Infectious Lung Diseases: TB, Pertussis, Croup, Epiglottitis Flashcards
1
Q
Tuberculosis
TB Infection v. TB Disease
A
- TB Infection:
- Eaiser to treat than Dz
- People can get this with NO presentation
- Infection….Latency… Disease!
- Disease:
- Bacteria overcome the Immune System, mutiply & progress from latent infection to DISEASE
- Some symptoms:
- Weight loss, Loss of Appetite, Fatigue, Chills, Fever
2
Q
TB
A Quick History
A
- Has affected humans for millennia
- Historic names:
- Consumption
- Wasting Disease
- White Plague
- Used to cause many deaths, not well-controlled
- Before 1800’s, thought was hereditary
- 1882- R. Koch disovered M. tuberculosis
3
Q
TB
Sanatoriums
A
- Before Abx, many sent to locations where they were isolated
- Provided with: open air, bed rest, sunshine
- Lots of people could not afford this
- 70-75% fatalities in the “olden days”
- As drugs were created, death rates dropped
- Sanatoriums closed by mid-1970’s
4
Q
TB
Drugs created in the 1940’s & 50’s
A
- 1943: Streptomycin
- 1943-1952:
- Isonizaid (INH)*
- p-aminosalicylic acid (PAS)
*Same drug formula used today!!
5
Q
TB
Why was there a resurgence in 1980’s?
A
- Inadequate funding
- HIV epidemic
- Increase immigration from countries were TB is common
- Spread in close-quarters (shelters)
- Multi-drug resistant TB increase and spread
*Still a global issue!
6
Q
TB
Epidemiology
‘The study of the distribution & causes of disease and other health problems in different groups of people”
A
- One of the leading causes of death due to infectious disease in the world
- ~2 Billion people are Infected!
- About 9 million people develop TB/year
– About 2 million people die of TB/year
7
Q
TB
Trend in the U.S.
A
- Before 1953, more than 84,000 cases in US
- Declined by 6%/year after 1953
- Reached a low in 1985, but then picked up again in 1986…
8
Q
TB
Transmission
A
“Transmission is defined as the spread of an organism, such as M. Tuberculosis from one person to another”
9
Q
TB
Transmission
A
- There are several type of Mycobacteria that cause TB
- M. tuberculosis is the most common
- Some others: M. bovis, M. africanum, M. microti, M. canetti
***M. avium complex DOES NOT caused TB
10
Q
TB
Transmission
A
-
Air Droplet Nuclei - spread person-to-person
- The other person inhales the nuclei and BAM!
- Can catch it from:
- Coughing
- Sneezing
- Speaking
- Singing…
11
Q
TB
Transmission
Probability of Transmission
A
- Chance of Transmission depends on:
- Infectiousness of person w/ TB dz
- Enviroment in which exposure occured
- Blewett 15… no good.
- Length of Exposure
- Virulence (strength) of tubercle bacilli
12
Q
TB
How to stop transmission!
A
- Isolate the infected person(s)
- Negative pressure room in hosp.
- Provide effective treatment to infectious persons ASAP
13
Q
TB
High Risk Groups
@ High Risk for Becoming Infected
A
- Close contacts
- Foreign born
- Low-income & homeless
- Healthcare workers serving high-risk groups
- Racial and ethnic minorities
- Infants, children, & adolescents
- Injectable drug users
14
Q
TB
High Risk Groups
People at High Risk for developing TB Dz after Infection!!!
A
- People living with HIV
- W/ medical condition that increases the risk
- Those infected w/ M. tuberculosis w/in past 2 years
- Ages 4+ younger
- Injectable drug users
15
Q
TB
High Risk Groups
People Living with HIV
A
- HIV is the Strongest known risk factor for developing the disease
- TB is the Leading Cause of Death for those w/ HIV/AIDs
16
Q
TB
High Risk Groups
People with Certain Medical Conditions
A
- Prolonged therapy w/ corticosteroids & other immunosuppresive therapy
- ex: TNF-a antagonists
- Silicosis
- Diabetes
17
Q
TB
High Risk Groups
Recently Infected
A
- If you are infected w/in past 2 years, more likely to develop disease!!
- 5% risk of developing disease in the first two years
- 10% risk over a lifetime
- (unless you get treated)
18
Q
TB
High Risk Groups
Ages under 4 Years
A
- Undeveloped Immune System =’s Higher Risk!
19
Q
TB
Pathogenesis: Latent TB Infection
“How an Infection or Disease develops in the Body”
A
- Latent TB Infection (LBTI)
- Tubercle bacilli in are in body, but
- Immune System is keeping them under control!
*NOT INFECTIOUS!!!
- Dectected by:
- Mantoux TB Skin Test (TST)
- Blood tests: Interferon-gamma release assays (IGRAs); ex: T-SPOT
20
Q
TB
Pathogenesis
TB Disease
A
- Immune System CANNOT keep tubercle bacilli under control
- May develop soon after infection, or man y years later
- About 10% w/ LTBI will develop TB
- May develop soon after infection, or man y years later
If you have the Disease, you are often Infectious!!
21
Q
TB
Pathogenesis, pt. 1
A
- Droplet Nuclei containg the Tubercle Bacilli are inhaled
* Enter the lungs &
* Travel to the small air sacs (alveoli)
* These nuclei just sneak through your system!
- Droplet Nuclei containg the Tubercle Bacilli are inhaled
- They mutiply in your alveoli (asymptomatic)
* Infection begins…
- They mutiply in your alveoli (asymptomatic)
- Small number of Bacilli enter bloodstream & spread through the body!
