Causes of prolonged low grade temperature


  • The concept of long-term low-grade fever
  • Infectious causes of long-term low grade temperature
  • Non-infectious causes of low grade temperature

  • The concept of long-term low-grade fever

    Under low grade body temperature realize itoscillations from 37 to 38? C. Long-term low-grade fever takes in therapeutic practice a special place. Patients with long-term low-grade fever is the dominant complaint, found at the reception quite often. To determine the cause subfebrile such patients are subjected to various studies, they exhibited a variety of diagnoses and assigned (often unnecessary) treatment.

    In most cases, prolonged low-gradetemperatures common in young women with symptoms of asthenia. This is due to the physiological characteristics of the female body, ease of infection of the urogenital system, as well as the high frequency of psycho-vegetative disorders.

    It should be borne in mind that long-termlow-grade fever is much less expression of any organic disease unlike prolonged fever with temperatures above 38 C. In most cases, prolonged low-grade fever banal reflects autonomic dysfunction. Relatively long subfebrile causes can be divided into two large groups - infectious and non-infectious.

    Infectious causes of long-term low grade temperature

    Low-grade fever is always a suspicion of infectious disease.


    When an obscure low-grade fever in the first place it is necessary toeliminate tuberculosis. In most cases, this is not easy. From history are essential presence of direct and prolonged contact with the patient any form of tuberculosis. The most important is to find in one place with an open form of tuberculosis patients - office, apartment, staircase or entrance of the house, where a patient with bacterial, as well as a group of nearby buildings, united by a common courtyard.

    A history of previously adjournedTuberculosis (regardless of location) or the presence of residual changes in the lungs (presumably tuberculous etiology), previously detected by prophylactic fluorography.

    Any disease with treatment failure during the past three months.

    For complaints (symptoms), suspicious for TB include:

    • the presence of intoxication syndrome - a long low-grade fever, general unmotivated weakness, fatigue, sweating, loss of appetite, weight loss
    • with suspected pulmonary tuberculosis - chronic cough (lasting longer than 3 weeks), coughing up blood, shortness of breath, chest pain
    • for suspected extrapulmonary tuberculosis - complaints on violation of the affected organ function, with no signs of recovery against the backdrop of ongoing non-specific therapy

    focal infection

    Causes of prolonged low grade temperatureMany authors believe that long-termlow-grade fever may be due to the existence of chronic foci of infection. However, in most cases of chronic infection foci (dental granuloma, sinusitis, tonsillitis, cholecystitis, prostatitis, adnexitis et al.), As a rule, are not accompanied by fever and do not cause changes in the peripheral blood. To prove the causal role of chronic infection can only be the case when the reorganization of focus (eg, tonsillectomy) leads to the rapid disappearance of the previously-existing subfebrile.

    Persistent symptoms of chronic toxoplasmosis in 90% of patients is a low-grade fever. In chronic brucellosis predominant type of fever is also a low-grade fever.

    Acute rheumatic fever (systemicinflammatory disease of the connective tissue involvement in the pathological process of cardiac and joints caused by beta-hemolytic group A streptococci and occurs in genetically predisposed individuals) often proceeds with only body subfebrile temperature (especially at the process II degree rheumatic activity).

    Low-grade fever may occur afterthe transferred infectious diseases ( "temperature tail"), as a reflection of fatigue syndrome poslevirusnoy. In this case, low-grade fever is benign, not accompanied by changes in the analyzes and resolves on its own, usually within 2 months (sometimes "temperature tail" can last up to 6 months). But in the case of typhoid fever a long low-grade fever that occurs after the reduction of the high body temperature, is a sign of incomplete recovery, and is accompanied by continued adynamia, undiminished hepato-splenomegaly and persistent aneozinofiliya.

    Non-infectious causes of low grade temperature

    Long-term low-grade feverinfectious nature may be due to somatic diseases, but more often it can be attributed to physiological causes or by the presence of psycho-vegetative disorders.

    Because somatic disease should pay attention to iron deficiency anemia, which can occur with low grade fever, and thyrotoxicosis.


    Low-grade fever is almost a rulein case an excess of thyroid hormones in the blood. Apart from low grade temperature in thyrotoxicosis nervousness marked and often emotional lability, sweating and palpitations, fatigue and weakness, loss of mass of the body on the background of normal or increased appetite. For the diagnosis of hyperthyroidism is enough to determine the level of thyroid-stimulating hormone in the blood. Reducing the level of thyroid-stimulating hormone is the first manifestation of an excess of thyroid hormones in the body.

    Physiological causes

    For many people, low-grade fever isconstitutional in nature and is a variant of the individual standards. Low-grade fever may develop on the background of emotional and physical (sport) loads occur after eating, when in a hot room, after insolation. In women, low-grade fever available in the second half of the menstrual cycle, which is the beginning of menstruation to normal; low-grade fever rarely occurs in the first 3-4 months of pregnancy. Moreover, low-grade fever may be unequal to the left and right axilla (to the left more often 0.1-0.3? C above). Probably a reflex increase in temperature on the measurement procedure itself - in such patients, low-grade fever occurs only when measuring it in the armpits and in the rectum or mouth normal levels.

    Psycho-vegetative reason

    Long-term low-grade fever at thirdpatients is a psycho-vegetative character and is regarded as a manifestation of the syndrome of vegetative dystonia (vegetative neurosis, thermoneurosis). Periods of low grade fever in these patients can be kept for several years. Favorable background for the appearance of a psychogenic subfebrile, in addition to psycho-emotional stress, are allergy, endocrine dysregulation, traumatic brain injury history.

    Long-term low-grade fever is more common in young women with symptoms of asthenia, children in puberty and first-year students.

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