Renal and Metabolic Diseases Flashcards
List the glomerular disorders discussed in lecture
- Acute poststreptococcal glomerulonephritis
- Rapidly progressive glomerulonephritis
- Good Pasture’s Syndrome
- Chronic glomerulonephritis
- Nephrotic syndrome
List the two tubular disorders discussed in lecture
- Acute tubular necrosis
- Fanconi’s Syndrome
List the interstitial disorders discussed in lecture
- Cystitis
- Acute pyelonephritis
- Chronic pyelonephritis
- Acute interstitial nephritis
List the vascular disorders discussed in lecture
- Acute renal failure
- Chronic renal failure
This disorder results from immune-mediated processes whereby antigen-antibody complexes or complement complexes accumulate in the glomeruli; induces inflammation that leads to tissue damage
Glomerular diseases
Are the specimens in glomerular disorders sterile or non-sterile?
Sterile
This is the most common cause of acute glomerulonephritis; usually occurs in children and young adults following infection with certain strains of group A strep; inflammation damages glomeruli
Acute poststreptococcal glomerulonephritis
List symptoms of acute poststreptococcal glomerulonephritis
- Rapid onset of hematuria and edema
- Fever
- Hypertension
- Oliguria → anuria
Lab findings for acute poststreptococcal glomerulonephritis
- Blood cultures: negative
- ↑ BUN
Important urinalysis findings in acute poststreptococcal glomerulonephritis
- Marked hematuria
- RBC casts
Prognosis for acute poststreptococcal glomerulonephritis
Permanent kidney damage seldom occurs
This is caused by the deposition of immune complexes in glomerulus leading to the formation of crescentic structures which permanently damage the glomerulus; often associated with systemic lupus erythematosus (SLE)
Rapidly progressive glomerulonephritis
Important urinalysis findings in rapidly progressive glomerulonephritis
- Hematuria
- Low GFR
- Proteinuria
Prognosis for rapidly progressive glomerulonephritis
Progresses to chronic glomerular nephritis and eventually end stage renal failure
This disorder is due to the antiglomerular basement membrane autoantibody that is formed after a viral respiratory infection; complement activation destroys capillaries
Goodpasture Syndrome
Symptoms associated w/ Goodpasture Syndrome
Pulmonary complaints
- Hemoptysis
- Dyspnea
Important urinalysis findings in Goodpasture Syndrome
- Proteinuria
- Hematuria
- RBC casts
Prognosis for Goodpasture Syndrome
Progression to chronic glomerulonephritis and end-stage renal failure is common
This disorder is caused by a marked ↓ in renal function resulting from glomerular damage precipitated by other renal disorders; gradually worsening symptoms until eventual kidney failure
Chronic glomerulonephritis
Symptoms associated w/ chronic glomerulonephritis
- Fatigue
- Anemia
- Hypertension
- Edema
- Markedly ↓ GFR
- ↑ BUN and creatinine
- Electrolyte imbalance
Important urinalysis findings in chronic glomerulonephritis
Waxy and broad casts (indicating end-stage renal disease)
Prognosis for chronic glomerulonephritis
Will continually worsen until kidneys failure
This is a group of symptoms that often occur together following glomerular damage; this damage is coupled with the disruption of the electrical charge of the tubular epithelium resulting in a leaky tubular epithelium; gradual progression to chronic renal failure
Nephrotic syndrome
What is nephrotic syndrome called in children?
Minimal change disease
What is nephrotic syndrome called in adults?
Membranoproliferative glomerulonephritis
Important urinalysis findings in nephrotic syndrome
- Urine protein > 3.5 g/day (EXTREMELY HIGH)
- Lipiduria (oval fat bodies)
- Fatty casts
Prognosis for nephrotic syndrome
Gradual progression to chronic renal failure
This symptom in nephrotic syndrome is caused by lowered plasma albumin which lowers plasma oncotic pressure; this leads to increased reabsorption of sodium ions and water from the distal tubules
Edema
This tubular disorder is caused by the damage to the renal tubular cells caused by ischemia (lack of blood flow) or exposure to toxic agents
Acute tubular necrosis (ATN)
Important lab findings associated w/ ATN
Low hemoglobin and hematocrit
Important urinalysis findings in ATN
- Renal tubular epithelial cells
- Renal tubular epithelial cell casts
Prognosis for ATN
Variable prognosis depending on underlying cause
This tubular disorder is classified as generalized failure of reabsorption in the proximal convoluted tubule; glucose, Na+, K+, HCO3-, phosphorus, and amino acids not being reabsorbed normally; inherited or aquired
Fanconi’s Syndrome
What are 2 common disorders causing Fanconi’s syndrome?
