Abdominal tuberculosis constitutes a major public health problem in developing countries and carries significant morbidity and mortality [1, 2, 12]. In this review, males were slightly more affected than females, an observation which is in accordance with the results of other workers [14, 21]. Other authors have reported female predominance [22–25]. Some authors report that the disease is more common in males in the western countries while in developing counties the females predominate . We could not find in literature the reasons for this gender differences.
Abdominal Tuberculosis can affect any age group but is more common in young people at the peak of their productive life . This is reflected in this study as majority of our patients were in the second and third decades of life, which is consistent with other studies [14, 28]. The presentation of abdominal tuberculosis in this age group has great economic impact since these are people in their most productive years and this disease imposes a considerable burden on their families and the society as a whole.
In agreement with other studies [12, 29–31], the majority of patients inches study came from poor families in the rural areas located a considerable distance from the study area and more than ninety percent of them had no identifiable health insurance. This observation has an implication on accessibility to health care facilities and awareness of the disease.
In keeping with other authors [30–32], the majority of our patients in this study had symptoms of more than 6 months duration at the time of presentation. The reasons for late presentation in this study may be attributed to the fact that the diagnosis of abdominal TB in its initial stages is usually difficult due to vague and non-specific symptoms as a result patients remain undiagnosed and subsequently present late with complications such as intestinal obstruction and bowel perforation with peritonitis. Late presentation in this study may also be attributed to lack of accessibility to health care facilities, lack of awareness of the disease as a result some patients with tuberculous intestinal obstruction may decide to take medications in the pre-hospital period with hope that the symptoms will abate. It is also possible that some clinicians managing the patients initially may not have considered as a possible diagnosis. In resource-poor countries like Tanzania, difficulties in diagnosis of abdominal TB, patient transfer, and inadequate medical treatment often result in delayed presentation to a hospital.
In our study, majority of patients were having acute presentation and were admitted through emergency department with intestinal obstruction and peritonitis requiring emergency exploratory laparotomy. Other authors have also reported similar observations [25, 33]. The presence of large number of patients with intestinal obstruction and peritonitis in our series may be attributed to diagnostic delay of abdominal TB leading to development of complications such as intestinal obstruction and peritonitis as a result of bowel perforations. Anal tuberculosis (tuberculous anal fistulae) has been reported to be less uncommon and has a distinct clinical presentation. Tubercular fistulae are usually multiple and recurrent [33–36]. Shukla et al. reported that tuberculosis accounted for up to 14 per cent of cases of fistula in ano. In our study, fistula in ano was reported in only 2.3% of cases and all of them were multiple.
The majority of patients in this study had primary abdominal tuberculosis and only 22.7% of patients had associated pulmonary tuberculosis (secondary abdominal tuberculosis). The high prevalence of primary intestinal tuberculosis in the present series is in accordance with most of the other studies conducted in developing countries [14, 25, 38]. Studies from developed countries have shown secondary tuberculosis to be more common . We could not establish the reasons for this geographical variation.
The presence of co-existing medical illness has been reported elsewhere to have an effect on the outcome of patients with tuberculous intestinal obstruction . This is reflected in our study where patients with co-existing medical illness had significantly high mortality rate.
In this study, HIV seroprevalence was found to be 18.8%, a figure that is significantly higher than that in the general population in Tanzania (6.5%) . High HIV seroprevalence in our study may be attributed to high percentage of the risk factors for HIV infection reported in our study population. However, failure to detect HIV infection during window period and exclusion of some patients from the study may have underestimated the prevalence of HIV infection among these patients. HIV infection has been reported to increase the risk of surgical site infection and mortality . In our study, the rate of surgical site infections and mortality was found to be significantly higher in HIV positive patients than in non HIV patients.
