Fever of unknown origin

Sometimes there are cases when the patient's body temperature rises (more than 38 ° C) almost on a background of complete health. This condition can be the only sign of the disease, and numerous studies do not allow you to determine any pathology in the body. In this situation, the doctor, as a rule, makes a diagnosis - a fever of unknown origin, and after that appoints a more detailed examination of the body.

ICD Code 10

Fever of unexplained etiology of R50 (except for birth and postnatal fever, as well as newborn fever).

• R 50.0 - fever accompanied by chills.
• R 50.1 is persistent fever.
• R 50.9 is a persistent fever.

Causes of fever of unknown origin

• Systemic extensive infectious diseases:
  • tuberculosis;
  • typhoid diseases (rash, abdominal, endemic, etc.);
  • defeat with salmonella, shigella;
  • Maltese fever (brucellosis);
  • yersiniosis, chlamydia;
  • borelliosis;
  • Francis disease (tularemia);
  • syphilitic infection;
  • leptospirosis;
  • malarial disease;
  • cytomegalovirus, toxoplasm, histoplasm, mononucleosis;
  • AIDS;
  • sepsis.
• Localized infectious diseases:
  • inflammation of the endocardium, thrombotic inflammation of the vessels;
  •  abscesses, bronchiectasis;
  • hepatitis, cholangitis;
  • infectious diseases of the urinary tract and the genital area;
  • osteomyelitis, dental infectious diseases.
• Tumor processes:
  • malignant diseases of the blood or lymph (leukemia, lymphogranulomatosis);
  • tumors of the liver, kidneys, lungs, digestive system;
  • metastasis of tumors.
• Connective tissue pathologies:
  • granulomatosis;
  • SLE;
  • rheumatism;
  • periarteritis.
• Medicinal syndromes (malignant hyperthermia, extrapyramidal disorders).
• Pathology of the digestive organs (ulcerative inflammation of the intestine, alcohol intoxication, cirrhosis).
• Sarcoidosis.

[1], [2], [3], [4], [5], [6], [7], [8]

Symptoms of fever of unknown origin

The main (often and only) present sign of fever of unknown origin is an increase in temperature. Over a long period, fever may occur without concomitant symptoms, or may occur with chills, sweating, cardiac pain, dyspnoea.

• An increase in temperature values is necessarily present.
• The type of temperature increase and temperature characteristics, as a rule, help to uncover the picture of the disease.
• There may be other signs that usually accompany a fever (headaches, drowsiness, body aches, etc.).

Temperature indicators can be different, depending on the type of fever:

• low-grade (37-37,9 ° C);
• febrile (38-38.9 ° C);
• pyretic (39-40.9 ° C);
• hyperpyretic (41 ° C>).

A prolonged fever of unknown origin can be:

• acute (up to 2 weeks);
• subacute (up to one and a half months);
• chronic (more than one and a half months).

Fever of unclear genesis in children

Elevated temperature in a child is the most common problem with which a pediatrician is referred. But which temperature in children should be considered a fever?

Doctors separate fever from just high temperature when the indicators exceed 38 ° C in infants, and above 38.6 ° C in older children.

For most of the small patients, fever is associated with a viral infection, a smaller percentage of children are ill with inflammatory diseases. Often such inflammations affect the urinary system, or there is a latent bacteremia, which in the future can be complicated by sepsis and meningitis.

The most common pathogens of microbial lesions in childhood become such bacteria:

• streptococci;
• gram (-) enterobacteria;
• Listeria;
• Haemophilus infection;
• staphylococci;
• salmonella.

Most often, microbial infections affect children in the first half of life: premature neonates are particularly prone to such diseases.

[9], [10], [11], [12], [13], [14], [15]

Diagnosis of fever of unknown origin

According to the results of laboratory tests:

• a general blood test - changes in the number of leukocytes (with purulent infection - a shift of the leukocyte formula to the left, with a viral lesion - lymphocytosis), an acceleration of ESR, a change in the number of platelets;
• general urine analysis - leukocytes in urine;
• biochemistry of blood - increased content of CRP, elevated ALT, AST (liver disease), D-dimer fibrinogen (PE);
• bakposov blood - demonstrates the possibility of bacteremia or septicemia;
• bactose urine - to exclude renal tuberculosis;
• bacussis of bronchial mucus or feces (according to indications);
• bacterioscopy - when suspected of malaria;
• complex of diagnostics for tuberculosis infection;
• serological reactions - with suspected syphilis, hepatitis, coccidioidomycosis, amoebiasis, etc .;
• test for AIDS;
• examination of the thyroid gland;
• examination for suspected systemic connective tissue diseases.

