BASIC OUTLINE

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ACUTE RENAL FAILURE IN PREGNANCY

• BASIC OUTLINE
• Investigations
• MANAGEMENT PRINCIPLES
• Prerenal Vs ATN Vs ACN
• ROLE OF Nutrition
• Volume metabolic control
• Diuretics helpful or harmful
  ??
• Dopamine helpful or harmful
  ??
• Dialysis when which ??
• Renal biopsy ??
• Delivery
• Conditions specific to pregnancy

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DEFINITIONS OF ARF

• The syndrome is characterised by a sudden in
  parenchymal function (UOPlt400ml/d30ml/hr) which
  is usually but not always reversible
• This produces disturbance of water, electrolyte,
  acid base balance and nitrogenous waste products
  blood pressure.

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Normal Physiologic Alterations of Pregnancy
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Physiological changes in normal gestation

• Kidney weight and size increase
• Dilation of renal calyces, pelves, and ureters
• Urinary stasis
• Glomerular filtration, effective renal plasma
  flow, fractional clearance of urate increase
• Bicarbonate reabsorption threshold decreases

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Clinical relevance

• Concentrations of serum creatinine, urea N, and
  uric acid of 0.9, 14, and 5.6 mg/dl, normal in
  nonpregnant subjects, are already suspiciously
  high in gravid women.
• Asymptomatic bacteriuria - frank pyelonephritis.
• PP reduction in size should not be mistaken for
  parenchymal loss
• Post renal failure difficult to diagnose
• S.bicarb lower,PCO2 10 mmHg lower

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Causes Early in Pregnancy

• Most common cause is pre-renal failure due to
  hyperemesis gravidarum
• ATN due to septic abortion

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Causes - ARF Late in Pregnancy/Postpartum

• Thrombotic microangiopathy
• TTP-HUS
• Severe preeclampsia usually with HELLP syndrome
• Renal Cortical Necrosis
• Placenta previa
• Prolonged intrauterine fetal death
• Amniotic fluid embolism
• Intrinsic renal disease/autoimmune diseaes

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ARF Late in Pregnancy/Postpartum

• Acute pyelonephritis
• ATN from septicemia or hypotension
• ARF from microabscesses
• Acute fatty liver of pregnancy
• ARF in up to 60 of cases
• Preeclampsia hypoglycemia, hypofibrinogenemia,
  LFT abnormalities, prolonged PTT
• Obstructive uropathy
• Mild-moderate hydronephrosis is normal
• Occasionally, degree of obstruction sufficient to
  cause ARF.
• Nephrolithiasis if solitary functioning kidney

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Causes - Severe Preeclampsia/HELLP

• Typically develops late in 3rd trimester a few
  percent of cases can happen up to 48 hours
  post-partum.
• Preceded by hypertension, proteinuria, and severe
  edema
• ARF not typical unless marked DIC

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Severe Preeclampsia/HELLP

• But, there are cases reported in which renal
  abnormalities begin post-partum WITHOUT prior
  proteinuria
• Typically, spontaneous recovery 2-3 days
  post-partum complete recovery typical by 8 weeks
  post-partum.
• Corticosteroids have been utilized but no large
  randomized clinical trials

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Causes - TTP-HUS

• Thrombocytopenia microangiopathic hemolytic
  anemia ARF
• Traditionally, TTP if neurologic symptoms are
  abundant HUS if ARF is dominant. BUT,
  distinctions are often unclear and may not be
  important for management decisions

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TTP-HUS

• Timing variable
• 25 before mid-pregnancy
• 65 peri-partum
• 20 postpartum may follow normal pregnancy or
  be preceded by findings indistinguishable from
  preeclampsia
• Can relapse if TTP-HUS occurred once prior to
  pregnancy can occasionally relapse in
  subsequent pregnancy

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TTP-HUS

• Plasma infusion /- plasma exchange
  (plasmapheresis)
• In one series of 11 women
• 2 died
• 4 with residual CKD
• 5 recovered completely
• Prior to use of plasmapheresis, 90 mortality
  rate reported

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Causes - Renal Cortical Necrosis

• Bilateral cortical necrosis
• Severe renal ischemia or DIC with resultant
  endothelial damage
• Abruptio placenta, placenta previa, prolonged
  intrauterine death, amniotic fluid embolism
• THEN, patient develops acute onset of oliguria or
  anuria, gross hematuria, flank pain, and
  hypotension
• ANURIA, GROSS HEMATURIA, FLANK PAIN triad that
  is unusual in other causes of renal failure

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Renal Cortical Necrosis

• US or CT can be suggestive
• Biopsy can demonstrate necrosis
• No specific therapy many patients require
  dialysis but 20-40 have partial recovery with
  CrCl between 15 and 50 mL/min.

