Introduction.
Since the days of Hippocrates, the initial presentation of tuberculosis in temporal relation to pregnancy has been a subject of concern and controversy. Tuberculosis in pregnant woman can present in several ways. Pregnant women may give a past history of tuberculosis. Occasionally, the disease may be diagnosed in a pregnant woman when she develops symptoms and signs suggestive of tuberculosis. Mostly, pregnant women may remain asymptomatic and tuberculosis may be diagnosed either incidentally or by way of a screening programme. Atypical presentation of tuberculosis in pregnant women poses difficulties in confirmation of the diagnosis. Tuberculosis in pregnancy, thus, has important implications for the mother and child.
Clinical presentation of tuberculosis during pregnancy.
About one-half of pregnant women with tuberculosis remain asymptomatic. Some of the symptoms such as increased respiratory rate and fatigue may mimic the physiological changes that occur in pregnancy and thus make the diagnosis difficult.
Effect of pregnancy on tuberculosis.
It is currently believed that pregnancy neither predisposes to the development of tuberculosis nor results in the progression of the disease. However, clinical studies highlight a small but definite risk of relapse and deterioration in the postpartum period.
Effect of tuberculosis on pregnancy.
Reported literature does not suggest any adverse impact of tuberculosis on the course of pregnancy or labour.
Placental transmission of tuberculosis.
Endometrial infection can be an important source for transplacental transmission of disease in patients with congenital tuberculosis. Placental transmission of tuberculosis infection has now been conclusively proven by a number of case reports. In some cases a child had positive umbilical lymph nodes indicating umbilical vein as the route of transmission. MBT has also been demonstrated in placental specimens and tissues from stillborn infants.
Criteria for the diagnosis of congenital tuberculosis include:
- the disease must be bacteriologically proven;
- there must be a primary complex in the foetal or neonatal liver;
- the disease must appear early in the first few days of life;
- extrauterine infection must be excluded.
Congenital tuberculosis can occur by haematogenic spread from infected placenta, through umbilical vein, or, by aspiration of infected amniotic fluid in-utero. Liver is a major site of involvement reflecting haematogenic spread via foetal circulation. Lungs are involved by transplacental spread or by aspiration of infected amniotic fluid.
Diagnosis.
It is important to identify pregnant women suffering from tuberculosis infection. It may help to prevent transmission of disease to the newborn and close contacts.
Chest Radiograph.
A routine chest radiograph was advocated during pregnancy in order to detect active and inactive tuberculosis. Concern about radiation exposure to foetus does not justify the policy of routine chest radiograph examination during pregnancy. When indicated, the chest radiograph should be performed with abdominal shielding, preferably after the first trimester of pregnancy. Therefore, a chest radiograph carried out during preg-nancy does not seem to carry a measurable risk to the foetus since radiation exposure from chest radiograph is much less. It is not recomended to apply roentgenoscopy and fluorography.
Tuberculin Skin Test has emerged as an important screening test during pregnancy. Tuberculin test identifies persons infected by MBT but does not define activity or extent of disease. Patients with active tuberculosis may not have a positive skin test as a result of anergic state.
Microbiological Methods.
Demonstration of MBT in sputum, body fluids or material by Ziehl-Nielsen staining and Lowenstein-Jensen culture confirms the diagnosis of tuberculosis disease.
Treatment of active tuberculosis during pregnancy.
Pregnant women with tuberculosis should be treated without delay when diagnosed. Untreated tuberculosis represents a far greater hazard to a pregnant woman and her foetus than does the treatment of disease. Administration of chemotherapy remains the cornerstone in the management of active tuberculosis in pregnancy. The analysis of consolidated data on the teratogenic risk of the first line antituberculosis drugs (isoniazid, rifampicin, streptomycin and ethambutol) showed that despite the fact that all these drugs cross placenta, none of these drugs appeared to be teratogenic or toxic to the foetus with the exception of streptomycin induced autotoxicity. The decision of preservation of pregnancy lays both on the woman, and on the treating doctor. The treating doctor should insist on interruption of pregnancy at: fibrous-cavernous, chronic disseminated or widespread cirrhotic tuberculosis complicated by lung-heart insufficiency; at the newly revealed progressing tuberculosis; a combination of tuberculosis with diabetes or other chronic diseases. Next pregnancy should be recommended not earlier than in 2-3 years.
Exemplary management of the newborn child of the tuberculosis mother.
- The child should not be separated from the mother unless she is desperately ill.
- If the mother is smear-negative, the infant should be BCG vaccinated immediately.
- If the mother was sputum positive during pregnancy or is still so at the time of delivery:
- if the infant is ill at birth and congenital tuberculosis is suspected full anti-tuberculosis treatment should be administered;
- if the child is well, isoniazid 5 mg/kg in a single dose daily for 2 months should be prescribed.
- Then a tuberculin test must be performed.
- If tuberculin test is negative stop isoniazid and give BCG vaccination. The child for the period of immunity development should be isolated for 6 weeks from the mother, to exclude contact.
- If positive continue isoniazid for a further 4 months.