see uvea.
Most urinary tract stones are composed of calcium oxalate or other salts crystallized from the urine. These may be associated with a diet rich in oxalic acid (found in leafy vegetables and coffee); high levels of calcium in the blood as a result of hyperparathyroidism; or chronic dehydration. Other types of stone are associated with gout and some cancers. An infective stone is usually a result of chronic urinary tract infection.
In developing countries, bladder stones usually occur as a result of dietary deficiencies. In developed countries, they are usually caused by an obstruction to urine flow from the bladder and/or a longstanding urinary tract infection.
The most common symptom of a stone in the kidney or ureter is renal colic (a severe pain in the loin) that may cause nausea and vomiting. There may be haematuria (blood in the urine). A bladder stone is usually indicated by difficulty in passing urine. The site of the stone can usually be confirmed by intravenous or retrograde urography.
Renal colic is treated with bed rest and an opioid analgesic (painkiller).
With an adequate fluid intake, small stones are usually passed in the urine without problems.
The first line of treatment for larger stones is lithotripsy, which uses ultrasonic or shock waves to disintegrate the stones.
Alternatively, cytoscopy can be used to crush and remove stones in the bladder and lower ureter.
In some cases, surgery may be needed.... calculus, urinary tract
In both sexes, causes of urinary tract infections include stones (see calculus, urinary tract), bladder tumours, congenital abnormalities of the urinary tract, or defective bladder emptying as a result of spina bifida or a spinal injury. The risks of developing a urinary tract infection can be reduced by strict personal hygiene, drinking lots of fluids, and regularly emptying the bladder.
Urethritis can lead to the formation of a urethral stricture. Cystitis usually only causes complications if the infection spreads to the kidneys. Pyelonephritis, if it is left untreated, can lead to permanent kidney damage, septicaemia, and septic shock.
The infection is diagnosed by the examination of a urine culture. Further investigations using urography or ultrasound scanning may be necessary. Most infections of the urinary tract are treated with antibiotic drugs.... urinary tract infection