Answer

The answer is b. The patient’s history and physical examination are consistent with a diagnosis of neurofibromatosis (von Recklinghausen disease). The diagnosis of neurofibromatosis is made on the basis of the history and physical examination findings of at least two of the following:

Hypertension in these patients is usually secondary to renal artery stenosis, which can occur because of extrinsic compression of the renal artery, vascular neurofibroma formation, or aneurysmal dilation; and can occur at any age. Coarctation of the abdominal aorta may be associated with neurofibromatosis as well as other conditions such as tuberous sclerosis, William syndrome, or other vasculitic disorders. However, coarctation of the thoracic aorta is not a typical finding of neurofibromatosis, but
can occur in other conditions such as Turner syndrome. Additionally, pheochromocytomas have been associated with neurofibromatosis but this is seen much more frequently in adults, whereas pediatric patients with neurofibromatosis more commonly have renal artery stenosis. Urinary tract infections generally do not cause hypertension. Renal dysplasia may be associated with hypertension; however, the presenting signs are usually those of failure to thrive.

Answer

The answer is c. This patient presents with nephrotic syndrome as defined by edema, hypoalbuminemia, and proteinuria. The most common etiology in children is minimal change disease, which has a peak incidence in preschool children. Boys are more affected than girls in this age group. Clinical presentation includes generalized edema, often preceded by an infection. Laboratory evaluation will reveal proteinuria, hypoalbuminemia, and hypercholesterolemia. A hypercoagulable state because of derangement in anticoagulant proteins also occurs. In nephrotic syndrome caused by minimal change disease, the serum complement levels are normal.

Management of newly diagnosed nephrotic syndrome clinically consistent with minimal change disease demographically involves a trial of oral prednisone therapy. To induce initial remission, a dosage of 60 mg/m²per day is prescribed with a maximum dose of 80 mg/day. Although 80% of patients will respond within the first 2 weeks of therapy, a 4- to 6-week trial is given before the patient is declared steroid resistant. If the patient is found to be steroid resistant, a renal biopsy should be performed to determine a diagnosis and therapy altered on the basis of the diagnosis.

Although nephrotic patients are at higher risk of developing infections, especially due to Streptococcus pneumoniae, prophylactic antibiotics are not recommended at this time. These patients should, however, be immunized using the polyvalent pneumococcal vaccines. Patients with nephrotic syndrome have total body volume overload resulting from interstitial edema as a result of the hypoalbuminemia. Treatment with intravenous fluids may result in further third spacing and worsening of the nephrotic state. If the patient exhibits signs of intravascular volume depletion, replacement using colloid replacement solution (i.e., albumin infusion therapy) should be considered.

Answer

The answer is d. This patient presents with unilateral cystic disease. The diagnosis is consistent with a multicystic dysplastic kidney. The dysplastic kidney consists of a group of cysts with a small amount of connective tissue present without the presence of identifiable renal parenchyma. Cystic dysplasia may result from congenital obstructive abnormalities. The contralateral kidney may be enlarged to compensate for the multicystic dysplastic kidney; however, the parenchyma should appear and function normally. With time, the dysplastic kidney involutes and its function deteriorates. The management includes postnatal renal ultrasonography to confirm the diagnosis. Approximately 40% of patients have contralateral vesicoureteral reflux; therefore, a voiding cystourethrogram may be warranted. These patients should be followed up with ultrasound monitoring. The affected kidney need not be removed unless recurrent urinary tract infections or hypertension develop.

Autosomal-dominant polycystic kidney disease (ADPKD) and autosomal-recessive polycystic kidney disease (ARPKD) are genetic defects that cause cyst formation within the kidneys without dysplasia. The defect causes bilateral renal involvement. The management and prognoses vary depending upon clinical features.

Answer

The answer is b. On the basis of the American Academy of Pediatrics guidelines, all the children between 2 months and 2 years of age presenting with a first-time febrile urinary tract infection should undergo a screening renal ultrasonography and voiding cystourethrogram to evaluate for the presence of vesicoureteral reflux.

Recurrent urinary tract infections in the presence of vesicoureteral reflux may lead to renal scarring and eventually chronic renal failure, and as such, should be avoided. In the presence of reflux, children should be placed on once-daily prophylactic antibiotics, preferable at bedtime. Acceptable antibiotic choices include trimethoprim-sulfamethoxazole, nitrofurantoin, or amoxicillin. Quarterly urine cultures should be performed routinely, as well as during times of urinary infection symptoms or unexplained fevers. Annual cystograms should be performed. After the first voiding cystourethrogram, reevaluations can be performed using radionucleotide cystograms to decrease the risk of radiation exposure.

No absolute data define the resolution rates based on grade; however, large retrospective studies show that grades I to III of reflux often resolve. Of those cases of reflux that resolve, approximately 80% resolve within 5 years of diagnosis. Furthermore, approximately 80% of all cases of grades I to II reflux resolve spontaneously, as compared with 60% of those with grade III reflux, and 40% of those with grade IV reflux. Surgical intervention should be considered in children who have breakthrough infections, have high-grade reflux (IV or V) and evidence of renal scars, or children older than 6 year of age with persistent high-grade reflux.

Answer

The answer is d. Congenital nephrotic syndrome is an inherited disorder involving a defect in chromosome 19, NPHS1, which encodes for nephrin. This defect causes a disruption of the glomerular capillary filter. The result is loss of protein in the urine, initially albuminuria; however, because of the severity of proteinuria, losses of immunoglobulin, antithrombin III, vitamin D-binding protein, and thyroid-binding globulin occur. These children are often born prematurely, are below the fifth percentile for weight (with normal birth lengths), and the placenta is enlarged (comprising at least 25% of the birth weight). Approximately 90% of these children present with generalized edema within the first week of life. Progressive protein loss results in malnutrition, hypothyroidism, a markedly increased susceptibility to infections, and hypercoagulable state. Progressive renal failure also occurs, with most patients requiring dialysis or renal transplantation within the first decade of life. Because of a kwashiorkor state, these patients require aggressive nutrition therapy to achieve normal growth and development. Because of high protein losses, these patients often require daily albumin infusion therapy. In many cases, medical or surgical nephrectomy may be indicated to decrease the degree of proteinuria. Supplementation with thyroxine is required, often from birth, with adjustments for growth. The major cause of early death is sepsis. Most patients who survive for the first 12 months undergo renal transplantation. The major barrier is to overcome the nutritional deficiencies and achieve a dry weight that allows for a renal transplant to be performed. Many of the patients who have had transplantation have undergone unilateral or bilateral nephrectomies in order to limit protein losses and allow for more normal growth. Recurrent disease in the transplant has been reported but is a rare phenomenon.