A 9-month-old boy is brought to the office by his mother due to fever for 3 days. The patient has been irritable for the past 2 days. He normally drinks 6-oz bottles of expressed breast milk but has been taking 50,000 colony-forming units of Escherichia coli. After completion of the therapeutic antibiotic course, which of the following is the best next step in management of this patient?

Question

A 9-month-old boy is brought to the office by his mother due to fever for 3 days.  The patient has been irritable for the past 2 days.  He normally drinks 6-oz bottles of expressed breast milk but has been taking <3 oz per feed and voiding less frequently than usual.  He has had no rash, cough, congestion, vomiting, or diarrhea.  The patient takes no medications and has no known allergies.  Temperature is 38.9 C (102 F).  He is irritable but easily consoled by his mother.  Mucous membranes are moist, and tears are present with crying.  Tympanic membranes are gray and translucent bilaterally, and the oropharynx is normal.  Cardiopulmonary examination is normal.  The abdomen is soft, nontender, and nondistended.  The penis is uncircumcised.  Urine catheterization is performed and urine dipstick analysis reveals the following:  Oral antibiotics are started, and the patient is afebrile within 36 hours.  Urine culture yields >50,000 colony-forming units of Escherichia coli.  After completion of the therapeutic antibiotic course, which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c0a2_8778_8f63_451d3578fc57_MD0005_00 A urinary tract infection (UTI) is defined by the presence of pyuria (leukocyte esterase on dipstick analysis, white blood cell count of >5/hpf on microscopy) and bacteriuria. Fever without a source in an infant should always raise concern for UTI as infection can quickly ascend to the upper urinary tract. In addition, other clinical features of a UTI may be nonspecific (eg, poor feeding, irritability), and pain can be difficult to assess in nonverbal patients. Risk factors include uncircumcised infant boys and genitourinary abnormalities (eg, vesicoureteral reflux). All children age <24 months with a febrile UTI should undergo renal and bladder ultrasound to evaluate for hydronephrosis and ureteral dilation, which may suggest an underlying anatomic abnormality. Ultrasound should be performed after the acute illness has been treated as renal inflammation during infection can lead to false-positive results. (Choices A and D) Patients with an abnormal ultrasound or recurrent, febrile UTIs should undergo a voiding cystourethrogram (VCUG) in addition to renal ultrasound. VCUG can identify vesicoureteral reflux, which often requires treatment with prophylactic antibiotics. Neither VCUG nor prophylactic antibiotics are indicated for a patient with a single uncomplicated UTI. (Choice B) Children age >2 with an isolated UTI do not require imaging if treatment results in clinical resolution of symptoms. This infant has a higher risk of genitourinary tract abnormalities than an older child and should undergo renal and bladder ultrasound. (Choice E) Uncircumcised boys have an increased risk of UTI during infancy compared with circumcised boys. However, overall rates of UTI are still very low, and identification of potential urinary tract defects with renal ultrasound should be prioritized over consideration of circumcision. Educational objective: After a first-time febrile urinary tract infection, children age <24 months should undergo renal and bladder ultrasound to evaluate for anatomic abnormalities. Those with recurrent infections or abnormal ultrasound findings should also undergo a voiding cystourethrogram. References: Urinary tract infection: clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months. (http://www.ncbi.nlm.nih.gov/pubmed/21873693)

A 9-Month-Old Boy Is Brought to the Office by His