Causes and mechanisms of development
Brill-Zinsser disease occurs as a recurrent episode of typhus years or even decades after the primary infection. The causative agent, Rickettsia prowazekii, is capable of long-term persistence in the body.
The relapse is exclusively endogenous in nature and is usually triggered by factors that weaken the body's defenses. Triggering factors may include recently suffered acute infections (e.g., generalized salmonellosis) or major surgical interventions (abdominal surgery, cholecystectomy). An important epidemiological feature distinguishing this pathology from primary epidemic typhus is the absence of pediculosis in the patient.
Clinical presentation
The disease has an acute onset: the temperature rises to febrile levels (38.7–40.1 °C) and lasts on average about five to eight days. Patients complain of a throbbing headache, progressive weakness, insomnia, and anorexia.
Objective examination reveals characteristic markers of rickettsiosis:
- Appearance: bright hyperemia of the face, neck, and upper chest ("hood" sign). The face is often puffy.
- Mucous membrane and eye lesions: injection of scleral and conjunctival vessels. Positive Chiari-Avtsyn symptoms (conjunctival rash) and Jürgens symptoms (petechiae on the transitional fold of the conjunctiva) are detected. Enanthema on the mucosa of the soft palate is observed.
- Tongue changes: the tongue is dry, coated with brown or dark-brown plaque. Govorov-Godelier signs are noted — the tongue trembles, is not protruded fully, and deviates to the side (deviation).
- Exanthema: around the 5th day of fever, a sparse roseolous-petechial rash appears on the skin of the lateral surfaces of the torso, back, and abdomen.
- Abdominal organs: hepatosplenomegaly naturally develops.
The pathology is accompanied by involvement of the nervous system. Psychomotor agitation is pronounced (patients are fussy, talkative, speech is slurred), and general and hand tremors are observed. Meningeal signs are detected, in particular nuchal rigidity, while Kernig's sign may remain negative.
Laboratory and differential diagnosis
The hemogram reveals moderate neutrophilic leukocytosis with a left shift of band neutrophils and an accelerated ESR.
Diagnosis verification is based on serological methods. The basis is the study of paired sera with a 7-day interval. The indirect hemagglutination assay (IHA) and complement fixation test (CFT) with Rickettsia prowazekii antigen are used. Accounting for the immunoglobulin class (IgM/IgG) is mandatory. Diagnostic antibody titers can reach values of 1:1280 and 1:5120 as early as the 5th day of the illness.
Within the framework of differential search, depending on the epidemiological history, it is necessary to exclude generalized forms of salmonellosis, malaria (thick blood smear microscopy), plague, and various hemorrhagic fevers.
Complications
A severe consequence of the infection is vascular catastrophes caused by endothelial damage and thrombosis. In elderly patients against the background of prior vascular pathology, acute cerebrovascular accidents may develop.
Clinically, this manifests as persistent focal neurological symptoms: hemiplegia, facial nerve paresis, and motor aphasia (e.g., in a stroke in the middle cerebral artery basin). The development of such complications makes the prognosis unfavorable and requires transferring the patient to a neurological department with a CT scan of the brain.
Management and treatment
All patients with Brill-Zinsser disease are subject to mandatory hospitalization in an infectious diseases hospital (boxed ward), regardless of the severity of the course. In the presence of pediculosis, sanitary treatment is carried out.
- Regimen: strict bed rest is maintained until the 5th–7th day of persistently normal temperature. Continuous monitoring by medical staff of the patient's behavior is required due to the threat of developing typhus psychosis.
- Etiotropic therapy: immediate prescription of tetracycline antibiotics (e.g., doxycycline). Oral administration is optimal; if impossible, parenteral administration.
- Pathogenetic support: includes intravenous detoxification therapy, oxygen therapy, administration of catecholamines. It is extremely important to prescribe anticoagulants and antiplatelet agents for the prevention of thrombosis. Tranquilizers are used for pronounced agitation.
Discharge is permitted upon normalization of hemodynamics and persistent disappearance of clinical symptoms, but strictly no earlier than the 12th day of normal temperature.
Briefly: answers to topical questions
Which class of immunoglobulins (IgM or IgG) quantitatively predominates in blood serum in Brill-Zinsser disease?
In Brill-Zinsser disease, IgG class antibodies are detected in the blood serum.
During serological diagnostics of the recurrent form of infection, high titers of IgG-type antibodies are detected in paired sera (e.g., 1:1280 and 1:5120). Determining the belonging of antibodies to specific immunoglobulin classes is mandatory for differential diagnosis. Unlike relapse, in primary epidemic typhus, specific IgMs are detected in diagnostic titers on the 5th–7th day of the disease, whereas IgG antibodies in low titers can persist in the blood of recovered individuals for decades.
What are the specific typhus granulomas that form in the walls of small blood vessels of the brain and skin in this infection called?
Specific typhus granulomas are called Popov-Frankel-Davydovsky nodules.
According to the source, their formation is associated with acute universal destructive thrombovasculitis: vessel occlusion leads to ischemia in the surrounding proliferated tissues, then cellular infiltration of the ischemic zone occurs, and a typhus granuloma—the Popov-Frankel-Davydovsky nodule—is formed.
In the central nervous system, the maximum number of granulomas appears from the 6th–7th day of the disease; the predominant localization is indicated in the medulla oblongata, the gray matter of the cerebral cortex, the corpus striatum, and the meninges.
Class and exam questions
Can Brill-Zinsser disease be treated on an outpatient basis if the patient's condition is stable?
No. Hospitalization in an infectious diseases hospital is absolutely mandatory for all patients, regardless of the severity of the disease course.
Is a patient with Brill-Zinsser disease contagious to others?
The endogenous relapse itself occurs without the participation of a vector. However, if body louse infestation is present in such a patient or in their environment, it can become a source of infection for lice and provoke a new outbreak of epidemic typhus.
What neurological complication is most typical for this pathology?
Due to specific vascular lesions (endotheliosis), there is a high risk of acute cerebrovascular accidents (ischemic strokes), which manifest as hemiplegia, aphasia, and cranial nerve paresis.
What else to study on this topic
- Pathogenesis of vascular lesions: how rickettsia destroy the endothelium
- Specific eye symptoms: Chiari-Avtsyn and Jürgens
- Typhus psychosis: development mechanisms and management methods
- Interpretation of IHA and CFT results in rickettsioses
- Criteria for clinical recovery and rules for discharge from the hospital
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