Mycobacterium tuberculosis: Present in droplet nuclei of persons with pulmonary or laryngeal TB disease and transmitted through coughing, sneezing, singing and shouting.

Among HIV-infected persons, the presentation of active TB disease is influenced by the degree of immunodeficiency.

In HIV-infected patients without pronounced immunodeficiency (e.g., CD4+ count >350 cells/?L), HIV-related TB clinically resembles TB among HIV-uninfected persons. The majority of patients have disease limited to the lungs, and common chest radiographic manifestations include upper lobe fibronodular infiltrates with or without cavitation. Extrapulmonary disease is more common in HIV-infected persons than in HIV-uninfected persons, regardless of CD4+ counts.

In advanced HIV disease, the chest radiographic findings of pulmonary TB are markedly different compared with those among patients with less severe immunosuppression. Lower lobe, middle lobe, interstitial, and miliary infiltrates are common and cavitation is less common. Marked mediastinal lymphadenopathy also can be found.

With increasing degrees of immunodeficiency, extrapulmonary TB (e.g., lymphadenitis, pleuritis, pericarditis, and meningitis), with or without pulmonary involvement, is more common, and found in the majority of TB patients with CD4+ counts <200cells/?L.

In severely immunodeficient patients with a high mycobacterial load, TB disease may be subclinical or oligo-symptomatic. After initiation of antiretroviral therapy (ART), immune reconstitution might unmask active TB, resulting in pronounced inflammatory reactions at the sites of infection.

The most important symptoms in the diagnosis of PTB are the following:

Other symptoms

Respiratory: chest pain, haemoptysis, breathlessness.

Constitutional: fever, night sweats, tiredness, loss of appetite, secondary amenorrhoea. Weight loss and fever are more common in HIV-positive PTB patients than in those who are HIV-negative.

The common forms of extrapulmonary TB associated with HIV are the following: lymphadenopathy, pleural effusion, pericardial disease, miliary TB, and meningitis. Many patients with extrapulmonary TB also have coexistent pulmonary TB.

If a patient has extrapulmonary TB, pulmonary TB should be looked for. If the patient has had a productive cough for more than 2 or 3 weeks, sputum samples should be sent for Acid Fast Bacilli (AKB) testing. If AFB testing is negative, do a chest X-Ray(CXR).

Definitive diagnosis of EPTB is often difficult. Diagnosis may be presumptive, provided you can exclude other conditions. Patients usually present with constitutional features (fever, night sweats, weight loss) and local features related to the site of disease.

WHO (2009) recommends that in all HIV-positive TB patients, co-trimoxazole preventive therapy should be initiated as soon as possible and given throughout TB treatment. Co-trimoxazole preventive therapy substantially reduces mortality in HIV-positive TB patients.

WHO (2010) also recommends that individuals living with HIV who do not have active TB should be offered isoniazid preventive therapy (IPT). IPT should be given for at least 6 months. Also strongly recommend at least 6 months of IPT for children and adults including pregnant women, people living with HIV and those receiving ART, and those who have successfully completed TB treatment. IPT for a duration of 36 months is conditionally recommended in settings with a high transmission of TB among people living with HIV.

The first priority for HIV-positive TB patients is to initiate TB treatment, followed by co-trimoxazole and ART. The WHO^2,6 and HIV Medical Association of India (HIVMAI)³ guidelines recommend that all patients with TB should be offered an HIV test with pre-test counseling. This is essential as the management of TB differs amongst HIV-infected patients as compared to HIV-negative patients and TB is an indication to initiate ART irrespective of CD4 counts.

ART improves survival in HIV-positive patients. In addition, ART reduces TB rates by upto 90% at an individual level, by 60% at a population level and it reduces TB recurrence rates by 50%.

WHO recommends initiation of ART in all HIV-infected individuals with active TB, irrespective of the CD4 cell count. TB treatment should be started first, followed by ART as soon as possible afterwards (and within the first eight weeks).²

The HIVMAI guidelines recommend that for patients with CD4<50/mm3 ART should be initiated around 2 weeks of starting anti-TB treatment. For patients with CD4>50/mm3, ART may be delayed until 8 weeks of anti-TB treatment.³

WHO Recommendations for First-line ART Therapy²
The recommended first-line ART regimens for TB patients are those that contain EFV since interactions with anti-TB drugs are minimal. However, because of concerns related to teratogenicity, EFV should not be used in women of child-bearing potential without adequate contraception, nor should it be used for women who are in the first trimester of pregnancy.

WHO Recommendations for Second-line therapy²

HIVMAI Recommendations of ARVs/anti-TB drugs³

When TB is diagnosed in patients already receiving ART, TB treatment should be started irr lmediately. Th ere are two issues tc ) consider in such cases:

IRIS (Immune reconstitution inflammatory syndrome) or a paradoxical reaction occurring after the initiation of ART is thought to be the result of recovery of immune responses to previously recognized TB antigens, reconstituted by ART or by TB treatment itself.¹

Gastrointestinal reactions are common with many of the anti-TB medications and may be managed without discontinuing TB medications; either change the hour of administration or administer drugs with food.

Skin rashes are common with all of the anti-TB drugs.

Fever in an HIV-infected patient who has been receiving effective TB therapy for several weeks might represent drug fever, a paradoxical reaction, or IRIS.

Drug-induced liver injury can be caused by INH, rifamycins, or pyrazinamide and is defined as an AST elevation; disproportionate increases in bilirubin and alkaline phosphatase also occur occasionally.