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To summarise Causes

• Bimodal distribution -peaks in the first
  trimester (related to unregulated and/or septic
  abortion,hyperemesis) and the late third
  trimester (related to obstetric complications
  APH,PPH,Preeclampsia, Chorioamnionitis,AFE etc).

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ATN CORTICAL NECROSIS THOMBOTIC
MICROANGIOPATHIES
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• The RIFLE classification (ADQI group) of
  ARF
• Risk (R) - Increase in serum creatinine level X
  1.5 or decrease in GFR by 25, or UO lt0.5 mL/kg/h
  for 6 hours
• Injury (I) - Increase in serum creatinine level X
  2.0 or decrease in GFR by 50, or UO lt0.5 mL/kg/h
  for 12 hours
• Failure (F) - Increase in serum creatinine level
  X 3.0, decrease in GFR by 75, or serum
  creatinine level gt 4 mg/dL UO lt0.3 mL/kg/h for
  24 hours, or anuria for 12 hours
• Loss (L) - Persistent ARF, complete loss of
  kidney function gt4 wk
• End-stage kidney disease (E) - Loss of kidney
  function gt3 months

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PHASES

• OLIGURIA
• POLYURIA
• RECOVERY

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Investigations

• BLOOD
• CBC
• Urea,creatinine,uric acid
• Electrolytes
• LFT
• S.proteins
• Coagulation profile
• ABG
• RBS
• Osmolality

• URINE
• sp.gravity
• osmolality
• electrolytes
• proteins
• pigment casts
• c/s
• ECG

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Management

• Restore or maintain fluid balance
• The maintenance of electrolytes and acid base
  balance
• The maintenance of nutritional support
• Prevention of infection
• Avoid renal toxins (including NSAIDS)
• Instigate renal replacement therapies

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Prerenal failure

• Adequately replace blood fluid losses,maintain
  BP.
• Control continuing blood loss
• Mannitol (100ml, 25) trial to d/d b/w reversible
  prerenal failure established ATN (provided
  oliguria lt48 hrs UP osmolality gt 1.05)
• If diuresis (gt50ml/hr or doubling) established
  within 3 hrs,maintain NS infusion acc to UOP
  replace electrolytes acc to urinary loss
  estimations.
• If unsuccessful objective is to support the
  functionally anephric pt till kidneys recover.

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Volume control

• IP/OP charting daily
• State of hydration-wt,hct,protein
• Input Output/24hrs 500ml(nonfebrile)
  
• 200 ml/ deg C of inc. in Tem
• Balance 0.3-0.5kg wt loss/d
• Avoid overhydration Rx diuretics,dialysis
• CVP monitoring (b/w 10-15cm H2O)

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Diuretics

• Diuretics commonly have been given
  in an attempt to convert the oliguric state to a
  nonoliguric state. However, diuretics have not
  been shown to be beneficial, and they may worsen
  outcomes.
• In the absence of compelling contradictory data
  from a randomized, blinded clinical trial, the
  widespread use of diuretics in critically ill
  patients with acute renal failure should be
  discouraged.
• Useful only in management of fluid-overloaded
  patients

Cantarovich F, Rangoonwala B, Lorenz H, Verho M,
Esnault VL. High-dose furosemide for established
ARF a prospective, randomized, double-blind,
placebo-controlled, multicenter trial. Am J
Kidney Dis 200444402-9. Kellum JA.
Systematic review The use of diuretics and
dopamine in acute renal failure a systematic
review of the evidence. Critical
Care19971(2)539.
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DOPAMINE

• Dopamine traditionally has been used to promote
  renal perfusion(1-5 mcg/kg/min )
• However, systematic reviews of dopamine
  treatment in critically ill patients and in
  patients with sepsis do not support the use of
  dopamine to prevent renal insufficiency,
  morbidity, or mortality. In the majority of ARF
  studies, dopamine was associated only with an
  increase in urine output.

