What is ureter? – A ureter is a narrow tube connecting each of the kidneys to the urinary bladder.
What is ureteric stone? – This is a solid mass / crystal, found in the ureter, having been formed in the kidney (usually) and passed to the ureter along with urine.

How does ureteric stone form?

A ureteric stone is essentially a kidney stone formed from the build up of minerals and salts in the urine, especially when urine is concentrated, due to inadequate water intake. Save for structural abnormality of the ureters, urine hardly stays long enough in them for the minerals and salts to interact together to form stone. 

What are the types of ureteric stones?

The types of ureteric stones are those of kidney stones. They are:

1. Calcium stones – These are formed from calcium compounds e.g. calcium oxalate, calcium phosphate etc. They are the commonest ureteric / kidney stones
2. Uric acid stones – These are formed from excess uric acid (by-product of protein metabolism) in urine
3. Struvite stones – These usually form following urinary tract infection. They contain magnesium ammonium phosphate and calcium carbon-apatite. They grow very quickly and can be very large
4. Cystine stones – These are the least common types of ureteric / kidney stones. They contain the amino acid cystine. Its occurrence is usually due to a genetic disease known as cystinuria

What are the risk factors for ureteric stones?

The following factors predispose to ureteric stone:

1. Family history of ureteric stone (especially first degree relative)
2. Previous history of ureteric stone
3. Not drinking enough water (as evidenced by passage of deep yellowish urine)
4. Uncontrolled diabetes mellitus
5. Being a male – commoner in male than female

What are the symptoms of ureteric stones?

The symptoms of ureteric stones depend on the size. Tiny stones may be passed out with urine through the ureters without feeling any symptom. When ureteric stones are of considerable sizes, they may block the ureters and prevent the passage of urine.

An attempt to overcome the obstruction for urine to pass will result in symptoms which may include:

1. Intermittent bouts of abdominal pains towards the flanks, which may spread to the lower abdomen
2. Pain while passing urine
3. Bloody or brown coloured urine
4. Urinating more frequently than before and in small quantities 
5. Nausea and vomiting

What tests are done to diagnose ureteric stones?

Tests to diagnose ureteric stones may include:

1. Urine analysis – This will look at substances in the urine that could form stone as well as substances suggestive of urinary tract infection
2. Ultrasound – This may detect blockage along the ureters by showing areas of distension along the ureter
3. Computer tomography scan – A CT scan may help determine the location of the stone and the size

How is ureteric stone treated?

The treatment of ureteric stones depends on the:

1. Size of the stone
2. Location of the stone along the ureter
3. Type of stone (the chemical composition of the stone)

The size and location of the stone will determine if the stone can be passed with urine. Tiny stones can easily pass but bigger stones causing pain and obstruction to urine flow may require any of the following forms of treatment:

1. Medical treatment – This may entail using drugs to relieve the pain associated with the stone, or to dissolve the stone or treat urinary tract infection. Drinking adequate quantity of water (at least 2-3 litres) on a daily basis can help in dissolving small stones and also prevent the growth of small stones to larger ones. Proper evaluation by a doctor is very important. 
2. Ultrasound treatment – This is the use of high energy ultrasound to break a ureteric stone into small pieces which can be passed in urine. This procedure, referred to as shock wave lithotripsy, where available and applicable, may help the patient avoid surgery.
3. Surgical treatment – This could be by using a thin tube with light at the tip, passed through the urethra up into the ureter (through the bladder), to locate a ureteric stone and bring it out (Ureteroscopy).It may be useful for small sized stones which cannot be passed by the patient. For larger stones, there may be need for direct removal via open surgery in a procedure referred to as percutaneous nephrolithotomy. Sometimes, if the stone is difficult to remove through any of these means, a stent, in form of thin flexible tube, may be inserted inside the ureter to distend it and keep it open in order to allow urine to flow around the stone. This is referred to as ureteric stent. 

How can ureteric stones be prevented?

Ureteric stones can be prevented by some of the following measures:

1. Drinking adequate water – An average adult needs at least 2 to 3 litres of water daily. It could be more on hot days or with strenuous activities when insensible water loss (water loss through breathing or sweating) is high. The aggregate of water intake for the day can be obtained from different sources, including fruits, juice, vegetables etc. 
2. Reduction of salt intake – Table /cooking salt and other sources of sodium such as magi should be regulated. Other sources of flavour (e.g. crayfish, scent leaf etc) should be explored in order to reduce salt intake.
3. Reduce intake of animal protein – Animal proteins such as meat, fish, eggs etc increase the quantity of uric acid in the body, thus providing raw materials for stone formation. Reducing their intake will reduce the availability of raw materials for stone formation.