**2.1.2 Intrinsic causes**

The common intrinsic causes are from intraluminal obstructions such as nephrolithiasis / ureterolithiasis, papillary necrosis, blood clot, fungal ball and urethral strictures.

#### **Extrinsic causes** : Genitourinary system

264 Chronic Kidney Disease

Fig. 4. Percutaneous nephrostomy at upper calyx due to complete upper ureteral obstruction

The peak incidence of urinary tract obstruction in males is in the eighth and ninth decades secondary to benign prostatic hyperplasia and prostatic carcinoma, whereas the peak incidence in females is in the fourth to six decades secondary to pregnancy and carcinoma of

The etiology of urinary tract obstruction can be divided into intrinsic and extrinsic causes.

Extrinsic causes of urinary tract obstruction are the diseases of genitourinary system, gastrointestinal system, vascular system, retroperitoneal pathology and biologic agents such

The common causes of extrinsic processes are tumor of the kidney, ureter and bladder and other gastrointestinal pathologies such as Crohn's disease, appendicitis and diverticulitis.

The common intrinsic causes are from intraluminal obstructions such as nephrolithiasis /

ureterolithiasis, papillary necrosis, blood clot, fungal ball and urethral strictures.

from previous surgery. (single kidney)

the cervix or uterus. (Gulmi et al., 1998)

**2.1 Etiology of urinary tract obstruction** 

as actinomycosis. (Curhan & Zeidel, 1996)

**2. Urinary tract obstruction** 

(Table 2)

**2.1.1 Extrinsic causes** 

**2.1.2 Intrinsic causes** 


Table 2. Common etiologies of urinary tract obstruction.
