Obstructive Nephropathy - NACE

Question 1

What is Hydronephrosis?

Answer 1

Dilation of the Renal Pelvis

Question 2

What is proximal and distal when discussing the urinary tract?

Answer 2

Proximal = Close to the kidney

Distal = Far from the kidney

Question 3

What is an example of a function obstruction in urinary outflow?

Answer 3

• Neurogenic Bladder

Question 4

What are some common intraluminal causes of mechanical Obstruction to urinary outflow?

Answer 4

Intraluminal
• Stones
• Blood Clots
• Papillary Necrosis (SODA; sickle-cell, obstructive pyelonephritis, diabetes, analgesic use)
• Tumors

Question 5

What are some intramural causes of mechanical obstruction to urinary outflow?

Answer 5

• Neurologic/Neuromuscular dysfunction (kind of a functional problem too)
• Strictures (from infection or instrumentation)

Question 6

What are some common causes of compression in the urinary tract?

Answer 6

• Retroperitoneal Tumors (from prostate tumors)
• Local Extension of Prostate Cancers, Colon Cancer, Cervical Carcinoma
• AAA
• PROSTATIC HYPERTROPHY = big one

Question 7

Differentiate the severity of disease on the basis of UT obstruction relative to bladder?

Answer 7

Distal to Bladder:
• this BAD because it leads to damage in BOTH kidneys - something the body is not well-equipped to handle

Proximal to Bladder:
• Will lead to damage of single kidney only - body can handle this

Question 8

How can radiocontrast be used to detect Ureter Obstruction?

Answer 8

RETROGRADE PYLOGRAPHY can be performed

• inject radiocontrast from beginning of ureter in the bladder and follow it backwards
• It will stop wherever the obstruction is located

Question 9

What would you expect to see happen on Retrograde Pylography of someone with Retroperitoneal Fibrosis?

Answer 9

• Contrast Will just stop wherever retroperitoneum has fibrosed over the ureter

Question 10

What are the two types of consequence that result from obstruction in the GU system?

Answer 10

• Mechanical Consequences

* Functional Consequences

Question 11

What are the MECHANICAL consequences of GU obstruction?

Answer 11

• Dilation of the urinary Tract Proximal to the Obstruction

* Eventual Compression and thinning of the renal cortex with parenchymal Atrophy over time

Question 12

What are the FUNCTIONAL consequences of GU obstruction?
• early.
• Time associated with this?

Answer 12

Early (4-6 hours):
• Ureteral Pressure and Renal Blood flow increase, PROSTAGLANDINS (Vasoactive mediators) are released to attempt to maintain GFR

Question 13

What are the FUNCTIONAL consequences of GU obstruction?
• later.
• Time associated with this?

Answer 13

Later (greater than 6 hours)
• Vasocontrictors (Renin, Angiotensin, Thromboxane) are produced in the MACULA DENSA

• Leads to GRADUAL SUSTAINED decrease in GFR to about 20% of pre-obstructive values

Question 14

What are the FUNCTIONAL consequences of GU obstruction?

•Chronically

Answer 14

Chronic

• Ischemia and Inflammatory cytokines result in interstitial fibrosis

Question 15

What is the histopathology seen on H and E in the late stages of obstructive nephropathy?

Answer 15

INFLAMMATION and FIBROSIS

• both mononuclear cells and fibrin

Question 16

Why is GFR not completely predictive of renal damage?

Answer 16

• Other Nephrons Hypertrophy and Hyperfiltrate to pick up the slack

This means creatinine isn’t a great indicator of damage especially in unilateral renal dysfunction

Question 17

What important factors determine the signs and symptoms seen in urinary tract obstruction?

Answer 17

• Time Course
• Degree of Obstruction
• Level of Obstruction
• Cause
• Developement of Secondary Complications

Question 18

What are some secondary complications that may result from urinary tract obstruction?

Answer 18

• Infection
• Fluid and Electrolytes
• Renal Failure

Question 19

T or F: chronic progressive obstruction in urinary tract may be asymptomatic.

