سشنات دكتور سلام

Pyrexia of unknown orgin (PUO)

Dr. Salam Fareed
contents
Definition
Classification and causes
Approach to patient with PUO
Golden point
Case scenario

Objectives

To be able to define PUO, and its tyups.
To be able to have a plan to approach a patient with Fever when the basic clinical and laboratory tests did not reveal much as to the cause of fever
Fever of unknown origin (FUO) :-
is a sustained, unexplained fever despite a comprehensive diagnostic evaluation. Patients with undiagnosed FUO generally have a benign long-term course, especially when the fever is not accompanied by substantial weight loss or other signs of a serious underlying disease.

Classification of PUO

Classic
Health care associated
Neutropinc
HIV associated


Classic
Temperature >38.3 °C (100.9 °F)
for at least 3 weeks
with at least 1 week of in-hospital investigation
Causes
1- Infections (30%):-
Abscess at any site; Cholecystitis/cholangitis
Urinary tract infection: prostatitis
Dental and sinus infections
Bone and joint infections
Imported infections, e.g. malaria, dengue, brucellosis
Enteric fevers
Infective endocarditis
Tuberculosis (particularly extra pulmonary)
Viral infections (cytomegalovirus-CMV, Epstein-Barr virus-EBV, human immunodeficiency virus-HIV) and toxoplasmosis
2-Malignancy (20%):-
Lymphoma and myeloma
Leukemia
Solid tumors (renal, liver, colon, stomach, pancreas)
3-connective tissue disorders(15%):-
Vasculitic disorders (including polyarteritis nodosa and rheumatoid disease with vasculitis)
Temporal arteritis/polymyalgia rheumatica
Systemic lupus erythematosus (SLE)
Still's disease
Polymyositis
4-Miscellaneous (20%):-
Inflammatory bowel disease
Liver disease: cirrhosis and granulomatous hepatitis
Sarcoidosis
Drug reactions
Atrial myxoma
Thyrotoxicosis
Hypothalamic lesions
Familial Mediterranean fever
5-Factitious
6-No diagnosis (15%)



Health care associated
Temperature >38.3 °C (100.9 °F) in patients hospitalized ≥72 hours but no fever or evidence of potential infection at the time of admission, and negative evaluation of at least 3 days.
Causes
Drug fever
thrombophlebitis
pulmonary embolism
sinusitis, postoperative complications (occult abscesses)
Clostridium difficile enterocolitis
device- or procedure-related endocarditis

Neutropenic (immune deficient)

Temperature >38.3 °C (100.9 °F) and neutrophil count <500/µL for >3 days and negative evaluation after 48 hours.
Causes
Occult bacterial and opportunistic fungal infections (aspergillosis, candidiasis)
drug fever
pulmonary emboli
underlying malignancy
cause not documented in 40%-60% of cases

HIV associated

Temperature >38.3 °C (100.9 °F) for >3 weeks (outpatients) or >3 days (inpatients) in patients with confirmed HIV infection.


Approach to patient with PUO
History
Physical examination
Targeted investigations

History

Inquire about symptoms involving all major organ systems and get a detailed history of general symptoms (eg, fever, weight loss, night sweats, headaches, rashes).
The history can provide important clues to FUO due to surgery, zoonoses, malignancies, and inflammatory/immune disorders.
Record all symptoms, even those that disappeared before the examination. Previous illnesses (including psychiatric illnesses) and surgeries are important.

Make a detailed evaluation that includes the following:
Family history
Immunization status
Occupational history
Travel history
Nutrition (including consumption of dairy products)
Drug history (over-the-counter medications, prescription medications, illicit substances)
Sexual history
Recreational habits
Animal contacts (including possible exposure to ticks and other vectors)


Physical Examination
Definitive documentation of fever and exclusion of factitious fever are essential early steps in the physical examination.
On physical examination, pay special attention to the eyes, skin, lymph nodes, spleen, heart, abdomen, and genitalia.
Pulse-temperature relationships (ie, relative bradycardia) are useful in evaluating for typhoid fever, Q fever, psittacosis, lymphomas, and drug fevers.
Repeat a regular physical examination daily while the patient is hospitalized. Pay special attention to rashes, new or changing cardiac murmurs, signs of arthritis, abdominal tenderness or rigidity, lymph node enlargement, funduscopic changes, and neurologic deficits.