- See next flashcard
22
Q
A
23
Q
TB
Pathogenesis, pt. 2
A
- In 2-8wks, immune system produces Macrophages that surround tubercle bacilli & keep it in check!
* Macrophages form a barrier shell keeping the bacilli contained (LTBI)
- In 2-8wks, immune system produces Macrophages that surround tubercle bacilli & keep it in check!
- 5.
24
Q
TB
LTBI vs. Disease
A
- Latent:
- Inactive/contained
- TST or blood test
- Normal CXR
- No Symptoms, not infectious, not a Case!
- Disease:
- Active/bacilli are multiplying in body
- TST or blood test
- Abnormal CXR
- Symptoms: cough, fever, weight loss
- Infectious b4 treatment
- THIS IS A CASE OF TB!
25
**TB**
Diagnosis
* Mantoux tuberculin skin test (TST)
* Tuberculin injection
* Tuberculin = proteins from inactive bacilli
* + test = reaction at injection site
* **Induration (swelling), measure swelling in mm.**
* **15mm = + in healthy person**
* Blood-tests: Interferon-gamma release assays (IGRAs)
* Measures immune reactivity
* Pros:
* Single patient visit, fast results
* More accurate results than skin test
* Cons:
* Process blood samples quickly
* Limited data in use 4 some pops
* Errors can occur in running/interpreting tests
26
**TB**
Treatment
*LTBI*
* LTBI treated to prevent development into disease
* Treated with medication
* ex: Isoniazid for ~9months
27
**TB**
Pathogenesis
*Progression from LTBI to TB Disease*
* Highest risk first 2 years after infection
* Detect early!
* Prevents new cases
* Conditions = increasing probability
* HIV infection
* Organ Transplant
* CXR suggestive of previous TB
* DM
* Silicosis
28
**TB**
Diagnosis
*Medical Evaluation*
Components include:
1. Medical Hx
2. PE
3. TB Test
4. CXR
5. Bacteriological Exam
29
**TB**
Diagnosis
Medical Hx:
Does patient have...
1. Disease sxs
2. Been exposed
3. Any risk factors
4. LTBI or TB dz before?
30
**TB**
Lungs
31
**TB**
General Symptoms
* Fever
* Chills
* Night Sweats
* Weight Loss
* Appetite Loss
* Fatigue
* Malaise
\*Cough lasting 3+ weeks
\*\*Chest pain
\*\* Sputum or blood coming up wit cough
32
**TB**
Chest X-Ray
*Inflitrates & Cavities*
* CXR may show:
* **Inflitrates**
* Collections of fluid & cells in lung tissue
* **Cavities**
* Hollow Spaces w/in lung
33
**TB**
Bacteriologic Examination
*Pulmonary TB*
* Sputum Sample Specimen Collection:
* Patient cough into sterile container
* 3 sputum samples for examination
* Collect in 8-24 hour intervals
* One early in the morning!
* Induced Sputum Collection = use when patient cannot cough up sputum on their own. Label "induced specimen"
* Bronchoscopy: Use if the 2 above fail
* Gastric Washing: Use is all above fail. Used more often in children
34
**TB**
Bacteriologic Examination
*Extrapulmonary TB*
* Can collect samples other than Sputum depending on affected body part
* Ex: Urine samples for TB of kidneys
* Fluid samples from around Spine
35
**TB**
Bacteriologic Examination:
*Examination of AFB Smears*
* Specimens smear onto glass slide
* **AFB =** mycobacteria that remain stained after being washed in acid solution
* "Red Snappers"
36
**TB**
Bacteriologic Examination
* Nucleic Acid Amplification Tests (NAA)*
* &*
* Culturing*
* Directly ID *M. tuberculosis* from sputum specimens by:
* Amplification of DNA & RNA segments
* Can guide clinical decisions
* Does not replace the AFB smear
* Culture all specimens!! IDs TB
37
**TB**
Bacteriologic Examination
*Drug Susceptibility Testing*
* Conducted when patient is first found to have positive TB culture
* Determines which drugs kill the TB Bacilli
* Resistance vs. Susceptibility!!!
* Resistance = drugs can no longer kill bacteria
38
**TB**
Drug-Resistant TB
*Primary & Secondary*
* Primary:
* Caused by person-to-person transmission of drug resistant organism
* Secondary:
* Develops during treatment
* Bad practices:
* Inappropriate regimen
* Incompliance
39
**TB**
Drug Resistant TB
* Mono-resistant: Resistant to any one TB Treatment
* Poly-resistant: Resistant to any 2 TB drugs
* (not Isoniazid & Rifampin together)
* Multidrug Resistant: Resistant to Isoniazid & Rifampin
* Extensively Drug Resistant: Resistant to so many drugs!!
40
**TB**
Sites of TB Disease
* Common sites:
* LUNG
* Brain
* Lymph nodes
* Pleura
* Spine
* Larynx
* Bone
* Kidney
\*Extrapulmonary locations are found more often in HIV-infected, immunocompromised
41
**TB**
Treatment of TB Disease
* TB disease must be treated for at least 6 months, sometimes longer
* Initial Phase - 4 drugs used:
* First 8 weeks
* More bacilli killed during this phase
* Continuation Phase - at least 2 drugs used
* Relapse:
* Occurs when treatment is not continued for long enough
* Surviving bacilli may cause TB at a later time
42
**TB**
Treatment
*Drugs*
Inital regimen should include these 4 drugs:
1. Isoniazid
2. Rifampin
3. Pyrazinamide
4. Ethambutol
**(At least 2 of these drugs should be susceptible to dz; using only 1 drug can create a population that is resistant to drugs)**
\*TB is a treatable, curable disease!
\*\*Work with patients to adhere to treatment regimen
