Diagnostic fundamentals and general principles
The foundation for establishing a diagnosis is the detection of the pathogen in the biological fluids of the body: feces, urine, as well as in duodenal contents.
Serological screening is often performed prior to bacteriological culture. Its purpose is to detect specific Vi-antibodies in the patient's blood serum.
Since many infections in the initial stages manifest with severe intoxication and high fever, differential diagnosis is carried out taking into account the period of the disease and accompanying symptoms (encephalopathy, hepatosplenomegaly, skin rashes).
Differentiation in the first week
In the first days of the illness, typhoid fever must be differentiated from paratyphoid fevers A and B, as well as generalized salmonellosis, influenza, malaria, pneumonia, and epidemic typhus.
Paratyphoid fevers A and B and generalized salmonellosis:
- Intoxication and fever are less pronounced and last for a shorter time.
- Skin rashes appear earlier (end of the first week) and are more abundant.
- Leukocytosis may be observed in the blood, and eosinophils persist.
Influenza: Begins abruptly, with myalgia, headache (in the frontal and temporal regions), and pain with eye movement. Facial flushing, injection of sclerae, and the onset of tracheitis from the second day are characteristic. Confirmed by detecting the virus in nasal swabs.
Epidemic typhus: Associated with a history of pediculosis. Manifests with insomnia, psychosis, and facial hyperemia. The rash is roseolous-petechial, appearing on days 4–5. An important sign is neurological symptoms (tremor, Govorov-Godelier sign).
Malaria: Depends on the epidemiological history (stay in endemic areas). The fever becomes paroxysmal, accompanied by severe chills, sweats, and hepatosplenomegaly. The diagnosis is made by the presence of plasmodia in the blood.
Differentiation in the second week and later
At later stages, infectious mononucleosis and brucellosis are included in the differential diagnosis.
Infectious mononucleosis (EBV infection):
- Proceeds with tonsillitis (up to necrotic), lymphadenopathy (especially in the occipital and cervical regions), and hepatosplenomegaly.
- Ampicillin administration often provokes a rash.
- Atypical mononuclear cells appear in the blood, confirmed by the detection of IgM to EBV and heteroagglutination assays.
Brucellosis:
- Associated with occupational risks (contact with animals, raw products).
- Prolonged fever, polyadenopathy, and arthralgia are characteristic, but the patient retains working capacity for a long time.
- Blood tests show leukopenia, lymphomonocytosis. For diagnosis, hemocultures and myelocultures are examined, serological tests and the Burnet skin test are used.
Specific complications
Despite frequently moderate-to-severe courses, typhoid fever can lead to life-threatening conditions.
Typical severe complications include:
- Intestinal hemorrhage.
- Intestinal perforation.
In addition, relapses of the disease are possible, requiring careful monitoring during the convalescence period.
Briefly: answers to topical questions
At what timeframe and stage of pathogenesis does intestinal hemorrhage occur in typhoid fever?
Intestinal hemorrhage in typhoid fever occurs in the third week of the disease. At this stage of pathogenesis, the rejection of necrotic masses and the formation of "dirty" ulcers occur in the intestine, with the formation of which the development of this specific complication is associated.
What vaccines are used for the specific prevention of typhoid fever?
For the specific prevention of typhoid fever, the sources indicate:
- Adsorbed typhoid vaccine.
- Alcohol-extracted vaccine enriched with Vi-antigen.
Vaccinations are carried out according to epidemiological indications. For emergency prophylaxis, contact persons in foci are prescribed dry typhoid bacteriophage.
What do the measures of non-specific prevention of acute intestinal infections consist of?
Non-specific prevention of acute intestinal infections includes sanitary and bacteriological control of water supply and compliance with sanitary and hygienic standards. Upon detection of a patient or carrier of acute intestinal infection pathogens, mandatory referral of an emergency notification to the territorial state sanitary and epidemiological supervision authority is recommended. The notification is submitted by all medical organizations regardless of ownership.
What specific serological reactions are used to confirm brucellosis?
For the serological diagnosis of brucellosis, the following reactions are used:
- Agglutination reaction — Wright test and Huddleson-Kaitmazova test.
- Indirect hemagglutination test — IHA.
- Complement fixation test — CFT.
- Immunofluorescence assay — IFA.
- Enzyme-linked immunosorbent assay — ELISA.
- Antiglobulin test — Coombs test (allows the detection of incomplete blocking antibodies).
What complications of acute intestinal infections exist, apart from perforation and hemorrhage?
In addition to perforation and hemorrhage, the sources indicate the following complications of acute intestinal infections:
- infectious-toxic shock;
- acute adrenal cortex insufficiency;
- encephalitic syndrome;
- rectal prolapse;
- hemolytic-uremic syndrome;
- non-specific complications: pneumonia of various etiologies, otitis, urinary tract infections, oral cavity infections;
- for typhoid fever, thrombophlebitis, parotitis, and cholecystitis are also indicated as non-specific complications.
In severe cases, the sources also describe exicosis and the risk of developing mixed hypovolemic and infectious-toxic shock.
What else to study on this topic
- Methodology for blood and stool culture collection
- Interpretation of serological tests (Widal test, IHA)
- Pathogenesis of intestinal hemorrhage and perforation
- Chiari-Avtsyn and Rosenberg signs in typhus
- Clinical features of paratyphoid fever C
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