approach to fever - PowerPoint PPT Presentation

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approach to fever


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Title: approach to fever

Approach to FEVER
  • Dr.Bilal Natiq Nuaman
  • Lecturer at Ibn-Sina Medical College
  • C.A.B.M. ,F.I.B.M.S. ,D.I.M. ,M.B.Ch.B.
  • 2013-2014

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  • Because Temperature affects how the enzymes work
    in your body , People should maintain a normal
    body temperature of about 37C despite wide
    variations in both their metabolic activity and
    the temperature of their environment. Enzymes are
    proteins that catalyze chemical reactions in
    living cells.
  • Almost all enzymes have an "optimal" temperature.
    For example, most human derived enzymes will
    function best at around 37 C .If it gets too
    hot or cold the enzymes might denature and lose
    the shape of their active site, which means the
    substrate may no longer fit and this decreases
    the rate of the chemical reactions.

  • The body keeps its core temperature constant at
    about 37 C by physiological adjustments
    controlled by the hypothalamus (Thermostat
    Center) where there are neurons sensitive to
    changes in skin and blood temperatures. The
    temperature-regulating centers are found in the
    Preoptic Area (the anterior portion of the
    hypothalamus). This area receives input from
    temperature receptors in the skin and mucous
    membranes (Peripheral Thermoreceptors) and from
    internal structures (Central Thermoreceptors),
    which include the hypothalamus itself.

Normal Features of Body Temperature
  • 1-the mean oral temperature is 36.8 0.4C
  • 2-The normal diurnal variation is typically
  • (6 A.M. readings lt 6 P.M. readings by 0.5 C)

Fever (Pyrexia)
  • definition-
  • Fever is an elevation of body temperature that
    exceeds the normal daily range and occurs in
    conjunction with an increase in the hypothalamic
    set pointfor example, from 37 C to 39 C .
  • an A.M. temperature of gt37.2 C
  • (98.9F ) or a P.M. temperature of gt37.7 C

Mechanisms of fever
  • (1) Exogenous pyrogens (micro-organism , toxin )
    induce host cells, such as blood leukocytes and
    tissue macrophages, to produce fever-producing
    mediators called Endogenous pyrogens (e.g.,
  • (2) resetting of hypothalamus thermostatic set
    point to a higher level through the action of
    prostaglandin E2.(prodrome)
  • (3) generation of hypothalamic mediated responses
    that raise body temperature (chill)
  • (4) development of fever with elevation of body
    to new thermostatic set point
  • (5) production of temperature lowering responses
    (defervescence-sweating) and return of body
    temperature to a lower level.

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  • Exogenous pyrogens induce host cells, such as
    blood leukocytes and tissue macrophages, to
    produce fever-producing mediators called
    endogenous pyrogens (e.g., interleukin-1).
  • The endogenous pyrogens mediate a number of other
    responses. For example, interleukin-1 is an
    inflammatory mediator that produces other signs
    of inflammation, such as leukocytosis, anorexia,
    and malaise.
  • The phagocytosis of bacteria and breakdown
    products of bacteria that are present in the
    blood lead to the release of endogenous pyrogens
    into the circulation.
  • The endogenous pyrogens are increase the set
    point of the hypothalamic thermoregulatory center
    through the action of prostaglandin E2.
  • In response to the sudden increase in set point,
    the hypothalamus initiates heat production
    behaviors (shivering and vasoconstriction) that
    increase the core body temperature to the new set
    point, and fever is established.

  • This shift of the set point from normothermic
    to febrile levels very much resembles the
    resetting of the home
  • thermostat to a higher level in order to
  • raise the ambient temperature in a room.

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Benefits of fever
  • 1-It enhance immune function
  • Increases motility and activity of the white
    blood cells (T cells and B cells ).
  • Stimulates the interferon production .
  • Increase phagocytic activity
  • 2-Inhibits growth of some microbial agents
  • Many of the microbial agents that cause infection
    grow best at normal body temperatures, and their
    growth is inhibited by temperatures in the fever

Adverse effects of fever
  • Dehydration occurs because of sweating.
  • Metabolic effects
  • Increased need for oxygen (13 for every 1 C
    increase in body temp.).
  • Increases the heart rate (10 /min. for every 1
    C increase in body temp.).
  • Increases the respiration rate (4/min. for every
    1 C increase in body temp.).
  • Increased use of body proteins as an energy
    source (catabolism)
  • With prolonged fever, there is increased
    breakdown of endogenous fat stores .(metabolic
  • Precipitates febrile convulsions

  • Some Features of Fever
  • Relative bradycardia(rising of HR lt5 /min. for
    each 1C rise )
  • Causes Typhoid,Brucellosis,Leptospirosis,and
    Factitious fever
  • Relative tachycardia (rising of HR gt15/min. for
    each 1C rise )
  • Causes Myocarditis, rheumatic fever
  • Reversed diurnal pattern (AM Temp. gtPM Temp.)
  • Causes Typhoid , disseminated TB
  • Failure to have fever
  • Cause Elderly,CRF,Corticosteroid

components of fever
  • 1-Onset of fever (warming chill phase )
  • Sudden rise pneumonia,malaria,meningitis
    (associated with oral herpes simplex).
  • Gradual rise typhoid fever (step-ladder) .

