Calcification of nodes is seen in 35% of cases 2. Pleural effusions are more frequent in adults, seen in 30-40% of cases, whereas they are only present in 5-10% of pediatric cases 1.Īs the host mounts an appropriate immune response both the pulmonary and nodal disease resolve. Occasionally these nodes may be large enough to compress adjacent airways resulting in distal atelectasis 1. These nodes typically have low-density centers with rim enhancement on CT 1-3. This pattern is seen in over 90% of cases of childhood primary TB, but only 10-30% of adults 1. The more striking finding, especially in children, is that of ipsilateral hilar and contiguous mediastinal (paratracheal) lymphadenopathy, usually right-sided 3. In most cases, the infection becomes localized and a caseating granuloma forms ( tuberculoma) which usually eventually calcifies and is then known as a Ghon lesion 1-2. Cavitation is uncommon in primary TB, seen only in 10-30% of cases 2. Radiographic evidence of parenchymal infection is seen in 70% of children and 90% of adults 1. In primary pulmonary tuberculosis, the initial focus of infection can be located anywhere within the lung and has non-specific appearances ranging from too small to be detectable, to patchy areas of consolidation or even lobar consolidation. Radiographic features depend on the type of infection and are discussed separately. miliary tuberculosis is evenly distributed throughout both lungs.post-primary infections have a strong predilection for the upper zones.primary infection can be anywhere in the lung in children whereas there is a predilection for the upper or lower zone in adults 1.The location of infection within the lung varies with both the stage of infection and age of the patient: Nodal enlargement is also common at this stage. When CD4 counts drop below 200 cells/mm 3 then the pattern of infection is more likely to resemble primary infection or miliary tuberculosis 4. When CD4 count drops to below 350 cells/mm 3 pulmonary manifestations appear similar to run-of-the-mill post-primary infections (see below). Patients with AIDS demonstrate altered patterns of infection depending on their CD4 count. Occasionally patients may present with massive hemoptysis due to an erosion of a bronchial artery 1,3. A productive cough that is often blood-stained may also be present 1. In symptomatic patients, constitutional symptoms are prominent with fever, malaise, and weight loss. Patients with post-primary pulmonary tuberculosis are often asymptomatic or have only minor symptoms, such as a chronic dry cough. Only 5% of patients, usually those with impaired immunity, go on to have progressive primary tuberculosis. The primary infection is usually asymptomatic (the majority of cases), although a small number go on to have symptomatic hematological dissemination which may result in miliary tuberculosis.
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