Fever pdf - د. جاسم محمد

Third stage

Medicine

Lec-3

جاسم

محمد

1/1/2014

FEVER

DEFINITION OF FEVER

Fever is an elevation of body temperature that exceeds the normal daily variation, in
conjunction with an increase in hypothalamic set point

NORMAL BODY TEMPERATURE

Maximum normal oral temperature
At 6 AM : 37.2
At 4 PM : 37.7

Temperature Classification

Hypothermia

<35.0 °C

Normal

36.5–37.5 °C

Fever

>37.5–38.3 °C

Hyperthermia

>37.5–38.3 °C

Hyperpyrexia

>40.0–41.5 °C

Note: The difference between fever and hyperthermia is the mechanism

PATHOGENESIS OF FEVER

CAUSES OF FEVER



Infection



Tissue injury - infarction, trauma



Malignancy



Drugs



Immune-mediated disorders



Other inflammatory disorders



Endocrine disorders



Factitious of self-induced fever

Infections presenting as fever

without localizing signs or symptoms



Viral

Rhinovirus, adenovirus, parainfluenza

Enterovirus Influenza



Bacterial

Staphylococcus aureus

Salmonella thyphi, S. parathyphi

Streptococci



Post animal exposure

Coxiella burneti (Q fever)

Leptospira interrogans

Brucella species



Granulomatous infection Mycobacterium tuberculosis

Histoplasma capsulatum

Infections with Fever and Lymphadenomegaly

(generalized)



Viral

Measles,Rubella



Bacterial

Brucellosis,Tuberculosis,Syphilis

(regional)



Pyogenic infection

Sta. aureus, Stre.



Tuberculosis

Scrofula (tbc. Cervical adenitis)



Inguinal lymphadenopathy Syphilis, herpes



Plague

Yersinia pestis

DISCOMFORT DUE TO FEVER

For each 1 °C elevation of body temperature:



Metabolic rate increase 10-15%



Insensible water loss increase 300-500ml/m2/day



O2 consumption increase 13%



Heart rate increase 10-15/min

HYPERTHERMIA

Heat production exceeds heat loss, and the temperature exceeds the individuals set point.
Heat stroke ,drugs

Hyperpyrexia

Hyperpyrexia is a fever with an extreme elevation of body temperature greater than or
equal to 41.5 °C . Such a high temperature is considered a medical emergency as it may

indicate a serious underlying condition or lead to significant side effects. The most
common cause is an intracranial hemorrhage. Other possible causes include
sepsis, Kawasaki syndrome, neuroleptic malignant syndrome, drug effects, serotonin
syndrome, and thyroid storm and infections like viral.

TREATMENT OF FEVER



Most fevers are associated with self-limited infections, most commonly of viral origin.



Treatment of underlying cause

Treatment Strategies



Acetaminophen is generally a first-line antipyretic due to being well tolerated with
minimal side effects.



Pediatric dose: 10-15mg/kg q4-6h (2400mg/day); adult: 650mg q 4 h(4000mg)



Can be hepatotoxic in high doses; can upset stomach

Clinical Pearls



Don’t give aspirin to children under 18 years (Reye’s Syndrome)



Try water sponge bath; remove blankets and heavy clothing; keep room at
comfortable temp

DRUG FEVER

PATHOGENEGIS



Contamination of the drug with a pyrogen or microorganism



Pharmacologic action of the drug itself



Allergic (hypersensitivity) reaction to the drug

Onset and duration:



Onset: 1-3 weeks after the start of therapy



Duration: remits 2-3 days after therapy is stoped

Fever out of proportion to clinical picture
Associated findings:



Rigor (43%), Myalgia (25%), Rash (18%), Headache (18%),



Leukocytosis (22%), Eosinophilia (22%), Serum sickness,Proteinuria Abnormal liver
function test

APPROACH TO THE PATIENT WITH FEVER

ACUTE FEBRILE ILLNESS

History:



Personal History:
o  Age
o  Occupation
o  Place of origin,Travel History
o  Habits

 Sexual Practices

  Injection Drug Abuse
  Excessive Alcohol Use
  Consumption of Unpasteurized Dairy Products



Underlying Diseases:
o  Splenectomy
o  Surgical Implantation of Prosthesis
o  Immunodeficiency
o  Chronic Diseases:

