Differentials
Parapelvic cyst
SIGNS / SYMPTOMS
Usually asymptomatic. May appear similar to hydronephrosis but there is no obstruction present.
INVESTIGATIONS
If a radiologist cannot differentiate on ultrasound, MRI/CT scan with intravenous contrast can define the anatomy and rule out obstruction.
Hydronephrosis of pregnancy
SIGNS / SYMPTOMS
Hydronephrosis is found in 43% to 100% of pregnant women and tends to progress throughout gestation; most patients are clinically asymptomatic.[22]
INVESTIGATIONS
If a patient is asymptomatic, no further testing is indicated.
Renal ultrasonography is indicated if a patient has flank pain, pyelonephritis, or renal failure. Hydronephrosis beyond the level of the pelvic brim is a sign that obstruction from another cause may be present.
Magnetic resonance urography is an option to evaluate the level of obstruction.
Abdominal aortic aneurysm
SIGNS / SYMPTOMS
Haemodynamic instability, personal or family history of abdominal aneurysm, bilateral loin pain; pulsatile mass in the abdomen.
INVESTIGATIONS
CT abdomen/pelvis with contrast will demonstrate aneurysm sac and extravasation of contrast if leaking.
Appendicitis
SIGNS / SYMPTOMS
Focal tenderness over McBurney's point. Patient often prefers to lie still to avoid pain on movement. Gradual onset of symptoms.
INVESTIGATIONS
Diagnosis usually clinical.
CT scan can identify an inflamed appendix.
WBC and CRP often elevated.
Testicular torsion
SIGNS / SYMPTOMS
May present with abdominal pain with associated nausea and vomiting, especially in children or adolescents.
INVESTIGATIONS
Diagnosis usually clinical, can use a clinical risk score; for example, Testicular Workup for Ischaemia and Suspected Torsion. Trans-scrotal ultrasound can confirm diagnosis.
Gynaecological disorders (e.g., ovarian torsion, cyst)
SIGNS / SYMPTOMS
No haematuria; pain may be associated with menses.
INVESTIGATIONS
Perform urine pregnancy test in all females of reproductive age before imaging.
CT scan of the abdomen and pelvis may demonstrate ovarian pathology.
Transvaginal ultrasound is first-choice investigation if a gynaecological cause is more likely than renal colic: may demonstrate ovarian torsion.
Ectopic pregnancy
SIGNS / SYMPTOMS
May be haemodynamically unstable; unilateral abdominal pain more pronounced than loin pain; may have features of peritonitis (e.g., guarding and rebound tenderness).
INVESTIGATIONS
Positive pregnancy test and gestation of about 6 weeks with ectopic pregnancy.
Transvaginal ultrasound reveals ectopic pregnancy, dilation of fallopian tube and free fluid if present.
Renal failure
SIGNS / SYMPTOMS
No lower abdominal pain, no bladder distention; may be pruritic, have nausea or anorexia; may have other systemic illness or recent history of dehydration or fluid loss (e.g., post surgery).
INVESTIGATIONS
Catheterisation: minimal urine.
Urea and creatinine: elevated urea and creatinine.
Bowel obstruction
SIGNS / SYMPTOMS
Bilious vomiting typically associated with small bowel obstruction; severe constipation; previous abdominal surgery or obstructed hernia present. May have concurrent dehydration and acute renal failure.
INVESTIGATIONS
Abdominal x-ray may demonstrate dilated bowel loops.
CT abdomen may show dilated loops of bowel and transition point if mechanical obstruction present.
Use of this content is subject to our disclaimer