Erased and acute manifestations of the infection
The disease often manifests subacutely in the form of so-called "ambulatory" variants. In this case, the temperature reaction is absent or limited to short-term low-grade fever. Patients complain of rapid fatigue, headache, malaise, and sleep disturbances. Pain appears in the joints, muscles, lower back, and along major nerve trunks. Patients continue their daily activities ("on their feet"), which leads to late seeking of medical care and the development of primary chronic brucellosis.
The classic acute course is characterized by prolonged irregular fever with chills and profuse sweating. A crucial diagnostic marker is that the patient feels quite well even with high temperature readings. Objectively, hepatosplenomegaly (enlargement of the liver and spleen) is detected, and less commonly, polyadenopathy and skin rashes.
Subacute brucellosis
This form is recorded in the interval from 1.5 to 4 months of the disease. The course becomes relapsing: periods of fever alternate with remissions. Patients' mood is depressed, and complaints are numerous.
Two clinical variants are distinguished:
- Without relapsing generalization: focal lesions come to the forefront without pronounced general intoxication.
- With recurrent generalization: focal changes occur against the background of a severe toxic syndrome.
Focal lesions (may develop as early as weeks 2–5):
- Musculoskeletal system: arthritis, bursitis, synovitis, tenosynovitis. An important diagnostic aid is the detection of fibrositis and cellulitis.
- Reproductive system: in men, orchitis and epididymitis are typical; in women, endometritis, menstrual cycle irregularities, and spontaneous abortions.
- Peripheral nervous system: plexitis, neuritis, radiculitis.
- Rare lesions: thrombophlebitis, myocarditis, interstitial nephritis, meningoencephalitis.
Chronic and residual brucellosis
If the disease lasts longer than 4 months, it transitions into a chronic form. Intoxication becomes mild, remissions lengthen, but during exacerbations, new reactive-inflammatory focal lesions appear. In 80–90% of cases, joint and bone lesions dominate (sacroiliitis, osteoperiostitis, perichondritis). A change in neuropsychiatric status is characteristic: persistent neuroses develop, and patients acquire a specific "difficult personality".
Residual brucellosis refers to the consequences of a past infection. The pathogenetic essence is that the pathogen itself is no longer present in the body, but the symptoms persist. Patients are troubled by muscle and joint pain, weakness, and irritability. Body temperature is usually normal, and immunological reactions are negative. In rare cases (with the modern course of the disease), severe fibrous-scar joint deformations, ankylosis, and irreversible nerve trunk damage remain.
Laboratory diagnostics
Establishing a diagnosis requires an integrated approach that takes into account the epidemiological history (contact with animals, raw milk) and laboratory data.
- Hemogram (CBC): leukopenia, relative lymphocytosis, monocytosis, and thrombocytopenia are typical. ESR remains normal or moderately elevated.
- Serological tests: Wright's test (diagnostic titer from 1:200), Huddleson-Kaitmazova test, IHA, CF_T (complement fixation test), Coombs test (for incomplete antibodies).
- Burnet intradermal skin test: evaluated after 24 and 48 hours. Hyperemia and edema measuring 5–6 cm or more are considered positive.
- Bacteriology: cultures of blood, cerebrospinal fluid, or bone marrow are rarely used due to slow growth (3–4 weeks) and high risk of laboratory staff infection.
Differential diagnosis
Due to the polymorphism of symptoms, brucellosis requires careful differentiation from:
- Typhoid fever: differs by pronounced adynamia, facial pallor, appearance of roseola on the abdomen on days 8–10, "typhoid" tongue, and relative bradycardia.
- Leptospirosis: characterized by severe muscle pain, facial hyperemia, scleral injection, and neutrophilic leukocytosis on CBC.
- Malaria: has a clear periodicity of attacks (alternation of chills, heat, and sweat), anemia, and is detected by thick blood smear microscopy.
- Sepsis: proceeds with hemorrhages, presence of a primary focus, neutrophilia, and bacteremia.
Chronic brucellosis is differentiated from rheumatoid arthritis, osteomyelitis, tick-borne borreliosis, and gynecological pathologies.
Briefly: answers to topical questions
Which classes of immunoglobulins are detected using Wright's test and Coombs' test?
Wright's test detects IgM and IgG class antibodies, while Coombs' test detects incomplete blocking antibodies of IgA and IgG classes. Wright's agglutination test is used in the acute form of the infection and during chronic exacerbation to detect high antibody titers: IgM appear from the first week, and IgG from the third week. The Coombs test is used in the subacute form, remission, or latent course, when standard agglutination reactions may be negative despite a typical clinical picture. This method aims specifically at detecting incomplete blocking antibodies.
Which antibacterial drugs are the drugs of choice for etiotropic therapy of brucellosis?
The drugs of choice for etiotropic therapy of brucellosis are rifampicin, doxycycline, streptomycin, and ofloxacin. Treatment principles require the simultaneous prescription of two antibacterial drugs, one of which must penetrate the cell membrane. Main therapeutic regimens include the following combinations:
- Rifampicin — used together with doxycycline (continuous course of at least 6 weeks) or ofloxacin.
- Doxycycline — prescribed in combination with rifampicin or streptomycin.
- Streptomycin — used intramuscularly during the first 2 weeks of the course along with doxycycline.
- Ofloxacin — used together with rifampicin.
In case of disease relapses, repeated courses with a change of drugs are indicated.
For the classic picture of acute brucellosis, remember the rule of the three "P"s: Profession (contact with animals), Profuse sweats, Perfect well-being (good tolerance of fever).
Class and exam questions
What is the paradox of fever in acute brucellosis?
In its good tolerance. Despite a prolonged temperature elevation accompanied by chills and profuse sweats, the patient feels relatively well and even maintains working capacity.
What is residual brucellosis?
These are residual phenomena after a past disease. The pathogen is absent in the body (immunological tests are negative), but functional disorders, pain, and sometimes irreversible joint deformations persist.
Why is the bacteriological method rarely used in practice?
Cultivation of Brucella requires 3–4 weeks, is technically difficult to perform, and carries a high risk of infection for medical personnel.
Which organs are predominantly affected in the chronic course?
In 80–90% of cases, musculoskeletal lesions (arthritis, tenosynovitis, sacroiliitis) come to the forefront in combination with mental changes (neuroses).
What else to study on this topic
- Criteria for evaluating the Burnet skin-allergic test
- Comparative characteristics of serological reactions (Wright, CFT, Coombs)
- Hemogram changes in infectious diseases (differential search)
- Epidemiological risk factors: alimentary and occupational routes of transmission
- Indications for hospitalization of patients with brucellosis
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