • Pregnancy
  • Pelvic masses or tumors
  • Some medications
  • Family history of urinary alterations
  • Injuries or pathology affecting the neurologic system, spine, or pelvic organs
• Blood urea nitrogen (BUN):
  • An elevation of the BUN may indicate that the body is creating too much nitrogen waste or the kidneys are not removing enough.
• Serum creatinine:
  • Creatinine, a byproduct of skeletal muscle contractions, is only excreted through the kidneys, making this test a reliable measure of glomerular filtration.
• Serum pH:
  • As the renal tubules fail to control the acid-base balance, the serum pH falls, resulting in metabolic acidosis.
• Red blood cells (RBC), hematocrit (Hct), and hemoglobin (Hgb):
  • The kidneys produce erythropoietin, a hormone that promotes the development of red blood cells and helps regulate iron metabolism.
• Serum electrolytes:
  • Changes in serum electrolytes may require monitoring and treatment as kidney function decreases.
• Antibody levels:
  • Antibody titers are used to confirm the presence of poststreptococcal glomerulonephritis.
• Renin levels:
  • Renin is a substance produced by the kidneys that contributes to blood pressure regulation.
• Urinalysis:
  • Used to screen for conditions, some associated with renal function and others not (e.g., glucose in urine is associated with diabetes mellitus).
• Culture and sensitivity:
  • Used to confirm a urinary tract infection, specify the causative organism, and determine which antibiotic will be effective.

Prevention of Urinary Issues

• Staying hydrated, including drinking water.
• Emptying the bladder when the urge occurs, rather than delaying emptying.
• Quitting smoking, which is a significant cause of bladder cancer.
• Controlling chronic medical conditions, including diabetes mellitus, hypertension, and obesity.
• Eating a well-balanced diet.
• Limiting foods that irritate bladder problems, such as alcohol and caffeine.
• Maintaining a healthy weight.
• Wearing cotton underwear and loose clothing to promote dryness.
• Avoiding environmental pollutants, such as heavy metals in drinking water.
• Following current screening recommendations.
• Wiping from front to back after urinating (women) to prevent gastrointestinal bacteria from entering the urethra.

Incontinence and Retention

• Incontinence: Loss of voluntary control of the bladder.
• Retention: Inability to empty bladder.
• Stress incontinence (more common in women):
  • Increased intra-abdominal pressure forces urine through the sphincter (coughing, lifting, laughing, multiple pregnancies).
• Urge incontinence:
  • Involuntary leakage associated with urgency due to involuntary contraction of the bladder.
• Overflow incontinence:
  • Incompetent bladder sphincter, common in older adults.
  • Weakened detrusor muscle may prevent complete emptying of the bladder, leading to frequency and incontinence.
• Neurogenic incontinence:
  • Spinal cord injuries or brain damage interfere with CNS and ANS voluntary controls of the bladder.
• Functional Incontinence:
  • Due to physical or cognitive limitation (mobility issues, arthritis, dementia).

UTIs: Acute Cystitis and Pyelonephritis

• Escherichia coli: Contamination with fecal matter (wiping back to front).
• Acute Cystitis: Lower Urinary Tract Infection (UTI).
  • Signs and Symptoms: Groin pain, pain or burning during urination, low-grade fever, urgency, frequency, hematuria, dark/cloudy/smelly urine.
• Pyelonephritis: Infection moves up to the kidneys.
  • Signs and Symptoms: Flank pain, high fever, dysuria, hematuria.
• Risks for UTIs:
  • Elderly
  • Incontinence
  • Retention
  • Poor hygiene
  • Women (short urethra)
  • Pregnancy
  • Diabetes (increased sugar).
• Complications of UTIs: Sepsis, renal failure.

Nephrolithiasis and Glomerulonephritis

• Nephrolithiasis (kidney stones): Crystallization of urine; calcium oxalate crystals; obstruction.
  • Causes: Dehydration; < 50 years old; male (prostate hypertrophy).
  • Signs and Symptoms: Flank pain; hematuria; N/V, pain; frequency and urgency; dysuria.
• Glomerulonephritis: Inflammation.
  • Causes: Type III hypersensitivity reaction; antigen-antibody complex; streptococcal infection.
  • Signs and Symptoms: Hematuria; proteinuria; HTN; oliguria.

Acute Kidney Injury

• Sudden decrease in renal function.
• Causes:
  • Dehydration
  • Direct injury
  • Nephrotoxins
  • Obstruction
  • Inflammation
  • Decreased blood flow
• Signs and Symptoms:
  • Acute: Oliguria leading to anuria, increased serum metabolic waste.
• Prognosis: Will kidneys regain function?
• Types:
  • Pre-renal: Problem is above the kidneys (dehydration, decreased blood flow to kidneys).
  • Intra-renal: Problem is in the kidneys (direct damage, trauma, pyelonephritis, glomerulonephritis).
  • Post-renal: Problem is below the kidneys (UTI, obstruction).

Chronic Kidney Injury or Disease

• Gradual and irreversible destruction.
• Causes:
  • Diabetes (#1)
  • HTN
  • Nephrotoxins
  • Coronary artery disease
• Risk factors:
  • Aging
  • Family History
  • Ethnicity
  • Smoking
  • Obesity
  • Access to healthcare
• Complications:
  • Dysrhythmias (F & E imbalance)
  • Bone loss (no vitamin D)
  • Muscle wasting (proteinuria)
  • Immune suppression (proteinuria)
  • HTN (RAAS system)
  • Encephalopathy (uremia)
  • Anemia (EPO)
  • Metabolic acidosis (decreased H+)
• GFR (Glomerular Filtration Rate): How fast kidneys filter blood per minute.
  • Normal = >90 mL/min/1.73 m^2

Chronic Kidney Injury or Disease - Progression Stages

• Stages 1-2: Loss of 60% of nephrons; no S/Sx; increased Serum creatinine, decreased GFR.
• Stages 3-4: Loss of 75% of nephrons; F & E imbalances; anemia; decreased BP; dilute urine; severely decreased GFR.
• Stage 5: Oliguria to anuria; dysrhythmias; uremia; GFR decreases more.
  • Build up of fluids, all waste and electrolytes (except Ca/Na).
  • Dialysis is required.