Lecture 5: Fever of Unknown Origin & TB

Question 1

What is the definition of fever

• in the AM
• in the PM

in combination w/ ________

Answer 1

Definition of Fever

> 37.2 in AM
37.7 in PM

in combination w/incr in hypothalmic set point

Question 2

What is the nornmal range for body temp

Answer 2

normal body temp range = 35.6 - 38.2

Question 3

Comparing Temps

1. elderly: higher or lower than avg body temp
2. rectal temps: higher or lower than oral and core temps
3. What is the effect ovulation has on temp?
4. lowest temp at what time? what time for highest?
5. 2 things that cause incr in oral temp

Answer 3

Comparing Temps

1. elderly = lower than avd body temp
2. rectal temps = higher than oral or core
3. ovulation incr temp
4. lowest temp = 6am, highest = 4-6pm
5. incr oral temp w/smoking + chewing

Question 4

1. exposure
2. aging
3. sepsis
4. CHF
5. drug OD
6. Hypoglycemia
7. Renal or Hepatic Failure

are all causes of what?

Answer 4

1. exposure
2. aging
3. sepsis
4. CHF
5. drug OD
6. Hypoglycemia
7. Renal or Hepatic Failure

all causes of HYPOthermia

Question 5

1. hypothalmic lesion
2. Thyrotoxicosis
3. Anticholinergic blockade
4. Exercise

are all causes of what?

Answer 5

1. hypothalmic lesion
2. Thyrotoxicosis
3. Anticholinergic blockade
4. Exercise

all causes of HYPERthermia

others (obvious): heat stroke, malig hyperthermia

Question 6

What are 2 major benefits of fever

Answer 6

1. decr viral replication to fight infxn

2. suppress microbial growth

Question 7

1. incr immunoglobulin synthesis
2. activation of T cells
3. incr cytokine production
4. incr NK cell activity
5. incr phagocytic activity

are examples of ______

Answer 7

1. incr immunoglobulin synthesis
2. activation of T cells
3. incr cytokine production
4. incr NK cell activity
5. incr phagocytic activity

are examples of the benefits of fever

Question 8

What is the definition of FUO (Fever of Unknown Origin)
- 4 components

MEMORIZE AND KNOW THIS!!

Answer 8

definition of FUO (Fever of Unknown Origin)

1. Fever > 38.3C
2. illness lasting 3 wks
3. NOT immunocompromised
4. failure to reach dx w/ labs, XR

Question 9

What is the MC etiology of FUO

Answer 9

MC etiology of FUO = Infections

Question 10

Etiology of FUO: Infections

• are most caused by microbes in the environment or by normal flora in our body

Answer 10

Etiology of FUO: Infections

-Infections mostly caused by normal flora in our body

Question 11

Etiology of FUO

-what are the 4 other major classifications for the cause of FUPO>

Answer 11

Etiology of FUO

1. Neoplasia
2. Misc
3. Connective Tissue D/o
4. Undiagnosed

Question 12

FUO workup

- what 3 tests are generalized/less invasive and a good place to start when working up FUO

Answer 12

FUO workup

1. CBC w/diff
2. CMP
3. UA & culture

Question 13

what is more common as the cause of FUO

• uncommon dzs -OR-
• uncommon manifestations of common dzs

Answer 13

Cause of FUO

• Uncommon manifestations of COMMON DZs MORE COMMON than uncommon dz

Question 14

FUO

- once the site of infection determined what should be done next

Answer 14

FUO

• site of infection determined –> start empiric therapy

Question 15

Etiology of FUO

-what is a common infectious cause of FUO

Answer 15

common infectious cause of FUO = TB!!!!

Question 16

Tuberculosis

1. what is the name of the species that causes this infection
2. what is the hallmark of this dz
3. how is this dz spread

Answer 16

Tuberculosis

1. cause = mycobacterium tuberculosis
2. hallmark = CASEATING granulomas
3. spread is by respiratory droplets

Question 17

TB

1. what 2 groups = incr risk of exposure to TB
2. what 2 groups = incr risk of TB infxn
3. what types of pts = incr risk of active TB once infected
   (gen and 1 spp example)

Answer 17

TB

1. Incr risk of exposure to TB
   - close contacts of pts w/active TB + healthcare workers
2. Incr risk of TB infxn
   - immigrants from high prev area, homeless
3. Incr risk of active TB once infected
   - immunodeficient pts –> HIV+

Question 18

What cells in the body are responsible for the pathophysiology and granuloma formation seen in TB