Radiological investigation is the mainstay in making presumptive diagnosis of abdominal TB, this include chest x-rays, ultrasound or CT scan of the abdomen and barium studies [43, 44]. Of all the radiological investigations, CT scan of the abdomen, which is a costly investigation, gives a better view of intestinal and extra intestinal structures. However, in this review, CT scan of the abdomen was done in only 9.0% of patients, which is in keeping with other studies [45, 46]. This was attributed to irregular availability of CT scan due to breakdown or inability of patients to afford. Diagnosis made on the basis of radiology is rapid, easy and less expensive but it is presumptive and cannot exclude completely other diseases like Crohn’s disease and malignancies of solid abdominal viscera .
Demonstrating tuberculous granuloma is probably the most important investigation for a definitive diagnosis of abdominal tuberculosis. In our study, histopathology was the basis of diagnosis in 86.3% of patients; however a typical granuloma with caseation was found only in 21.9% of patients in our series. Similar histopathological pattern was reported by Khan et al.. The yield of demonstrating tuberculous granuloma has been reported to be high when the specimen is taken surgically or through laparoscopy than when it is taken colonoscopically. On colonoscopic biopsies, if granuloma is non-caseating, interpretation is difficult because Crohn’s disease cannot be excluded .
Many authors advocated therapeutic trial with anti tubercular therapy but it should not be encouraged routinely as it may delay the diagnosis of malignancy, lymphoma and Crohn’s disease [45, 49]. In the present study, response to therapeutic trial of anti TB drugs was the basis of diagnosis in 13.7% of patients with suggestive clinical history and negative diagnostic workup. This figure is high than 2.0% reported by Khan et al.. In the literature up to 40% of patients were given therapeutic trial of anti TB drugs .
In keeping with other reports [14, 32, 48, 49], intestinal TB was the most predominant form of abdominal TB in this series and accounted for 49.6% of patients. The majority of patients in this review had ileocaecal region involvement. This is in agreement with other reviews on abdominal tuberculosis in which intestinal type of abdominal tuberculosis ranged from 50%-78% [48, 50]. It is postulated that ileocaecal involvement is due to either physiological stasis, large surface area of this part of the intestine, complete digestion of food and abundant lymph nodes in the region . It has been shown that the M cells associated with Peyer’s patches can phagocytes BCG bacilli .
Bands and adhesions were the most common operative findings in this study. Similar operative findings were reported by Ali et al., but in sharp contrast to other authors who reported bowel strictures as the most frequent intra-operative findings [31, 32].
In our series, release of bands and adhesions was the most frequent surgical procedure performed followed by segmental bowel resection with end to end anastomosis. Similar surgical treatment pattern was reported by other writers also [25, 52]. This is in contrast to that reported by Akbar et al. who reported stricturoplasty as the most common surgical procedure performed. As reported by others [31, 32, 48, 52], anti-tuberculous therapy was prescribed in all the tubercular patients postoperatively.
In agreement with other studies [25, 30], surgical site infection was the commonest postoperative complications in the present study attributing this to HIV seropositivity and low CD 4 count.
In this study, the overall median duration of hospital stay was 32 days which is higher than that reported by other authors [30–32]. This can be explained by the presence of large number of patients with postoperative complications in our study. However, due to the poor socio-economic conditions in Tanzania, the duration of inpatient stay for our patients may be longer than expected.
Our mortality rate of 18.8% was significantly higher than that reported by other authors [30, 48]. High mortality rate was reported in patients with advanced age, co-morbid illness, HIV positivity with low CD 4 count and those who presented late to the hospital. Addressing these factors responsible for high mortality in our patients is mandatory to be able to reduce mortality associated with this disease.
Discharge against medical advice is a recognized problem in our setting. Similarly, poor follow up visits after discharge from hospitals remain a cause for concern. In this study, the follow up of our patients was generally poor as more than sixty percent were lost to follow up. These issues are often the results of poverty, long distance from the hospitals and ignorance. Delayed presentation, lack of theatre space, delayed histopathological confirmation of abdominal tuberculosis and the large number of loss to follow up was the major limitations in this study.
However, despite these limitations, the study has provided local data that can be utilized by health care providers to plan for preventive strategies as well as establishment of management guidelines for these patients. The challenges identified in the management of patients with abdominal tuberculosis in our environment need to be addressed, in order to deliver optimal care for these patients.