Patho Week 15 Study Guide (Exam 5)

How does Urinalysis reflect kidney function?

Color and levels of things like protein or fats in urine are indication of poor kidney function

Define azotemia

The increase of blood urea nitrogen (BUN) within the bloodstream.

How does Blood Urea Nitrogen reflect kidney function?

High BUN can be an indicator of renal dysfunction because waste is not being filtered after protein breakdown

How does Glomerular Filtration Rate reflect kidney function?

• Decreased = impaired kidney function

• Renal blood filtered/unit of time

How does Serum Creatinine reflect kidney function?

• Increased levels in blood stream indicate decreased filtration in glomerulus

• Creatinine is a muscle breakdown product

How does Creatinine Clearance reflect kidney function?

Decreased levels indicates decreased GFR and impaired renal function

What is the trend for GRF with age?

• Peaks at 30 years old (90-120mL/min)

• For every year after that GFR decreases by 1mL/min until by age 70 years, normal GFR is 70mL/min

What is the consequence of hypertension?

High risk of developing kidney disease because it causes intrarenal dysfunction especially if the HTN is long term because HTN constricts and weakens blood vessels which reduces blood flow and impairs filtration.

What is the consequence of hypotension?

Leads to a lack of circulation to the kidney

Describe Prerenal

Caused by decreased blood flow and perfusion to the kidney

Examples of Prerenal

Hemorrhage

Describe Intrarenal

Develops secondary to actual injuries to the kidney itself

Examples of Intrarenal

Nephrotoxicity caused by NSAIDs and poststreptococcal glomerulonephritis (PSGN)

Describe Postrenal

Related to obstruction of urine outflow from the kidneys

Examples of postrenal

Kidney stones in the ureter, prostate gland enlargement, and bladder cancer

What is Acute Glomerulonephritis?

Renal disorder that is due to inflammation of the glomerulus

What causes Acute Glomerulonephritis?

• Poststreptococcal glomerulonephritis (PSGN) = most common cause

• Bacterial, viral, fungal, or parasitic infections can cause it too

• Autoimmune and immunological diseases

  • Lupus (SLE)

What is the pathophysiology of Acute Glomerulonephritis?

• Antigen-antibody complex (antigen stimulates antibody synthesis) damages the structure of glomerular and cause nephron dysfunction throughout kidney

• Glomerular injury causes hyperpermeability of capillaries which allows loss of albumin and RBC’s in the urine

  • Albumin content of bloodstream decreases which leads to decreased colloid oncotic pressure which leads to imbalance in hydrostatic and oncotic pressure which leads to decreased COP overcome by hydrostatic pressure causing edema

What is the clinical presentation of Acute Glomerulonephritis?

• Sudden edema in periorbital region (puffy eyes)

• Hematuria 

• Proteinuria

• Oliguria

• HTN

• Dark urine bcos of RBC’s

• Point tenderness over the flank

• CVA tenderness (costovertebral/mid-back pain)

What causes Nephrotic Syndrome?

• Implicated in more than 90% of cases:

  • Diabetes Mellitus

  • Amyloidosis

  • Systemic Lupus

• Other causes:

  • Immune-complex deposition disease

  • Vasculitis

  • Allergies

  • Preeclampsia 

  • Morbid obesity

  • Malignant HTN

  • Infections

• In children 70%-90% of cases caused by minimal change disease (MCD)

What is the pathophysiology of Nephrotic Syndrome?

• Glomerular damage occurs either as a primary result or secondary to one of the causes

• Leads to massive albuminuria or proteinuria

• Albumin lost in vascular space leads to edema formation because of the decrease COP

What is the clinical presentation of Nephrotic Syndrome?

• Edema (puffy eyes is common, lower extremities)

• Pleural effusion (fluid in pleural space of lungs)

• Ascites (abdominal cavity fluid buildup)

• Hematuria

• HTN

What are the 4 phases of Acute Kidney Injury?

