Pyonephrosis: hydronephrosis with dirty echoes

Question 1A patient with a ureteric stone has a temperature of 39°C, a low blood pressure and hydronephrosis with layering debris. What is the priority after resuscitation and antibiotics?

1. aAdmission for oral antibiotics and a repeat scan in a week
2. bA trial of medical expulsive therapy
3. cUrgent urology referral for decompression of the kidney
4. dDischarge with a urology clinic appointment

Question 2Which ultrasound finding suggests pyonephrosis rather than simple hydronephrosis?

1. aUreteric jets seen in the bladder
2. bA normal-sized kidney with no dilatation
3. cBlack, branching calyces connected to the renal pelvis
4. dA fluid-debris level in the dilated collecting system

Question 3How do you check that echoes inside the collecting system are real?

1. aMeasure the renal length
2. bReduce the gain, use harmonics and see whether the echoes move when the patient rolls
3. cIncrease the gain until the echoes are bright
4. dSwitch to the high-frequency linear probe

Question 4A febrile patient has moderate hydronephrosis with clear, anechoic fluid. What does this tell you?

1. aIt does not exclude an infected, obstructed kidney
2. bIt means the cause is a parapelvic cyst
3. cIt excludes pyonephrosis
4. dIt proves the obstruction has resolved

Question 5Why are antibiotics alone not enough for pyonephrosis?

1. aPyonephrosis is a viral infection
2. bAntibiotics cannot be given intravenously in renal failure
3. cThe obstruction traps pus in the collecting system, so it needs drainage
4. dThe bacteria are always resistant to standard antibiotics