  • 2-Main (pattern-plateau phase)
  • Continuous fever does not fluctuate more than
    1C during 24hrs, but at no time touches the
    normal.e.g.pneumonia, typhoid fever, urinary
    tract infection, brucellosis
  • Remitent daily fluctuations exceed 2C but at
    no time touches the normal.
  • It is associated with viral upper respiratory
    tract, legionella, and mycoplasma infections
  • Intermittent fever reaches normal level
  • Quotidian wn. Paroxysms of fever occur
  • Tertian wn. Paroxysms of fever on alternate
    days(P.Vivax ,Ovale)
  • Quartan every 72 hrs (P.Malaiae)

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  • 3-End of fever
  • Crisis (sudden reduction )associated with
  • e.g. pneumonia
  • Lysis ( gradual reduction)
  • e.g. Typhoid

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Approach to patient with fever
  • 1- History taking
  • 1)Onset (sudden vs. gradual)2) grade (High
    vs. low grade)
  • Low grade temp.lt38.5 , not associated with
    rigor (but chills ) , relieved by antipyretics or
    sponging , not interfere with usual activity .
  • High grade temp.gt38.5 , associated with rigor
    and sweating , not relieved by antipyretics or
    sponging , interfere with usual activity.
  • Rigors.
  • profound chills accompanied by chattering of
    the teeth and severe shivering, implies a rapid
    rise in body temperature. Can be produced by
  • 1) brucellosis , malaria , pyelonephritis ,
  • 2) abscess ,cholangitis , septic arthritis
  • 3) lymphoma

  • 3)Duration of the fever
  • 4)Fever pattern (Remittent fever, Intermittent,
    continuous fever)
  • 5)Timing (through out the day, at night, day
  • 6)Severityinterfere with sleep , interfere with
    usual activity
  • 7)Relieving and aggravating factors
  • 8)Treatment received or/and outcome

  • 9)Associated symptoms
  • Complete review of systems a) Upper respiratory
    tract infection (sore throat, coryza)b) Lower
    respiratory tract infection (cough, chest pain,
    shortness of breath)c) GIT symptoms (diarrhea
    watery or mucous, abdominal pain,
    constipation)d) GUT (Pain on micturation,
    hesitancy, urgency)e) Skin lesion (rash,
    infection), night sweat.
  • f) Musculoskeletal pain,
  • Excessive sweating.
  • Night sweats are characteristic of
    tuberculosis, brucellosis , endocarditis

  • Drug and allergy History
  • Drug fever is a disorder characterized by a
    febrile response coinciding temporally with the
    administration of a drug in the absence of
    underlying conditions that can be responsible for
    the fever. A key feature that differentiates drug
    fever from fever of other causes is that it
    disappears once the offending drug is
    discontinued. Drug fever tends to be a diagnosis
    of exclusion, often suspected in patients with
    otherwise unexplained fevers. causes
  • antibiotics (penicillin) ,anticonvulsants(phe
    nytoin) , and some cardiac drugs
  • Blood transfusion.
  • Immunization and vaccinations .

Personal and Social History
  • Smoking history - amount, duration type
  • Alcohol history - amount, duration type
  • Occupation, social education background, family
    social support financial situation, Social
  • Home conditions-Water supply, Sanitation status
    in his home surrounding, Geographic area of
    living, fresh-water swimming.
  • Animals / birds in his/her house- exposure to
    birds (psittacosis) or animals (,avian flu ,
    toxoplasmosis, brucellosis, rabies.)
  • Consumption of unpasteurized milk or milk
    products (tuberculosis, brucellosis and Q fever).

  • Sexual History- Unprotected exposure to sexual
    partner with STD, HIV,syphilis
  • Illicit drug usage- injections and sharing of
    needles (HIV, hepatitis B C, infective
    endocarditis), site of injection (e.g Femoral
    vein-septic arthritis, ilio-psoas abscess)
  • Travel History
  • Travel to an area known to be endemic for certain
  • Name of the area, duration of stay
  • Onset of illness- (incubation period)
  • If the patient has been in an endemic area
  • The most common diagnoses
  • Malaria, Typhoid fever, Viral hepatitis .

