Respiratory Infections Flashcards
(111 cards)
1
Q
What is included in the upper respiratory tract?
A
- nose - pharynx - larynx
2
Q
What is included in the lower respiratory tract?
A
- trachea - bronchial tree - lungs
3
Q
Are acute infections always dangerous?
A
- no - but higher incidence of mortality in low socioeconomic countries
4
Q
What are some of the most common respiratory infections that have the highest mortality worldwide?
A
- HIV/AIDS
- Tuberculosis
- Measles
- Whooping Cough
5
Q
Certain patients have a decreased immune system, which groups of patients are at highest risk?
A
- elderly - young children - malnourished
6
Q
What has reduced the impact of microorganism infections worldwide?
A
- vaccinations - antibiotics - 23% reduction since 1990
7
Q
What are some risk factors, that could contribute to an increased risk of respiratory infection?
A
- poverty - smoke/pollution - overcrowding - immunocompromised (HIV)
8
Q
What is pathogenesis?
A
- disease/condition caused by microorganisms
9
Q
What are microorganisms?
A
- bacteria - virus - fungi
10
Q
What is the mucocillary escalator?
A
- mucus and ciliary working together
- remove microorganisms and debris
11
Q
What are alveolar macrophages?
A
- macrophages located in alveolar
12
Q
What is the function of alveolar macrophages?
A
- phagocytose pathogens/debris
- secrete antimicrobials
- recruit immune cells
- antigen present to T helper cells
13
Q
What are 2 of the key aspects of the innate immune system in the lower respiratory tract?
A
- physical barrier = mucocillary escalator
- immune cells = alveolar macrophages
14
Q
What are the main adaptive cells and immunoglobulin secreted in the lower respiratory tract?
A
- T cells
- B cells
- IgA antibodies
15
Q
What happens at a microscopic level to lung tissue during an acute inflammatory response?
A
- ⬇️ vasodilation
- ⬆️ permeability (Extravasation - margination, rolling, adhesion)
- ⬆️ inflammatory cell infiltration (neutrophils then macrophages)
16
Q
If inflammation becomes chronic in the lungs, what could this lead to?
A
- morphological changes - fibrosis
17
Q
What are commensals?
A
- microorganisms functioning in symbiotic relationship with the host
18
Q
What are 2 important commensals located in the mouth?
A
- staphylococcus aureus (grape like)
- streptococcus pneumonia (chain of beads)
19
Q
What are some of the important commensals located in the sinus/nasal passage?
A
- streptococcus pneumonia
- haemophilus influenze (most common cause of flu)
- meticillin-resistant Staphylococcus aureus (MRSA)
- rhinovirus (common cold)
20
Q
What is one important commensals located in the throat?
A
- meticillin-resistant Staphylococcus aureus (MRSA)
21
Q
Bronchitis is common in the lower respiratory tract, what is it?
A
- infection in large and medium airways
- causes inflammation
22
Q
Pneumonia is common in the lower respiratory tract, what is it?
A
- infection of lung parenchyma
- air sacs fill with fluid of pus (purulent)
- ⬇️ perfusion
- empysema can be a complication of pneumonia
23
Q
Pulmonary Tuberculosis is common in the lower respiratory tract, what is it?
A
- infection
- caused by Mycobacterium tuberculosis
24
Q
Empyema, also referred to as purulent pleuritis is a common in the lower respiratory tract, what is it?
A
- infection causes pus to gather in pleural space
- can follow from pneumonia
25
What is the viral infection influenza, also commonly known as?
- common flu
- viral infection
26
What is the viral infection rhinovirus, also commonly known as?
- common cold
- most common viral infectious agent
27
What is the Respiratory Syncytial Virus (RSV)?
- common viral infection affecting the lungs
- mainly affects children \<2 years of age
28
What is the most common symptoms of the Rhinovirus?
- runny discharge (snotty nose)
- common cold
29
What is Tonsilitis?