Answer 19

True, acute obstructions are more likely to have symptoms

Question 20

How will complete and partial obstruction affect urinary outflow?
• creatinine

Answer 20

Complete:
• ANURIA
• Serum Creatinine results in full blown renal failure

Partial:
• POLYURIA - this is the result of concentrating defects
• small transient effect on Serum Creatinine

Question 21

What type of GU obstruction is associated with the following:
•acute, excruciating flank pain radiating to the groin

Answer 21

Ureteral Stones

Question 22

What type of GU obstruction is associated with the following:
prevention of complete emptying of the bladder, producing urinary hesitancy,
diminished stream, dribbling, nocturia, frequent small volume voiding, and straining

Answer 22

Prostatic Disease

Question 23

What type of GU obstruction is associated with the following:
Gross Hematuria

Answer 23

may suggest a clot as the cause of obstruction or may accompany a kidney stone
or sloughed papilla (from papillary necrosis).

Question 24

**What are the Functional Consequences of CHRONIC Bilateral PARTIAL obstruction of ureters?

Answer 24

SYMPTOMS RESEMBLE Type 4 RTA (renal tubule acidosis)

• Polyuria
• Volume Depletion
• Azotemia
• ELECTROLYTE PROFILE of non-anion gap metabolic acidosis
• Hyperkalemia

Question 25

What diagnostic Tests are useful in determining if there has been an obstruction in the GU system? • advantages and disadvantages to each.

Answer 25

Ultrasound: • Advantage: easy availability, good at detecting kidney stones • Disadvantage: Depends on demonstration of hydronephrosis CT: • Advantages: Highly sensitive for obstruction, no contrast is necessary for this indication • Disadvantages: Inconvenient, Ionizing radiation

Question 26

Why is it a disadvantage that ultrasound depends on hydronephrosis to aid in Dx?

Answer 26

Hydronephrosis Can be FALSELY NEGATIVE in cases of: • Recent Obstruction • Volume Depletion • Retroperitoneal Fibrosis

Question 27

What are your 3 Treatment goals for a patient with Urinary Tract Obstruction?

Answer 27

1. Relieve the Obstruction 2. Treat the underlying Cause 3. Prevent and Treat Infection*** this is a big one because obstruction + infection = BAD combo. for the kidney

Question 28

T or F: recovery of the kidney even after LONG periods (several days/weeks) of obstruction is possible.

Answer 28

True, degree of recovery will be correlated to the extend of obstruction and duration

Question 29

What are some common locations of intraluminal obstruction?

Answer 29

• Uretero-Pelvic Junction, Uretero-Vescicle Junction, Intersection of Ureters and Iliac Vessels

Question 30

An adult male with 2 healthy kidneys developes ACUTE RENAL FAILURE. What is the most likely obstructive cause? • what would his labs show?

Answer 30

• Urethral Obstruction by Prostatic Hyperplasia Labs: • Hyperchloremic Metabolic Acidosis with Hyperkalemia

Question 31

T or F: UT obstruction is always associated with Intraluminal Obstruction or Extrinsic Compression.

Answer 31

FALSE

Question 32

T or F: allergy medication s may cause difficulty urinating

Answer 32

True

Question 33

NOTE about distention of structures under acute and chronic conditions

Answer 33

ACUTE: • things that distend quickly Hurt CHRONIC: • things that gradually distend will distend much more and be less symptomatic

Question 34

What determines the consequences and symptoms of obstruction?

Answer 34

The level at which it occurs

Question 35

T or F: polyuria excludes UT obstruction

Answer 35

FALSE, could be bilateral partial obstruction

Question 36

How would EKG indicate Chronic Obstruction? | • explain these findings

Answer 36

EKG: | • Big T waves from HYPERKALEMIA - (excessve repolarization)

Question 37

T or F: if you put the catheter in and they start making a lot of urine, you have made the diagnosis

Answer 37

True, ***note that if someone has been obstructed for a long time and you catheterize them they may DIURESE SO MUCH THEY THEY BECOME HYPOCALCEMIC.