Fuo

Fever of Unknown Origin:differential diagnosis

DEFINITIONFever lasting > 3 weeksTemperature > 38.3 C (several measurement)Cause still undetermined after 3 days in hospital

30% FUO die of undetected diseaseDx FUO has to be taken SERIOUSLY !!!

The most frequent causes of FUO

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INFECTION25%

IMMUNE DISEASES25%

NEOPLASM15%

UNCLEAR30%

MISCELLANEOUS DISEASES5%

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3 age groups< 6 yo: infection of: - Upper respiratory - Urinary tract - Systemic viral6-14 yo: Gastrointestinal tract & Colagenoses> 14 yo: -Infection, -Neoplasm, -Rheumatology or autoimmune diseases

Cause of Infection

COMMON BACTERIAL INFECTIONSAbscesses Liver, spleen, pancreas, subphrenic, true pelvis, prostate, appendicitis, chrohnn disease, diverticulitisEndocarditis Rheumatic fever or diagnostic procedureBilliary tract infectionsCholangitis, cholecystitis, bile empyema or infection of pancreatic ductBuccal cavity/ upper respiratory tractDental abscesses, sinusitisOsteomyelitis Osteomyelitis of the spinal column, mandible, maxilla, infection of joint prostheses TuberculosisParticulary in immune-deficient patients

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VIRAL INFECTIONMost commonEBVCMVHBVHerpes simplexParvovirus B19

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Less common infectionsAmoebiasisHotter countriesBorreliosis Tick bitesBrucellosis Slaughterhouse workers, veterinarians, zookeepers, cooks, laboratory infectionsChlamydialHandling of certain species of birdCat scratch feverContact with catsLeishmaniasis Asia, tropics, mediterranean countriesLeptospirosis Listeriosis Haemodialysis patients, after kidney transplan, in tumour of leukopoetic system

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Less common infectionsMalaria Travel in malaria areasFungal Travel in endemic area coccidiodomycosis (north/ southAmerica, histoplasmosis (North America). Immune deficient: systemic candida albican, aspergillosis, cryptococcosisRickettsiosis Tick or mite bite, Q-fever transmission from pets ot airborne (infected wool)Toxoplasmosis Contact with cats, consumption of raw mwat, immunodeficiencyTularemia Hunters, foresters, farm workers, deallers in game animals, fur and pelt processors, kitchen staff

NeoplasmsHodgins diseasenon-Hodgin lymphomaMyelodysplastic syndromeLeukemiaSolid tumor (especially bronchial, pancreas, colon, hepatic cell, renal cell ca)

Collagenvascular diseasesRheumatic feverLupus erythematosusRheumatoid arthritisStills diseaseTemporal arteritisPeriarteritis nodosaWegeners diseaseChrohns disease

Other causesDrug feverMultiple pulmonary emboliThrombophlebitisHaematomaHepatitis Adrenal insufficiencyThyroiditisSarcoidosisUnspecific pericarditisThermoregulatory disturbancesPsychogenic fever: habitual hyperthermia, artificial fever

Diagnosis Observation of fever courseAnamnesis Physical examinationLaboratory parametersNoninvasive diagnostic measurement (e.g chest Ro)Exclude drug fever

Definition of drug feverFever that arises on administration of drug and vanishes after discontinuation, almost always within 48-72 h, in absence of another cause.The interval between first intake of the drug and the onset of fever varies widely among different groups of drugs (AB: 8 days, cardiac medication: 45 days)

Most frequent causes of drug feverAntibiotics 31%: Penicillin G 6%Cephalosporins 4,7%Oxacillin 1,3%Ampicillin Cardiovascular sustances 25% (-Methyldopa, Quinidine, procainamide, hydralazine, nifedipine, oxprenolol CNS substances 20% (diphenylhydantoin, LSD, carbamazepine, chlorpromazine)

Important physical examinations Lymph nodes Ocular investigation:Ptosis: Wageners granulomatosisScleritis, uveitis: rheumatoid arthritis, SLE, & other collagenosesConjonctival lessions: systemic infection viral & chlamydialConjunctival petechiae: endocarditis & lymphomasConjunctivitis: TB, syphilis, tularemia, mycotic infection ((histoplasmosis)Retinitis: toxoplasmosis, CMVRoths spot on the retinas: endocarditis, leukemiasChoroid lessions: TB, fungalSkin & mucosae

Examination of skin & mucosaeOslers node & ptechiae of the gum: endocarditisRoseolae of the abdominal skin: salmonellosisHyperpigmentation: Whipples diseaseSkin metastases of various solid tumors & lymphomasCutaneous vasculitis: rheumatologic diseases

Laboratory parametersThe most important:Differential blood count, urine culture, electrolytes, LFT, pancreas function test, blood culture Sputum, tracheal secretionStool Non specific parameter

Non specific parametersBSG, Fibrinogen, Haptoglobin, CRP, Ceruloplasmin, netrophil granulocytesIron, zink < NEosinophilia or exanthema (20% of cases)Imunological parametersLDH, Cu hematological neoplasms

Other indispenables investigationsInspection of the headOcular fundusConjunctiva (petechiae)Finger & toenail (endocarditis)Perineal region (fistulas)Meningism Lymph nods (Ca, Hodgins disease, HIV)Joints (arthritis)Thyroid gland (subacute thyroiditis)Spleen (endocarditis, lyphoma) Liver (abcess)Rectal examination Pressure on nasal sinuses (sinusitis)Auscultation of the heart (endocarditis)The lung

Further diagnostic measuresRadiography (regular: thoracic), USG, CT/MRI abdomenMone marrow biopsyLiver biopsyTemporal artery biopsy

Skin testingMantoux test: every patient with FUO