Tuberculosis in the elderly. Epidemiology and optimal management

The problem with the emergence of HIV-associated tuberculosis (which usually occurs in young adults) is that attention has been diverted away from the fact that, in the developed world, the elderly represent the biggest pool of tubercular disease and therefore the greatest pool of infection within the community. Although the incidence rate of tuberculosis continues to decline in most countries, there is evidence from parts of the developing world that rates may be beginning to increase. The presentation of the disease in the elderly is often uncharacteristic, e.g. disease tending to be more insidious in onset, pyrexia often absent and haemoptysis less common. Chest x-ray changes may also mislead the clinician in that disease is frequently present in the mid or lower zones. The elderly are probably at greater risk of extrapulmonary tuberculosis, which also presents in uncharacteristic ways. The diagnosis remains based on clinical presentation and the presence of smear and culture positivity, although some patients may be treated in the absence of microbiological proof. Standard treatment is with a combination of isoniazid, rifampicin and pyrazinamide, with or without a fourth drug such as ethambutol. The incidence of adverse effects in the elderly is much greater than that in younger patients, often resulting in the need to change the medication to drugs which are better tolerated. This may require changing to regimens which are less effective and therefore have to be taken for a longer period of time. The presence of concomitant disease such as liver or renal failure may also necessitate the administration of a suboptimal regimen. Mortality in elderly patients with tuberculosis is considerably higher than that in younger patients, even when treatment appears to have been started on time; even in the developed world mortality exceeds 30% in those patients over 70 years of age.

Pattern of utilization of rifabutin for prophylaxis of Mycobacterium avium complex among patients with advanced human immunodeficiency virus disease in a community setting

OBJECTIVE

To characterize the pattern of utilization, effectiveness, and safety profile of rifabutin for Mycobacterium avium complex (MAC) prophylaxis among individuals with advanced human immunodeficiency virus disease in a community setting.

METHODS

Individuals who, while registered in the provincial drug distribution program, had at least one CD4 count below 100 cells/mm3 for the period 1 May 1993 to 31 March 1994 were included. MAC diagnoses were identified through a record linkage with the mycobacterial reference laboratory of the Provincial Centre for Disease Control. In order to determine the occurrence of adverse events, a survey was sent in March 1994 to the 98 primary care physicians prescribing rifabutin prophylaxis in the province. We achieved 100% response rate to the survey.

RESULTS

During the study period 515 patients in our drug treatment program were eligible to receive MAC prophylaxis. Of these, 340 (66%) were being prescribed rifabutin as recommended by current guidelines. Rifabutin prophylaxis use was significantly associated with use of antiretroviral therapy. The product limit estimate of the cumulative incidence of MAC at 10 months was 13.0% among those receiving rifabutin prophylaxis. Diagnosis of MAC was significantly associated with a lower baseline CD4 count (cumulative incidence 7.1% and 18.1% for CD4 > or = 50 and < 50 cells/mm3, respectively, P = 0.01). A total of four cases of uveitis, eight cases of pseudo-jaundice, and five cases of arthralgia in 16 patients were identified by our survey.

CONCLUSION

Our data demonstrates that rifabutin prophylaxis of MAC is being used by approximately 66% of eligible individuals. Rifabutin use was associated with antiretroviral use, which may reflect individuals' attitudes towards medications. Our intention-to-treat analysis, with a 10 month cumulative MAC incidence of 13.0% among those receiving rifabutin prophylaxis, is in keeping with break-through rates previously reported in the context of clinical trials. Our results also support previous observations that the risk of MAC infection greatly increases at CD4 counts < 50 cells/mm3. Rifabutin prophylaxis was generally well-tolerated in our program.

Uveitis during treatment of disseminated Mycobacterium avium-intracellulare complex infection with the combination of rifabutin, clarithromycin and ethambutol

Three patients with a cellular immunodeficiency were treated with rifabutin, clarithromycin and ethambutol for a disseminated infection with Mycobacterium avium-intracellulare complex (MAC). The patients developed uveitis, sometimes in combination with a transient rash, arthralgia, arthritis, jaundice and pseudojaundice. It seems likely that these reactions were caused by rifabutin, alone or together with other drugs such as clarithromycin. These adverse reactions probably depend on the dose, metabolism and excretion of the drug. Inhibition of cytochrome P450 seems to be an important mechanism.

Hepatotoxic effects of tuberculosis therapy. A practical approach to a tricky management problem

Side effects of the most commonly used first-line antituberculosis drugs range from minor gastrointestinal symptoms to severe hepatotoxicity. If unrecognized, they can lead to increased morbidity and mortality as well as to higher healthcare costs. Side effects are most evident in patients with underlying compromise in hepatic function. Erratic treatment protocols not only promote secondary drug resistance but also offset all gains in tuberculosis control. Recognition of this problem, mandatory directly observed therapy, judicious standardized follow-up planning, and implementation of modified treatment protocols when needed may play a dominant role in treating and controlling tuberculosis and may also prevent the morbidity and mortality sometimes associated with tuberculosis treatment. In view of the changing epidemiology of tuberculosis and its global impact, the American Thoracic Society and the Centers for Disease Control and Prevention may need to look closely into the issues outlined here to develop a consensus and establish more specific guidelines.