2-Complete Physical Examination
  • DAY1 Chicken pox
  • DAY2 Scarlet fever
  • DAY3 Rubella
  • DAY4 Measles
  • DAY5 Typhus
  • DAY6 Typhoid
  • (rose spot)

  • Koplik's spots in measles
  • Forchheimer spots in rubella

  • Brucellosis
  •  Cytomegalovirus
  • Epstein-Barr virus
  • Human immunodeficiency virus(AIDS)
  • Lymphoma
  • Syphilis (secondary) 
  • Toxoplasmosis

  •     Fever and Jaundice
  • Cholangitis ,  Hepatic abscesses,  Malaria
    ,  Viral hepatitis  , Yellow fever
  • Fever and pulmonary involvement
  • Influenza
  • Pneumonia
  • Severe acute respiratory syndrome (SARS)

3-Full Investigations
  • Lab.
  • 1-DÖhle bodeis , toxic granulation , band form
    bacterial inf.
  • 2-neutropenia viral inf.,SLE ,typhoid ,
    brucellosis , and b.marrow infiltration(lymphoma,T
  • 3-lymphocytosis typhoid , brucellosis , TB
    ,viral inf.
  • 4-Atypical lymphocyte viral inf.
  • 5-monocytosis typhoid , brucellosis , TB
  • 6-eosinophilia drug reactions ,hodgkin s
    dis.,adrenal insufficiency
  • 7-thich and thin bld film for malaria

  • B-Biochemical
  • urea and electrolytes, liver function tests
    (LFTs), blood glucose , GUE, GSE,
  • Sputum for routine microscopy and culture, and
    microscopy and culture for mycobacteria ,
  • Culture of blood , urine .
  • inflammatory markers, erythrocyte sedimentation
    rate (ESR) and C-reactive protein (CRP)
  • autoantibodies, including antinuclear antibodies
  • C- Radiology
  • CXR, Abdominal US , Echocardiogram , CT/MRI of
    thorax and abdomen

Treatment of fever
  • Fever must be reduced in some groups of patients
  • 1- Patients with preexisting cardiac disease
  • 2- Patients with cerebrovascular disease
  • 3- patient with preexisting pulmonary disease
  • 4-Children with a history of seizure
  • 5-Pregnants
  • 6-Elderly.
  • 7-Temp.gt39
  • Oral aspirin and NSAIDS (paracetamol, ibuprufen
    ) effectively reduces fever.
  • Also reduce systemic symptoms of headache,
    myalgias, arthralgias due to reduction of PGE2
  • It is better to avoid aspirin in children to
    prevent Reye syndrome.

A fever of gt41.5C (gt106.7F) is called
hyperpyrexia. This extraordinarily high fever can
develop in patients with severe infections but
most commonly occurs in patients with central
nervous system (CNS) hemorrhages.
  • Hyperthermia is characterized by an unchanged
    (normothermic) setting of the thermoregulatory
    center in conjunction with an uncontrolled
    increase in body temperature that exceeds the
    bodys ability to lose heat.
  • Causes of Hyperthermia Syndromes
  • Exercise in higher-than-normal heat and/or
  • Anticholinergics, including antihistamines
    antiparkinsonian drugs diuretics antipsychotics
    , anesthetics
  • Thyrotoxicosis, pheochromocytoma

Hyperthermia Vs Fever
  • 1-Daily temperature swings do not occur in
    patients with hyperthermia
  • 2-hyperthermia can be rapidly fatal
  • 3-characteristically does not respond to
  • 4-Hyperthermia is characterized by an unchanged
    setting of the thermoregulatory center
  • 5-Hyperthermia is often diagnosed on the basis of
    the events immediately preceding the elevation of
    core temperaturee.g ., heat exposure or
    treatment with drugs
  • that interfere with thermoregulation.
  • 6-In patients with heat stroke syndromes and in
    those taking drugs that block sweating , the skin
    is hot but dry.

Treating Hyperthermia
  • Physical cooling with sponging, fans, cooling
    blankets, and even ice baths should be initiated
    immediately in conjunction with the
    administration of intravenous fluids and
    appropriate pharmacologic agents ,if insufficient
    cooling is achieved by external means , internal
    cooling can be achieved by gastric or peritoneal
    lavage with iced saline. .
  • In extreme circumstances, hemodialysis or even
    cardiopulmonary bypass with cooling of blood be

Pyrexia of unknown origin (PUO) Fever of
Unknown origin (FUO)
  • PUO (FUO) is defined as a temperature
    persistently above 38.0 C for more than 3 weeks,
    without diagnosis despite initial investigation
    during 3 days of inpatient care or after 3
    outpatient visits or more . (rule of 3 )

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  • Three major Infectous causes
  • Abscess .. especially occult ..
  • Intracellular organisms. (salmonella
    mycobacterium, brucella)
  • Intravascular Endocarditis

