MCD - Fever Flashcards
Etiology of Fever - Respiratory infections?
- Acute bronchitis.
- Pneumonia.
- Influenza.
- Empyema.
- Infective exacerbation of bronchiectasis/COPD.
- TB.
Etiology of fever - GI causes?
- Gastroenteritis.
- Appendicitis.
- Biliary sepsis.
- Viral hep.
- Diverticulitis.
- Intra-abdominal TB.
- Hepatic abscess.
Etiology of fever - Skin/soft tissue?
- Cellulitis.
- Erysipelas.
- Necrotizing fasciitis.
- Pyomyositis.
- Infected pressure sore.
- Wound infection.
Etiology of fever - Musculoskeletal causes?
- Septic arthritis (native and prosthetic joint).
- Osteomyelitis.
- Discitis.
- Epidural abscess.
Etiology of fever - Genitourinary tract?
- Lower UTI, e.g. cystitis, prostatitis.
- Upper UTI (pyelonephritis).
- Perinephric collection.
- Pelvic inflammatory disease.
- Epididymo-orchitis.
- Syphilis.
Etiology of fever - CNS?
- Meningitis (bacterial, viral, fungal, TB).
- Encephalitis.
- Cerebral abscess.
Etiology of fever - ENT?
- Upper RTI, eg tonsillitis.
- Otitis media.
- Quinsy.
- Dental abscess.
- Mumps/Parotitis.
- Glandular fever (EBV).
- Sinusitis.
Etiology of fever - Immunocompromised patients?
- Pneumocystis jiroveci (carinii) pneumonia.
- Aspergillosis.
- TB.
- Atypical mycobacterial infection, eg MAI.
- CMV infection.
- Toxo.
- Cryptococcal meningitis.
- Nocardia.
- Disseminated herpes/fungal infection.
Etiology of fever - Returning travelers?
- Malaria.
- Typhoid.
- Infective diarrhea, eg cholera, amebiasis, Shigella.
- Amebic liver disease.
- Strongyloides infection.
- Schistosomiasis.
- Dengue.
Etiology of fever - Other infectious causes?
- Leptospirosis.
- Brucellosis.
- Lyme.
- Q fever.
- HIV.
- Toxo.
- Fungal infection.
- Measles.
- Rubella.
- Herpes zoster infection (chickenpox or shingles).
Etiology of fever - Malignancy?
- Hematological malignancy - Lymphoma/leukemia/myeloma.
2. Solid tumors - Renal, Liver, colon, pancreas.
Etiology of fever - Connective tissue disease?
- Giant cell arteritis/Polymyalgia rheumatica.
- RA.
- SLE.
- Polymyositis.
- Polyarteritis nodosa.
- Wegener.
- Churg-Strauss.
- Cryoglobulinemia.
- Adult-onset Still’s disease.
Etiology of fever - Drugs?
- Drug fever (almost any drug).
- Antipsychotics (neuroleptic malignant syndrome).
- Anesthetics (malignant hyperthermia).
- Cocaine, amphetamines, ecstasy.
Etiology of fever - Miscellaneous causes?
- Transfusion-associated.
- Thyrotoxicosis, thyroiditis.
- Pheochromocytoma.
- DVT/PE.
- Pancreatitis.
- Alcoholic hep/ delirium tremens.
- Rheumatic fever.
- IBD.
- Sarcoidosis.
- Atrial myxoma.
- Familial Mediterranean fever.
- Erythroderma/Stevens-Johnson syndrome.
- Factitious (fever or apparent fever surreptitiously engineered by the patient).
Fever overview - Step 1?
Exposure to blood products, anesthetic, antipsychotics or stimulants. If YES: 1. Transfusion reaction. 2. Malignant hyperthermia. 3. Neuroleptic malignant syndrome.
Fever overview - Step 2?
HR>90, RR>20, or abnormal WBC/CRP.
If YES –> SIRS/sepsis.
