Respiratory Infection I Flashcards
What structures exist within the nasal cavity to help rid the body of particles & pathogens?
- hairs (filter large particles)
- turbinate bones
- air swirls as it passes & forces particles to contact mucous
After the nasal cavity, what structures of the respiratory tract help rid the system of particles & pathogens?
- Change in air-flow direction after nasal cavity
- particles impinge in back of throat
- adenoids & tonsils
- lymphoid organ that help with immune response
- mucosal surfaces
- trap particles & pathogens
- Cilia
- drive mucus upwards to back of throat
- Sneeze & cough reflex
What are the 2 main functions of the microbiota of the respiratory tract?
- compete with pathogenic organisms for potential attachment sites
- produce substances that are bactericidal & prevent infections by pathogens
What is the most important means of eliminating pathogenic organisms that enter the lungs?
alveolar macrophages
List the location & most common pathogens the cause the following disease:
Common cold (nonspecific URI)
Nasal passage
Rhinovirus
What pathogen is the most common cause of summer grippe?
various enteroviruses
Enterovirus, Coxsackievirus, Echovirus
What characteristics can help you differentiate between the common cold & summer grippe?
Colds usually do not cause a fever & are most common in the winter
Summer grippe usually results in a fever & is most common in summer months
Identify the diagnosis based on the following symptoms
general malaise, lacrimation, sore throat, no fever, anosmia/hypoasmia, ageusia/hypogeusia, anorexia
winter month
cough & substernal discomfort
common cold
SARS-CoV2 infection can cause what additional symptoms to the common cold?
fever, anosmia, ageusia & is not limitd to the winter months
GI discomfort
common all year long
Identify the diagnosis based on the following symptoms:
fever, malaise, headace, possible uper respiratory symptoms, possible nausea & vomiting
summer month
lasts 3-4 days
Summer Grippe
Describe the general transmission of the viruses tha cause the Common Cold, Summer Grippe & SARS-CoV-2
- Common Cold: person to person, usually hand-to-hand contact
- SARS-CoV-2: droplets, aerosols & contact with contaminated objects
- Summer grippe: fecal oral means
What is the receptor
What is the receptor that SARS-CoV-2 is able to attach to on the host cell?
ACE-2
angiotensin converting enzyme-2
How long does it take the common cold to reach its pathological peak?
2 - 4 days
What illness fits the following pathogenesis?
Days 1-2: runny nose, clear mucoid nasal secretions
Day 2: Secondary bacterial infection from respiratory microbiota & secretions become purulent
Common cold
The common cold can cause what complications?
blockage of the sinus ostia / eustacian tube, leading to acute rhinosusitis or otitis media
compilcations are usually related to bronchitis
What is the treatment for Summer Grippe & the Common Cold?
supportive thearpy to ease discomfort
What are the 4 preventative measures to avoid infection by SARS-CoV-2?
- vaccine
- social distancing
- masks
- handwashing
What measures can be taken to avoid the common cold in children and in adults?
- Children:
- probiotics
- vitamin C
- zinc sulfate
- nasal saline irrigation
- Adults:
- garlic
- vitamin C
- Both
- handwashing & disinfecting?
What is the definintion of rhinosinusitis?
inflammation or infection of the mucosa of the nasal passages and at least one of the paranasal sinuses that lasts no longer than 4 weeks
What are the most common etiological causes of rhinosinusitis?
Respiratory viruses:
- rhinovirus
- parainfluenza virus
- respiratory syncytial virus
- adenovirus
How does acute bacterial rhinosinusitis usually occur?
Most common etiological causes?
as a complication of acute viral rhinosinusitis
- Streptococcus pneumoniae
- Haemophilus influenzae
What is Rhinocerebral mucormycosis?