Investigations

PUO should be investigated in a stepwise fashion in order of increasing complexity and invasiveness, starting with blood tests and moving to imaging techniques and, finally, more invasive procedures such as 'blind' biopsies
FBC with differential , (ESR) and C-reactive protein (CRP)
Urea, creatinine and electrolytes
Liver function tests (LFTs) and γ-glutamyl transferase
Blood glucose
Urinalysis, Midstream urine (MSU) for microscopy and culture
Creatine phosphokinase
Malaria blood films
Faeces culture
Sputum for routine microscopy and culture and microscopy and culture for mycobacteria
Blood cultures ×3
Chest X-ray
Ultrasound examination of abdomen
Electrocardiogram (ECG)
Echocardiogram
Viral (CMV, Infectious mononucleosis, HIV, Hepatitis A, B and C)
Bacterial (chlamydial infection, Q fever, brucellosis , mycoplasma infection, syphilis, leptospirosis, Lyme disease, Yersinia infection, streptococcal infection)
Fungal(Cryptococcus antigen, histoplasmosis, coccidioidomycosis)
Protozoal and parasitic (toxoplasmosis, amoebiasis, schistosomiasis, leishmaniasis, trypanosomiasis)
PCR e.g for tuberculosis, herpes simplex virus (HSV), CMV, HIV, erythrovirus, dengue, Toxoplasma, Whipple's disease
Immunology like Autoantibody screen, including anti-double-stranded DNA, anti-neutrophil cytoplasmic antibody (ANCA), Immunoglobulins, Complement (C3 and C4) levels &Cryoglobulins
Imaging like CT/MRI chest and abdomen, skeletal survey , isotope bone scan, labelled white cell scan
Biopsy: Bone marrow biopsy, Temporal artery biopsy


Factitious fever
It is most commonly encountered among young adults with health care experience or knowledge.
Evidence of psychiatric problems or a history of multiple hospitalizations at different institutions is common in patients with factitious fever.
Rapid changes of body temperature without associated shivering or sweating, large differences between rectal and oral temperature, and discrepancies between fever, pulse rate, or general appearance are typically observed in patients who manipulate or exchange their thermometers.

Golden Point

The longer a fever persists without a diagnosis, the less likely it is to have an infectious origin.

MCQs

The most probable cause of immune deficient PUO is :-
Streptococcal pneumonia
Thrombophlebitis
Drug fever
Unknown
2-A 45 years old male known to have chronic renal failure, admitted to the hospital to start hemodialysis at that time he was afebrile, 3 days later he developed fever of (39°C) persist for 3 days.
CBC showed Hb=9 g/dl, WBC=13*109 cells/l, platelets count=170*109 this type of fever is most probably:-
Immune deficient PUO
Health care associated PUO
Classic PUO
None of above


3) All the followings are criteria for immune deficient (neutropenic) PUO except :-
Temperature >38.3°C
Duration > 3 weeks
Neutrophile count 400
No valuabie diagnosis despite initial 48 hours of assessment

4-A patient can be considered to have classic PUO in which of the followings scenario :-

69 years old female with fever ranging (38.4°C - 38.8°C) for 40 days without finding a source of infection despite 10 days of inpatient investigations.
33 years old diabetic female present with fever of (39.5°C) for 3 days associated with rigor and loin pain.
18 years old female presented with fever ranging (38.5°C -39.7°C) for 1 month duration, with previous history of multiple hospital admissions and history of psychiatric problem.
23 years old female presented with fever of (38.9°C) and backache for 14 days duration, initial assessment showed high titer of Brucella agglutination test.