Renal Disease and Pregnancy (1) Flashcards
What do we need to remember about when interpreting renal ultrasound in a pregnant woman?
Renal calyces and ureters dilate in pregnancy
This is due to high levels of progesterone inducing smooth muscle relaxation throughout the body (so uterus does not contract)
What is symptomatic hydronephrosis in pregnancy?
Aching back pain due to backpressure to the kidney -> as ureters are dilated
* normally benign but painful
What happens to renal plasma flow and GFR in pregnancy?
GFR and renal plasma flow increase
* this is due to CVSan increase changes e.g. in stroke volume and HR
* happen in early stages of pregnancy
What happens to a urinary protein that is excreted (in pregnancy)?
Urinary protein and creatinine excretion will be increased
*this is due to increased renal blood flow and GFR
What is the upper limit of serum creatinine for a woman in the 2nd trimester of the pregnancy?
65 umol/l-it falls
* as renal clearance of creatinine is increased (so more creatinine is cleared off - less stays in serum)
What is the upper limit for proteinuria throughout the pregnancy?
300 mg/24 hours
* limit is increased due to increased GFR - more protein excreted in the urine
Common disorders of renal system in pregnancy
Why is UTI more common in pregnancy?
UTI is more common in pregnancy because of physiological dilatation of the upper renal tract -> less peristalsis of ureters -> more opportunity to the bugs to invade(ascend)
Factors that increase risk of UTI in pregnancy
- previous Hx of UTI
- diabetes
- steroids
- immunosuppression
- polycystic kidneys
- congenital abnormalities of renal tract
- neuropathic bladder (e.g. spina bifida, MS)
- urinary tract calculi
What do we do in terms of UTI screen during antenatal visits?
Screen MSU - to look for asymptomatic bacteriuria *
* additional MSU are indicated in pregnancy for those at increased risk of UTI or with symptoms
Clinical features of lower UTI
Lower UTI
- urinary frequency
- dysuria
- haematuria
- proteinuria
- suprapubic pain
Symptoms suggestive of pyelonephritis
- fever
- loin/ abdominal pain
- vomiting
- rigors
What is seen on urine dipstick
- nitrites
- leukocyte esterase
- proteinuria
The dipstick should be followed by MSU (to confirm diagnosis)
What Dx do we consider if proteinuria found on the dipstick in late pregnancy?
Always considered pre-eclampsia unless ruled out
What do we consider as significant bacteriuria?
> 106 organisms/ml
What if we do MSU culture and there would be non-significant/mixed growth?
Repeat with a fresh specimen
Why do we treat bacteriuria in pregnancy?
It is to prevent pyelonephritis and preterm delivery
How long is a Rx for asymptomatic bacteriuria?
3 days for asymptomatic bacteriuria
*but 7 - 10 days for pyelonephritis
What do we need to investigate after the Rx of asymptomatic bacteriuria?
Regular urine cultures - to make sure we eradicated the bacteria
*2nd course of antibiotics may be required
What antibiotics for UTI/ bacteriuria are safe in pregnancy?
- Penicillins (amoxycillin, augmentin), Co-amoxiclav (amoxicillin + clavulanic acid)
- cephalosporins
What antibiotic to avoid in 3rd trimester?
Nitrofurantoin - to be avoided in 3rd trimester
*haemolytic actions - baby vulnerable to haemolytic anaemia
What antibiotic to avoid in 1st trimester of pregnancy?
Trimethoprim
* it is anti-folate drug -> neural tube defects (e.g. spina bifida)
How long is a Rx in pregnancy:
- acute cystitis
- pyelonephritis
- acute cystitis -> 7-day course
- pyelonephrtis -> 10 - 14 days
Pyelonephritis + vomiting or pyrexia in a pregnant woman
- what to do?
Admit for IV antibiotics + IV fluids (until apyrexial)
What further investigations do we do if a pregnant woman has pyelonephritis or >1 proven UTI?
- check renal function
- renal USS
* we want to exclude hydronephrosis, congenital abnormalities, calculi)
What if a pregnant woman has >1 UTIs + risk factor
continuous prophylactic antibiotics
What are the commonest causes of renal impairment in women of childbearing age:
- reflux nephropathy
- diabetes
- SLE
- other forms of glomerulonephritis
- polycystic kidney disease
How do we classify renal impairment?
mild, moderate or severe -> depends on serum creatinine or GFR
What renal disease may first manifest with in a pregnancy?
What further Ix should these signs prompt?
- hypertension
- proteinuria
- +/- haematuria
Further Ix: urea and creatinine
How reflux nephropathy can lead to renal impairment?
Recurrent reflux -> recurrent UTI -> scarring -> renal impairment
Complications of renal disease on pregnancy outcome (3)
- pre-eclampsia
- prematurity
- IUGR
*outcome depends on the level of impairment and pre-existing hypertension
*common to all these happen at the same time (as Rx for PE is delivery)
What is a chance of a successful pregnancy in severe renal impairment?
<50%
Due to frequent severe pre-eclampsia + IGUR
What should we counsel a woman in terms of pregnancy if she’s got a severe renal impairment?
Counsel against pregnancy/delay until she had a kidney transplant
*due to risk of bad outcomes for mum and baby
What can happen (apart from PE, IGUR, premature birth) in a pregnancy if a woman has a severe renal impairment?
Development of polyhydramnios -> leading to cord prolapse
*this results from foetal polyuria in response from high osmotic load from increased maternal urea
What high urea in a women does to fertility?
High urea = embryotoxic - woman unlikely to get pregnant
*if get pregnant there is a high chance of spontaneous miscarriage
Why does polyhydramnios develop in a woman with severe renal impairment?
this results from foetal polyuria in response from high osmotic load from increased maternal urea
What complications are associated with nephrotic syndrome + heavy proteinuria
- worsening hypo-albuminaemia
- risks of pulmonary oedema and thrombosis
