Lec .3 presenting problems in infectious diseases
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Transcript of Lec .3 presenting problems in infectious diseases
PRESENTING PROBLEMS IN INFECTIOUS DISEASES
Fever• Documentation of fever: feeling hot or sweaty is not synonymous with fever Body temperature >38 ºC is a fever. • Axillary is less accurate than oral or rectal temp.
• Rigors. Shivering (followed by excessive sweating) implies a rapid rise in body temperature but rarely give a clue to etiology.
• Night sweats. These are characteristic of several infections (e.g TB, infective endocarditis).
• Excessive sweating without fever. Caused by Alcohol, anexiety, thyrotoxicosis, D.M, acromegaly,
lymphoma and excessive environmental heat
Accompanying features with fever:
• Headache. severe headache and photophobia, although characteristic of meningitis, may company other infections.
• Delirium. Mental confusion during fever is more common in young children or the elderly.
• Muscle pain. Myalgia may occur with viral infection, such as influenza, and with septicemia.
• Shock. Shock may accompany severe infections and sepsis.
HISTORY-TAKING IN FEBRILE PATIENTS
• Symptoms of common respiratory infections.• Genitourinary symptoms. Abdominal symptoms. • Joint symptoms. • Rash. • Travel history . • Drug history. Drug fever is uncommon and therefore
easily missed.• Alcohol consumption .
EXAMINATION OF THE FEBRILE PATIENT
Rash• Erythematous rashes (irregular erythematous patches that pale on
pressure and may be papular) Infectious causes include • human erythrovirus 19 infection • Measles, • scarlet fever• rubella may be non-infective, e.g. as a reaction to
medication.
A purpuric or petechial rash does not pale on pressureCaused by :• Meningococcal infection and meningococcemia• sepsis from any cause.• vasculitic lesions• thrombocytopenia• disseminated intravascular coagulopathy
Vesicular rashes may be caused by • chickenpox, shingles, • herpes simplex infection, • Coxsackie A virus infection (hand, foot and mouth
disease)
• Nodular skin lesions are caused by disseminated fungal infection and malignancy.
• Erythematous painful lesions on extensor surfaces of the limbs suggest erythema nodosum related to tuberculosis, sarcoid or drug reactions.
• Neck stiffness
• Cervical lymph nodes Enlargement of anterior and tonsillar nodes is
usually associated with tonsillitis or pharyngitis; posterior lymphadenopathy may suggest a glandular fever syndrome or HIV infection.
Mouth and oropharynx• Vesicular lesions, tonsillar exudates and palatal
petechiae suggest possible infectious aetiologies • Hairy leucoplakia of the tongue suggests HIV disease. • Oropharyngeal candidiasis may indicate immune
deficiency.
Eyes• Red eye suggests conjunctivitis, scleritis or uveitis.
• Conjunctival petechiae may be due to endocarditis.
• Proptosis may suggest thyroid eye disease. If it is unilateral, consider orbital infiltration by malignancy
or granulomatous disease.
PYREXIA OF UNKNOWN ORIGIN
DEFINITION 0f PUO
PUO is defined as a
• Fever higher than 38.0°C (101°F) on several occasions Persisting without diagnosis for more than 3 weeks without
diagnosis despite initial investigations for at least 3 outpatient visits or
3 days in the hospital without elucidation of a cause
AETIOLOGY OF PYREXIA OF UNKNOWN ORIGIN
1- Infections (30%):• Abscess at any site; • Imported infections, e.g. malaria, dengue, brucellosis • Enteric fevers .• Infective endocarditis. • Tuberculosis .• Viral infections • Fungal infections .
2- Malignancy (20%)• Hematological malignancies (Lymphoma, myeloma,
Leukaemias). • Solid tumors: bronchogenic ca. ca breast, hypernephroma,
retinoblastoma, ca pancreas 3- Connective t issue disorders (15%) • Vasculitic disorders .• Temporal arteritis /polymyalgia rheumatica .• SLE .• Still's disease .• Polymyositis .• Rheumatic fever.
AETIOLOGY OF PUO
AETIOLOGY OF PUO
4- Miscellaneous (20%) • Inflammatory bowel disease .• Liver disease. • Sarcoidosis. • Drug reactions. • Atrial myxoma .• Thyrotoxicosis .• Hypothalamic lesions. • Familial Mediterranean fever. 5- Idiopathic (15%)
Some important causes
• Extrapulmonary tuberculosis is the most frequent cause of FUO • Drug-induced hyperthermia, as sole symptom of an adverse
reaction to medication, should always be considered. • Disseminated granulomatoses such as Tuberculosis,
Histoplasmosis, Coccidioidomycosis, Blastomycosis and Sarcoidosis are associated with FUO.
• Lymphomas are the most common cause of FUO in adults• Thromboembolic disease (i.e. pulmonary embolism, deep venous
thrombosis) occasionally shows fever. • Although infrequent, its potentially lethal consequences warrant
evaluation of this cause.• Endocarditis, although uncommon, is another important etiology to
consider. • An underestimated reason is factitious fever. Patients frequently are
women that work, or have worked, in the medical field and have complex medical histories.[
EARLY TESTS IN THE INVESTIGATION OF PUO IN DEVELOPED COUNTRIES
• Full blood count (FBC) and differential .• ESR and CRP .• Serum ferritin. • Urea, creatinine and electrolytes .• Liver function tests (LFTs) and γ-glutamyl transferase. • Blood glucose .• Creatine phosphokinase (CPK).
