Oliguria and anuria

definition and describtion of anuria and oliguria

1. Oliguria & Anuria

2. Oliguria The normal range of urine output is 800 to 2,000 milliliters per day if you have a normal fluid intake of about 2 liters per day. Oliguria is U.O. < 1 mL/kg/h in infants < 0.5 mL/ kg/h in children < 300 mL daily in adults Oliguria is not a clinical diagnosis but a sign that indicates an underlying disorder. Oliguria if left untreated oliguria may lead to acute renal failure and its sequelae , including hyperkalaemia , acidosis, and fluid overload.

3. Anuria Anuria is the production of urine less than 50 ml / day. There are numerous causes for anuria, such as renal impairment, urinary tract obstruction (kidney stones), pharmaceutical agents or severe infections (septicemia). Anuria is a symptom, not a disease . The patient often complains about weakness, fatigue, lack of appetite, vomiting tendency and dyspnea.

4. Causes : 1. prerenal

5. Post renal (obstructive): Calculi: the most common cause leading to anuria Pelvic malignancy: carcinomas arising from the bladder, prostate, cervix, ovary or rectum can all lead to obstruction of one or both ureters Surgery: ureters are vulnerable to damage during pelvic and retroperitoneal surgery Bilharzia : lead to ureteric fibrosis and stenosis Crystalluria: causing urinary tract obstruction used to be associated with sulphonamides .

6. Oliguria

7. Things you should keep in mind: Age of the patient. The nature of onset. Recent drinking habit .

8. Bladder neoplasm BPH Flank pain Fever, chills, tenderness pyelonephritis No fever, chills, tenderness Bladder neoplasm Calculi Discharge No discharge Urethral stricture Calculi

9. If there is history of water loss or hypovolemia oliguria Signs of heart failure diarrhea & vomiting History of trauma, shock, bleeding burns AKI Cholera Sunken eye Poor skin turgor Dry mucus membrane Those causes share common things including: 1- signs of hyperkalemia (weakness, cardiac arrhythmia) 2- features of uremia (anorexia, confusion, lethargy, twitching, seizures, pruritis , kussmaul’s respiration)

10. Postoperative oliguria The comments cause of oliguria postoperatively is reduced renal perfusion resulting from perioperative hypotension or inadequate fluid replacement. If untreated, acute renal failure may develop. Renal failure may progress through three recognizable phases: 1. oliguria 2. diuretic phase 3. recovery

11. Common causes of acute renal failure:

12. Management of Oliguria

13. Mx of Oliguria…. Pre-renal Volume challenge (i.e. 500mL NS for 30 mins) Monitor volume replacement to ensure circulatory adequacy (i.e. use arterial and R. heart catheters to measure CVP to be above 10mmHg) Follow hourly urine output (w a catheter in place) Consider additional measures (some doctors may disagree with this) Frusemide (but usually reserved for fluid overload)

14. Renal causes Consider frusemide and mannitol Emergency dialysis in the following: – Severe hypovolemia unresponsive to diuretics – Intractable acidosis – Severe hyperkalemia – Pericarditis secondary to uremia – Severe uremic symptoms or encephalopathy Post Renal causes Place a catheter, if immediate flow starts then urethral obstruction is very likely If catheter already present, replace or irrigate it as it could be obstructed Consult a urologist

15. Urinalysis high specific gravity suggests volume depletion large amounts of protein or red cell casts suggests glomerular disease significant hematuria (renal embolization or stones) WBC casts (infection or sever inflammation) Frequent granular casts (acute tubular necrosis)

16. The following studies are indicated 1-Midstream specimen of urine (MSU) dipstick 2-Blood urea nitrogen and serum creatinine 3-Serum sodium 4-Serum potassium 5- Urinary index 6-Complete blood count

17. Midstream specimen of urine (MSU) dipstick: Prerenal : There are few hyaline and fine granular casts. There is little protein, haemoglobin or red cells .

18. Serum creatinine: compare blood urea and creatinine if ratio >10:1, prerenal cause is likely but could also be obstruction , GI bleeding, severe catabolic states If ratio <10:1 renal cause is likely