renal conditions in pregnancy Flashcards
Renal physiological changes in pregnancy
Increased renal perfusion due to increased cardiac output perfusion increased 60-80% in T2, T3 50% increase (slight fall)
eGFR doesnt apply in pregnancy
Increased filtration - 55%
Drop in Cr / urea / bicarb measurement
Protein excretion is increased
PCR 30 mg/mmol or 300 mg / 24 hours
Microscopic haematuria is not uncommon in absence of infection and proteinuria
If USS normal no further Ix needed (unless persists post partum)
Physiological water and salt retention
Renal secretion of Vit D, renin and erythropoietin is increased
Physiological dilatation of the ureters and the caliceal collecting system in pregnancy R>L
this may be progesterone causing smooth muscle dilatation or obstruction from a gravid uterus
Normal pelvicaliceal diameter of 2 cm
Asymptomatic bacteriuria Incidence Significance - risk of progression What is the bug What is the cut off for bacterial load When does the infection occur
Affects 4-7% of pregnancies
40% develop acute cystitis
30% develop pyelonephritis
75-90% EColi - likely from large bowel (maybe ascending colonisation from sexual intercourse)
> 100,000 /mL
Non significant/ mixed growth should be repeated
Usually early in pregnancy
Treatment for asymptomatic bacteriuria
Must be treated reducing the risk of preterm babies and low birth weight
High risk of ascending infection
ABs depend on sensitivities
Tx for 3 days
Regular cultures to prove eradication
15% will require another course of ABs
What ABs do you avoid in which trimesters for UTI
Trimethoprim should be avoided in T1 due to anti folic action
Nitrofuritoin should be avoided in T3 as may precipitate neonatal haemolytic anaemia
Long acting sulphonamides should be avoided at the end of pregnancy due to the risk of neonatal kernicterus
Rate of acute cystitis in pregnancy
risk factors
How long to treat
1% of pregnancies
Risk factors: Diabetes Systemic steroid Immunosuppression Previous recurrent UTIs
again most are EColi
Treat 5-7 days
How to reduce the risk of recurrent UTIs in pregnancy
Pass urine after sexual intercourse
Perineal hygiene - wipe front to back
Double voiding to prevent residual in the bladder
Increase fluid intake - high volume dilute urine better
Incidence of acute pyelonephritis
Risk factors
Risk to pregnancy
Management
1-2%
Same as UTI (diabetes, immunosuppressed, on steroids, recurrent UTIs) as well as congential abnormalities of the renal tract, neuropathic bladder, calculi in the urinary tract, polycystic kidneys
Risk is of PTB
Management
Admission, IVAB for 24 hours then 2 weeks of orals
Monitor renal function for AKI
USS to exclude hydronephrosis, calculi or congential abnormalities
Antibiotic prophylaxis in pregnancy against infection of the urinary tract
if woman usually take prophylaxis - then keep taking it
Low dose cephalosporin / nitrofurantoin depending on sensitivities
(check resistance if intervening infection)
Once 2 or more UTIs in pregnancy - she should have a renal USS and prophylaxis should be considered
Local protocol 3 or more UTI or 1 pyelonephritis and monthly MSUs + prophylaxis
Chronic kidney disease
How does pregnancy affect CKD
Accelerated decline Escalating HTN Worsen proteinuria (this is exacerbated by withdrawal of ACEi) Flare of disease (especially if lupus)
What are the risks of pregnancy with CKD?
Miscarriage PTB HTN, PET IUGR Fetal death
The worse the renal disease the higher the risk
CKD 3-5 60-90% preterm
accelerated risk of renal decline 20-50%
What factors about renal disease affect outcome (of the CKD and the pregnancy)
Severity of renal disease
Renal disease is categorised by eGFR Stage 1-5
Woman with severe disease will have a decline and permanent worsening of their renal function
Woman with stage 5 disease are typically advised against pregnancy
HTN
Degree proteinuria
Underlying disease
Pregnancy dialysis patient
what is risks of pregnancy outcomes
50% perinatal mortality
90% PTB and IUGR
75% risk PET
What risks are associated with a high maternal urea?
Polyhydramnios (and associated Cord prolapse, PPROM and PTB) resulting from fetal polyuria due to the high osmotic load
Urea over 20-25 there is a risk of fetal death
Glomerulonephritis
Which types are worse?
What are the associated risk factors?
What are the pregnancy risks?
The type is less important then the compromise on renal function
If HTN - increased PET risk
Fetal loss and PTB 20%
3% overall decline in function from pregnancy
25% increase in BP - most reversible
Reflux nephropathy
How common is it?
What is the pregnancy risk?
What are the risk factors for deterioration?
How is it inherited?
