The Clinical and Laboratory Immunology Committee of the American Academy of Allergy, Asthma and Immunology has assembled a set of practice parameters for the diagnosis and management of immunodeficiency (37). These may help provide guidelines for the allergist-immunologist and the referring physician to those screening tests that might first be ordered and interpreted by the primary physician, as compared with situations in which referral to the specialist becomes appropriate. Often, the specialist is called by the primary care physician to determine whether a patient should be referred.
A review of laboratory tests already obtained by the primary care physician may yield important clues to the presence of an immune deficiency disorder and may save steps in the evaluation of patients by suggesting which of the more specialized tests are most likely to be informative. The complete blood count (CBC) and differential will help to exclude neutropenia or may indicate lymphopenia, which could be seen in SCID or Bruton agammaglobulinemia. Abnormal or decreased platelets may suggest Wiskott-Aldrich syndrome, and fragmented erythrocytes may suggest sickle cell disease. General blood chemistry panels will show low total protein but normal albumin in agammaglobulinemia. A low uric acid level may be indicative of ADA deficiency or purine nucleoside phosphorylase deficiency, two causes of SCID (16,38); whereas a low serum calcium level may suggest DiGeorge syndrome.
In addition to assessing the airways and lung parenchyma, the chest radiograph should be reviewed for the absence or presence of a thymus in infants and for the possibility of a thymoma, which may be associated with hypogammaglobulinemia in adults (39). Hyperinflation with patches of atelectasis, suggestive of asthma, might suggest that additional details of the past history should be carefully reviewed in patients, particularly small children, referred because of cough or recurrent pneumonia, because similar densities seen on previous films may not have actually been due to infection. The presence of old scars and active disease should be documented. Hilar adenopathy may be seen in cellular and humoral immune defects. Abnormalities of the ribs resembling those seen in rickets might suggest ADA deficiency (13), and cardiovascular abnormalities may suggest asplenia (40) or DiGeorge syndrome (41) or may steer the workup away from immune deficiency and toward Kartagener syndrome (situs inversus and ciliary dysmotility) or cystic fibrosis.
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If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.