Obstetrics Simplified - Diaa M. EI-Mowafi
Urinary Tract Infection in Pregnancy
ASYMPTOMATIC BACTERIURIA
Definition
It is the presence of 100000 organisms/ml of the same species in two cultured fresh, mid-stream specimens of urine.
Incidence
2-5% of pregnant women. If not treated 30% of them will develop symptomatic infections.
Complications
- Symptomatic infections as cystitis and pyelonephritis.
- Anaemia.
- Hypertension.
- Intrauterine growth retardation.
- Pre-term delivery.
Treatment
- Ampicillin or cephalosporin 500 mg/ 6 hours for 10 days or
- Nitrofurantoin 100 mg/6 hours.
PYELONEPHRITIS
Definition
It is inflammation of the renal pelvis and parenchyma.
Incidence
30% in cases with asymptomatic bacteriuria and 1% in cases without.
Predisposing Factors during Pregnancy
- Urine stasis during pregnancy due to:
- Compression of the ureter by the gravid uterus against the pelvic brim particularly on the right side. So infection is more common on the right side.
- Relaxation of the ureter by progesterone effect.
- Increased urinary excretion of glucose and amino acids favours the growth of bacteria.
Causative Organisms
- Escherichia coli (E.coli) (90%).
- Klebsiella, streptococcus, staphylococcus, proteus, pseudomonas and others.
Diagnosis
Symptoms
Started usually after 16 weeks in the form of:
- malaise,
- anorexia,
- nausea and vomiting,
- rigors,
- dysuria,
- urgency and frequency of micturition,
- renal pain commonly on the right side.
Signs
- Fever reaching 40oC,
- rapid pulse,
- tenderness in one or both renal angles (costovertebral angle).
Investigations
- Urine analysis: pus cells, organisms and proteins. Casts and RBCs
may be present.
- N.B. Presence of organisms without pus cells suggests contamination, while pus cells without organisms creates suspicion of tuberculosis.
- Culture and sensitivity: for urine.
- Blood picture: leucocytosis.
Differential diagnosis
- Causes of acute abdomen as appendicitis, abruptio placentae and complications of pelvic tumours.
- Causes of vomiting.
Complications
- Chronicity: with recurrent infections. In these cases, plain X-ray and intravenous pyelography (IVP) should be done after delivery to exclude urinary stones. Chronic pyelonephritis may result in hypertension and renal failure later on .
- Abortion, intrauterine foetal death, IUGR or premature labour may result.
Treatment
- Bed rest: light diet and plenty of fluids. Intravenous fluid may be needed if there is vomiting
- Analgesics and antipyretics.
- Alkalies: as potassium citrate to inhibit the growth of E.coli.
- Antibiotics and chemotherapy: The following therapy is started until
the result of culture and sensitivity is obtained.
- Ampicillin 500 mg/ 6 hours, or
- Nitrofurantoin 100 mg/ 6hours, or
- Cephalosporins 500 mg/ 6 hours.
- Treatment is continued for 7-10 days.
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Edited by Aldo Campana,