Urinary Tract Infections

Because of anatomic, functional, and hormonal modifications, urinary tract infection is frequent during pregnancy. It can present as three different entities: asymptomatic bacteriuria, acute cystitis, or acute pyelonephritis (Ovalle and Levancini 2001).

Different risk factors have been discussed: maternal age, socioeconomic status, antecedents of UTI, sexual intercourse, hemoglobinopathies, diabetes, immunodepression of HIV infection, multiparity, and race (Connolly and Thorpe 1999; Ovalle and Levancini 2001; Pastore et al. 1999a, b).

The most frequently encountered bacteria are ent-erobacteria, with E. coli ranked first (65%-90%), although streptococci are found more and more often (Hill et al. 2005).

Although many authors have established a relation between asymptomatic bacteruria and the risk of prematurity and low birth weight, today this relation is disputed. However, it is clear that untreated bacteruria induces a 20 % - 50 % risk of acute pyelonephritis, with this risk dropping to 1 % - 2 % if the bacteriuria is treated (Connolly and Thorpe 1999; Naber et al. 2001; Ovalle and Levancini 2001; Santos et al. 2002).

Although nitrite test strips and leukotests are useful in screening and monitoring, with a negative predictive value of 97.5%, cytobacteriological urine analysis

Fig. 7.1. Treatment of urinary tract calculi in pregnant patients

should be systematic to establish the diagnosis and have an antibiogram done. The upper limit of 105 bacteria/ml for the cytobacteriological urine analysis established by Kass to confirm the diagnosis ofUTI has been questioned. The association of clinical signs with 102 of a single pathogenic bacterium per milliliter provides the diagnosis (Delcroix et al. 1994).

The treatment of asymptomatic bacteriuria can be based on a single-dose treatment, as effective as classical antibiotic treatment lasting 1 week (Dafnis and Sa-batini 1992; Gerstner et al. 1978; Jakobi et al. 1987; McNeely 1987). On the other hand, there is no consensus on the duration of the optimal treatment of acute cystitis (Delcroix et al. 1994). The risk of recurrence (18%) requires monthly monitoring of urine and, in case of recurrence, antibiotic prophylaxis until delivery. Sometimes postcoital antibiotic prophylaxis is sufficient (Connolly and Thorpe 1999; Delcroix et al. 1994; Naber et al. 2001). Hygiene and diet advice is always useful: high fluid intake, voiding every 4 h, postcoital voiding, and perineal hygiene (Santos et al. 2002). The prescription of cranberry juice or extract can be pro posed but is much debated (Connolly and Thorpe 1999).

Acute pyelonephritis in a pregnant woman often requires hospitalization (Ovalle and Levancini 2001) to make the diagnosis, begin treatment, and provide the initial monitoring. For some authors, however, this hospitalization is not always necessary (Wing et al. 1999). Parenteral antibiotic therapy, often a third-generation cephalosporin, is the preferred treatment, and can be started presumptively, then change subsequently to the antibiogram results to an appropriate oral antibiotic treatment for a total duration of 10-14 days (Connolly and Thorpe 1999; Mauroy et al. 1996). Severe forms often require prescription of an aminoglycoside during the first 48 h of treatment. Ultrasound to look for pyelo-caliceal dilatation is particularly useful. When infectious or severe local signs do not respond to antibiotics or when there is substantial dilatation of the urinary tract with suspicion of obstruction, urine diversion using a ureteral stent or percutaneous nephrostomy is necessary (Naber et al. 2001). In all cases, noninvasive obstetric monitoring is indispensable (Delcroix et al. 1994).

History, clinical examination, plasma ionogram, elevated serum creatinine, CBEU, ultrasound, obstetriced consultation

Suspicion of calculus

Calculus seen

Spontaneous No spontaneous elimination elimination

Calculus not seen

Simplified IVU Uro-MRI

Calculus seen

Simplified IVU Uro-MRI

Spontaneous No spontaneous elimination elimination

Calculus <1 cm Calculus >1 cm Term not reached Term reached

Calculus <1 cm Calculus >1 cm Term not reached Term reached

1. JJ PCN ureteroscopy

2. Open surgery

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