Nonobstructive Hydronephrosis Due to Social Polydipsia

A Case Report

Natallia Maroz; Uladzimir Maroz; Saima Iqbal; Ravi Aiyer; Ganesh Kambhampati; A A Ejaz


J Med Case Reports. 2012;6(376) 

In This Article

Case Presentation

A 53-year-old African-American female medical assistant with a past medical history of asthma, diabetes mellitus for two years and a hysterectomy was referred to our nephrology clinic for a second opinion regarding persistent bilateral hydronephrosis. Her family history did not include nephrogenic or central diabetes mellitus or malignancies. Twelve months prior to the renal consultation, our patient presented to the emergency department with mild-to-moderate bilateral flank pain without fever, chills, dysuria, difficulty urinating or hematuria. Her blood and urine chemistry and a complete blood count tests yielded normal results (Table 1). Abdominal computed tomography (CT) revealed the presence of moderate bilateral hydronephrosis and hydroureter (Figure 1A). Given the normal laboratory findings for renal function and good urine output at home and in the emergency department, she was discharged with symptomatic treatment and a referral to a local urologist for further evaluation. Her only prescription medication was 50mg of sitagliptin daily.

Figure 1.

Time course of hydronephrosis. (A) Abdominal computed tomography. Initial presentation; mild to moderate bilateral hydronephrosis. (B) Abdominal computed tomography. Persistent hydronephrosis despite ureteral stent placement in right kidney. (C) Abdominal computed tomography. Persistent hydronephrosis after exploratory laparoscopy and right oophorectomy. (D) Ultrasound of right kidney. (D1) Mild hydronephrosis prior to reduction of fluid intake. (D2) Resolution of hydronephrosis after fluid intake reduction.

After a delay of six months for health insurance issues, a repeat CT and intravenous pyelogram were performed by our patient's urologist that confirmed persistent, moderate hydronephrosis on her right side, and mild hydronephrosis on her left side. Despite a lack of any anatomical abnormality evident by cystoscopy, a right ureteral stent was inserted (Figure 1B). The discomfort in our patient's flank pain persisted; a repeat abdominal CT performed two months later did not show resolution or improvement of the hydronephrosis, and the ureteral stent was removed. She was then evaluated by a gynecologist and underwent exploratory laparoscopy with lysis of adhesions and a right oophorectomy. Another abdominal CT, performed a month after the exploratory laparoscopy, failed to show any improvement in the degree of bilateral hydronephrosis (Figure 1C). Our patient was then referred to an academic medical center for a second opinion regarding persistent bilateral hydronephrosis.

Our patient complained only of intermittent, mild, bilateral flank pain that was unrelated to physical activity, but sometimes related to fluid intake. She reported drinking 4.5L to 5.5L of fluid daily for the last three years, stating that 'all (her) friends do so to stay healthy.' Her physical examination revealed the following: blood pressure, 136/90mmHg; heart rate, 87 beats per minute; temperature, 36.9°C; height, 165cm; weight, 8.7kg; body mass index, 29.61kg/m2; normal heart and lung examination results; no organomegaly or tenderness on abdominal examination; no suprapubic fullness; mild right costovertebral angle tenderness with percussion; no extremity edema; and normal musculoskeletal and neurological examination results. Her laboratory data is presented in Table 1. A renal ultrasound revealed bilateral moderate hydronephrosis with normal echogenicity of the parenchyma (Figure 1D1).

Based on her history, her laboratory and imaging study results, and previous evaluation, our patient was suspected to have nonobstructive fullness in the urine excretory system as a result of a mismatch of its capacity to produce excessive urine volume. She was advised to decrease her fluid intake to less than 2L/day. A mercaptoacetyltriglycine (MAG-3) nuclear renogram with furosemide (Lasix) showed prompt bilateral excretion with no evidence of any obstruction. A repeat renal ultrasonography after six weeks showed normal-sized kidneys and complete resolution of the hydronephrosis (Figure 1D2). Our patient was discharged from the nephrology clinic with recommendations to drink according to her thirst and follow-up with her local physician.