Rifabutin as salvage therapy for cases of chronic multidrug-resistant pulmonary tuberculosis in Taiwan

This study was aimed at assessing the efficacy and tolerability of rifabutin for the re-treatment of cases of chronic, multidrug-resistant pulmonary tuberculosis. The study design was self-controlled, single center. Rifabutin was administered as part of an individual-tailored multidrug regimen. In-patients suffering from pulmonary tuberculosis, infected with Mycobacterium tuberculosis bacilli resistant to isoniazid, rifampicin and other drugs with progressive disease unresponsive to prior courses with standard anti-tuberculosis medications were treated. Overall, 43 patients were enrolled and treated with rifabutin at 300 or 450mg/day according to body weight in conjunction with available anti-tuberculous drugs for a mean time of 353 days (range 42-678). Of these, 36 met all eligibility criteria (i.e. positive baseline culture of sputum with bacilli resistant to rifampicin at least) and were retained for the analysis of efficacy. Seventeen patients (47%) achieved a sustained conversion to a negative culture of sputum in a mean time of 47.7 days with a range of 14-120 days. Treatment prevented deterioration in most patients and resulted in clinical and radiological cure or marked improvement in more than half of cases. No correlation was found between treatment outcome and use of medication concomitant to rifabutin or susceptibility of bacilli to the drugs used. Four deaths occurred due to disease progression, in no case being related to study drugs. Ten patients reported a total of 18 adverse events that led to treatment discontinuation in 5 cases. Rifabutin should be considered for inclusion in regimens for cases of pulmonary multidrug-resistant tuberculosis which fail to respond to previous therapy.

Use of rifabutin in the treatment of pulmonary tuberculosis

This article reviews recent studies conducted outside the United States assessing the efficacy and safety of rifabutin in the treatment of tuberculosis (TB) in HIV-infected patients, in patients with newly diagnosed TB, and in patients with multidrug-resistant TB. A 6-month pilot study of 50 Ugandan patients with TB associated with HIV infection showed that rifabutin and rifampin were similarly effective with regard to conversion of sputum-smear findings (sputum conversion) and in bringing about clinical and radiologic improvement. Compared with rifampin, rifabutin showed potential for reducing the time to sputum conversion for these patients. Multicenter studies in five countries compared two rifabutin dosages (150 mg/d and 300 mg/d) with rifampin as part of a combination regimen for treatment of newly diagnosed TB in 935 patients. Rifabutin compared favorably with rifampin in sputum conversion; administration of 150 mg/d of rifabutin yielded good results and the fewest adverse effects. The use of rifabutin by 270 patients in five countries who had multidrug-resistant TB (approximately 90% of isolates tested were resistant to rifampin and isoniazid) was assessed in another study. For the majority of these patients, signs and symptoms diminished; one-third had bacteriologic conversions.

[Fulminant, rapidly reversible hepatitis and life-threatening anaphylaxis following rifampicin in an HIV-positive female patient with latent adrenal cortex insufficiency]

We report the case of a 28-year-old-prostitute from Thailand with HIV infection stage B2 associated with retroperitoneal lymph node tuberculosis. 6 days after the beginning of anti-tuberculous therapy (isoniazid, rifampicin, pyrazinamid and ethambutol) the temperature rose to 40.5 degrees C, diarrhea, vomiting, and tachycardia developed and systolic blood pressure fell to 80 mm Hg. Liver function tests revealed acute hepatic failure (ALT 800 IU/l rising to 1500; serum bilirubin 89 mumol/l rising to 238.0; alkaline phosphatase 199 IU/l; glucose 1.8 mmol/l; prothrombin time 20%). Isoniazid, rifampicin, and pyrazinamid were replaced by streptomycin and PAS. A few days after withdrawal the liver profile returned to normal. Hours after the reintroduction of rifampicin total body erythema, pruritus, vomiting and severe hypotension developed, requiring saline methylprednisolone and epinephrine administration. The next reexposure to intravenous rifampicin produced a rash and was rapidly discontinued. Liver function tests remained normal. Later mild adverse reactions to streptomycin and pyrazinamid occurred, two drugs which had been well tolerated before. Subsequently the diagnosis of adrenal insufficiency was established. After initiation of steroid replacement (50 mg prednisolone) the antituberculous therapy with isoniazid, pyrazinamid and ethambutol was well tolerated. We conclude that the shock in this HIV-infected patient was either due to severe anaphylaxis to rifampicin or acute adrenal insufficiency ensuing on this drug. The reversible fulminant acute hepatic failure represents either an adverse effect of antituberculous drugs, especially hepatotoxic interactions of drug combinations, or an ischemic liver injury during hypotension caused by anaphylaxis. The case illustrates the complex nature of side effects of antituberculous drugs in HIV patients and their aggravation by adrenal insufficiency.

