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Typhus - Diagnosis
Last reviewed: 03.07.2025
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Diagnosis of epidemic typhus is based on clinical and epidemiological data, and the diagnosis is confirmed by laboratory tests. Of significant importance are the presence of pediculosis, the characteristic appearance of the patient, intense headache combined with insomnia, the appearance of a rash on the 5th day of illness, damage to the central nervous system, and hepatosplenic syndrome.
Isolation of the pathogen is usually not carried out due to the complexity of cultivating rickettsia, which is only possible in specially equipped laboratories with a high degree of protection.
The main diagnostic method (diagnostic standard) is serological: CSC, RIGA, RA, RNIF, ELISA. When conducting CSC, a titer of 1:160 is considered diagnostically reliable. A positive result in RNGA can be obtained from the 3rd to 5th day of illness, the diagnostic titer of this method is 1:1000. RA is less sensitive than RNGA and has a diagnostic titer of 1:160. RNIF and ELISA determine specific IgM and IgG. Reliable diagnostics of epidemic typhus is possible when using several serological tests in parallel, usually CSC and RNGA.
PCR can be used to detect antigens of Rickettsia prowazekii.
Differential diagnostics of epidemic typhus
In the initial period, differential diagnostics of epidemic typhus is carried out with influenza, meningococcal infection, pneumonia, hemorrhagic fever, tick-borne encephalitis and other conditions with manifestations of fever; during the peak period, epidemic typhus is differentiated from typhoid fever, measles, pseudotuberculosis, sepsis and other febrile diseases accompanied by rashes.
Flu is characterized by a more acute onset, severe weakness, constant profuse sweating (with typhus, the skin is dry in the vast majority of cases), no puffiness of the face and amimia, as well as the Govorov-Godelier symptom. With flu, there is no rash, the spleen and liver are not enlarged. Headache is usually localized in the forehead, superciliary arches and in the temporal regions, pain is characteristic when pressing on the eyeballs and when moving them. Intoxication is most pronounced in the first 3 days of the disease, from the second day the picture of tracheitis dominates.
Differential diagnosis of epidemic typhus and pneumonia is carried out taking into account the characteristics of breathing, physical data, cough, moderate sweating, pain when breathing in the chest area, absence of rash, Chiari-Avtsyn symptom, CNS damage, radiological data and blood picture.
Bacterial meningitis is differentiated from typhus by the presence of a more pronounced meningeal syndrome (rigidity of the occipital muscles, positive Kernig and Brudzinski symptoms), as well as by higher rates of leukocytosis with neutrophilia. When analyzing the cerebrospinal fluid in patients with bacterial meningitis, cytosis and protein are detected, and in typhus, meningism is observed.
In hemorrhagic fever, especially with renal syndrome, hyperemia of the face and conjunctiva is more pronounced, the rash has the character of scanty point hemorrhages, most often detected on the lateral surfaces of the body and in the axillary areas. Characteristic: vomiting, hiccups, pain in the lower back and abdomen, thirst and oliguria are typical. In these diseases, erythrocytosis, normal or increased ESR, increased urea and creatinine in the blood, hematuria, proteinuria, cylindruria are observed. The development of hemorrhagic phenomena occurs against the background of a decrease in temperature.
Typhoid fever is characterized by paleness of the face, general adynamia, lethargy, bradycardia with dicrotic pulse. The tongue is thickened, coated, with teeth marks on the edges. Flatulence and rumbling in the right iliac region are characteristic, as well as an enlarged liver and spleen at a later date. The rash is scanty roseola, appears later (not earlier than the 8th day of illness) on the chest, abdomen and lateral surfaces of the body with subsequent rashes. Leukopenia with eosinopenia, band shift with relative lymphocytosis, thrombocytopenia are found in the blood.
Differential diagnostics of epidemic typhus with tick-borne typhus, which occurs in Siberia and the Far East, is based on the symptoms characteristic of this disease: the presence of a primary affect at the site of the tick bite in most patients and the development of regional lymphadenitis almost simultaneously with the primary affect. The roseola-papular rash is bright, spread throughout the body. The appearance of rashes on the 2nd-4th day of the disease is typical.
In ornithosis, it is important to have contact with birds in the epidemiological history. The rash is only roseolous, and it is most often located in nests on the body and limbs. In the blood - leukopenia, eosinopenia, relative lymphocytosis and a sharp increase in ESR. Interstitial pneumonia is characteristic, confirmed by X-ray.
Sepsis is distinguished from typhus by the presence of a septic focus and the entrance gate of the infection. Sepsis is characterized by a hectic temperature, severe sweating and chills, hemorrhagic rashes on the skin, a significant increase in the spleen, clearly defined bright red hemorrhages on the mucous membrane of the eye, anemia, leukocytosis with neutrophilia, high ESR.
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