Uric Acid Nephrolithiasis -in a nutshell

ByDr. Khalid Shakeel Babar (KSB)

KIDNEY STONE TYPES

MAJOR RISK FACTORS FOR UA STONES

•Low Urine Volume•Hyperuricosuria

•Low Urinary pH

•High Serum Uric Acid Level

H+

Urate

Uric

AcidpH

lighter heavier

MECHANISMS FOR URIC ACID STONES

Dietary Ingestion

De Novo Purine Synthesis

Decrease in Elimination

PURINE RICH FOODS

PREDISPOSING CONDITIONS

Gout Uricosuric Drugs Uric Acid Overproduction Chronic Diarrhea DM and Metabolic Syndrome

PRESENTATION

1. PAIN IN MOST OF THE CASES

“RENAL COLIC” IF SEVERE AND ACUTE

A) KIDNEY STONE

FIXED PAIN IN THE LOIN

B) URETERIC STONE

PAIN RADIATES ® LOIN TO GROIN

C) BLADDER STONE

PAIN WITH LUTS

Both Stomach & Kidney supplied by celiac ganglion hence Nausea & vomiting common in renal colic

HISTORY

A. IS PATIENT DRINKING ENOUGH WATER?

B. PROFESSION

C. ENQUIRE ABOUT UTI ® STONES

D. FAMILY HISTORY

E. LONG ILLNESS ® BEDRIDDEN ®

STONES

ON EXAMINATION

1. ACUTE PRESENTATION

ABDOMEN TENSE AND RIGID

TENDERNESS PRESENT IN THE LOIN

Renal Punch positive

2. IN ROUTINE PRESENTATION

NO FINDINGS IN ABDOMEN

INVESTIGATIONS

1. FULL BLOOD COUNT

2. Abdominal Ultrasound

3. URINE R/E

INVESTIGATIONS (CONT...)

4. KUB Xray

5. Stone Analysis

6. Serum Uric acid,

Blood urea and serum creatinine

7. 24 hour urine for uric acid

INVESTIGATIONS (CONT...)

8. IVU OR IVP (INTRA VENOUS

UROGRAM)

9. CT Scan

10. Renogram (DMSA / DTPA / MAG3)

TREATMENT

Alkalinization of urine Increased fluid intake Xanthine oxidase inhibiters ( if 24hr

urinary uric acid excretion more than 6 mmol/day)

Dietary restriction of purine rich foods.

DDS

Renal Pyelonephritis. Obstruction of the ureter due to other

causes (such as a blood clot, stricture, papillary necrosis, or urothelial tumour).

Acute renal infarction. Renal rupture. Renal abscess (very rare, and in the UK

usually secondary to stones).

DDS

Gynaecological Ectopic pregnancy. Endometriosis. Ovarian cyst: rupture or torsion. Pelvic inflammatory disease. Salpingitis.

DDS

Gastrointestinal Appendicitis. Diverticulitis. Biliary colic. Bowel obstruction. Bowel ischaemia. Crohn's diseaseOthersAAA

PROGNOSIS

Mortality and morbidity are not increased with uric acid stones compared with other stones; however, the process that leads to excess uric acid production (eg, malignancy, Lesch-Nyhan syndrome) may cause death.

RECURRENCE

Restrict purine rich diet to reduce recurrence.

Repeat Urine pH, serum uric acid, abdominal ultrasound and CT scan for recurrence.

STONES IN PREGNANCY

Rare event Normal physiology of pregnancy Factors favoring stones in pregnancy Most stones appear to be

predominantly composed of calcium phosphate

DIAGNOSIS

Renal and pelvic ultrasound Transvaginal and doppler ultrasoundIf further diagnosis is required

MR urography Low dose CT. limited intravenous pyelogram (IVP)

TREATMENT

Most (75 to 85 percent) stones pass spontaneously

Decompression of the kidney with placement of a ureteral stent percutaneous nephrostomy tube, ureteroscopy to remove the stone may be

required in the patient who is septic, has persistent severe pain, or has persistent obstruction.

shock wave lithotripsy use during pregnancy is contraindicated

CASE PRESENTATION Presentation:On 17th November, 2012, 8:00 AM26 year old boy presented withSevere Radiating Right Lumbar PainAssociated with nausea and vomiting.On examination: Renal Punch +ve on Right Side.Ultrasound Abdomen Report: Normal exceptRight Kidney shows minimal hydronephrosis with

dilated proximal ureter raises the suspicion of distal ureteric obstruction.

Urine R/E Report: Normal , except Urine pH 5.0KUB xray: Normal, No stone seen.

Initially managed with Inj. Diclofenac Sodium i/mInj. Spasfan i/mInj. Gravinate i/v After the pain was relieved patient was

asked detailed history, he told about Family history of stones.

Serum uric acid level advised and it was 7.8 mg/dl (normal range 3.5 – 7.2).

Patient started on conservative treatment

Alkalinization of urine Increased fluid intake24hr urinary uric acid excretion test doneIt was less than 6mmol/day, so patient

did not start Xanthine oxidase inhibiters.

Video

Special Thanks to Dr. Kamran sahib for solving all my queries regarding stones and immensely helping me in preparing presentation.

Thanks to Dr. Qais Falah and Prof; Dr. Zahid Ahmed Hashmi for encouragement and help.