Renal stone formation or Urolithiasis Types, composition and clinical features.

 Urolithiasis or Renal stone formation and its types. 

Urolithiasis:

It is formation of stones or calculus  in kidney.

 i.  more common in man than women.

ii. above age of 70 almost 11% of men and 5.6% of women will likely to develop Renal stones.

Types of Renal stones and it composition:

Following are most common  types of kidney stones with their common causes.

1.      1. Calcium stones: about 80% of stones majorly contain calcium, either in form of Calcium Oxalate or mixture of Calcium Oxalate and Calcium Phosphate.

Common causes of Calcium stones:

a.      Most common cause is Idiopathic Hypercalciuria.

b.      Hypercalcemia and Hypercalciuria  

c.       Hyperoxaluria.

d.      Hyperuricosuria.

e.      In some cases (15 to 20%) there is no any known metabolic abnormality.

2.     2. Struvite stones : Almost 10% of stones are composed of Magnesium Ammonium Phosphate, these are commonly  known as Magnesium stones.

Causes of Struvite or Magnesium stones:

a.      Such stones are associated with Urinary track infections, specifically infections of Urea splitting bacteria like Proteus vulgaris and staphylococci. These bacteria either increase the chances of Struvite stone formation (like staphylococci and protease vulgaris etc.) or directly  cause any stone formation. During formation of these stones Patients produce alkaline Urine.

3.      3.Uric acid stone:

         Almost 6 to 7% of stones has Uric acid composition.

Causes of Uric acid stones :

a.      Almost half of cases associated with Hyperuricemia and Hyperuricosuria.

b.      Other half cases are idiopathic. There acid urine are produced, probably this lower pH urine favours uric acid stone formation.

4.      4.Cystine stones: 

       1 to 2 % of stones  has cystinic composition.

Causes of Cystine stone formation:

a.      This is almost always associated with genetic defects in renal transport of amino acids like Cystine. These also form when Urine is acidic.

Clinical features of Renal stones/ Urolithiasis:

a.     a. Clinical significance of Renal stone is associated with their capacity of abstracting urine flow or causing trauma and leading to haematuria or renal bleeding.

b.     b. Stones at their original sites are asymptomatic.

c.      c.  Flank pain (Renal pain) starts when stones dislocate or cause abstraction of urine.

d.    d.   Renal or ureteral colic is condition when renal stones replace inside kidney or to ureter, and initiate flank pain.