  • Tuberculosis
  • The single most common infection in most PUO
  • Tuberculosis (TB) is an infection, primarily in
    the lungs (a pneumonia), caused by bacteria
  • tuberculosis. Mycobacterium
  • It is spread usually from person to person by
    breathing infected air during close contact.
  • TB can become active and cause infection in the
    lungs or other parts of the body (Caseating
  • The most common symptoms and signs of TB are
    fatigue, fever, weight loss, coughing, and night

  • The diagnosis of TB involves
  • PPD (Skin Tuberculin Test),
  • sputum analysis (smear for AFB and culture),
  • Chest-X-ray (Apical cavitation , pleural effusion
  • PCR(polemerase chain reaction) tests to detect
    the genetic material of the causative bacteria.
  • Diagnosis sometimes requires Biopsy of Lymph
    nodes , Bone marrow, Liver .
  • Active TB is treated W multiple AntiTB Drugs for
    6 months

  • Abscess
  • An abscess is a collection of pus (neutrophils)
    that has accumulated within a tissue because of
    an inflammatory process in response to an
    infectious process (usually caused by bacteria)
  • Usually located in abdomen or pelvis.
  • Secondary to appendicitis or diverticulitis.
  • Pyogenic liver abscess usually follow biliary
    tract dis./abd. Suppuration.
  • Splenic abscess is usually secondary to
    hematogenous seeding.
  • Perinephric or renal abscess is usually secondary
    to UTI.
  • Intracranial abscess, lung abscess

  • Bacterial Endocarditis
  • Endocarditis is an inflammation of the valves of
    the heart caused by the growth of bacteria on one
    of the heart valves, leading to a mass known as a
  • Symptoms can be nonspecific and include fever,
    shortness of breath, and weakness , and it
    carries a high complications and mortality rates
  • People with existing diseases of the heart valves
    are at an increased risk of developing
  • Diagnosis of Endocarditis depend on Duke Criteria
    ( ve blood cultures and presence of vegetation
    on Echo )

The most accurate method of detecting the valve
vegetations of endocarditis is with a procedure
called transesophageal echocardiography (TEE) but
transthoracic echocardiography (TTE) may benefit
. The treatment for endocarditis consists of
aggressive (multiple) antibiotics, generally
given intravenously, usually for 4 to 6 weeks.
  • Malignancy
  • Cancer is the uncontrolled growth of abnormal
    cells anywhere in a body. The abnormal cells are
    termed cancer cells, malignant cells, or tumor
    cells. a mass of cancer cells develop
  • Many cancers and the abnormal cells that compose
    the cancer tissue are further identified by the
    name of the tissue that the abnormal cells
    originated from (for example, breast cancer, lung
    cancer, colon cancer).
  • Frequently, cancer cells can break away from this
    original mass of cells, travel through the blood
    and lymph systems, and lodge in other organs
    where they can again repeat the uncontrolled
    growth cycle.
  • This process of cancer cells leaving an area and
    growing in another body area is termed metastatic
    spread or metastatic disease.

  • Malignant causes of fever
  • Renal cell carcinoma
  • Hepatocellular carcinoma
  • Hepatic metastases from any primary
  • Leukemia
  • Lymphoma
  • Fever is a well-recognized manifestation in
    Lymphoma .
  • A Pel-Ebstein phenomenon is one type of
    Intermittent Fever
  • noted in patients with Hodgkin's lymphoma in
    which the patient experiences fevers which
    cyclicly increase then decrease over an average
    period of one or two weeks.(2weeks fever then
    2weeks normal)

  • Family History
  • Search for possible infectious or hereditary
  • Tuberculosis
  • FMF
  • Periodic Fever (Familial Mediterranean fever-FMF)
  • An inherited disorder featuring short recurring
    crises of severe abdominal pain and bouts of
    fever. Other symptoms include arthritis, chest
    pain from inflammation of the lung cavity, and
    skin rashes. Between attacks, the patient seems
  • Amyloidosis (the abnormal deposition of a
    particular protein, called amyloid, in various
    tissues of the body) is a potentially serious
  • Treatment W Colchicin

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for PUO Invasive Investigations
  • 1-Aspiration of fluid for analysis (pleural ,
    ascitic, joint, CSF)
  • 2- Lymph node Biopsy
  • When there is LAP( lymphadenopathy) to diagnose
    Lymphoma , TB , Malignancy
  • 3-bone marrow biopsy
  • A biopsy is most useful in revealing
    haematological malignancy, and tuberculosis. It
    may also lead to a diagnosis of brucellosis,
    enteric fever or visceral leishmaniasis.

  • 4-Liver biopsy
  • The procedure may be required to diagnose
  • It is unlikely to be helpful in patients with
    normal LFTs and normal liver parenchyma on
  • 5-Temporal artery biopsy
  • Temporal artery biopsy should be considered in
    patients over the age of 50 to diagnose giant
    cell arteritis

  • Questions??

Thank you
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