Fever overview - Step 3?
Specific risk factor for infection.
If YES –> Further targeted investigation.
Fever overview - Step 4?
Clinical findings/initial tests suggest a likely source.
If YES –> Confirm diagnosis +/- empirical treatment.
Fever overview - Step 5?
Positive cultures.
If YES –> Seek source +/- specific antimicrobial therapy.
Fever overview - Step 6?
Persistent fever.
If YES –> See further assessment of pyrexia of unknown origin.
Fever caused by transfusion - What to do?
- Stop the transfusion.
- Ensure compatibility.
- Contact the blood bank and seek immediate Hematology input if there is any suspicion of ABO incompatibility or other major transfusion reaction.
- Otherwise, monitor temperature and vital signs, and consider restarting the transfusion at a slower rate if observations are stable, the patient is systemically well and the rise in temperature is <1.5C.
Fever due to neuroleptic malignant syndrome - When to suspect?
If the patient has received neuroleptics, eg haloperidol, within the past 1-4weeks and exhibits muscular rigidity, tremor and excessive sweating and/or altered mental status, especially in association with incr. CK.
Fever due to toxic hyperthermia?
- Ask about cocaine, ecstasy, amphetamines.
- Temperature >39.
- UP BP, UP HR, dilated pupils, aggression, psychosis or serotonin syndrome eg rigidity, hyper-reflexia.
Fever due to rhabdomyolysis, ARF, arrhythmia, DIC, acute liver failure - What to measure?
- CK.
- U+E.
- LFTs.
- Coagulation.
- Monitor ECG, HR, BP, urine output.
Fever due to malignant hyperthermia - When to assume?
Severe pyrexia with tachycardia +/- rhabdomyolysis during administration of, or within 1-2 hrs of exposure to, a volatile anesthetic, eg halothane, or succinylcholine.
Fever with HR>90, RR>20 or abnormal WBC/CRP - What to think?
Assess the patient for SIRS/sepsis.
SIRS/Sepsis - What is ESSENTIAL to minimize mortality?
EARLY + APPROPRIATE antibiotic treatment.
Criteria for determining SIRS:
2 or more of:
- Temperature >38C or 90.
- RR>20.
- WBC>12.000 or <4.000 or 10% immature forms; or UP CRP.
Criteria for determining sepsis:
SIRS + suspected or proven infection.
Criteria for determining SEVERE sepsis:
Sepsis + Organ dysfunction or hypotension.
Criteria for determining septic shock:
Severe sepsis that persists despite adequate fluid resuscitation.
What is the septic screen?
- Combines clinical assessment with lab analysis and imaging studies to identify a source of infection.
- It may also reveal non-infectious causes of pyrexia, eg malignancy.
- Full septic screen may NOT be required in all patients, especially if there is an OBVIOUS focus of infection.
Septic screen - General?
- > 2sets of blood cultures.
- Urinalysis.
- FBC.
- U+E.
- LFTs.
- CRP.
- CXR.
Septic screen - Respiratory:
- Assess suspected RTI - eg new/worsening cough with purulent sputum or CXR consolidation.
- Perform a pleural tap and send fluid for biochemical, microbiological and cytological analysis if unilateral pleural effusion.
- If other respiratory features - eg Hemoptysis, non-specific CXR hypoxia, consider further investigation - eg CT, bronchoscopy to exclude atypical infection, lung cancer and PE.
Septic screen - Abdominal?
- Stool –> Microscopy, culture, C.difficile toxin if acute diarrhea.
- IBD –> Flexible sigmoidoscopy, if persistent bloody diarrhea.
- Fever + ASCITES –> Treat empirically SBP, pending culture, if >250Neutros. Consider TB/malignancy if cultures(-) and fluid exudative.
Septic screen - Abdominal - New-onset jaundice?
Arrange an abdominal USS and serology for viral hep.
- Empirically for biliary sepsis and arrange surgical review.