Based on the results of instrumental research:

• radiograph;
• tomographic studies;
• scanning of the bone system;
• ultrasonography;
• echocardiography;
• colonoscopy;
• electrocardiography;
• bone marrow puncture;
• biopsies of lymph nodes, muscle or liver tissue.

The algorithm for diagnosing a fever of an unknown origin is developed by the doctor on an individual basis. To do this, the patient determines at least one additional clinical or laboratory symptom. It can be joint disease, decreased hemoglobin level, lymph node enlargement, etc. The more such auxiliary signs are detected, the easier it will be to establish the correct diagnosis by narrowing the range of prospective pathologies and determining targeted diagnostics.

[16], [17], [18], [19], [20], [21], [22], [23], [24], [25]

Differential diagnosis of fever of unknown origin

Differential diagnosis, as a rule, is divided into several main subgroups:

• infectious diseases;
• oncology;
• autoimmune pathologies;
• other diseases.

When differentiating, pay attention not only to the symptoms and complaints of the patient for the moment, but also to those that were before, but have already disappeared.

It is necessary to take into account all the diseases that preceded the fever, including surgical interventions, traumas, and psychoemotional conditions.

It is important to clarify hereditary characteristics, the possibility of taking any medications, the subtleties of the profession, recent travel, information about sexual partners, about the animals at home.

At the very beginning of the diagnosis, it is necessary to exclude the intentionality of febrile syndrome - there are not so rare cases of conceived introduction of pyrogenic agents, manipulations with the thermometer.

Of great importance are skin rashes, heart problems, an increase and soreness of the lymph nodes, signs of eye fundus abnormalities.

[26], [27], [28], [29]

Treatment of fever of unknown origin

Experts do not recommend blindly prescribing drugs for fever of unknown origin. Many doctors rush to apply antibiotic therapy, or corticosteroid treatment, which can lubricate the clinical picture and make it difficult to further reliable diagnosis of the disease.

Despite everything, most doctors agree that it is important to establish the causes of fever, using all possible methods. And while the cause is not established - it is necessary to carry out symptomatic therapy.

As a rule, the patient is hospitalized, sometimes isolated, if the suspicion falls on an infectious disease.

With a persistent increase in temperature, a lot of fluids are recommended. Excludes the use of foods of high allergenicity (citrus, chocolate, etc.).

Drug treatment can be prescribed taking into account the detected underlying disease. If such a disease is not found (which happens in about 20% of patients), then such medications can be prescribed:

• antipyretic drugs - non-steroidal anti-inflammatory drugs (taking indomethacin 150 mg per day or naproxen 0.4 mg per day), paracetamol;
• the initial stage of taking antibiotics is the penicillin series (gentamicin 2 mg / kg three times a day, ceftazidime 2 g intravenously 2-3 times a day, azlin (azlocillin) 4 grams up to 4 times a day);
• if antibiotics do not help, they start taking stronger drugs - cefazolin 1 g intravenously 3-4 times a day;
• amphotericin B 0.7 mg / kg per day, or fluconazole 400 mg per day intravenously.

Treatment is continued until complete normalization of the general condition and stabilization of the blood picture.

Prevention of fever of unknown origin

Preventive measures consist in that in time to find out diseases which can become in the future the reasons of temperature increase. Of course, it is equally important to treat the diagnosed pathologies correctly, based on the doctor's recommendations. This will avoid many adverse effects and complications, including fever of unknown origin.

What other rules must be followed to avoid diseases?

• Avoid contact with carriers and sources of infection.
• It is important to strengthen immunity, increase the resistance of the body, fully eat, consume enough vitamins, remember about physical activity and observe the rules of individual hygiene.
• In some cases, specific prophylaxis can be used in the form of vaccinations and vaccinations.
• It is desirable to have a permanent sexual partner, and in case of accidental links, barrier methods of contraception should be used.
• When traveling to other countries, you should avoid eating unknown foods, strictly follow the rules of personal hygiene, do not drink raw water and do not eat unwashed fruits.

Forecast of fever of unknown origin

The prognosis of the disease directly depends on its cause, as well as on the age and general condition of the patient. Statistics on the annual survival rate for fever of unexplained etiology are as follows:

• more than 90% for patients under 35;
• more than 80% for patients from 35 years to 64 years;
• about 70% for patients from 64 years of age.

The most unfavorable prognosis is observed in the children's and the elderly age group, but a clear percentage and statistical information on this issue has not been received.

Fever of unknown origin requires a specific approach and often non-standard treatment regimens. Control and supervision of a specialist during the course of therapy is mandatory - this, above all, is the key to a speedy recovery.

[30], [31], [32], [33], [34], [35], [36]