Discussion
In this article, we reported a 42-year-old woman who had no history of livestock contact, sternoclavicular joint or left breast trauma, and also there were not any risk factors of sternoclavicular arthritis such as intravenous drug use, distant site of infection, diabetes mellitus, trauma, and infected central venous line. She had experienced purulent discharge from the left breast and underwent left breast abscess drainage and antibiotic treatment on an outpatient basis one and a half months before hospitalization, but there was no improvement so occasional discharge continued following abscess evacuation. Furthermore, two weeks before admission, pain and redness, and swelling of the left sternoclavicular joint were added. So she was hospitalized with the diagnosis of acute left sternoclavicular arthritis for further examination. MRI showed signs of left sternoclavicular arthritis. In addition, laboratory tests that were performed to rule out causes of arthritis, including rheumatoid arthritis and systemic lupus erythematosus, all were negative [2]. Since brucellosis is one of the causes of arthritis in endemic areas, blood culture and serology of brucellosis were requested. Blood culture × 2 was reported positive for brucellosis and Wright agglutination test:1/160, Coombs Wright test: 1/320, 2-mercaptoethanol (2ME): 1/80 in favor of brucellosis [5,10,11]. According to the patient’s complaint about purulent discharge from the left breast and history of abscess drainage one and a half months ago, at the same time as we were performing diagnostic tests for left sternoclavicular arthritis, a breasts ultrasound was performed which showed a fibrocystic change of both breasts and a mass in the left breast then she underwent left breast abscess biopsy. The results of pathology and immunohistochemistry (IHC) were not in favor of malignancy. Breast abscess culture was reported as having few colonies of coagulase-negative staphylococcus which is considered as contamination because she did not have a fever, leukocytosis and other systemic signs also colony count was low.
Breast abscess due to brucellosis is extremely rare. So to rule out endocarditis and its metastatic abscess [11] to the breast and a sternoclavicular joint, transthoracic echocardiography was performed and its result was normal, without any vegetation or valve abnormality.
Fever, chills, sweating, fatigue, headache, splenomegaly, hepatomegaly, arthralgia and musculoskeletal pain, which are seen in most patients with generalized and localized brucellosis [1,5,11], were not present in our patient and she also had no other positive findings except left sternoclavicular arthritis and left breast abscess.
As reported in other studies, there were no specific hematological or biochemical findings in our case [2,11,12]. There was no leukocytosis in this patient and liver function tests were normal but ESR and CRP were high.
As Since the diagnosis of brucellosis arthritis is confirmed by signs and symptoms of arthritis (pain, tenderness, swelling of the joint)[17,18] in the presence of an antibody titer greater than 1:160 in the tube agglutination test or by a positive culture [10,11], brucellosis was diagnosed in our patient and considering two very rare complications of brucellosis: left sternoclavicular arthritis and left bursal abscess both simultaneously in this patient due to the lack of history of trauma and external inoculation and because she had no history of direct contact with livestock, we concluded that these complications are hematogenous. Therefore, with the diagnosis of localized brucellosis, which requires a combination of antibiotics and a prolonged course of treatment to prevent failure or relapse of brucellosis [2,10,11], the patient was treated with a standard regimen (streptomycin and doxycycline for two weeks, then rifampin and doxycycline for ten weeks). On the fourth day of treatment, she responded and the joint symptoms improved significantly the discharge from the patient’s left breast was stopped after starting the treatment and she was discharged and recommended to continue the outpatient treatment and follow-up. The prognosis of brucella arthritis will be very good if appropriate and in time treatment is begun [12,19]. Unlike spondylitis, both sacroiliitis and peripheral arthritis are nondestructive and quickly curable with no sequelae [2,12].
Thirty days after discharge at the follow-up visit, the patient did not relate a feeling of stiffness or heaviness in the left breast and occasional discharge from it which she had previously experienced, and also left sternoclavicular arthritis completely was cured. She completed treatment of two localized complications of brucellosis simultaneously (sternoclavicular arthritis and left breast abscess) without any complications.
Each of the complications of sternoclavicular arthritis and Brest abscess due to brucellosis is solely a very rare complication of brucellosis. However, we found both of these rare complications simultaneously in one patient. Then, we could successfully treat her using the standard treatment of streptomycin and doxycycline for two weeks followed by rifampin and doxycycline for ten weeks.
Given that brucellosis is a thousand-face disease, especially in endemic areas, clinicians in all regions of the world, especially endemic areas should be familiar with rare complications of it so we reported this patient with very rare complications of this zoonotic disease and its successful treatment.