Approach to a patient with oliguria

  • Oliguria is defined as a decrease in urine production below the minimal acceptable rate of 1 to 2 ml/kg/hr.
  • Oliguria can occur as a normal physiologic response or as a manifestation of pathology within the renal system.
  • Differentiating between physiologic and pathologic oliguria is essential to making appropriate clinical decisions and assessing the severity of disease.
  • Physiologic oliguria is usually characterized by a high urine specific gravity and maximal reabsorption of urine sodium.
  • Pathologic oliguria resulting from renal failure is characterized by an inappropriately isosthenuric urine and an increase in fractional excretion of sodium.
  • Pathologic oliguria usually is seen with severe renal impairment but also can be seen when urine cannot be eliminated from the body.

CAUSES OF OLIGURIA

  • Pre Renal:
    • Dehydration
    • Hemorrhage
    • Sepsis
    • Hypoalbuminemia
    • Cardiac failure
  • Intrinsic renal
    • Glomerulonephritis
      • Post infectious/Post streptococcal
      • Lupus erythematosis
      • HSP
      • Membranoproliferative
      • Anti–Glomerular basement membrane
    • HUS
    • Acute tubular necrosis
    • Renal vein thrombosis
    • Rhabdomyolysis
    • Tumor lysis syndrome
  • Post Renal
    • Posterior urethral valve
    • Uretero pelvic junction obstruction (10% B/L)
    • Ureterovesical junction obstruction (B/L)
    • Ectopic ureterocele causing bladder outlet obstruction
    • Tumor (rhabdomyosarcoma)
    • Urolithiasis (Vesicle calculi, B/L ureteral calculi)
    • Neurogenic bladder (Spina bifida, trauma or tumor of spinal cord)

History

  • Onset and duration:
    • Sudden onset: Snake bite, trauma
    • Acute: AGE,HUS, AGN, obstruction, HSP
  • Age/sex: Post Strep AGN ( 5-12 yrs), HUS ( <4yrs) HSP ( 2- 8yrs Male>female), NS (2-6 yr Male 2x>female)SLE adolescent femalesObstruction PUV in males, PUJ (M2x>F), Ureterocele (F>M)
  • Asses urine output, number of times passed in last 24 hr
  • App oral intake last 24 hr
  • Associated symptoms
    • Diarrhea : AGE, HSP, SLE, HUS (preceding), RVT
    • Vomiting: AGE, HUS
    • Bleeding from any site: Good Pastures syndrome, Sepsis, DIC
    • H/O trauma (rhabdomyolysis), hemorrhage, burns
    • Pain abdomen: HSP, HUS, Ureteric calculi, Renal vein thrombosis (flank pain), SLE
    • Fever: AGN, Sepsis, SLE, HSP, HUS, infections (leptospirosis, malaria)
    • Swelling: AGN, NS, ARF, HSP (dependent parts)
    • Rash over body :HSP, HUS, SLE, AGN
    • Joint pains: SLE, HBV, HSP
    • Icterus: HBV, leptospirosis, Malaria
    • Pallor: HUS, hemorrhage
    • Red urine: AGN, malignancy, calculi, Alport, IgA nephropathy
    • Drug ingestion: diuretics, methotraxate, anticholinergic/ exposure snake bite
  • R/O Complications
    • SOB: Fluid over load, HTN, CCF
    • Pedal edema: AGN, NS, ARF
    • Abd distention: NS, AGN, CCF
    • Headache, visual disturbance, epistaxsis: ↑BP
    • Altered sensoruim
    • Seizures: Dyselectrolytemia, ↑BP, uremia, meningitis, thrombotic event (Nephrotic Syndrome, HUS)
  • Past history
    • Recent URTI/ AGE: HUS, HSP
    • Skin infection, sore throat: AGN, Hemoptysis (Good pastures disease, SLE, HSP)
  • Treatment history: NS (Steroid Toxicity, indication for biopsy), Nephrotoxic drug received or not.
  • Family History: Similar complaints infections, Hereditary disorders :- deficiency of factor v leiden, SLE, Alports syndrome, IgA nephropathy
  • Dietary history: AGE, Cereal diet without milk (vesicle calculi)
  • Contact history: Contact with animal (leptospirosis, mosquito bite:- malaria)

General physical examination

VITALS:
Pulse: Rapid weak and feeble pulse in hemorrhage
Sepsis : rapid bounding pulse
RR: Deep and rapid: acidotic in ARF
Temp: with fever, hemorrhage. in sepsis
BP: in AGN, ARF. in hemorrhage , sepsis, shock
Anthropometry: wasting and stunting in Acute on chronic RF, increased weight gain in AGN with edema
Icterus: HBV, Leptospirosis, Malaria
Pallor: ARF, HUS, SLE, Malignancy, Malaria
Cyanosis: CCF, Subglottic obstruction- post strep AGN
LNP: SLE, HSP, leptospirosis, pyoderma, Malignancy
Pedal edema: CCF
Increased JVP: CCF

Specific examination:

