Urinary Tract Obstruction and Urolithiasis

Question 1

What does untreated obstruction lead to?

Answer 1

• Permanent renal atrophy, termed hydronephrosis, or obstructive uropathy

Question 2

What happens in acute obstruction?

Answer 2

• May provoke pain correlating to site of obstruction
• Most of the early symptoms occur due to the underlying cause of the hydronephrosis
• Calculi lodged in ureters may give rise to renal colic, and prostatic enlargements may give rise to bladder symptoms

Question 3

How does unilateral complete or partial hydronephrosis usually present?

Answer 3

• May remain silent for long periods because the unaffected kidney can maintain adequate renal function

Question 4

How is unilateral complete or partial hydronephrosis first seen and diagnosed?

Answer 4

• Imaging studies like U/S are used to diagnose

Question 5

What happens in bilateral partial obstruction?

Answer 5

• Inability to concentrate urine reflected by polyuria and nocturia
• Some may develop tubular acidosis, renal salt wasting, secondary renal calculi, and chronic tubulointerstitial nephritis with scarring and atrophy of the papilla and medulla
• HTN is common

Question 6

What is seen in complete bilateral obstruction?

Answer 6

• Rapid onset results in oliguria or anuria

- Incompatible with survival unless the obstruction is relieved

Question 7

What happens after the obstruction is relieved in complete bilateral obstruction?

Answer 7

• Post obstructive diuresis occurs

- Kidney excreting large amounts of urine that is rich in sodium chloride

Question 8

Who is most likely to have a kidney stone?

Answer 8

• Men in their 20s or 30s

Question 9

What are some familial or hereditary factors that predispose to kidney stones?

Answer 9

• Cystinuria and primary hyperoxaluria

- HGPRT deficiency

Question 10

What makes up the majority of kidney stones seen?

Answer 10

• Calcium

Question 11

What are calcium oxalate stones associated with?

Answer 11

• Hypercalcemia and hypercalciuria like in hyperparathyroidism, diffuse bone disease, sarcoidosis, and other hypercalcemic states

Question 12

What is the most important determinant for the initiation and propagation of stones?

Answer 12

• Increased urinary concentration of the stones’ constituents, such that it exceeds their solubility

Question 13

When are magnesium ammonium phosphate stones seen?

Answer 13

• Largely seen after infection by urea splitting bacteria (proteus, pseudomonas, klebsiella, and some staph/enterococci)

Question 14

Why are magnesium ammonium phosphate stones worrisome?

Answer 14

• Because they are some of the largest stones formed due to the very large amounts of urea that is excreted
• Form a staghorn calculi which occupy large portions of the renal pelvis and can be seen on Xray

Question 15

Who are uric acid stones common in?

Answer 15

• Individuals with hyperuricemia, but most don’t have hyperuricemia or increased urinary excretion of uric acid
• MOST excrete a urine that has pH below 5.5 which is a pH that uric acid is insoluble

Question 16

What are the symptoms of kidney stones?

Answer 16

• May be asymptomatic
• Renal colic and abdominal pain
• Significant renal damage
• Larger stones –> hematuria