Pediatric Urology Clinics:
Dysuria refers to painful micturition. When a child presents with dysuria, it is important to clarify the location of the discomfort. Such discomfort is usually localized to the urethra, but suprapubic, groin, and flank pain might also be experienced with voiding--either as an isolated symptom or in conjunction with urethral dysuria. The differential diagnosis of dysuria varies according to the location of the pain.
The differential diagnosis of urethral dysuria in a circumcised elementary school-aged boy includes:
•Trauma to the urethra.
•Crystalluria (most commonly, calcium crystals).
•Meatal stenosis and other causes of urethral obstruction.
In this boy, there is no historical or clinical evidence of inflammation of the glans or meatus to suggest a diagnosis of meatitis. The dipstick urine test did not reveal the presence of white blood cells (WBCs) or bacteria, which makes an infectious cystourethritis or urethritis less likely. There is no history of trauma to the urethra. Calcium crystalluria is a reported cause of urethral dysuria that can also manifest with RBCs in the urine; with calcium crystalluria, urinary frequency is also common and there might be a family history of kidney stones. The circular and relatively small appearance of the urethral meatus suggests--but does not confirm--the possibility of meatal stenosis. There is no history of a urinary stream abnormality to suggest urethral obstruction, but specific questions were not asked to clarify this possibility.
THE CONSULTANT'S CHOICE:
We recommend observation while the boy voids and examination of the fresh urine specimen under a microscope.
We do not recommend treatment with an antibiotic unless a UTI has been confirmed. Urethral obstruction and calcium lithiasis with calcium crystalluria might be revealed with ultrasonography and a voiding cystourethrogram, but the presentation is not specific enough for these diagnoses to justify an invasive diagnostic imaging study at this stage in the investigation. A random urine specimen for evaluation of calcium and creatinine levels might help determine whether hypercalciuria is present; this is not an invasive test, but we would not recommend it until UTI--which is the most common cause of urethral dysuria--has been ruled out.
With specific questioning, the boy relates that the discomfort with voiding is localized only to the tip of his penis. He denies any discomfort in the suprapubic, groin, or flank areas. Also, with specific questioning, the boy relates that the discomfort occurs only several times a week, and is usually limited to an isolated void. The discomfort is often noted with his first morning void, and he acknowledges that he does not always void before going to bed. The discomfort is also often noted when he voids with an exceptionally full bladder--such as after he has ingested a full can of soda. Specific questions about his urinary stream reveal that he does not need to wait or push to initiate voiding. He acknowledges that his urinary stream is deflected upward such that he needs to push his penis down to direct the urine into the toilet. He does not know whether his stream is thin or thick but is confident that the stream is strong and continuous to the end.
The boy allowed observation of his urinary stream with voiding. He did not need to wait or push to initiate voiding. The boy pushed the head of his penis down such that the upwardly deflected stream was directed into the center of the toilet. The stream was strong and continuous but thinner than normal.
The fresh urine was centrifuged and the spun specimen revealed 1 to 2 non-dysmorphic RBCs per high-power field. No WBCs, bacteria, or crystals were evident.
THE CONSULTANT'S CHOICE:
We recommend all of the measures cited.
In this boy, discomfort with voiding is likely the result of the passage of a large volume of urine from a full or an overly distended bladder across the relative obstruction caused by mild to moderate meatal stenosis.
Episodes of dysuria might be minimized by avoiding an overly distended bladder with the following measures:
•Voiding regularly during the day and not holding the urine until the last minute.
•Voiding just before bedtime (to avoid an overly distended bladder first thing in the morning).
The average bladder capacity of a 6-year-old is about 8 oz. The child should be instructed to void within an hour of ingesting a full glass or can of soda or any other beverage. When the child voids, he should take his time--and not rush or push. His pants or zipper should be pulled down such that the penis is not bent during voiding.
Definitive treatment requires a meatotomy, which can be performed by a pediatric urologist in the office in an awake child after application of a topical anesthetic. Meatal stenosis, which develops almost exclusively in circumcised boys, is presumed to result from recurrent episodes of meatitis. The meatus of the circumcised penis is subject to recurrent traumatic inflammation as the unprotected glans is compressed against synthetic or cloth diaper material and is subject to chemical inflammation from ammonia and other substances in the urine. Meatal stenosis might also occur subsequent to hypospadias repair or prolonged urethral catheterization, or after other causes of trauma to the urethral meatus.
Classically, meatal stenosis presents with a small circular meatal opening rather than the normal elliptic shape. A web often develops over the dorsal aspect of the meatus and results in a relative obstruction to flow and a urinary stream that is deflected upward. The stream is often narrow and of high velocity. With more severe degrees of obstruction, the child might need to push to begin voiding. Occasionally, the forceful micturition causes the web to tear, with a resultant drop of blood after micturition. Meatal stenosis can be prevented by regular application of a petroleum ointment to the meatus for several weeks after circumcision. *
FOR MORE INFORMATION:
m Persad R, Sharma S, McTavish J, et al. Clinical presentation and pathophysiology of meatal stenosis following circumcision.
Br J Urol.
1995;75:91-93. m Upadhyay V, Hammodat HM, Pease PW. Post circumcision meatal stenosis: 12 years' experience.
N Z Med J.