  • Abdomen:
    • Distended ( ascitis : CCF, AGN, NS)
    • Hepatomegaly: CCF (tender), Hepatitis (tender), leptospirosis, SLE, HUS
    • Splenomegaly: Malaria, leptospirosis, HUS
    • Flank mass : RVT, HUS, Uretero pelvic junction obstruction, Tumor, hematoma, abscess
  • CVS: Gallop rhythm, Locate apex beat (CCF, cardiomyopathy)
  • Chest: Wheeze or crepts , pulmonary edema in CCF
  • CNS: Focal (Thrombosis, hemorrhage) or general neurological signs.
  • Ophthalmoscopy: Hypertensive retinopathy, Alports syndrome ( anterior lenticonus)
  • Hearing examination : Alports syndrome

INVESTIGATION

  • CBC
    • Hb decrease: Hemorrhage, Hemolysis (HUS, SLE, Malaria, RVT), dilutional ARF, Tumor, HSP (malena), Sepsis
    • Platelet decrease: HUS, RVT, Bacterial sepsis, SLE. Mod increased in HSP
    • P/S: Microangiopathic hemolytic anemia: HUS, RVT, DIC
  • ASO titer: ↑post strep AGN, SLE
  • AntiDNAse B: post strep AGN
  • C3: Decreased in post strep AGN, SLE, membranoproliferative GN
  • Serum electrolytes: Na, K, Ca
  • Blood Urea
  • Serum Creatinine
  • URE
    • RBC : AGN, nephrocalcinosis, Alports disease.
    • WBC: UTI, AGN
    • RBC casts : AGN, SLE, IgA nephropathy
    • WBC casts: UTI, SLE

Differentiating pre and post renal ARF

IndexPre renalIntrinsic renal
Specific gravity> 1.020< 1.010
Urinary osmolality>500<350
UNa <20>40
FENa<1>2
BUN/Cr>20<20

  • Chest Xray: Cardiomegaly, features of pulmonary edema
  • ECG: Evidence of Hyperkalemia, Cardiomyopathy
  • Plain Xray abdomen: radio opaque calculi (Struvite stones)
  • CT/MRI: Spinal cord tumor, MS, Ureteral calculus
  • USG abd: Renal size
    • ARF normal/↑ size (hydronephrosis, RVT, cystic disease, tumor, AGN)
    • Acute on Chronic renal failure: small contracted kidney.
USG Abd: Structural anomaly, Dilatation of urinary tract, Calculi, Tumor. Other abdominal organs, lymphadenopathy, tumor
  • Obstructive lesions: VCUG, IVP, DTPA (diethylene tetra pentaacetic acid)

Management

General Management
  • Vitals maintenance: ABCD
    • Fluid support in dehydration
    • Blood transfusion in hemorrhage, blood products in sepsis
    • Dopermine : ARF, Sepsis
    • Maintain electrolyte balance, treat complication
    • Dialysis as indicated
    • Control BP

Indications of dialysis in ARF

  • Volume overload with evidence of hypertension and/or pulmonary edema refractory to diuretic therapy
  • Persistent hyperkalemia (k+> 6.5meq/l; k+>5.5 – 6.5 with ECG changes
  • Severe metabolic acidosis (pH<7.2) unresponsive to medical management, or NaHCO3 administration not feasible due to volume overload
  • Neurological symptoms (altered mental status, seizures)
  • BUN > 100–150 mg/dl or lower if rapidly raising
  • Calcium/phosphorus imbalance , with hypocalcemic tetany
  • Hyponatremia Na+ < 120 – 125 especially if symptomatic
  • Hypercatabolic state; marked tissue injury, crush syndrome, burns, sepsis
  • Inability to provide adequate nutritional intake because of severe fluid restriction

Decreased urine output

No signs of fluid over load or CCF
Intravenous fluid (Isotonic saline 20ml/kg over 30 min, may repeat as required)
Furosemide 3-4ml/kg after 2hrs with urine output <1ml/kg/hr. with no evidence of intravascular volume deficit.
If not passed urine go for fluid restriction, 400ml/m2/day with estimated urine output for the day

Indications of kidney biopsy

  • Steroid resistant NS
  • ARF of unknown cause
  • Rapidly progressive ARF
  • Systemic renal disease
  • Inherited nephropathies
  • Renal allograft dysfunction
  • AGN with
    • ARF
    • Nephrotic syndrome
    • Absence of evidence of streptococcal infection
    • Persistent hematuria and proteinuria
    • Decreased C3 level persisting for more than 2months
  • Nephrotic syndrome with
    • unexplained hematuria and proteinuria, HTN
    • age <1yr, >8yr
    • Hypocomplemantemia
    • Renal insufficiency

Specific management:

  • Antibiotics for sepsis and infection
  • Vasculitis: steroids
  • SLE : Steroids
  • Obstruction: Catheterization
    • PUJ obstruction: Pyeloplasty
    • PUV: Surgical ablation
    • Ureterocele: Excision of ureterocele and ureteral reimplantation
    • Vesical calculi (suprapubic cystolithotomy)
  • Neurogenic bladder: Catheterization, Anticholinergic agents (Oxybutynin)


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