Brucellosis Presenting with Febrile Pancytopenia: An Atypical Presentation of a Common Disease and Review of Brucellosis

Abstract

Brucellosis is a febrile zoonotic disease caused by one of several species of the Gram-negative coccobacillus Brucella. It is endemic to the Middle East, sub-Saharan Africa, and Central America. However, cases have also been reported in the United States. Infection is most commonly transmitted via unpasteurized dairy products or through occupational exposure to livestock. The clinical presentation is highly variable; symptoms may include fever, myalgias, night sweats, weight loss, nausea, and vomiting. Less common features include orchitis, osteomyelitis, and sacroiliitis. In addition, pregnant women who contract brucellosis face a markedly increased risk of miscarriage. A presumptive diagnosis is typically established through correlation of patient history and classic laboratory findings, which include transaminitis, anemia, and leukopenia with relative lymphocytosis. Definitive diagnosis can only be established through isolation of Brucella species from blood or tissues. Treatment involves a prolonged course of multiple antibiotics; six weeks of combination therapy with aminoglycoside or rifampin and tetracycline represents the most common regimen. Healthy individuals who develop brucellosis have a generally favorable prognosis, as the case fatality rate is less than 2%. Nevertheless, early detection and treatment are essential to reduce the risk of long-term sequelae that may result from chronic, indolent disease.

Undulant Fevers and Bitemporal Headaches: A Clinical Presentation of Human Brucellosis

“…Four species known to cause human brucellosis are B. melitensis (goats, sheep, and camels) which is most common, B. abortus (cows), B. suis (pigs), and B. canis (dogs). Typically, infection with B. melitensis and B. suis tends to be more virulent [ 1 ]. In endemic countries, transmission occurs from consumption of unpasteurized dairy products, contaminated meats, and exposure to tissue and fluids; however, in developed countries, infection occurs due to occupational exposure, direct skin or mucosal contact with infected livestock.…”

“…While incidence in the United States is only about 100-200 cases/year (which may be underreported), the number of human infections worldwide has continued to increase due to greater travel and globalization [ 3 ]. Thus, brucellosis infection must be further investigated in any patient presenting with concerning symptoms following travel to high-risk areas [ 1 ].…”

“…Symptoms of nausea and vomiting, such as in our patient, were observed in only 24.9% of the cases. A useful distinguishing tool in the diagnosis of brucellosis is the potential of the bacteria to manifest as febrile pancytopenia, in contrast to the classical bacteremia presentation of leukocytosis and neutrophilia with bandemia [ 1 ].…”

“…Brucellosis (also coined Mediterranean fever, Malta fever, or undulant fever) is transmitted by the bacteria of the genus Brucella . It is a common zoonotic infection endemic to countries of the Mediterranean, Middle East, Central America, Central Asia, the Indian subcontinent, and Sub-Saharan Africa [ 1 , 2 ]. Transmission occurs from animals to humans by ingestion of unpasteurized dairy products, contaminated food, or exposure to tissue and fluids.…”

“…Symptoms commonly present non-specifically and include fevers, chills, myalgia, nausea, vomiting, diarrhea, weight loss, and headaches. Pancytopenia represents one of the most common laboratory findings [ 1 , 2 ]. Brucellosis is typically not seen in developed countries, but this disease should still be considered in patients who travel to high-risk regions or suffer from atypical symptoms.…”