Most common etiological agents?
invasive, life-threatening fungal infection
Rhizopus, Rhizomucor
(less commonly) Aspergillus & Fusarium
Identify the diagnosis based on the following symptoms:
sneezing, rhinorrhea, nasal congestion, post nasal drip, aural fullness, facial pressure & headache, sore throat, cough & fever and myalgias
less than 4 weeks duration
acute rhinosinusitis
What is a complication of advanced frontal rhinosinustis?
Pott’s puffy tumor
soft tissue swelling & pitting edema over frontal bone from superiostal abscess
Identify the diagnosis based on the following symptoms:
upper respiratory tract infection, blood nasal discharge, dusky or necrotic turbinates, changes in metal state, black eschar of the palate
rhinocerebral mucormycosis
At what time of year is rhinosinusitis most commonly occur?
winter months
What type of patients are most susceptible to rhinocerebral mucormycosis?
immunocompromised
diabetic w/ ketoacidosis, transplant recipient, patients w/ hematologic malignancies & patients on chronic glucocorticoid or deferoxamine therapy
What virulence factor allows Streptococcus pneumoniae to cause bacterial acute bacterial rhinosinusitis?
capsule
protects it from phagocytosis
What virulence factor allows Haemophilus influenzae to cause bacterial acute bacterial rhinosinusitis?
LOS
helps it to bind to host nonciliated epithelial cells
causes an increase in mucin production by host cells
What symptoms would help you differentiate between bacterial & viral acute rhinosinusitis?
bacterial is more likely when persists beyond 7 days or severe symptoms of any duration
persistent fever, altered mental status, diplopia (double vision), infraorbital hypesthesia (diminished physical sensatio)
What are treatment options for patients with acute rhinosinusitis?
increase oral hydration, nasal saline & steam
antipyretics, analgesics, decongestants & mucolytics
What are the 3 major factors for successful cerebral mucormycosis?
- Reversal of underlying predisposition
- Aggressive surgical debridement
- removal of all dead tissues & severely compromised tissue
- Aggressive antifungal therapy
What are strategies to prevent acute viral or bacterial rhinosinusitis?
- Good management of allergies
- Not getting flu or common cold
- Avoid jumping in water without plugging the nose
- Have septal deviation corrected & polyps or foreign bodies surgically removed
- Practice proper dental management
What is a strategy to prevent rhinocerebral mucormycosis?
encouraging diabetic patients to maintain good control over serum glucose levels
What is pharyngitis?
sore throat
Most common etiological causes of bacterial pharyngitis?
- S. pyogenes* (B-hemolytic group A Streptococcus)
- Neisseria gonorrhoea* (following oral sex)
Identify the diagnosis based on the following symptoms:
fever, sore throat, edema, hyperemia of tonsils and pharyngeal walls
pharyngitis
What symptoms suggest a viral rather than bacterial agent causing pharyngitis?
conjunctivitis, cough, coryza, hoarseness, anosmia, ageusia & diarrhea
anterior stomatitis and discrete ulcerative lesions & viral exanthem
What finding is specific for S. pyogenes pharyngitis?
scarlet fever rash
What are complications that can develop from untreated S. pyogenes pharyngitis?
- Suppurative: peritonsillar abscess, cervical lymphadenitis & mastoiditis
- Nonsuppurative: acute glomerulonephritis & rheumatic fever
What is acute glomerulonephritis?
sudden onset of hematuria, proteinuria & red blood cell casts
hypertension, edema & impaired renal function
What are the most common causes of acute pharyngitis?
viruses
- rhinovirus
- COVID
- adenovirus (military & boarding schools)
- HSV
- Parainfluenza (children)
- Influenza
- Coxsackievirus
- RSV (children)
- Epstein-Barr (adolescents)
What virulence factors allow S. pyogenes to cause bacterial pharyngitis?
M-protein (prevents phagocytosis)
lipoteichoic acid
fibronectin-binding protein (protein F)
capsule with hyaluronic acid
protease & hyaluronidase
Why can S. pyogenes cause damage to renal & heart tissue?