- tonsils become enlarged and inflammed
- can be due to bacterial or viral infection
- Streptococcus is Group A is the most common cause
30
Does the lower respiratory tract generally contain commensals?
- no
31
What are 2 common organisms that can cause bronchitis?
- Streptococcus pneumoniae
- Haemophilus influenzae
- both are bacterial infections
32
In infants (\<2 years of age) what is the main organism that causes of Bronchiolitis?
- Respiratory syncytial Virus (RSV)
- bronchitis = primary bronchi (1 bronchi)
- bronchiolitis = lower down bronchi (\>1 bronchi)
33
What are the most common organisms causing pneumonia?
- Streptococcus pneumoniae
- Haemophilus influenzae
- Legionella pneumophila
- Mycoplasma pneumoniae
34
What is the most common viral infection that causes the common cold?
- rhinovirus (30-50%)
35
What other virus accounts for 10-15% of common colds?
- coronavirus
36
What is bradykinin?
- a peptide that promotes inflammation
37
How is bradykinin released?
- mast cells secrete it
38
In a common cold what do mast cells secrete that causes the common symptoms such as sore throat and nasal congestion?
- bradykinin
- ⬆️ vasodilation
39
In a common cold a component is released from mast and basophils that causes sneezing, what is this?
- histamine, one of main components of allergies
- induces nasal itch and sneezing
40
In a common cold a component is nasal discharge, what is the most common enzyme released from neutrophils that contributes to this?
- myeloperoxidase - greeny/yellow in appearance
41
What are the most common symptoms of a cold?
- appears gradually - nose and throat mainly affected - may feel unwell - should be fine to work
42
What are the most common symptoms of the flu caused by influenza?
- appears quickly
- systemic effects
- fever and myalgia (muscle pain)
- unable to work
43
What are the most common types of influenza that infect humans?
- Type A and B
44
Haemagglutinin is a protein on the surface of influenza that can vary slightly in structure. This is called the H protein. How do variations in H proteins help influenza infect humans?
- bind to sialic acid (sugars) receptors on cells
- once bound they can enter the cell and infect
45
What are sialic acid receptors on cells?
- sugars with a carbon backbone
46
Neuraminidase are N proteins located on the surface of influenza. How do variations in N proteins help influenza infect humans?
- cleaves sialic acid molecules from cell surfaces
- the virus can freely move and infect other cells
- helps evade host immunity
47
Why is influenza able to infect people consistently?
- changes in H and N proteins randomly during replication
- able to evolve over time for survival
- able to do this in or outside of host cells
- called genetic drift - IMPORTANT
- called drift as its a slow process
48
Does B type influenza contain as many H and N protein variations?
- no - still able to infect just not as often
- doesnt adapt as well as influenze type A
49
Which groups of patients are most at risk from influenza?
- immunocompromised - co-morbidities - \<2 and \>65 years old - BMI \>40
50
Influenza is generally not life threatening, but in patients who are at high risk there can be some complications. What are the most common complications that can occur in higher risk patients?
- primary viral pneumonia
- secondary bacterial pneumonia
- CNS disease
- death
51
More than one influenza virus can infect the same cell. This is called antigenic shift. What can this do the influenze virus?
- influenze virus has a segmental genome
- segmental genomes can therefore mix, similiar to miosis
- creates mixed and unqiue genome with new H and N proteins
52
Why is antigenic shift important?
- non human viruses are mixed with human virus
- creates unique H and N containing influenza
- this is why vaccinations need to be changed each year
53
What are simple day to day activities that can reduce infection and transmission of influenza?
- hand hygiene - PPE
54
What do annual vaccinations aim to do against influenza?
- reduce risk of infection
- vaccination created against common H and N proteins
- most common is H1N1
55
What is Tamiflu, commonly known as oseltamivir?
- antiviral medication to treat influenza types A and B
56
How does Tamiflu, commonly known as oseltamivir work?
- inhibits neuraminidase (N protein)
- virus is unable to spread and replicate
57
What are the common symptoms associated with bacteria pneumonia?
