tailieunhanh - Chapter 060. Enlargement of Lymph Nodes and Spleen (Part 3)

Laboratory Investigation The laboratory investigation of patients with lymphadenopathy must be tailored to elucidate the etiology suspected from the patient's history and physical findings. One study from a family practice clinic evaluated 249 younger patients with "enlarged lymph nodes, not infected" or "lymphadenitis." No laboratory studies were obtained in 51%. When studies were performed, the most common were a complete blood count (CBC) (33%), throat culture (16%), chest x-ray (12%), or monospot test (10%). Only eight patients (3%) had a node biopsy, and half of those were normal or reactive. The CBC can provide useful data for the diagnosis of. | Chapter 060. Enlargement of Lymph Nodes and Spleen Part 3 Laboratory Investigation The laboratory investigation of patients with lymphadenopathy must be tailored to elucidate the etiology suspected from the patient s history and physical findings. One study from a family practice clinic evaluated 249 younger patients with enlarged lymph nodes not infected or lymphadenitis. No laboratory studies were obtained in 51 . When studies were performed the most common were a complete blood count CBC 33 throat culture 16 chest x-ray 12 or monospot test 10 . Only eight patients 3 had a node biopsy and half of those were normal or reactive. The CBC can provide useful data for the diagnosis of acute or chronic leukemias EBV or CMV mononucleosis lymphoma with a leukemic component pyogenic infections or immune cytopenias in illnesses such as SLE. Serologic studies may demonstrate antibodies specific to components of EBV CMV HIV and other viruses Toxoplasma gondii Brucella etc. If SLE is suspected then antinuclear and anti-DNA antibody studies are warranted. The chest x-ray is usually negative but the presence of a pulmonary infiltrate or mediastinal lymphadenopathy would suggest tuberculosis histoplasmosis sarcoidosis lymphoma primary lung cancer or metastatic cancer and demands further investigation. A variety of imaging techniques CT MRI ultrasound color Doppler ultrasonography have been employed to differentiate benign from malignant lymph nodes especially in patients with head and neck cancer. CT and MRI are comparably accurate 65-90 in the diagnosis of metastases to cervical lymph nodes. Ultrasonography has been used to determine the long L axis short S axis and a ratio of long to short axis in cervical nodes. An L S ratio of has a sensitivity and a specificity of 95 for distinguishing benign and malignant nodes in patients with head and neck cancer. This ratio has greater specificity and sensitivity than palpation or measurement of either the long or the short axis .