1. Initial

2. Oliguria

3. Diuresis

4. Recovery

What happens during the oliguria phase?

• GFR decreases

• Retention of urea, potassium, sulfate, creatinine

• Signs of fluid overload

• Nephrons filled with WBC’s

• Inflammation

What happens during the diuresis phase?

• Healing occurs

• Fibrotic tissue

What are common causes of Acute Kidney Injury?

• Reduced renal blood flow that reduces GFR (major cause)

• Common causes:

  • Acute illness

  • Complication of meds

  • Medical procedures

What is the clinical presentation of Acute Kidney Injury?

• Oliguria

• Fluid overload → edema

• Encephalopathy, anemia → Uremia

• Hyperkalemia

What is the clinical presentation of Chronic Renal Failure?

• Encephalopathy

• Thrombocytopenia

• Anemia - fatigue, weakness, dyspnea

• Bruising

• Spontaneous bleeding

• Hyperkalemia - muscle weakness

• Bone demineralization

• Hypocalcemia - tetany and seizure

• GI diseases (PUD, gastritis)

• Infertility

• Glucose metabolism impaired

• Sexual dysfunction

What happens to calcium during Chronic Renal Failure?

• Hypocalcemia

  • Caused by kidneys inability to synthesize vitamin D which leads to decreased calcium reabsorption in GI tract

    • Neuromuscular irritability

    • Tetany

    • Seizures

    • Leads to hyperphosphatemia

What happens to potassium during Chronic Renal Failure?

• Hyperkalemia 

  • Caused by hypervolemia

    • Cardia dysrhythmias

    • Extreme muscle weakness 

What causes Polycystic Kidney Disease?

• Genetic mutation of PKD₁ located at 16p13.3 which encodes for a protein called polycystin 1 (ADPKD₁)

• Mutation of PKD2 on 4q21-22 (ADPKD2)

What is the pathophysiology of Polycystic Kidney Disease?

• ADPKD leads to formation of fluid filled cysts in both kidneys which compresses and damages renal tissue. It leads kidneys to enlarge as the cysts grow.

• The cysts also have fragile blood vessels prone to rupturing causing hematuria. 

What are the complications of Polycystic Kidney Disease?

• Higher risk for renal carcinoma and aneurysms

• Cysts develop in other organs

What is the significance of glucose being positive in an urine analysis?

• It’s abnormal

• Means hyperglycemia, diabetes

What is the significance of ketones being positive in an urine analysis?

• It’s abnormal

• Means starvation, or diabetic ketoacidosis

What is the significance of protein being positive in an urine analysis?

• It’s abnormal

• Minimal amounts: exercise or infection

• Moderate amounts: PKD, infection, heart failure, diabetic kidney disease

• High amounts: PKD, glomerulonephritis, diabetic kidney disease, nephrosis, lupus nephritis

What is the significance of blood being positive in an urine analysis?

• It’s abnormal

• Means infection, kidney stone, or bladder cancer

What is the significance of bilirubin being positive in an urine analysis?

• It’s abnormal

• Means hemolysis or liver disease

What is the significance of urobilinogen being high in an urine analysis?

• It’s abnormal

• If high: liver disease

What is the significance of nitrite being positive in an urine analysis?

• It’s abnormal

• Means urinary tract infection

What is the significance of leukocyte esterase being positive in an urine analysis?

• It’s abnormal

• Means UTI

Define micturition reflex

A reflex involving the spinal cord and cortex of the brain, controls voiding

Explain neuromuscular control of bladder

• Nerve impulses from urinary bladder to the spinal cord and vice versa

• Neurons in spinal cord coordinate this reflex

• Cerebral cortex can override it, thereby enabling conscious control of micturination

• Full bladder stretches to accommodate fluid which triggers parasympathetic nerves in the reflex arc to respond by stimulating the detrusor muscle in bladder wall to contract

Define Dysuria

Pain and burning on urination

What causes Dysuria?