Kellum JA, Decker MJ. Use of dopamine in acute
renal failure a meta-analysis. Crit Care Med
2001291526-31. Denton MD, Chertow GM, Brady
HR. "Renal-dose" dopamine for the treatment of
acute renal failure scientific rationale,
experimental studies and clinical trials. Kidney
Int 1996504-14.
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Nutrition

• INTAKE
• 1500 cal (protein free)
• Oral/parenteral
• If vol limitation-50D via central vein
• Essential L-aminoacids K,Mg,PImprove wound
  healing, hasten recovery
• Protein intake of 0.6 g per kg per day

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Electrolyte acid-base correction

• Hyperkalemia, which can be life-threatening,
  should be treated by
• decreasing the intake of potassium,
• delaying the absorption of potassium,
• exchanging potassium across the gut lumen using
  potassium-binding resins,
• controlling intracellular shifts
• dialysis.
• Acidosis- sodabicarb ,dialysis

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• Treat coagulopathy with FFP for a prolonged aPTT,
  cryoprecipitate for a fibrinogen level less than
  100 mg/dL, and transfuse platelets for platelet
  counts less than 20,000/mm3
• Timely identification of UTI, proper treatment
  prevention using prophylactic antibiotics

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Should we Initiate Dialysis in Pts w/Low Cr
Clearance?

• Hou, S., Pregnancy in Women on Hemodialysis,
  1994, revealed better outcomes of pregnancy in
  women w/ significant residual renal function or
  who initiate pregnancy before they need dialysis.
• May reduce incidence of polyhydramnios, lower
  urea and lowers water load, also reducing risk of
  dialysis-induced hypotension

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Hou, et al, 1998
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Hou, et al, 1998
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Hou, et al, 1998
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Indications for Kidney Replacement Therapy

• Acidosis unresponsive to medical therapy
• Acute, severe, refractory electrolyte changes
  (e.g., hyperkalemia)
• Encephalopathy
• Significant azotemia (blood urea nitrogen level
  gt100 mg per dL 36 mmol per L)
• Significant bleeding
• Uremic pericarditis
• Volume overload

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Early Prophylactic Dialysis

• Allows more liberal fluid, protein salt intake.
• Prevent hyperkalemic emergencies.
• infectious Cx.
• Improves comfort survival

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Hemodialysis Vs Peritoneal
dialysis

• Limited usefulness if hypotension
• C/I in actively bleeding pt.
• Controlled anticoagulation reqd
• Volume shifts-careful
• Faster correction

• Can be used in preg/PP pt.
• Easily available
• Simple,inexpensive
• Lower Cx rate
• Minimises rapid metabolic pertubations fluid
  shifts
• Insert cath high direct vision

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Delivery

• Development of ARF in obs pt is indication of
  delivery in majority cases.
• Deliver if UOPlt20 ml/gt2hrs despite adequate vol
  expansion immediate delivery not expected
• Redistribution of CO better renal perfusion.
• Remove fetus from hostile environment.
• Neonate urea osmotis diuresis -dehydration

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Renal biopsy

• Potentially v.risky in pregnancy
• Defer until postpartum even if ACN( for
  prognostication).
• Rare indication sudden renal failure before 32
  wks with no obvious cause.

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Preeclampsia

• A decrease in the GFR occurs secondary to
  intrarenal vasospasm. This may manifest as a
  "prerenal" picture. Acute renal failure (ARF) may
  develop, and acute tubular necrosis (ATN) may
  ensue if this hypoperfusion persists.

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Pre-eclampsia ManagementRenal problems

• Hyperuricaemia and proteinuria are NOT
  indications for delivery per se
• Consider delivery for progressive renal
  impairment (creatinine gt0.09 mmol/L)
• Care with fluids (pulmonary oedema can kill!)
• Kidney Function is Criticalfor Drug Elimination

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Pre-eclampsiaInvasive monitoring

• CVP monitoring may NOT be helpful!
• poor correlation between CVP and PCWP
• PA catheters have risks!
• rare indications
• pulmonary oedema resistant to diuretics
• oliguric renal failure despite volume expansion

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Idiopathic postpartum renal failure

• Associated primarily with microangiopathic
  processes
• Postpartum hemolytic-uremic syndrome.
• These were often irreversible and were
  associated with substantial mortality.
• Now improved outcome with plasma
  exchange,dialysis,prostacyclin infusion,
  correcting coagulopathy

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ACUTE FATTY LIVER OF PREGNANCY

• Associated with acute renal failure in up to
  60 percent of cases.
• The diagnosis should be suspected in a woman
  with preeclampsia who has jaundice,hypoglycemia,
  hypofibrinogenemia, and a prolonged PTT in the
  absence of abruptio placentae.

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KEY RECOMMENDATIONS FOR PRACTICE

• Identify prevent at prerenal phase as early as
  possible
• Dopamine should not be used to prevent
• acute renal failure. (Evidence level A)
• Diuretics should not be used to treat oliguria in
  patients with acute renal failure unless volume
  overload (Evidence level B)
• Early prophylactic dialysis should be strongly
  considered.
• The maintenance of electrolytes,acid base balance
  nutritional support plays vital role.

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• THANK YOU