renal calculi and hydronephrosis

Renal calculi

Renal calculi

Presented By Prof. Dr.

Nabil Tadros Mikhail MBBS, MS Pathol., PhD Pathol.

Prof. of Pathology Alexandria University - Egypt

Consultant & Chief Pathologist King Fahad Central Hospital

Gizan - KSA

Renal stones is a frequent disorder , occur more common in males.

A familiar tendency has been recognized..

Pathogenesis: The cause of stone formation is

often not completely understood , but there is many factors involved in stone formation.

Factors involved in stone formation

1. Increased urine concentration of stone constituents, so that it exceeds their solubility in urine (This is the most important factor).

2. Decreased urine flow.3. Absence of a substance in urine that

inhibit precipitation of salts and minerals (ex: pyrophosphate)

Types of renal calculi The most important types are:

1. Calcium oxalates 67%.

2. Calcium phosphate 8% 3. Magnesium ammonium phosphate

15%4. Uric acid 8%5. Cystine stone 2%

Etiology of renal calculi 1- calcium stone: It may be due to

A-Hypercalciuria that is not associated with hypercalcemia(50%).

It is either due to Increased calcium absorption from gut

(absorptive hypercalciuria) or

Defect in renal reabsorption of Ca (renal hypercalciuria).

Etiology of renal calculi 1- calcium stone: It may be due to

B-Hypercalcaemia (10%) ; as in cases of

1. Primary hyperparathyroidism, 2. Vitamin D toxication, 3. Sarcoidosis,…

Etiology of renal calculi 1- calcium stone: It may be due to

C- Excessive uric acid excretion in urine:

account for 20% of cases of calcium stones because uric acid favors calcium stone formation..

Etiology of renal calculi 1- calcium stone: It may be due to

D- hyperoxaliuria 5%. E- Idiopathic 15%.

Calcium stone occur at any pH of urine.

Etiology,…2- Magnesium ammonium phosphate stone

It occur in alkaline urine due to urinary tract infection.

In particular urea splitting bacteria as proteus vulgaris

Etiology,… 3- uric acid stone

It occur in acidic urine due to high uric acid levels .

Hyperuricaemia may be primary due to defect in enzyme involved in purine metabolism (1ry gout)

Etiology,… 3- uric acid stone

Hyperuricaemia could be also secondary (2nd gout).

with increase cell turnover as in leukemia, chemotherapy and psoriasis.

Also is seen in cases of decreased excretion of uric acid as renal failure.

Etiology,… 4- Cystine stone

Is genetically defect in renal transport of cystine .

It is formed in acidic urine

Morphology of renal calculi

Calcium stone: Hard, Small to medium in size, Often multiple, Radiopaque.

Morphology of renal calculi

Magnesium ammonium stone: may be large size with branching structure

(stag horn stone). it is radiopaque.

Morphology of renal calculi

Uric acid stone Yellow Friable Radiolucent

Morphology of renal calculi

Cystine stone Brown color May be large Radiolucent

Clinical course of renal calculi

May be asymptomatic. May present with renal colic

(during its passage into ureter)

Hematuria. It predispose the patients to urinary

tract infection.

Clinical course of renal calculi

Larger stone that cannot pass will lead to

Obstruction and produce

1. hydronephrosis2. hydroureter.

Clinical course of renal calculi

Diagnosis is done radiological. Also investigations to detect the

cause is done 1. Serum calcium 2. Phosphorus 3. Uric acid 4. Para Thyroid Hormone,…

The passage of calculus through urinary tract

Hydronephrosis with calculus at ureteropevic junction.

HydronephrosisHydronephrosis

Causes of hydronephrosis

Hydronephrosis refers to dilatation of renal pelvis and calyces with accompanying atrophy of parenchyma.

Cause by obstruction to outflow of urine,

The most common causes are:

Causes of hydronephrosis

Congenital Atresia of urethra, Aberrant renal artery compressing

the ureter, Renal ptosis with kinking of ureter.

Causes of hydronephrosis

Acquired; Foreign Body: Stones Tumors: cancer prostate & bladder tumors

Inflammation: prostatitis, ureteritis, urethritis

Neurogenic: spinal cord damage with paralysis of bladder.

The unusually high pressure generated at renal pelvis causes compression of renal vasculature.

Both artery insufficiency and venous stasis occur.

The most severe effects is seen in the papillae because they are subjected to the greatest increase in pressure.

Accordingly the Initial functional disturbances are largely tubular,

Manifested by impaired concentration ability,

Later on glomerular filtration begins to diminish

The kidney is massively enlarged with greatly distended pelvicalyceal system.

The renal parenchyma is compressed and atrophied with obliteration of the papilla and fattening of the pyramids.

Depending on obstruction one or both ureter may also dilated (hydroureter)

Morphology :

Bilateral complete obstruction produce anuria which need soon medial attention

Incomplete bilateral obstruction produce polyuria rather than oliguria as a result of defect in tubular concentrating mechanism

Clinical course

Unilateral hyronephrosis may be silent for long period unless other kidney is affected.

Bilateral hydronephrosis usually lead to uremia.

Early removal of obstruction can return the kidney function.

However with the time the changes become irreversible.

Clinical course

Hydroureter & hydronephrosis

Severe hydronephrosis .The kidney is markedly enlarged.

Hydronephrosis affecting mainly the lower pole of kidney due to stone at this site .The upper pole of the kidney is normal