- Cystinosis
- Hartnup disease
What is cystinosis?
The accumulation of cystine in lysosomes
What is Hartnup disease?
Defect in absorption of certain amino acids from intestines or kidneys
Important lab findings associated w/ Fanconi’s syndrome?
- Abnormal serum electrolytes (↓)
- Abnormal amino acid chromatography (↓)
- Normal blood glucose
Important urinalysis findings associated w/ Fanconi’s syndrome?
- Glucose (b/c PCT can’t reabsorb it)
- Cystine crystals (VERY RARE)
This group of disorders usually involves infections and inflammatory conditions
Interstitial disorders
Most common bacterial causes of UTIs
- E. coli (most common)
- Proteus spp
- Klebsiella spp
- Enterobacter spp
This disorder is known as a lower UTI or bladder infection
Cystitis
Symptoms associated w/ cystitis
- Burning and pain in urination,
- Dysuria
- Increased frequency of urination
- Mental confusion in elderly
Important lab findings associated w/ cystitis
Normal BUN and creatinine
Important urinalysis findings associated w/ cystitis
- Urine culture: positive
- Leukocyte esterase: positive
- Bactera: small to large
- NO CASTS
This disorder is an infection of the tubules and interstitium; caused by ascending movement of bacteria from a lower UTI or from reflux nephropathies
Acute pyelonephritis
Symptoms associated w/ acute pyelonephritis
- Burning during urination
- Increased frequency of urination
- Flank and lower back pain
- Nausea and headache
- Confusion (in elderly)
Important urinalysis findings associated w/ acute pyelonephritis
- Urine culture: positive
- Leukocyte esterase: positive
- WBC casts present
- Bacteria: small → large
Prognosis of acute pyelonephritis
Proper antibiotic treatment should resolve the problem w/o permanent damage to tubules
This disorder occurs when persistent inflammation of the renal tissue causes permanent scarring that involves the renal calyces and pelvis
Chronic pyelonephritis
What is the most common cause of chronic pyelonephritis?
Reflux nephropathies
Important lab findings associated w/ chronic pyelonephritis
↑ BUN
Important urinalysis findings associated w/ chronic pyelonephritis
- Urine culture: positive
- Leukocyte esterase: positive
- WBC casts
- Granular and waxy broad casts: present
- Bacterial casts: present
Prognosis for chronic pyelonephritis
- Usually diagnosed in childhood
- 10-15% will end in renal failure requiring dialysis
This disorder is caused by inflammation of the renal interstitium followed by inflammation of the renal tubules; often caused by allergic reactions to medications
Acute interstitial nephritis
Rapid onset of symptoms associated w/ acute interstitial nephritis
- Skin rash
- Oliguria
- Edema
Important lab findings associated w/ acute interstitial nephritis
- ↑ BUN and creatinine
- ↓ GFR
- Fever
Important urinalysis findings associated w/ acute interstitial nephritis
- WBCs: numerous (no bacteria seen)
- Eosinophils
- Proteinuria: mild to moderate
This group of disorders results from any conditions which reduces the blood flow to the kidneys
Vascular disorders
This disorder is characterized by a SUDDEN onset, decrease in GFR, azotemia, oliguria (leading to anuria) and has a high mortality
Acute renal failure
What are the three stages of acute renal failure?
