Pyrexia of unknown origin Flashcards
What temperature is considered a fever?
> 38.3C
What are the clinical stages of fever?
Chill
Fever
Flush
What is a pyrexia of unknown origin?
Temperature >38.3.
Initially more than 3 weeks duration of illness.
Failure to reach a diagnosis despite 3 days of inpatient investigation.
Nocosomial pyrexia
Immunodeficient PUO
HIV-associated PUO
What are the aetiologies of fever?
Infection Malignancy Drugs Connective tissue disease Endocrine Other
Which region determines temperature?
Organum vasculosum of lamina terminalis (OVLT) in anterior hypothalamus
What are the endogenous pyrogens?
IL-6
TNF-alpha
What are exogenous pyrogens?
Micro-organisms, LPS
Stimulate cytokines or act directly on OVLT
What causes fever post brain injury?
Thermal dysregulation. Shift to anaerobic metabolism and reperfusion injury - thermogenesis. Cerebral production of cytokines. Cell death Excitotoxicity Blood and degradation products - heat
Give some endocrine causes of fever.
Hyperthyroidism: increased peripheral tissue metabolism, resetting of hypothalamus thermostat.
Phaeochromocytoma: necrosis, metabolite excretion .
Adrenal insufficiency: AI, malignancy, infectious process
What are the complications of infective endocarditis?
Septic embolisation
Cardiac - valvular insufficiency, heart failure, peri-valvular abscess, intracardiac fistula, pericarditis
Neurological - brain abscess, stroke
Systemic immune reaction
Metastatic infectoin - psoas abscess, vertebral osteomyeltitis, septic arthritis.
What are the differential diagnosis of infective endocarditis?
Bacteraemia without valvular vegetation: sepsis, PVC/CVC infection, Deep-seated infections
Valvular vegetation without bacteraemia:
atrial myxoma, vasculitis, acute rheumatic fever, antiphospholipid syndrome
What are the investigations for endocarditis?
Blood cultures: 3 sets, one hour apart.
Urinalysis
ECG - new/evolving conduction disease, ischaemia
Transthoracic echo initially, transoesophageal echo- high sensitivity//specificity
What is the major Duke’s criteria?
Positive blood cultures:
2 positive blood cultures with typical organisms
Persistent bacteraemia from 2 blood cultures more than 12 hours apart, or 3 blood cultures with less specific organisms
Positive serology for coxiella burnetti, barrtonella species, or chlamydia psittaci
Endocardial involvement:
Echo: vegetation, abscess, new partial dehiscence of prosthetic valve
Positive molecular assays for specific gene targets
What are the minor duke’s criteria?
Predisposing heart disease/IVDU
Fever >38
Immunological phenomena: glomerulonephritis, Osler’s nodes, Roth spots, or positive rheumatoid factor
Microbiological evidence not fitting major criteria
Elevated CRP or ESR
Vascular phenomena: major emboli, splenomegaly, clubbing, splinter haemorrhages, petechiae, or purpura
How many Duke’s criteria need to be filled to diagnose endocarditis?
Pathological criteria positive OR
Two major criteria OR
One major and two minor criteria OR
Five minor criteria
What is the management of endocarditis?
Antibiotics by organism and sensitivty - if clinically stable hold off until known
If clinically unwell - empmirical antibiotics
Repeat blood cultures
4-6 weeks of antibiotics usually
Monitor renal function
What are the indications for surgery in endocarditis?
Failure of medical management
Acute left heart failure
Recurrent systemic emoblic episodes
Pathogens resistant to current antibiotics
>1cm mitral leaflet vegitation
Prosthetic valve involvement with non-strep
What are the complications of hepatitis A?
Cholestatic hepatitis
Relapsing hepatitis
Autoimmuen hepatitis
What are the features of neuroleptic malignant syndrome?
Fever Muscular rigidity Elevated CK Tachycardia Labile BP Tachypnoea Sweating Altered GCS Elevated WCC
What does neuroleptic malignant syndrome occur in association with?
Dopamine antagonists
What are the features of serotonin syndrome?
Mental status change Agitation Myoclonus Hyperreflexia Sweating Shivering Tremor Diarrhoea Incoordination Fever
