Dr. Teltscher -- Fever of Unknown Origin Flashcards
6 sites to measure body temperature
- Tympanic
- Oral
- Axillary
- PA-catheter
- Rectal
- Vaginal/urethral
Gold standard site for body temp measurement
PA - catheter
2 cons of using PA-catheter to measure body temperature
Invasive
Limited availability
Best estimate of body temperature
Rectal
3 cons to using rectal temperature
- Underestimate temp in shock
- Small risk of cross contamination
- Semi-invasive
Deviation from standard of oral temperature
-0.4 C
2 pros to using oral temperature
- Accessible
- Quickly change in response to change in core temp
Cons of using oral temperature
False readings from:
- Ingestion
- Mastication
- Smoking
- Mouth breathing (not tachypnea)
Deviation from standard of tympanic temperature
-0.8 C
Pros of TM
Rapid, very accesible
3 cons to using TM
- Wide variability
- User dependent concerns
- Concerns about actual site (i.e. cerumen, canal)
Notoriously inaccurate and unreliable temperature
Axillary
3 fastest methods of body temperature measurement by adjustment period
- TM (seconds)
- Digital oral (seconds to minutes)
- Rectal (1 - 5 min)
6 states that commonly cause variability in body temperature
- Fertile women
- Lower AM temp 2 wees prior to ovulation
- Temp then rises by 0.6C until ovulation
- Postprandial state
- Pregnancy
- Endocrinologic dysfunction
- Age
- Fixed variation in childhood
- Inability to mount fever in even extreme infection in elderly
- Nutritional status (i.e. catabolic, malnourished)
Define fever
Regulated rise in core temperature due to a corresponding rise in the thermoregulatory set point in response to a physiologic threat to the host
Define hyperthermia (3)
- **Unregulated **increase in core temperature in which inflammatory cytokines play only a minor role
- Sustained elevation of core temperature lacking diurnal fluctuations characteristic of both fever and normal body temp
- Does not respond to antipyrtic drug therapy
Define hyperpyrexia
Fever >41.5 degrees C
2 conditions associated with hyperpyrexia
- Severe infection
- CNS hemorrhage
7 causes of hyperthermia
- Heat stroke
- Illicit drug induced
- Neuroleptic Malignant Syndrome (NMS)
- Toxidromes/ODs/Drug Fever
- Malignant Hyperthermia
- Andocrinopathies
- CNS insults
6 illicit drugs that can cause hyperthermia
- PCP
- Ecstacy
- LSD
- Amphetamines
- Cocaine
- Lithium
2 causes of NMS
- Antipsychotics
- Withdrawal of dopaminergic agent
10 toxidromes or drugs that you can overdose on or which cause drug fever that can cause hyperthermia
- SSRIs
- MAOIs
- TCAs
- Anticholinergic
- Salicylates
- Antihistamines
- Antiparkinsonian drugs
- Diuretics
- Cardiovascular meds
- ABX
2 drugs that can cause malignant hyperthermia
- Anesthetics
- Succinylcholine
2 endocrinopathies that can cause hyperthermia
- Thyrotoxicosis
- Pheochromocytoma
3 CNS insults that can cause hyperthermia
- Cerebral hemorrhage
- Status epilepticus
- Hypothalamic injury
4 increased endocrine components of febrile response
- Glucocorticoid production
- GH secretion
- Aldosterone secretion
- Acute-phase proteins
2 decreased endocrine components of febrile response
- Vasopressin secretion
- Levels of circulating divalent cations
3 autonomic components of febrile response
- Shift of blood flow from cutaneous to deep circulatory beds
- Increased HR and BP
- Decreased sweating
5 neurobehavioral components of febrille response
- Shivering
- Search for warmth
- Anorexia
- Malaise
- Somnolence
Describe the increase in heat production by the liver in response to fever
- For each 1 degree C increase in body temperature, there is a 13% increase in O2 consumption without shivering
- Shivering –> increased oxygen consumption to 100% - 200% above base-line
8 fever patterns
- Circadian
- Intermittent
- Remittent
- Continuous
- Typhoid inversus
- Temp-Pulse dissociation
- Relapsing
- Cyclic neutropenia
Define circadian fever
Normal variation of increase in temperature as day progresses
Define intermittent fever
Fever interrupted by at least a daily return to normal body temperature
Define remittent fever
Fever may fluctuate but never returns to a normal body temperature
Define continuous fever
Fever varies less than 1C over several days
3 diseases that can cause intermittent fever
- Abscess
- Still’s disease
- P. falciparum malaria
3 diseases that can cause remittent fever
- TB
- Endocarditis
- Typhoid
4 diseases or conditions that can cause continuous fever
- Encephalitis
- Drug reactions
- Salmonellosis
- Factitious fever
Defin typhoid inversus fever
Inversion of circadian pattern
Define temp-pulse dissociation fever
Febrile episodes with relative bradycardia
4 types of relapsing fever
- Quartian
- Tertian
- Biphasic
- Pel-Ebstein
Define cyclic neutropenia fever
Fever occuring every 21 days accompanied by neutropenia
Define relapsing fever
Febrile episodes separated by periods of normal body temp:
- Quartian = every 3 days
- Tertian = every 2 days
- Biphasic = days of fever followed by afebrile period lasting days w/ subsequent days of fever recurring once