- Pre-renal
- Renal
- Post-renal
This mechanism of acute renal failure is caused by decrease in blood flow below 80 mmHg, decreased cardiac output, blood loss, severe diarrhea, and vomiting
Pre-renal
This mechanism of acute renal failure is due to damage to the glomerulus or tubular regions, usually in acute tubular necrosis
Renal
This mechanism is due to obstructions in urine flow such as crystalline deposition (calculi) or neoplasms
Post-renal
Lab findings associated w/ acute renal failure
- Urine osmolality > serum osmolality
- ↑ BUN (uremia)
- ↓ GFR (low creatinine clearance)
- Edema
- Oliguria
Prognosis for acute renal failure
- High mortality rate usually caused by simultaneous infection or potassium intoxication
- Monitor electrolytes and fluids along w/ dialysis to control azotemia
This disorder is caused by a gradual loss of function caused by glomerulonephropathies, diabetic nephropathy, chronic pyelonephritis, and hypertension
Chronic renal failure
Important lab findings in chronic renal failure
- Azotemia
- ↓ GFR
- Bleeding
- Electrolyte imbalance
Important urinalysis findings in chronic renal failure
- Isotenuria
- Marked protein
- All types of casts ESPECIALLY waxy and broad
This disorder is caused by renal calculi as they form in the calyces and pelvis of the kidney, ureters, and bladder; 75% are composed of calcium oxalate or calcium phosphate
Renal lithiasis
Four factors that affect the formation of kidney stones
- Super saturation of chemical salts in urine
- Optimal urinary pH
- Urinary stasis
- Nucleation or initial crystal formation
Symptoms associated w/ kidney stones
- Pain radiating from kidney and continuing down to genitalia and leg
- Nausea
- Vomiting
- Sweating
- ↑ urge to urinate
- Bloody urine
Where do kidney stones form?
- Calyces and pelvis of kidney
- Ureters
- Bladder
Use of high energy waves to break stones into smaller pieces
Lithotripsy
75% of stones are composed of ____ ____ or ____ ____
Calcium oxalate; calcium phosphate
Four factors that prevent formation of kidney stones
- Maintaining urine pH at a level which will prevent crystallization of the crystals in question
- Medication to prevent excretion of or to change metabolism of calculi forming compound
- Adequate hydration to prevent urinary stasis
- Dietary restrictions
What is the GFR historical reference method?
Inulin clearance
What is the advantage of using inulin?
Not absorbed by GI system or tubules, not modified, readily passes through glomerulus
Disadvantage of using inulin?
Exogenous substance that must be administered intravenously during test
Most common methods currently used for assessment of glomerular function
- Creatinine (most common)
- Beta2-microglobulin
- Cystatin C
Creatinine clearance test
- Not affected by urine flow rate
- Not reabsorbed by tubules
- Not affected by diet
- Produced at a constant rate
- Dependent on muscle mass
What is the average production of creatinine?
- 2 mg/day
- Proper preservation must be used (bacteria may falsely lower creatinine)
How is a creatinine clearance tested?
Time specimen is necessary (24 hour urine collection)
Normal GFR
120 mL/min
- If GFR > 90 mL/min, patient is normal
This calculation uses serum creatinine, age, gender, and ethnicity; typically reported in patients with <60 mL/min GFR
Estimated GFR
this assessment of glomerular function is a more sensitive indicator of a decrease in GFR than crea clearance; not reliable in patients with immunologic disorders or malignancy; good test to assess tubular function; it dissociates from the membrane of nucleated cells at a constant rate and is rapidly filtered by the glomerulus and reabsorbed and catabolized by the tubules
Beta2-Microglobulin
This is produced at a constant rate by all nucleated cells; readily filtered by the glom and reabsorbed and broken down by tubules; recommended test for peds, elderly, diabetics, and critically ill; INDEPENDENT of muscle mass
Cystatin C
Three treatment options for renal failure
- Hemodialysis
- Peritoneal dialysis
- Renal transplant
In this treatment, the patient’s blood is cleansed as particles diffuse across a semipermeable membrane into a commercially available dialysis solution; preferred access point is through a fistula
Hemodialysis
This treatment involves using a sterile solution of dialysis solution allowing it to drain into the peritoneal cavity; the peritoneal membrane acts as a selectively permeable membrane that allows diffusion and osmosis of wastes into the dialysis solution; this solution is then drained and discarded
Peritoneal dialysis