- fever (rigors = cold feelings)
- breathlessness (dysponea)
- cough with sputum production
- pleuritic chest pain
58
What happens to respiratory rate in bacteria pneumonia?
- ⬆️ respiratory rate - tachypnoea
59
What happens to chest expansions and breathe sounds in bacteria pneumonia?
- ⬇️ chest expansion - ⬇️ breathe sounds - bronchial breathing
60
What happens to tremor vocal resonance in patients with bacteria pneumonia?
- ⬆️ vocal resonance
- indicates increased density
- if hyperinflation, this would be reduced
61
In patients with bacterial pneumonia they are at risk of a type 1 respiratory failure, what can this cause?
- ⬇️ PaO2 (60mmHg) - hypoxia
62
Do elderly patients present with the same symptoms as younger patients with bacterial penumonia?
- not always - absence of typical symptoms - confused - generally unwell - ⬇️ appetite - dehydrated
63
What are the 3 main classifications (of how pneumonia can be contracted) of pneumonia that we need to know about?
- community acquired pneumonia (CAP) (MAIN one)
- hospital acquire pneumonia (HAP)
- ventilator acquired pneumonia (VAP)
64
What is community acquired pneumonia (CAP)?
- pneumonia acquired in the general community - away from healthcare setting
65
What % of patients admitted to hospital with community acquired pneumonia (CAP) require admission to the intensive care unit (ICU)?
- 1.2-10% - 30% of whom die
66
What are some of the clinical signs that medics can look for in younger patients?
- cough
- ⬆️ temperature
- tachypnoea (respiratory rate \>20b/min)
- tachycardia (pulse \>100bpm)
- consolidation (can include crackles)
67
What is consolidation in the lungs?
- air in lungs is replaced with something else
- generally replaced with liquid or pus
- appears as a white area on imaging
68
As with any other lung disease/condition, what is one of the first tests that must be done?
- chest X-ray
- shadows present called infiltrates (as in image)
- consolidation
69
What is a lobar pneumonia?
- infection of one lobe
70
What are the 2 most common bacteria that can cause community acquired pneumonia?
- Streptococcus pneumonia
- Haemophilus influenza
71
What is streptococcus pneumonia?
- pneumonia infection caused by streptococcus
- Gram - cocci
- most common bacteria in community acquired pneumonia (CAP)
72
Which groups of patients may be more susceptible to streptococcus pneumonia?
- alcoholics - current lung disease - smokers - heart disease - HIV patients
73
How is streptococcus pneumonia initially acquired and does it cause symptoms in everyone?
- acquired in nasopharynx
- no patients can be asymptomatic carriers
74
What human fluid can antigen from streptococcus pneumonia be measured in clinically?
- urine
75
in addition to hand cleaning and PPE, what is another method for reducing transmission and infection of streptococcus pneumonia?
- vaccinations
76
If a patient has streptococcus pneumonia, what is the most common antibiotic treatment, which is 2 of the core drugs we need to know?
- amoxicillin or clarithromycin antibiotics
77
What is the mechanism of action of amoxicillin, which is a Beta Lactam?
- binds and blocks transpeptidase
- cell wall breaks and bacteria is destroyed
78
What is the mechanism of action of clarithromycin?
- binds to RNA and inhibits reading of tRNA
- protein synthesis is reduced or stopped
79
What is Haemophilus Influenza pneumonia?
- pneumonia infection caused by Haemophilus Influenza - Gram -anaerobe
80
Which groups of patients may be more susceptible to Haemophilus Influenza pneumonia?
- those with co-morbidities - common complications in patients with empyema (pus collection in pleural space)
81
Does Haemophilus Influenza pneumonia generally cause symptoms in everyone?
- no - can be asymptomatic carrier
82
What are the mortality rates for Haemophilus Influenza pneumonia?
- 12-29%
83
What is the common treatment for Haemophilus Influenza pneumonia?
- Tetracycline (doxycycline)
84
What is the mechanism of action of Tetracycline?
