L11 - Fever Examination And Investigation Flashcards
What is the definition of a fever?
100.4F
38C
What is a fever?
A regulated rise to a new set point of body temperature in the hypothalamus
Induced by pyrogenic cytokines —> increased heat production (e.g. shivering) or decreased heat loss (peripheral vasoconstriction)
What is hyperthermia?
Not cytokine mediated, set point of hypothalamus remains unchanged
Occurs when environmental heat load or body metabolic heat production exceeds normal heat loss capacity
Ex. Heat stroke, thyrotoxicosis, neuroleptic malignant syndrome
Can be rapidly fatal if untreated
Which organisms can cause a fever pattern of every other day?
P vivax and ovale (malaria)
Which organism can cause a fever pattern of every 3rd day?
P malariae
What can cause a stepwise fever pattern?
Typhoid fever
What can cause a pel-Epstein pattern of fever (lasts 3-10 days followed by afebrile period of 3-10 days)?
Lymphoma
What are the main causes of fever?
Infection (viral, bacterial, fungal) Malignancy (lymphoma) Autoimmune (SLE) Drugs (serotonin syndrome, neuroleptic malignant syndrome) Endocrinopathy (thyroid storm)
What are some differential dx for a fever and sore throat?
Viral URI, step pharyngitis
What are some DDx for a fever and cough?
Viral URI
Pneumonia
Flu
COVID
What are some DDx for fever and a rash?
Cellulitis
What are some DDx for fever and dysuria?
UTI
Pyelonephritis
What is sepsis?
Life threatening organ dysfunction caused by dysregulated host responses to infection
What are the key findings for sepsis?
Hypotension, altered mental status, acute kidney injury, coagulopathy and increased RR
May or may not present with fever
What are the associated sx for SLE?
Malar rash, photosensitivity, oral ulcers, arthritis, hx of pleuritis or pericarditis, hx of seizures or other CNS disorders, hematuria, alopecia
What are some commonly overlooked portions of the PE in pts with unexplained fever?
Dental (visible dental abscess/gum swelling? —> odonotogenic infection)
Female GU (vaginal discharge, cervical motion, tenderness? —> PID)
Bones/joints (hot red swollen joint, tender vertebral processes? —> septic arthritis, osteomyelitis)
Rectal (prostate severely tender to palpation? —> prostatitis)
Complete skin exam (abscess, cellulitis)
Localized LAD can help you localize what?
An infection
Generalized LAD can be a sign of what?
Systemic infection, autoimmune condition or malignancy
What is a fever of unknown origin (FUO)?
Febrile illness (temp of 101F/38.3 or higher) for 3 weeks or longer without an etiology despite a one week inpatient evaluation Not just a new fever without an identified caused
What is the etiology for a FUO?
May be infection, auto immune, malignancy (IMADE)
Atypical presentation of common illness»_space; typical presentation of rare illness
What is the work up for FUO?
Complete history and physical
Extensive lab and imaging work up
What is on a CBC?
WBC, platelets, Hb, hematocrit
What can cause leukocytosis?
DDx include stress, infection, malignancy, allergic reaction, medication effect (i.e. corticosteroids)
What are some causes for leukopenia?
Wide differential including certain infections, malignancy, drugs, auto immune conditions
Low WBC count is a classic finding for SLE
Sepsis can present with what?
A high or low WBC count
When would monocytes be elevated?
Atypical infections (EBV, fungal, Protozoa, rickettsial, TB)
What are infectious causes of thrombocytopenia?
Certain viral infections (EBV, CMV),hepatitis C, HIV, tick borne disease
What are autoimmune causes of thrombocytopenia?
SLE
What are malignant causes for thrombocytopenia?
Hematologic malignancies causing bone marrow failure or infiltration
Thrombocytopenia can be seen in sepsis and is often due to what?
DIC
What are CMP findings associated with sepsis?
Increased BUN and creatinine
Anion gap acidosis (with low HCO3)
Liver function test abnormalities can be a sign of multi organ dysfunction
What is lactic acidosis?
Serum lactate concentration above 4mmol/L
Can be a marker of impaired tissue oxygenation due to tissue hypoperfusion
Describe the leukocyte esterase test
High sensitivity, low specificity
Positive = pyuria, presence of WBCs in urine
Describe the nitrite urine test
Low sensitivity, high specificity
Positive = presence of bacteria that reduce nitrate
Specificity helps with what?
Ruling in a disease
SPIN
Sensitivity helps with what?
Ruling out a disease
SNOUT
Blood cultures are important to check if there are signs of what?
Sepsis/systemic infection
Or concern for bacteremia
Best to draw before giving abx (but do not delay abx to draw cultures)
Presence of which organisms in a blood culture is always clinically significant?
Staph aureus
E. coli
Pseudomonas aeruginosa
The presence of which organisms in a blood culture may be clinically significant but may also signify contamination?
Coagulate negative staph
Corynebacterium species
Enterococcus
Describe molecular tests for COVID
PCR and NAAT tests Detection target = viral RNA Specimen types = nasopharyngeal, nasal, sputum and saliva Turnaround time = hours, days High sensitivity and specificity
Describe antigen tests for COVID
Rapid tests Viral protein = detection target Specimen types = nasopharyngeal, nasal Turnaround time = minutes Low sensitivity, high specificity
CXR is helpful in identifying what?
Pulmonary causes of fever
Including infectious, auto immune and malignant causes
A focal infiltrate can be suggestive of what?
Bacterial pneumonia
What are typical findings with COVID on a CXR?
Bilateral infiltrates
Basal and peripheral predominance
What CXR findings are seen with SLE?
Pleural involvement and pleural inflammation (pleuritis)
Can see pleural effusion
Suspected CNS infection is a medical emergency and important indication for what?
Lumbar puncture
What are the symptoms of an CNS infection?
HA, fever, meningismus
What does each tube test for during a lumbar puncture?
- Chemistries (glucose and protein)
- Cell count with diff
- Gram stain and culture, other micro studies
- Other studies as needed
Describe bacterial meningitis
Deferential includes elevated neutrophils
High opening pressure
Low glucose
Elevated protein levels
Describe viral meningitis
Lymphocyte predominance
Normal opening pressure
Normal glucose and protein level
