Infectious peritonitis (IP) is a frequent complication in peritoneal dialysis (PD) [1]. It is the leading cause of transfer to hemodialysis, repeated hospitalizations and increased mortality [2].

Tuberculous peritonitis (PT) is rare (<3%) [3]. [4], but serious. Its clinical picture is nonspecific, so the diagnosis is often late, hence the interest in specific tests for the detection of mycobacteria.

We report three cases of PT diagnosed at our PD center over a 15-year period.

Tuberculosis, regardless of location, is the ninth leading cause of death worldwide. According to a report by the WHO, there were 10 million new cases of tuberculosis in 2019, particularly in developing countries in Africa and Asia [5]. The risk of developing tuberculosis is higher in people who have a deficient immune system, especially during HIV infection and end-stage renal disease (ESRD). Thus, the incidence of tuberculosis in patients at the stage of ESRD is 5 to 15 times higher than in the general population [6];[7].

The onset of tuberculosis is relatively early compared to the start of dialysis; it is often diagnosed in the first years of dialysis treatment [8,9,10]. In our series, it occurs on average in the first three years. This phase is characterized by a drop in cell-mediated immunity linked to chronic renal failure, favoring the reactivation of old foci [8].

In our series, the incidence of PT was approximately 1.12% among 267 episodes of peritonitis over a 15-year period. This is relatively low compared to the 4.47% incidence reported by Ram et al. in their series of 11 episodes of tuberculous peritonitis in India [9], 6.52% reported by Rohil et al. in their series of 6 episodes of tuberculous peritonitis in India [10], or 7.1% reported by Tamayo Isal et al. in their series of 170 episodes of peritonitis over a period of 6 years in South Africa [11]. This difference compared to our rate is explained by the higher incidence rate of tuberculosis in these geographical areas.

The diagnosis of tuberculous peritonitis in peritoneal dialysis is difficult. Symptoms are nonspecific and include fever (78%), abdominal pain (92%) and cloudy fluid (90%) [12]. Regarding the cytobacteriological examination of the dialysate, the predominance of lymphocytes was noted in all our patients, but this is not the rule. Often the percentage of polynnuclear neutrophils is higher initially, and a lymphocyte predominance appears later [13].

The search for Koch’s bacillus in the dialysate fluid is rarely positive on direct examination, its sensitivity being evaluated between 0% and 6% [14];[15]. A culture on specific Löwenstein-Jensen medium has better sensitivity with a positivity rate of up to 85%, but it requires delays ranging from 4 to 8 weeks. Our three patients had a negative AAFB smear and the culture was positive with a delay of 6 to 8 weeks. The polymerase chain reaction (PCR) of mycobacterial DNA can be performed on the dialysate, allowing rapid diagnosis with a sensitivity of 81% and a specificity of 99% [16]. It was positive in one of our patients.

The dosage of interferon gamma (IFN-γ) is also of interest in the diagnosis of tuberculous peritonitis. This dosage can be done in the dialysate, whose sensitivity is better compared to blood; the sensitivity is 77.8% and the specificity 84.6% [17]. This test was not performed in our patients given the availability of other diagnostic means which are less expensive.

If the indication for removal of the PD catheter has been retained, the typical appearance of the peritoneum is a scattering of disseminated or confluent granulations on a hyperemia peritoneal serosa or covered with a fibrinous exudate. Biopsy of the peritoneum is recommended, the characteristic histological appearance of which is epithelioid and giant cell granuloma with caseous necrosis in the center of the granuloma [18].

Therapeutically, the treatment is based on four molecules: rifampicin (RIF), isoniazid (INH), pyrazinamide (PZA) and ethambutol (EMB). The duration of treatment varied between 6 months and 12 months [12]. In our national protocol, the duration was 6 months with a quadruple therapy of INH, RIF, PZA and EMB for 2 months, then a dual therapy of INH and RIF for 4 months. The dosage must be adapted to weight [19](Table II), with monitoring of residual serum levels of RIF and INH in order to adapt the dosages and avoid their toxicity [20]. The maximum target concentrations vary from 4 to 24 μg/mL for RIF and from 1 to 2 mg/L for INH.

Favorable response to treatment results in resolution of symptoms and clearing of dialysate fluid. It is a treatable infection with no real consensus on the removal of the PD catheter [9], and the curing of patients in several series has been achieved without the need to remove the catheter [21]; [22]; [23]. The ISPD recommends reinsertion of the catheter at minimum between 2 and 3 weeks if catheter removal was chosen [24].

A diagnosis of tuberculous peritonitis should be considered in any patient on peritoneal dialysis with refractory or recurrent culture-negative peritonitis.

Bacteriological or histological confirmation is often late, and should not delay therapeutic management.

Early diagnostic guidance based on clinico-biological arguments and the rapid initiation of antituberculosis drugs are the key to effective management and the only guarantee of a good prognosis.