Kidney Diseases That Can Complicate Pregnancy

Regardless of the aetiology of the pregnant patient presenting with pre-existing renal disease, there are several generalisations which can be made.

• First of all, the best time for consultation is prior to conception. At this time, some prediction of prognosis during pregnancy as well as formulating a plan of management during pregnancy can be discussed.
• Screening patients with pre-existing renal disease during pregnancy should involve the frequent use of a carefully collected creatinine clearance . Any deterioration in creatinine clearance as the pregnancy progresses should warrant admission and evaluation for a reversible cause, such as urinary tract infections or dehydration.
• Frequent ultrasounds of the foetus to monitor its growth as well as biophysical assessment may be required.
• Patients should be instructed to weigh themselves frequently and to look for signs of increasing oedema (excess fluid in body cells/cavities which causes swelling). There are many cases now reported of patients who have previously undergone renal transplant who have successfully carried a pregnancy as well as cases of patients who have had renal dialysis performed throughout pregnancy.

Urinary Tract Infections During Pregnancy

A more common urologic problem during pregnancy is that of urinary tract infection . Asymptomatic bacteriuria (defined as two cultures of the same organism of greater than 103 colonies) has been found to occur in between 3-6% of pregnant patients. This rate is the same as that seen in non-pregnant individuals. The unique problem during pregnancy is that the presence of asymptomatic bacteriuria markedly increases the risk of pyelonephritis . As many as 30% of patients with asymptomatic bacteriuria may develop pyelonephritis, and in those patients who develop pyelonephritis, there is an increased risk of septic shock. As many as 10% of patients with pyelonephritis during pregnancy have been reported to suffer consequences of septic shock.

The clinical approach to urinary tract infection during pregnancy is much the same as in the non-pregnant individual. For patients with asymptomatic bacteriuria or uncomplicated cystitis, sulfa remains a reasonable first line treatment unless the patient is allergic to the medication, near term, or is in premature labour. The reason for these latter contraindications is that sulfa competes with bilirubin for binding sites for protein and infants born with sulfa on board may have more jaundice . After the treatment of these conditions, a follow-up culture is mandatory. If the culture persists with positive results, long-term suppression with drugs such as nitrofurantoin or low-dose ampicillin are currently recommended.

If the diagnosis of acute pyelonephritis during pregnancy is made, the patient must be admitted to the hospital. It is important in this condition, as in others, to rule out other reasons as to why the pyelonephritis developed rather than just blame it on the pregnancy state. Other conditions such as kidney stone, tumour of the urinary tract or perinephric abscess must be excluded in the evaluation. These patients need to have an adequate urine for UA and culture. A mid-stream clean catch urine specimen should be obtained. Baseline serum creatinine, electrolytes and blood cultures should be drawn and frequent vital signs observed.

Patients should be advised to rest in the lateral recumbent position to decrease the pressure on the urinary tract and the patient should be well hydrated.
The drug treatment usually involves initial high doses of ampicillin such as 2 grams and 1-2 grams every 4-6 hours thereafter. If the patient does not show clinical improvement within 24-36 hours, either the wrong diagnosis has been made or the wrong drug has been used. The patient should be re-evaluated and if the diagnosis is felt to be correct, then broader gram-negative coverage with an aminoglycoside should be used. It is particularly important in the pregnant patient to follow peak and trough values due to the fact that they have a larger intravascular and extravascular volume and distribute the drug to a larger compartment. It is very common to have to adjust the aminoglycoside dose upward to provide adequate peak and trough values. A follow-up culture in such patients is mandator and serious consideration toward long-term suppression should be given.

The information in this page is presented in summarised form and has been taken from the following source(s):
1. Robert J. Blaskiewicz, M.D. Clinical Professor, Department of Obstetrics, Gynecology and Women's Health, Saint Louis University, U.S.A.: http://obgyn.slu.edu/