UTI

Define Frequency

An abnormally high number of times that the patient needs to urinate

What causes frequency?

UTI, BPH, urological obstruction, IC/PBS

Define Hesitancy

Interrupted flow of a urinary stream

What causes Hesitancy?

BPH (Benign Prostatic Hyperplasia)

Define Urgency

A feeling that urination will occur imminently

What causes Urgency?

UTI, BPH, IC/PBS

What are the types of urinary obstruction?

1. Ureteropelvic junction where the ureter attaches to kidney

2. Midureter at the level of the iliac vessels

3. Posterior aspect of female pelvis where ureter crosses broad ligament

4. Ureterovesical junction where ureter connects with bladder

What causes a urinary obstruction

• Urolithiasis

• Benign prostatic hyperplasia

• Kidney stones

What are common symptoms of urinary obstruction?

• Costovertebral angle pain that radiates to groin

• Renal colic

What are the consequences of urinary obstruction?

• Renal failure

• Pelvic swelling

What are the symptoms/signs of a lower infection?

• Dysuria

• Small amounts of frequent urine flow

• Frequency

• Urgency

• Occasionally hematuria 

• Feeling of incomplete peeing

What are symptoms/signs of an upper infection?

• Elevated WBC count

• Fever

What is stress incontinence?

Involuntary leakage of urine as abdominal pressure rises, which typically occurs during coughing and sneezing. The leakage occurs because of either poor pelvic support or weakness in the urethral sphincter.

What is urge incontinence (overactive bladder; OAB)?

Detrusor muscle overactivity is the cause of the urine leakage. The cause is unclear, but IC is thought to be the etiology in some patients. The patient complains of feelings of urgency and frequency or urination many times a day.

What is overflow incontinence?

Chronic overdistention and urinary retention in the bladder results in overflow incontinence. BPH, which obstructs urine outflow, is the most frequent cause in men. Failure of the detrusor muscle caused by damage of the pelvic spinal nerves can also cause this type of oincontinence.

What is neurogenic bladder?

This disorder is the result of an interruption of the sensory nerve fibers between the bladder and the spinal cord or the afferent nerve tracts to the brain. Chronic overdistention of the bladder occurs.

What is functional incontinence?

Inability to hold urine caused by CNS problems such as stroke, psychiatric disorders, prolonged immobility, dementia, or delirium

What is mixed incontinence?

Combination of stress incontinence and OAB

What causes Nephrolithiasis (formation of stones in kidney?

• The exact cause is unknown

• About 90% of patients who get this have at least one metabolic risk factor: hypercalcemia, hyperoxaluria, hyperuricemia, hyperparathyroidism, gout

• Dehydration huge risk factor

What is the pathophysiology of Nephrolithiasis?

• Formation of renal calculi involves many different factors that include dietary and intestinal absorption factors, endocrine abnormalities, crystalline components in the blood, constituents of urine, pH of urinary, urinary tract structures, and heredity

• The first theory proposes that there is supersaturation of the urine by stone-forming crystalline constituents

• The second theory proposes that there is a deposition of calcium phosphate, a normal compound from breakdown of bone, onto an area of tubule cell membranes in the renal papilla, an area of kidney that empties into the minor calyx

• The third theory suggests that persons with nephrolithiasis have a deficiency of one or all proteins that inhibit stone formation.

What is the clinical presentation of Nephrolithiasis?

• Pain (renal or ureteral colic)

• Acute, excruciating pain in the flank and upper outer quadrant of abdomen on affect side

• Radiating pain into the lower abdomen and groin

• Patient bent over

• Writhe in pain or pacing to change position and find comfort

• Cool, clammy skin

• Nausea

• Vomiting

• Hematuria

Flank pain with radiation into the groin, hematuria, and crystalluria are classic signs

Types of kidney stones?

• 75% of stones consist of calcium

• Most common stones

  • Calcium

  • Struvite

  • Uric acid

  • Cystine