Clinical presentation and leading syndromes
The disease can be suspected based on an acute onset and a combination of several characteristic syndromes. Patients experience a sharp spike in body temperature (up to 39.5 °C), chills, body aches, anorexia, insomnia, and intense headache.
Key clinical manifestations include:
- Intoxication syndrome: nausea, repeated vomiting, severe generalized weakness.
- Hemorrhagic syndrome: epistaxis (epistaxis), petechial rash on the trunk (especially on the back and chest), bruising at injection sites, enanthema on the soft palate mucosa. The "hood" sign (hyperemia of the face, neck, and shoulder girdle), injection of scleral and conjunctival vessels are characteristic.
- Renal syndrome: severe pain in the lumbar region, forced patient position in bed, sharply positive Pasternatsky's sign (costovertebral angle tenderness) bilaterally. Pronounced oliguria developing into anuria (urine output of 50–100 ml per day) against the background of severe thirst (polydipsia).
- Other manifestations: arterial hypotension, bradycardia, dryness of mucous membranes and skin. Visual impairment is considered a specific sign: patients complain of "fog" and "floaters" before their eyes.
Epidemiological history
To confirm the diagnosis, it is critically important to identify risk factors for hantavirus infection. Transmission typically occurs through contact with rodents or their excreta.
The physician needs to clarify the following anamnestic details:
- Agricultural or construction work (especially in basements and summer cottages).
- Staying in the forest (occupational activities, e.g., in loggers, or recreation).
- Swimming in natural water bodies.
- Consumption of unboiled (raw) water and food products that may have been contaminated with rodent excreta.
Laboratory diagnostics
The evaluation plan for a patient with suspected HFRS includes both routine and specific methods:
- Specific diagnostics: the gold standard is the indirect immunofluorescence assay (IFA). Testing is performed on paired sera with a 5-day interval. A reliable criterion is a 4-fold or greater rise in specific antibody titers. If technically feasible, polymerase chain reaction (PCR) is performed.
- Complete blood count (CBC): leukocytosis, neutrophilia with a left shift, and an elevated erythrocyte sedimentation rate (ESR) are detected.
- Blood chemistry panel: elevated urea, creatinine, and residual nitrogen levels are characteristic, reflecting the degree of impaired renal function.
- Urinalysis: proteinuria, microhematuria, and hyposthenuria (decreased urine specific gravity) are detected. Strict monitoring of daily diuresis is mandatory.
Diagnosis formulation and management tactics
The definitive clinical diagnosis must reflect the presence of infection, its severity, laboratory confirmation, and complications. Severity is determined by the severity of acute kidney injury (AKI) and hemorrhages. Example: HFRS (IFA titer 1:1000 dated 30.10.2018), severe course. Complication: Uremia.
Basic management tactics:
- Hospitalization: strictly mandatory. The patient is not contagious (not dangerous to others), so if infectious disease beds are unavailable, they can be hospitalized in other departments.
- Monitoring: strict control of diuresis, water-electrolyte balance, and acid-base status.
- Treatment: intensive detoxicating therapy (infusions, fresh frozen plasma, vitamins), improvement of microcirculation (intravenous pentoxifylline), antihistamines. Glucocorticoids are prescribed for a short course under strict indications. Hemodialysis is justified if necessary.
Briefly: answers to topical questions
What consecutive periods are distinguished in the clinical course of HFRS?
The clinical course of HFRS comprises the following consecutive stages:
- Incubation period.
- Initial period.
- Period of full-blown disease — development of renal and hemorrhagic syndromes; includes oliguric and polyuric periods.
- Convalescence period.
What specific hantavirus serotypes cause HFRS?
Hemorrhagic fever with renal syndrome is caused by several pathogenic hantaviruses. The specific causative agents of this disease include the following viruses:
- Hantaan (Hantaan, HTNV) — circulates in the Russian Far East.
- Puumala (Puumala, PUUV) — the most frequent cause of HFRS in European foci of the Russian Federation.
- Seoul (Seoul, SEOV) — causes HFRS.
- Dobrava/Belgrade (Dobrava, DOBV) — one of the pathogenic serotypes.
- Amur (Amur, AMRV) — Far Eastern serotype.
For rapid data collection, remember the four pillars of diagnosis: epidemiological history (forest, rodents) + triad (intoxication, kidneys, hemorrhages) + vision ("floaters") + lab confirmation (IFA, 4-fold titer rise).
Class and exam questions
Does a patient with HFRS pose an epidemiological hazard to others?
No, the patient is completely non-contagious. Hospitalization of the patient in specialized departments of another type is permitted if there are no beds in the infectious disease hospital.
What are the criteria for confirming the diagnosis using IFA?
The diagnosis is considered confirmed upon a 4-fold or greater rise in specific antibody titers when testing paired sera with a 5-day interval.
Which urine parameters need to be monitored especially closely?
First and foremost, strict monitoring of daily diuresis is necessary (to detect oliguria or anuria), along with assessment of specific gravity (hyposthenuria) and protein levels.
What else to study on this topic
- Criteria and markers of acute kidney injury (AKI) in hantavirus infection
- Justification of indications for extracorporeal detoxification (hemodialysis)
- Criteria and timeline for discharging a convalescent from the hospital
- Outpatient follow-up plan for recovered patients
- Differential diagnosis of HFRS with diseases of similar presentation (e.g., acute pyelonephritis)
Master the complete topic in the «Infectious Diseases» course
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- Complete study guide on "HFRS Diagnostics" and 3,312 more pages of the subject
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Other topics in the section "Zoonotic infections — 2024 study guide"
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