- Pel-Ebstein = 3 - 10 days of fever –> 3 - 10 days afebrile
Example of disease causing general relapsing fever
Brucellosis
Example of disease causes Quartian fever
P. malariae
Example of disease causing tertian fever
P. vivax
3 examples of diseases causing biphasic fever
- Borrelia
- Rat bat fever
- Dengue
2 examples of diseases that cause Pel-Ebstein fever
- Hodgkin’s disease
- Lymphomas
Classic definition of fever of unknown origin (FUO) (3)
- Temperature >38.3C on severl occasions
- Duration of fever >3 weeks
- Failure to diagnose despite 1 week of inpatient evaluation and investigation
4 new paradigms of FUO
- Classic FUO
- Nosocomial FUO
- Neutropenic FUO
- FUO associated with HIV infection
Define nosocomial FUO (4)
- Hospitalized
- Acute care
- No diagnosis of infection when admitted
- 3 days under investigation
Define neutropenic FUO
- ANC <500/ul or expected in 1 - 2 days
- 3 days under investigation
Treatment for neutropenic FUO
Empiric antibiotic coverage typically initiated early
Define HIV-associated FUO
- Confirmed HIV positive
- 3 days under investigation
- 4 weeks as outpatient
Define classic FUO accordign to new paradigm
- All other cases with fever of at least 3 weeks
- 3 days or 3 outpatient visits or 1 week of intelligent and invasive ambulatory investigations
2 requirements for all types of FUO according to new paradigm
- Temperatures of at least 38.3 C on several occasions
- 2 days of microbiology cultures
8 infectious causes of FUO
- Occult abscesses
- Localized - prostatitis, sinusitis, dental abscesses, cholangitis
- Infective endocarditis
- TB: pulmonary and extrapulmonary (fever and night sweats)
- Organisms difficult to culture
- Prolonged viral syndromes
- Fungal disease
- Malaria, especially if cyclic or if returned traveler
4 occult abscesses that can cause FUO
- Intra-abdominal
- Renal
- Retroperitoneal
- Paraspinal
Pathogens responsible for FUO in IE
Culture negative – HACEK group
6 difficult to culture organisms that can be the cause of FUO
- Legionella
- Brucella
- Bartonella
- Coxiella
- Chlamydia
- Francisella
Describe fungal disease as a cause of FUO
- Especially of RES – hepatosplenic, candidiasis, histoplasmosis
- FUO + headache –> consider cryptococcus neoformans
7 infectious causes of fever in returned traveler
- Malaria (P. falciparum)
- Malaria (P. falciparum)
- Malaria (P. falciparum)
- Enteric/typhoid fever (salmonellosis)
- RIckettsial diseases (i.e. African tick typhus, scrub typhus)
- Others (i.e. STDs, HAV, HBV, others based on geography)
- Standard diseases (i.e. pneumonia, URTI, UTI, etc)
9 malignant diseases as possible causes of FUO
- Colon
- Gall bladder
- Hepatoma
- Hodgkin’s lympoma
- Non-Hodgkin’s lymphoma
- Leukemia
- Pancreatic cancer
- Renal cell carcinoma
- Sarcoma
3 non-malignant diseases that can be a cause of FUO
- Atrial myxoma
- Castleman’s disease
- Renal angiomyolipoma
9 infammatory causes of FUO (esp. non-infectious FUO)
Autoimmune, systemic rheumatologic, vasculitic disease, auto-inflammatory:
- Temporal arteritis, Still’s disease
- Polymyalgia rheumatica, SLE, RA
- Wegener’s granulomatosis, polyarteritis nodosa
- Granulomatous disease
3 granulomatous diseases that may be the cause of inflammatory FUO
- Sarcoidosis
- Crohn’s disease
- Granulomatous hepatitis
8 types of causes for FUO
- Infectious
- Inflammatory
- Malignant
- Drug fever
- Tissue sources
- Central/peripheral thermoregulatory disorders
- Familial disease
- Other (i.e. habitual hyperthermia, factitious fever)
4 types of drugs that can cause drug fever
- Antimicrobial agents
- Cardiovascular
- Chemo treatment
- CNS acting
5 tissue sources of FUO
- Gout
- Recurrent/chronic PE
- Hematoma
- Infarction
- Necrosis
6 central/peripheral thermoregulatory disorders as potential causes of FUO
- Brain tumors
- CVA
- Encephalitis
- Hypothalamic dysfunction
- Hyperthyroid
- Pheochromocytoma
2 familial diseases as potential causes of FUO
- Familial mediterranean fever
- Fabry’s disease
4 considerations for causes of FUO in elderly
- Most common = multisystem disease
- Temporal arteritis
- Giant cell arteritis/polymyalgia rheumatica
- Infectious (mycobacterial leading)
- Neoplastic (i.e. colon cancer)
- Thrombosis
7 investigative tests that have been proven to be useful in the work up of FUO
- CT scan
- Esp. abdominal; high diagnostic yield, should be one of first)
- Nuclear medicine scans
- Galium, PET, Technetium, Indium
- IE classification systems (Modified Duke’s Criteria and Echocardiogram)
- Liver biopsy
- Temporal artery biopsy
- Duplex doppler scans (for DVT)
- Bone marrow biopsy (for when other not yielding positive results)
2 common causes of FUO that CT scan can identify
- Occult intra-abdominal abscesses
- Neoplasm
3 complications of temporal artery biopsy
- Damage of the facial nerve
- Skin necrosis
- Drooping of the eyebrow
6 investigative tests for FUO that are often performed by have no evidence for their usefulness
- Emperic antibiotic therapy (uncertain)
- Exploratory laparotomy (uncertain)
- ESR
- CRP
- D-Dimer
- Bone scan