- inhibit binding of tRNA to RNA
- ⬇️ protein synthesis
85
What is Mycoplasma pneumonia?
- pneumonia infection caused by Mycoplasma
86
Which patients are most commonly affected by Mycoplasma pneumonia?
- young patients
- experience vague general upset for weeks
87
Why is penicillin not used to treat mycoplasma pneumonia?
- resistant to penicillin - lack of cell wall
88
What is the common treatment for mycoplasma pneumonia?
- macrolides (clarithromycin)
- tetracyclines (doxycycline)
- both target protein synthesis
89
How can mycoplasma pneumonia be diagnosed?
- qPCR of throat swab
- amplify bacterial sequence
90
What is Legionella pneumonia?
- bacterial infection, normally contained water
- gram -
91
Is Legionella pneumonia common and dangerous?
- uncommon (350 cases/year) - can causes severe life threatening infections
92
What are the 2 most common risk factors for Legionella pneumonia?
- current lung disease
- smoking
93
How can Legionella pneumonia be diagnosed?
- urinary antigen
- difficult to grow in culture
94
What is the common treatment for Legionella pneumonia?
- macrolides (clarithromycin) target ribosome and protein synthesis
- quinolones (ciprofloxacin) target DNA replication
95
What is the mechanism of action of quinolones?
- inhibits DNA winding and structure
96
In patients with community acquired pneumonia (CAP) the CURB score is used to determine the severity of the patients, what does CURB stand for??
- test to assess severity of CAP
- C in CURD can be CAP to remember
- C = confusion - U = urea - R = respiratory rate - B = blood pressure
97
What is hospital acquired pneumonia (HAP)?
- someone who did not have pneumonia upon admission - pneumonia develops 48 hours after admission
98
Hospital acquired pneumonia (HAP) is generally caused by highly virulent organisms, what are the 4 most common?
1 - Pseudomonas aeruginosa
2 - Klebsiella pneumoniae
3 - Escherichia coli
4 - Methicillin Resistant Staphylococcus Aureus (MRSA)
99
What % of hospital infections are caused by Hospital acquired pneumonia (HAP)?
- 1.5%
100
Why is hospital acquired pneumonia (HAP) more dangerous than community acquired pneumonia?
- ⬆️ virulence in organisms - ⬆️ antibiotic resistance
101
In patients with hospital acquired pneumonia (HAP), 50% who are intubated and ventilated then go on to develop ventilator associated pneumonia (VAP). Is this dangerous?
- yes
- same organisms as HAP, but ⬆️ antibiotic resistance
- ⬆️ morbidity and mortality
102
What is the incidence and mortality of empyema?
- 80,000/year - 20% mortality
103
Diagnosis of empyema?
- pus collects in pleural space, commonly following pneumonia
- imaging (chest X-ray, thoracic ultrasound, CT thorax)
- pleural aspiration/sampling
104
How do we treat empyema?
- chest drains
- surgery
- antifibrotic drugs
- long course of antibiotics
105
What is one of the most common risk factors for opportunistic infections?
- HIV
- always do a HIV test
106
What is pneumocystis carinii (PCP)? (also known as pneumocystis jirovecii).
- pneumocystis is a genera of fungi
- pneumocystis carinii (jirovecii is a strain)
- causes pneumonia
107
What are the common symptoms of a patient with a pneumocystis carinii (PCP) (jirovecii) infection?
- cough - severe breathlessness - hypoxia
108
How is pneumocystis carinii (PCP) (jirovecii) infection treated?
- sulfonamides called co-trimoxazole
- inhibit nucleic acid generation
109
Streptococcus pneumonia is a common bacteria located in the sinus/nasal passage. What can this bacteria cause?
- can infect the ears through the sinuses
- infect sinuses
- pneumonia
110
Haemophilus influenza is a common bacteria located in the sinus/nasal passage. What is the most common illness this bacteria can cause?
- flu - most common cause of the flu
111
Rhinovirus is a common virus located in the sinus/nasal passage. What is the most common illness this virus can cause?
- common cold