- Blood + urine samples for LEPTOSPIROSIS and serology +/- PCR if symptoms include purpura/down platelets/conjunctival congestion or recent exposure to potentially contaminated water eg freshwater sports, sewage worker.
Septic screen - Abdominal - Amylase?
Check amylase and assess accordingly.
Septic screen - Abdominal - Palpable mass?
If palpable abdominal mass investigate for infective eg diverticular or appendiceal abscess, non-infective eg carcinoma, lymphoma, causes with USS or CT +/- aspiration or biopsy.
Septic screen - Urinary tract - Step 1:
Send a mid-stream urine (MSU) specimen if new-onset urinary tract symptoms, an indwelling catheter, or leukocytes/nitrites on urinalysis (Highly unlikely in the absence of either nitrites or leukocytes).
Septic screen - Urinary tract - Step 2:
Arrange USS to exclude renal obstruction, calculus, or a perinephric collection if loin pain or renal angle tenderness.
Septic screen - Urinary tract - Step 3:
Exclude urinary tract cancer +/- inflammatory renal disease if peristent hematuria (visible or non-visible) or loin pain with repeated negative MSU.
Septic screen - Urinary tract - Step 4:
Send swabs for N.gonorrhea and Chlamydia if urethral or PV discharge.
Septic screen - Skin and soft tissue - Steps:
- Swabs from any wounds or sites discharging pus.
- Suspect cellulitis if there is an area acutely hot, erythematous, painful - Look for potential entry sites.
- Severe necrotizing infection –> Immediate surgery + Antibiotics.
- DVT may produce low grade fever.
- Osteomyelitis eg bone scan, persistent non-healing ulcer.
- Whole body for rashes - urgent dermatology advice if blistering, mucosal involvement or pustules.
Septic screen - CNS - Steps:
- Assume CNS infection, initially, if severe meningism, purpuric rash etc.
- Immediate empiric treatment after blood cultures.
- Arrange neuroimaging.
- If no contraindications - Perform LP.
- If meningitis suspected, send a throat swab for Neisseria meningitidis PCR.
Septic screen - Cardiovascular - Steps:
- Endocarditis investigations - See criteria.
2. Consider TE echo if transthoracic images equivocal or persistent high clinical suspicion.
Septic screen - ENT - Steps:
- Autumn/winter –> Throat swab for influenza.
- Pustular exudates –> Swab for S.pyogenes.
- Parotitis/Tender lymphadenopathy –> Throat swab for mumps, PCR and, if age-appropriate, check EBV serology (>95% of patients >35yr will have evidence of previous exposure).
Septic screen - Musculoskeletal - Steps:
- If acutely swollen, painful joint, seek urgent orthopaedic assessment and perform diagnostic aspiration to exclude septic arthritis.
- If unexplained back pain with no other obvious source for fever, take >3 blood cultures + arrange spinal MRI to exclude discitis.
Modified Duke Criteria for the diagnosis of infective endocarditis - Major criteria:
A. Positive blood culture:
1. Typical organism from 2 cultures.
2. Persistent positive blood cultures taken >12hrs apart.
3. >3 positive cultures taken over >1hr.
B. Endocardial involvement:
1. Positive echocardiographic findings of vegetations.
2. New valvular regurgitation.
Modified Duke Criteria for the diagnosis of infective endocarditis - Minor Criteria:
- Predisposing valvular or cardiac abnormality.
- IV drug misuse.
- Pyrexia >38C.
- Embolic phenomenon.
- Vasculitic phenomenon.
- Blood cultures suggestive - organism grown but NOT achieving major criteria.
- Suggestive echocardiographic findings.
Modified Duke - DEFINITE endocarditis?
2M
1M + 3m
5m
Modified Duke Criteria - POSSIBLE endocarditis?
1M + 1m
3m
Septic screen in specific patient groups - Recent travel or residency abroad:
- Exact travel/ location/ activities.