Answer 18

alveolar macrophages

Question 19

What are the 3 outcomes of a TB infection

Answer 19

Outcomes of TB infection

1. Primary TB
2. Latent/Chronic TB
3. Reactivation/2ndary TB

Question 20

3 Outcomes of TB infection

1. what is the ONLY outcome where pts are NOT contagious
2. which outcome is a/w apical cavitary lesions
3. which outcome is characterized/controlled by granuloma formation and a (+) PPD
4. which outcome is the result of the initial infection

Answer 20

3 Outcomes of TB infection

1. ONLY outcome where pts are NOT contagious = LATENT/Chronic TB
2. which outcome is a/w apical cavitary lesions
   - Reactivation/2ndary TB
3. which outcome is characterized/controlled by granuloma formation and a (+) PPD
   - Latent/Chronic TB
4. which outcome is the result of the initial infection
   - Primary TB

Question 21

3 Outcomes of TB infection: Reactivation/2ndary TB

• what causes the reactivation of Latent TB

Answer 21

3 Outcomes of TB infection: Reactivation/2ndary TB

• cause of reactivation of latent TB = waning of immune defense

Question 22

why is the formation of caseating granulomas (central necrosis, acidic, Low O2) imp in TB

Answer 22

creates a hostile enviro for MTB

Question 23

Pt presents w/ constitutional Sxs, chronic productive cough and pleuritic chest pain. On lung exam you note rales, consolidation and dullness in the middle R lobe.

Dx? (be specific)

Answer 23

Dx = Primary TB (middle/lower lobe consolidation)

Question 24

Extrapulmonary TB

1. name of d/o that affects the vertebra
2. name of the term for affecting the LNs

Answer 24

Extrapulmonary TB

1. name of d/o that affects the vertebra = Pott’s Dz
2. name of the term for affecting the LNs = scrofula

Question 25

If a pt has HIV and TB what do they have an incr risk of

Answer 25

HIV + TB = incr risk of reactivation TB

Question 26

Name of the test to screen for TB

Answer 26

PPD

Question 27

PPD: Screening for TB 1. how long wait to see result? 2. what is a positive result? 3. what rxn size is considered (+) for HIV+, immunosuppressed, or close contact w/active TB pt 4. what rxn size is considered (+) for pts w/no RFs for TB

Answer 27

PPD: Screening for TB 1. wait 48-72hrs 2. (+) result = transverse induration 3. > 5 mm = (+) for HIV+, immunosuppressed, or close contact w/active TB pt 4. > 15 mm = (+) for pts w/no RFs for TB

Question 28

What are the names of the 3 diagnostic studies used in suspected cases of ACTIVE TB

Answer 28

3 diagnostic studies used in suspected cases of Active TB 1. Acid fast smear (bacilli) + sputum culture x 3 days 2. CXR (PA + Lateral) 3. Interferon Gamma Release Assay (Quantiferon)

Question 29

what is the gold std for dx TB

Answer 29

AFB (Acid Fast Bacilli) cultures

Question 30

What is the main indication of CXR for TB

Answer 30

to r/o active TB

Question 31

Patterns of TB seen on CXR 1. what type of TB is a/w middle/lower lobe consolidation? 2. what type of TB is a/w apical cavitary lesions? 3. what type of TB is a/w diffuse, small nodular lesions?

Answer 31

Patterns of TB seen on CXR 1. middle/lower lobe consolidation = Primary TB 2. apical cavitary lesions = reactivation TB 3. Diffuse, small nodular lesions = Miliary TB

Question 32

What is seen on CXR that indicates primary TB has healed

Answer 32

Granuloma on CXR indicates primary TB has healed

Question 33

Active TB Tx 1. Names of drugs given? 2. how long these 4 drugs given? 3. how long is the TOTAL active TB tx? 4. what 2 drugs given after the initial phase (continuation phase)

Answer 33

Active TB Tx 1. Drugs = RIPE or RIPS - Rifampin, INH (+ Vit B6), Pyrazinamide, Ethambutol (or Streptomycin) 2. given for 2 months 3. total duration of active TB tx = 6 mos 4. Continuation phase drugs = RI - Rifampin + INH (+ Vit B6)

Question 34

PPx of TB - when should ppx be started

Answer 34

PPx of TB indicated when exposure to TB and (-) CXR

Question 35

Latent TB and PPx TB Tx 1. what 2 things given in both situations 2. how does the length of Tx differ if pt is HIV+ 3. what is the minimum ppx duration needed

Answer 35

Latent TB and PPx TB Tx 1. INH + Vit B6 2. HIV+ --> longer tx 3. need ppx for at least 2 wks