1% of newborns
Most common renal disease in woman of childbearing age
25% risk PET - worse of bilateral scarring, HTN, Cr over 110
If no HTN/ normal Cr - risk PET 15% and HTN 30%
If renal disease present - can rapidly worsen
Particular association with IUGR
As autosomal dominant - child should be screened with a micturating cystogram
Diabetic nephropathy
Risks in pregnancy
Adverse outcomes X2 compared to diabetic with normal renal function
UTI
PET
Proteinuria and oedema - can be marked with low albumin, risk of pulmonary oedema and thrombus
Anaemia - due to deficient erythropoitin secretion
30% PTB
50% increased BP
Typically doesn’t affect overall rate of deterioration
Polycystic kidney disease
What is it
What is it associated with
Pregnancy risks?
autosomal dominant disorder
50% chance of transmission to offspring
Typically Dx in 40s with HTN, UTIs renal impairment and haematuria
Associated with liver cysts or subarachnoid haemorrhages
Increased risk PET esp if HTN, renal disease or recurrent UTIs
How to manage pregnancies complicated by CKD
Preconception
Antenatal
Preconception
MDT
Assess is pregnancy appropriate - counsel risk of deterioration
BP Renal function Proteinuria
Stop teratogenic medications eg ACE i
Optimise medical conditions eg HTN and Diabetes
Antenatal
MDT - joint care obs / med / renal
Low dose aspirin - especially if HTN / poor obs hx
If vit D deficiency must presribe active metabolite (deficient 1a hydroxylation in the kidney)
Obs management CFTS + Assess for fetal anomalies (detailed anatomy) Uterine artery doppler at 20 weeks Placental growth factor serial growth scans
renal management
Good control of hypertension - targets lower to protect any remaining renal tissue 120-140/75-85
Consider admission if deterioration
Screening
Ongoing assessment for PET - Urine dip and BP monitoring
Monitor progressive renal disease - Cr and proteinuria
Also albumin, Hb, bicarb and platelets
Intrapartum
Depending on obs and medical factors decide on delivery gestation
Postnatal
Restart ACE i
Contraception
Indications for a renal biopsy in pregnancy
Preexisting but undiagnosed nephrotic syndrome
New onset nephrotic syndrome before 16-20/40
Strong suspicion of treatable underlying cause eg lupus, allograft rejection
(ensure exclude renal vein thrombus, obstruction, Infection PET)
Dialysis patients
What is the chance of successful pregnancy?
What factors worsen prognosis ?
Fertility is reduced
1/200 woman / year become pregnancy on dialysis
Chance of success 50%
Poor prognosis is over 35, more then 5 years on dialysis, delayed dx of pregnancy
How does pregnancy affect dialysis
worsens anaemia
- erythropoitein and IV iron as well as transfusions are used
Pregnancy increases the dialysis requirement significantly
heparin may be needed
How does dialysis affect pregnancy
Miscarriage IUD HTN PET PTL PROM Polyhydramnios due to uraemia Abruption Bleeding risk due to heparinisation requirement of haemodialysis CAPD volumes are limited as gestation increases
Dialysis in pregnancy management
Often dialysis required 5-6 X / week
(20+ hours)
Maintain urea <15-20mmol/L
Intensified regimes increase live birth rate
Renal transplant
After a transplant how long until recommended pregnancy
What is their pregnancy outcomes like?
Often fertility rapidly returns after normalisation of renal function
Recommend 1 year delay - allow graft to stabilise, and maintenance levels of drug to be reached
If manage through 12 weeks - the risk of successful pregnancy is 95%
Pregnancy affect on transplant
If baseline Cr <100 no long term affects
If Cr >130 the survival 65% at 3 years
As with a normal kidney, grafts adapt to the physiology of pregnancy
As with everything the worse at the beginning the more likely to deteriorate
10% of woman will have new long term problems after pregnancy
Renal transplant affect on pregnancy
Like CKD this depends on the level of function and associated HTN/ proteinuria / previous episodes of graft rejection pre pregnancy
If Cr <125 97% success
if >125 75% success
Worse with diabetes and poor graft function
complication rate about 50%
HTN/ PET 25% FGR 25% PTB 50% Infection Graft rejection 2%
Antenatal management of pregnancy in woman with renal transplant
Prepregnancy Optimise conditions Change meds Common MMF and tacrolimus but MMF teratogenic so change to azathiprine Wait 3 months to ensure stable MDT - obs/ nephrologist
Renal management
Aggressively control HTN
Monitor for deteriorating renal condition (Cr and protein) and HTN
FBC LFTs Ca - Calcium regulation problems
anaemia
MSU each visit - treat promptly
Medications
Reassure woman the safety profiles so they dont stop taking them
Drug levels and uptitrate as needed
Obs management
Uterine artery doppler at 20 weeks
Serial growth scans
Deteriorating renal function causes
HTN / PET
Infection
Obstruction eg renal vein thrombus
Dehydration
Medication - if on immunosuppression tabs
Rejection if transplant patient (comes with fever, oliguria, graft swelling and pain, altered echogenicity on USS)
How does having a renal transplant affect delivery?
LSCS for obs indications
Although increased rates of PTB - increase LSCS rate
If LSCS it should ideally have a conversation between transplant surgeon to confirm location
Prophylactic antibiotics to cover any surgical procedure including episiotomy
If on maintenance steroids - will need parenteral steroid in labour