Treatment of nontuberculous mycobacterial lymphadenitis with clarithromycin plus rifabutin

Treatment with clarithromycin plus rifabutin in children with nontuberculous mycobacterial lymphadenitis was associated with resolution of chronic sinus formation and discharge after incomplete excision in five of five cases, and involution of the enlarged lymph nodes in two of three cases treated without surgery.

[Two cases of therapy-related myelodysplastic syndrome]

Myelodysplastic syndrome (MDS) was sorted out two types; primary type and secondary type caused by irradiation or several drugs. Clinical features and chromosomal analysis were investigated in two patients with secondary MDS, caused by cyclophosphamide (CPM) or rifampicin (RFP) respectively, and fourteen cases of primary MDS hospitalized from 1988 to 1993. Two cases of secondary MDS progressed refractory anemia with excess of blasts (RAEB), however two of 14 patients with primary MDS progressed to acute leukemia. Median survival was similar in two groups. In cytogenitic analysis, complex abnormalities including -5/5q- and/or -7/7q- have two cases of secondary MDS and nine out of 14 cases of primary MDS. Complex chromosomal abnormalities did not improve following chemotherapy. In this study, clinical features and cytogenetic analysis demonstrated no significant difference between primary and secondary MDS.

Increased incidence of tuberculosis in patients undergoing hemodialysis

Tuberculosis was diagnosed in 26 patients (6 females and 20 males) undergoing maintenance hemodialysis, with an incidence of 23.6%. Infection was characterized clinically by a very insidious onset, the main symptoms being anorexia, loss of weight and low-grade fever, a very high sedimentation rate and lymphocytes predominant in the peripheral circulation, pleural and peritoneal fluids. Pulmonary tuberculosis was seen in 18 patients (70%), 10 of whom presented with pleural effusions. There were extrapulmonary presentations in 8 of the 26 patients (30%). Most of the patients developed the disease about 1 year from the start of their dialysis treatment. With early therapy all patients survived their tuberculosis disease and no recurrence was seen in up to 5 years of follow-up. Despite earlier reports of high mortality, we suggest that awareness of the increased incidence of tuberculosis in dialysis patients, together with its unusual presentation and consequent early diagnosis, results in a very good prognosis.

Recurrent bilateral anterior uveitis with hypopyon and rifabutin therapy

Rifabutin is used in patients with human immunodeficiency virus infection to prevent and treat Mycobacterium avium complex infection. We report a case of recurrent bilateral anterior uveitis with hypopyon in a patient who was taking 600 mg of rifabutin daily. The rate of recurrence with the continuation of rifabutin seems to be high, especially in the opposite eye (alternate uveitis with hypopyon); rifabutin should be discontinued if uveitis recurs.

[Four cases of similar Hexheimer's reaction during the initial chemotherapy for tuberculosis bacillus]

In the report, 4 patients with similar Hexheimer's reaction during initial chemotherapy for pulmonary tuberculosis were presented. The literatures on clinical manifestations, predisposing factors, pathogenic mechanism, pathological changes, diagnosis and management of Hexheimer's reaction are reviewed.

Uveitis associated with rifabutin therapy

PURPOSE

To highlight the association of uveitis with the use of rifabutin.

METHODS

Retrospective study of two patients with acute anterior uveitis.

RESULTS

Both patients were receiving rifabutin for treatment of atypical Mycobacterium infection associated with AIDS when they developed unilateral acute anterior uveitis and arthritis. The inflammation resolved and vision improved with introduction of topical corticosteroids, mydriatics and cessation of rifabutin treatment.

CONCLUSION

Use of rifabutin with clarithromycin may precipitate acute uveitis in patients with AIDS being treated for systemic Mycobacterium avium complex infection. Uveitis produced by rifabutin may be analogous to Herxeimer reaction as seen in syphilis. Clarithromycin and fluconazole elevate levels of rifabutin due to inhibition of metabolism through cytochrome p-450 pathway. The differential diagnosis includes Reiter's syndrome, syphilis causing uveitis, metastatic endophthalmitis, and direct HIV-related uveitis.

[Monitoring ototoxic side effects in streptomycin therapy of tuberculosis patients with transitory evoked otoacoustic emissions TEOAE]

The transient stimulated otoacoustic emissions TEOAE's from 10 patients treated with Streptomycin for tuberculosis, were measured. The patients received a combination of four drugs consisting of isoniazid, rifampicin, pyrazinamid and streptomycin. All patients received a total of 30 grams of streptomycin during 30 days of treatment. Pure tone audiograms between 125 Hz and 8000 Hz were performed before, during and at the end of the treatment. The TEOAE's were measured in a soundproof cabin before during and after the streptomycin treatment. None of the patients experienced subjective dizziness, hearing loss or tinnitus. The pure tone audiograms showed no significant fluctuations. However, 14 of the 20 examined ears showed a significant decrease in the amplitudes of the TEOAE's. An observation of the TEOAE-amplitudes of each patient during the treatment allows an assessment of impending cochlear dysfunction before subjective hearing loss can be recognized.