M protein shares antigenic epitopes with heart & renal tissue
antibody made to certain type sof M protein can cross reaction with heart tissue causing carditis
What bacteria is B-hemolytic, catalase-negative, gram-positive cocci & sensitive to bacitracin?
S. pyogenes
How should the diagnosis of Group A Strep pharyngitis established?
- Testing by rapid antigen detection tests (RADT)
- in children, (-) RADT should be backed up by throat culture
- Back up cultures of (-) RADT is not necessary for adults b/c risk rheumatic fever is v. low
- Anti-streptococcal antibody titer non recommended (reflect past events)
Who should & shouldn’t be tested for GAS pharyngitis?
- Shouldn’t
- if strongly suggest viral etiology
- under 3 yrs old
- follow-up post treatment
- asymptomatic household contacts of patients with GAS pharyngitis
- Should
- under 3 w/ older sibling with GAS infection
What is the general treatment for acute pharyngitis?
antipyretics, analgesics & supportive care
There is an adenovirus vaccine available for what demographic of people?
military
not recommended for general public
What is the treatment for S. pyogenes pharyngitis?
antipyretics, analgesics & supportive care
antimicrobials
What is Lemierre’s Disease?
anaerobic infection Fusobacterium necrophorum
starts as sore throat
neck pain, swelling & stiffness
sepsis 3-10 days after sore throat
postanginal septicemia
What bacteria causes Diptheria?
Shape? Gram stain?
How does the vaccine agains this bacteria work?
Corynebacterium diptheriae with toxin-producing lysogenic bacteriophage (B-phage)
irregularly staining gram-positive, rod-shaped
induces antibody production to inhibit diptheria toxin
Identify the diagnosis based on the following presentation:
pharyngeal pain, pseudomembrane on tonsils & back of oropharynx, regional lymphadenopathy (“bull neck”), edema of surrounding tissue, fetid breath, low-grade fever, and cough
can cause tachypnea, stridor, and cyanosis
can cause neurologic abnormalities & myocarditis
Diptheria
How is C. diptheriae transmitted?
respiratory droplets & skin contact
How does diptheria toxin damage the pharynx?
kills the mucosal cells by adenosine diphosphate ribosylateion of elongation factor II and terminating protein synthesis
What are important symptoms to diagnose Diptheria?
pseudomembrane that bleeds upon removal & cervical lymph adenopathy
Neurologic abnormalities (palatine palsy, difficulty swallowing, etc.)
What is the treatment for Diptheria?
hospitalization, placed in isolation, immediately treated with antiserum & antimicrobial treatment
What pathologies are involved with “the croup” ?
acute laryngitis, laryngotracheobronchitis (viral croup), epiglottitis (bacterial croup)
Why are respiratory diseases particular concerning for young children?
their airways are narrower than older children / adults
What is the most common etiological cause of viral croup?
Parainfluenza virus type II
What are the most common causes of epitglotitis?
(1) Haemophilus influenzae type b
(2) S. pyogenes
Identify the diagnosis based on the following presentation:
upper respiratory infection, followed by dysphonia and reduced vocal pitch
odynophonia, dysphagia, odynophagia, sore throat, congestion, fatigue & malaise
acute laryngitis
Identify the diagnosis based on the following presentation:
fever (38-39), upper respiratory infection with coryza, nasal congestion, sore throat & cough (2-3 days)
hoarsness with harsh, brassy “bark-lke” cough, air hunger and restlessness, waking up at night
usually resolves 4-7 days
Viral Croup
Children with severe croup have what predominant stridor?
inspiratory stridor
Identify the daignosis based on the following presentation:
acute onset fever, sore throat, and hoarseness
Retraction of suprasternal notch & stridor with every breath
throat & epiglottis are swollen
Epiglottitis
How serious is epglottitis & what are the 4 signs to be watchful for?
medical emergency
dysphagia, dysphonia, drooling, and distress
What age group is most susceptible to viral croup?