- Ask about vaccinations/malaria prophylaxis.
- Consult an ID specialist.
- Exclude malaria if recent travel to an endemic region.
- If fever + diarrhea –> Isolate the patient and note all recent travel history on stool specimen requests.
- Send blood and stool cultures for typhoid (and start empirical treatment) if high fever.
- Consider acute schistosomiasis.
- Arrange US to exclude amebic abscess.
- Check dengue fever serology if recent return from the tropics/subtropics and an acute febrile illness.
Septic screen in specific patient groups - Immunocompromised HIV(+):
- HIV(+) - Check the most recent CD4 count and repeat if >3months ago.
- Fungal and viral infections are more likely if CD4 is PCP.
Further assessment of PUO - Step 1:
Discuss the significance of any positive serology with the ID/microbiology team and a positive ANA, ENA, ANCA with the Rheumatology team.
Further assessment of PUO - Step 2:
- Biopsy any suspicious masses or lymphadenopathy (incl. bilateral hilar lymphadenopathy) detected clinically or radiologically.
- If an abscess is identified, request a surgical opinion regarding drainage.
Further assessment of PUO - Step 3:
Discuss with Hematology and consider bone marrow exam if Bence-Jones protein, paraproteinemia or a significant blood film abnormality, eg atypical lymphocytes.
Further assessment of PUO - Step 4:
Arrange muscle biopsy if CK UP to exclude inflammatory myositis.
Further assessment of PUO - Step 5:
Perform a radioisotope bone scan to look for evidence of malignancy or osteomyelitis if persistent bony pain, UP Ca, UP PSA, UP ALP (with otherwise normal LFTs).
Further assessment of PUO - Step 6:
If LFTs persistently deranged or hepatomegaly without an obvious cause, request a liver biopsy (with material for culture) to look for TB, sarco, and granulomatous hep.
Further assessment of PUO - Step 7:
If persistent hematuria/proteinuria with negative MSU, discuss with the Renal team and consider renal biopsy to exclude GN.
Further assessment of PUO - Step 8:
Use the Duke and Jones criteria to confirm or refute a suspected diagnosis or endocarditis or RF respectively.
Further assessment of PUO - Step 9:
- Consider an ANCA(-) systemic vasculitis if palpable purpura, skin ulceration, or livedo reticularis.
- Measure serum cryoglobulins (cryoglobulinemic vasculitis).
- Consider arteriography eg renal, mesenteric, or tissue biopsy if PAN is suspected.
Further assessment of PUO - Step 10:
If ESR UP in a patient >50:
A. Treat for giant cell arteritis + biopsy.
B. Diagnose polymyalgia rheumatica if there is any proximal joint pain or stiffness - review the diagnosis if no response to steroids within 72hr.
Further assessment of PUO - Step 11:
Suspect adult-onset Still’s disease if microbiological and autoimmune investigations are consistently negative, and there are recurrent joint pains or a transient, non-pruritic, salmon-pink maculopapular rash that coincides with fever, especially if UP ferritin.
Further assessment of PUO - Step 12:
Review all drugs - Discontinue one at a time for 72hr and then reinstate if fever persists.
Jones criteria for the diagnosis of RF - Major:
- Carditis.
- Polyarthritis.
- Chorea.
- Erythema marginatum.
- Subcutaneous nodules.
Jones criteria for the diagnosis of RF - Minor:
- Fever.
- Arthralgia.
- Previous RF.
- UP ESR or CRP.
- Leucocytosis.
- 1st-degree AV block.
Jones criteria for the diagnosis of RF - PLUS:
Supporting evidence of preceding strep. infection:
- Recent scarlet fever.
- UP Anti-Strep O.
- Other strep antibody titre.
- Positive throat culture.
- –> Particularly important if there is only one major manifestation.
Definition of fever?
Core body temperature >38.
If it persists >3weeks without explanation it is termed pyrexia of unknown origin (PUO).