Difficulties of differential diagnosis of lymphadenopathy in acute brucellosis (clinical cases)

Brucellosis is a zoonotic disease caused by bacteria of the genus Brucella, characterized by prolonged fever with damage to the musculoskeletal system, nervous, reproductive, cardiovascular and other systems, prone to chronic course. The highest incidence of brucellosis (including among children) over the past 10 years in Russia is registered in Dagestan. One of the manifestations of the reaction of the immune system to the spread of infection in the acute course of brucellosis is generalized lymphadenopathy. Brucella is able to induce incomplete phagocytosis, as a result of which, with a significant accumulation of the pathogen, the lymph nodes become a source of bacteria reproduction, from where they can enter the bloodstream and spread to the cells of the mononuclear phagocyte system, liver, spleen, bone marrow and other organs. With long-term preservation of the pathogen in tissues and organs, brucella causes a specific inflammatory reaction with the formation of granulomas. The acute form of brucellosis is characterized by high fever with a fairly good tolerance. At the end of the first week of the disease, lymphadenopathy appears, an increase in the liver and spleen. All groups of lymph nodes can increase, they can be sensitive to palpation. With the transition of the acute form of brucellosis to the chronic form, the size of the lymph nodes often decrease, sclerosis, become dense on palpation and painless. This condition is called micropolyadenitis. According to the literature, the frequency of lymphadenopathy in the acute course of brucellosis varies greatly, which, apparently, is due to the lack of clear criteria for assessing damage to the lymph nodes, as well as assessing the duration of the disease and the presence of the fact of prescribed antibiotic therapy. The study of lymph nodes in brucellosis is an important part of the general examination of the patient, however, the presence of lymphadenopathy does not always indicate the course of this nosology. In addition, the absence of lymphadenopathy does not rule out brucellosis. The article presents three clinical cases that demonstrate the difficulty in diagnosing brucellosis and the low alertness of doctors in relation to this disease in a non-endemic region.