History and exam
Key diagnostic factors
common
history of contact with infected person
fever or chills
constitutional symptoms
Nonspecific symptoms such as sweating, lethargy, and weight loss are a feature of infection in up to 97% of patients.[81]
arthralgia
Particularly affecting hips, knees, or spine, is associated with 20% to 83% of infections.[81][82][95] Young children may present with difficulty walking, mimicking an irritable hip. Osteoarticular involvement is the predominant manifestation in children, with approximately 51% of cases having osteoarticular involvement. Hip and knee arthritis are the most common manifestations in children, but shoulder, elbow, and spine involvement may also occur.[116]
joint swelling and tenderness
Suggestive of arthritis. Typically occurs in about 50% of adult patients, but reported in up to 83% of infected patients.[95]
Signs include bursitis, decreased joint range of motion, and joint effusion.
The spine or sacroiliac joints may be tender, but gross deformity is unusual and more suggestive of tuberculosis.
hepatomegaly and/or splenomegaly
Occurs in up to one third of infected patients.[111]
Other diagnostic factors
common
nausea, vomiting, abdominal pain, constipation, diarrhea
Nonspecific gastrointestinal symptoms.
lymphadenopathy
Occurs in about 10% of adults and in up to two-thirds of children.[85]
dry cough
Usually associated with few clinical signs in the chest, although pulmonary involvement is reported in up to 20% of patients if a dry cough is present.[88]
uncommon
chest signs
There are increasing reports of consolidation, hilar lymphadenopathy, pleural effusions, pneumothorax, and lung nodules being associated with brucellosis. Up to 20% of patients with a dry cough have pulmonary involvement.[88]
testicular pain
neck stiffness
cranial nerve palsy or focal central nervous system deficit
Focal brain or cranial nerve lesions are rare manifestations. Long-tract neurologic signs are very unusual.
dullness to percussion, decreased air entry, crepitations
red eye
Suggestive of uveitis or conjunctivitis; rarely occurs.
skin rashes
A variety of nonspecific maculopapular or vasculitic skin rashes may occasionally be seen.[89]
Risk factors
strong
ingestion of contaminated foods
This is one of the most common modes of transmission in endemic countries. The consumption of uncooked animal products is a common practice in certain parts of the world, as is the consumption of unpasteurized milk and dairy products.[15][64] The highest prevalence of contamination in unpasteurized dairy products was in buffalo and goat products.[65]
exposure to infected animal products
The organisms are shed in animal excretions including urine and feces, and in products of conception. They can survive for long periods of time in the soil (up to 2 years), especially if moist, and, therefore, continue to infect humans and animals.[51]
In rural areas, it is common for contaminated products of conception to be discarded. Consequently, they dry out and are transmitted by inhalation in dust or contaminate the environment and are ingested by other animals or humans in contact with them.
inhalation of infected aerosols
conjunctival contact with infected material
Splashes of infected material onto the conjunctivae are a common route of infection in laboratories.
occupation with potential for exposure to Brucella species
Brucellosis tends to be an occupational disease predominantly affecting farmers, animal handlers, abattoir workers, veterinarians, and feral pig hunters.[39][40] Hunters and dogs can become infected following direct contact with feral pig tissues and blood during hunting and the slaughter process.[6] On farms, infection commonly occurs by inhalation of infected aerosols from dried animal products of conception. Less commonly, organisms can also gain entry into the body through cuts and abrasions in the skin, and veterinarians and animal handlers who use ungloved hands to deliver infected animals are, therefore, at risk.[68] In addition, veterinarians can acquire brucellosis by accidental inoculation of live animal vaccines.
Brucellosis may also occur in laboratory personnel working with cultures.[30][31][32][33][34][35][36][37][38] In the laboratory, infection occurs from inhalation of infected aerosols or splashes onto conjunctivae from infected material.
travel to an endemic area
A history of travel to an endemic area should always be asked about, and migrants from endemic areas should be asked specifically about consumption of imported dairy products.[69][70][71]
Major endemic areas worldwide include the Mediterranean, the Arabian Gulf, Central Asia, and parts of Central and South America.[2][5][7][18] There is evidence that the infection is common but under-reported in India, and emerging in other parts of the world (e.g., Polynesia, Thailand, and Vietnam).[9][10][11][12][13][14]
weak
cuts or abrasions in skin
The organism can also gain entry into the body through cuts and abrasions in the skin, and farmers, veterinarians, and animal handlers who use ungloved hands to deliver infected animals are, therefore, particularly at risk.[68]
sexual contact with infected individual
Species of Brucella that affect humans have been cultured from human semen, and sexual transmission has been reported. However, this is rare in comparison with other routes of entry such as inhalation and ingestion.[72]
newborn or infant of infected mother
Brucella species have been found in the placental tissue of humans, with subsequent miscarriage or disease presenting in the newborn.[58][59] Brucellae have also been cultured from breast milk in the absence of localized breast disease, suggesting that breast milk contamination is a possible source of infection for infants.[1] However, the evidence available for these forms of transmission is sparse.
recipient of blood products or of organ or tissue transplant
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