Investigations (continue)
• Malaria blood films (if travel history). • Urinalysis . Midstream urine (MSU) for microscopy and
culture • Stool culture. • Sputum for routine microscopy and culture, and
microscopy for AFB and culture for mycobacteria .
• Blood cultures ×3 .• Chest X-ray .• Ultrasound examination of abdomen .• Electrocardiogram (ECG).
USEFUL SEROLOGICAL INVESTIGATIONS IN THE MANAGEMENT OF PUO IN DEVELOPED COUNTRIES
Viral:• CMV infection • Infectious mononucleosis • HIV infection • Hepatitis A, B and C infection • Erythrovirus infection
Bacterial : Lyme disease Chlamydial infection Brucellosis Mycoplasma infection Syphilis Leptospirosis
FURTHER NON-INVASIVE INVESTIGATIONS IN THE MANAGEMENT OF PUO
• Nucleic acid detection (polymerase chain reaction, PCR)
for tuberculosis, herpes simplex virus (HSV), CMV, HIV, erythrovirus, dengue, Toxoplasma, Whipple's disease
Immunological investigations• Autoantibody screen, including anti-double-stranded
DNA, anti-neutrophil cytoplasmic antibody (ANCA) • Immunoglobulins. • Complement (C3 and C4) levels. • Cryoglobulins.
Tuberculosis screening tests :
• Tuberculin (Mantoux) test. • Early morning specimen of urine (EMSU) ×3 for
mycobacterial microscopy and culture .
Imaging techniques
• Chest and abdominal X-rays may show lymphadenopathy or the absence of a psoas shadow.
• Ultrasound is rapid and non-invasive but often requires to be augmented by
• computed tomography (CT) or • magnetic resonance imaging (MRI) .
Imaging techniques
Chest and abdominal X-rays may show lymphadenopathy or the absence of a psoas
shadow.Ultrasound of abdomen • Liver tumour or metastases, liver abscess ,Dilated
intrahepatic bile ducts ,Renal tumour, abscess or hydronephrosis ,Ascites
Echocardiogram • Vegetations ,Atrial myxoma ,Intracardiac thrombus
CT/MRI of thorax and abdomen • Enlarged lymph nodes ,Organomegaly, Tumors and
abscesses, Lung and liver metastases .
Imaging techniques
Limited skeletal survey • Multiple myeloma ,• Bone metastases
Isotope bone scan • Malignancy ,• Osteomyelitis/septic arthritis
Labelled white cell scan • Abscesses/local sepsis,• Inflammatory bowel disease
The role of biopsies in investigation of PUO
Liver biopsy • Liver biopsy is a low-yield investigation which carries an estimated mortality
of approximately 0.01%. • The procedure may occasionally be required to diagnose tuberculosis,
lymphoma, or granulomatous disease including sarcoidosis.
Bone marrow biopsy • the diagnostic yield of a bone marrow biopsy in PUO is about 15%, • A biopsy is most useful in revealing haematological malignancy,
myelodysplasia and tuberculosis. • It may also lead to a diagnosis of brucellosis, enteric fever or visceral
leishmaniasis.
Temporal artery biopsy • should be considered in patients over the age of 50 complaining of
headache, joint pain, morning stiffness and high ESR possibility of crainial arteritis/ polymyelgia rheumatica
Up to one third of cases of PUO remain undiagnosed.
Therapeutic trials like
treatment of malaria, brucellosis, T.B. typhid fever
steroid for C.T. diseases
Factitious fever
• This is defined as fever, or the appearance of fever, that is engineered by the patient .
• This tends to be relatively more common in female patients and those with a medical or nursing background.
CLUES TO THE DIAGNOSIS OF FACTITIOUS FEVER
• A patient who looks well • Bizarre temperature chart with absence of diurnal
variation and/or temperature-related changes in pulse rate
• Temperature > 41°C • Absence of sweating during defervescence • Normal ESR and CRP despite high fever • Evidence of self-injection or self-harm • Useful methods for the detection of factitious fever
include supervised (observed) temperature measurement and measuring the temperature of freshly voided urine .
Prognosis in PUO
• The overall mortality of PUO is 30-40% • (5% in patients aged under 55 years, 40% in those age
over 55 years).
• Older patients are more likely to have a malignancy.
• If no cause is found on exhaustive investigation, the long-term mortality is low.
FEVER IN THE NEUTROPENIC PATIENT • Neutropenia is defined as a neutrophil count of less than
1.5 × 109/l.
• Patients with neutropenia, particularly less than 1.0 × 109/l, from either drug toxicity (including chemotherapy for cancer treatment), marrow invasion or failure, are particularly prone to bacterial infections.
• Gram-negative infections is the most common pathogens in this condition.
• It is both appropriate and potentially life-saving to start empirical broad-spectrum antibiotic therapy in these cases as soon as neutropenia is recognised and relevant specimens have been taken.