  Cirrhosis
  Chronic Heart Diseases
  Chronic Lung Diseases



Drug History:
o  Antipyretics
o  Immunosuppressants
o  Antibiotics



Family History:
o TB in the Family
o Recent Infection in the Family



Associated Symptoms:
o  Shaking chills
o  Ear pain,Ear drainage,Hearing loss
o  Visual and Eye Symptoms
o  Sore Throat
o  Chest and Pulmonary Symptoms
o  Abdominal Symptoms
o  Back pain, Joint or Skeletal pain

PATTERN OF FEVER



Continuous fever: Temperature remains above normal throughout the day and does
not fluctuate more than 1 °C in 24 hours, typhoid.



Intermittent fever: The temperature elevation is present only for a certain period,
later cycling back to normal, e.g. malaria,



Remittent fever: Temperature remains above normal throughout the day and
fluctuates more than 1 °C in 24 hours, e.g., infective endocarditis.



Pel-Ebstein fever: A specific kind of fever associated with Hodgkin's lymphoma, being
high for one week and low for the next week and so on

Physical Examination:



Vital Signs



Neurological Exam.



Skin Lesions,Mucous Membrane



Eyes



ENT



Lymphadenopathy



Lungs and Heart



Abdominal Region (Hepatomegaly,Splenomegaly)



Musculoskeletal

LABORATORY STUDY:

IN PATIENT WITH FEBRILE ILLNESS



Assess the extent and severity of the inflammatory response to infection



Determine the site(s) and complications of organ involvement by the process



Determine the etiology of the infectious disease

FUO (FEVER OF UNKNOWN ORIGIN)

Classic FUO



Fever of 38.3 C or higher on several occasions



Fever of more than 3 weeks duration



Diagnosis uncertain, despite appropriate investigations after at least 3 outpatient
visits or at least 3 days in hospital

Nosocomial FUO



Fever of 38.3 or higher on several occasions



Infection was not manifest or incubating on admission



Failure to reach a diagnosis despite 3 days of appropriate investigation in hospitalized
patient

Neutropenic FUO



Fever of 38.3 or higher on several occasions



Neutrophil count is <500/mm3 or is expected to fall to that level in 1 to 2 days



Failure to reach a diagnosis despite 3 days of appropriate investigation

HIV-Associated FUO



Fever of 38.3 or higher on several occasions



Fever of more than 3 weeks for outpatients or more than 3 days for hospitalized
patients with HIV infection



Failure to reach a diagnosis despite 3days of appropriate investigation

Causes of classical FUO

Infections commonly associated with FUO



Localized pyogenic infections



Intravascular infections



Systemic bacterial infections (Tuberculosis, Brucellosis,…)



Fungal infections



Viral infections



Parasitic infections

Malignancies commonly associated with FUO



Hodgkin’s disease



Non-hodgkin’s lymphoma



Leukemia



Renal cell carcinoma



Hepatoma



Colon carcinoma



Atrial myxoma

Noninfectious inflammatory diseases with FUO



Collagen vascular/ hypersensitivity diseases
o  Lupus
o  Still’s disease
o  Temporal arteritis (Giant cell arteritis)



Granulomatouse diseases
o  Crohn’s disease
o  Sarcoidosis
o  Idiopathic granulomatouse disease

Miscellaneous causes of FUO



Drug fever



Factitious fever



FMF



Recurrent pulmonary emboli



Subacute thyroiditis

FACTITIOUS FEVER

Diagnosis should be considered in any FUO, especially in:



Young women



Persons with medical training



If the patients clinically well



Disparity between temperature and pulse



Absence of the normal diurnal pattern

Causes of FUO lasting > 6 month

Approach to FUO



Determine whether the patient has a true FUO



Workup of true FUO:
o Careful history

 Serial follow-up histories

o Careful physical examination

 Physical examination should be repeated

Laboratory examination:



CBC(diff)



PBS



ESR



U/A



S/E



Culture of blood, urine,…



Skin test



Serology



ANA

Imaging:



CXR



Ultrasonography



Radiographic contrast study



Radioneuclide scan



CT or MRI

Invasive Procedures:

Biopsies:



Bone marrow



Skin lesion



Lymph node



Liver



Temporal artery