The symptoms and signs of childhood renal disorders vary widely.
Diagnostic clues are provided from the history, which should include
a description of the amount, frequency, and color of the urine.
Changes in any of these may herald a renal disease. The presence
of symptoms such as pain on urination (dysuria), urgency (difficulty
holding urine in the bladder), incontinence, or dribbling of the
urinary stream in boys are also helpful. Pain is not typical of
most renal diseases. However, flank pain is common with renal stones
and pyelonephritis. Pain from renal stones is excruciating and often
radiates from the flank toward the groin. Loin pain may occur with
acute glomerulonephritis. Recurrent episodes of dehydration occur
in disorders that affect water reabsorption or sodium retention such
as tubular disorders, obstructive uropathy, and renal dysplasia.
A history of maternal oligohydramnios suggests that in utero renal function
was impaired. The family history is sometimes informative, especially
in children with heritable kidney disorders such as Alport syndrome,
hypercalciuria, cystinosis, and polycystic kidney.
Renal disorders also may present with more insidious symptoms
or signs. Chronic renal failure commonly presents with nonspecific
symptoms such as fatigue, sleep disturbances, headaches, nausea,
and anorexia. Children with severe hypertension (frequently related
to renal disorders) can present with seizures and changes in mental
status (see Chapter 479). Anemia may occur
due to a lack of erythropoietin production by the kidney.
Physical findings of hypertension and edema are common with renal
disorders. Periorbital or dependent edema is often an early symptom. The
presence of an abdominal mass or genital abnormalities may suggest
a renal disease. The kidneys are easily palpated in the first week
of life, and renal abnormalities such as multicystic dysplasia,
hydronephrosis, and agenesis can be detected by abdominal palpation.
Urinalysis is one of the most useful procedures in evaluating
patients who have suspected renal disease.1 However, some
abnormalities on urinalysis are transient; therefore, repeated urinalyses
is often useful to avoid more extensive and expensive evaluation.
The most informative urine to examine is the first morning specimen,
as this often is the most concentrated and acidified, and possible
increases in urine protein associated with an upright posture will
be minimized. Unfortunately, the practical aspects of collecting
first-morning urine often delays the time between urine collection
and examination. When obtaining a urine culture, the external genitalia
should be cleansed, especially in girls, to minimize contamination
by extraneous material, such as vaginal cells. The choice of cleansing
agent is important. Betadine may interfere with the dipstick reagents,
so the usual recommended agent is benzalkonium. Female patients
should be instructed to wipe front to back, to spread the labia
while voiding, and to collect the urine after some has been passed
to minimize bacterial contamination. Sitting backward on a standard
toilet is helpful in keeping the labia separated. Males should be
instructed to retract the foreskin and clean ...