6 months - 3 yrs (boys)
Acute laryngitis occurs most common in what age group?
18-40
Why has the incidence of epiglottitis drastically decreased?
Haemophilus influenzae type b (Hib) vaccine
What pathogenesis is responsible for the inspiratory stridor heard in viral croup?
narrowing of the subglottic trachea
What virulence factor that allows H. influenzae to cause epiglottitis?
type b capsule prevents phagocytosis
What treatments work on viral croup but not bacterial cropu?
racemic epinephrine or water-saturated air (steam)
What is the characteristic radiographic finding for viral croup?
steeple sign
in anteroposterior neck radiograph
What is the “epiglotitis triad”
- Severe sore throat (usually rapid onset)
- Hoarse voice
- Pyrexia, generally unwell, dehydrated
What is the most important component of treating epiglottitis?
securing the patient’s airway by intubation & antibiotic therapy
What is acute bronchitis?
It most commonly affects what age group?
inflammation of the trachea & bronchi but NOT the alveoli
young & older persons
What are the most common etiological causes of acute bronchitis?
Viruses:
- Respiratory Viruses
- Flu A & B, Parainfluenza birus, adenovirus, RSV, HSV, Rhinovirus, Coxsackievirus A & B, echovirus
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
How can you differentiate bronchitis from pneumonia on an X-ray?
Pneumonia shows consolidations or infiltrates
these are NOT seen in bronchitis
Identify the diagnosis based on the following presentation:
malaise, headache, coryza & sore throat
cough (from non-purulent to mucopurulent), substernal pain, fever (38.3-38.9), infected pharynx
rhonchi & crackles on auscultation
7-10 days
Acute bronchitis
What are predisposing factors in children for developing acute bronchitis?
poor nutrition, allegy, deficiencies in IgG2, IgG3, IgG4, and rickets
What treatments are abailable for bronchitis?
supportive therapy with analgesics, antipyretics, antitussives & expectorants
if greater then 14 days, antimicrobials may be needed
What is bronchiolitis?
It most commonly affects what age group?
inflammation of the bronchial tree as low as the bronchiles but does NOT involve the alveoli
infalnts younger than 1 year
What is the most common etiological causes of bronchiolitis?
RSV
human metapneumovirus, parainfluenza virus, adenovirus
What diagnosis can be made based on the following presentation?
mild rhinorrhea, cough, low-grade fever
paroxysmal cough & dyspnea
tachypnea, tachycardia, diffuse expiratory wheezing, inspiratory crackles, nasal flaring, intercostal retractions
bronchiolitis
What are risk factors for contracting RSV bronchiolitis?
age younger than 6 months, bottle feeding, prematurity (before 37 weeks), exposure to cigarette smoke, crowded living conditions
How is a diagnosis of bronchiolitis made?
patients symptoms
chest radiograph (AP & Lateral views: hyperinflation, & patchy infiltrates, air trapping, focal atelectasis, flattened diaphragm, peribronchial cuffing)
antigen test of nasal washings for RSV
What is the general treatment for bronchiolitis?
supplememntal oxygen & replacement of electrolytes
What drug can be given for prophylaxis in patients with hig-risk for bronchiolitis?
palivizumab (humanized monoclonal antibody reactive with rsv)
Influenza can lead to fatal complication in what demographics of people?
very young
elderly
underlying cardiovascular & pulmonary diseases
3rd trimester pregnancy
Idenfity the diagnosis based on the following presentation:
abrupt onset fever (38.9 - 40), chills, rigors, headache, congested conjunctiva, extreme prostation with myalgia in back & limbs, nonproductive cough
fever lasts 3-4 days
recovery usually complete in 7 days
Influenza
What is a symptom of influenza that is mostly unique to children?
diarrhea and vomiting
What are the etiological agents mostly likely to cause a secondary bacterial pneumonia after an initial influenza infection?
Staphylococcus aureus
- Haemophilus influenzae*
- Streptococcus pneumoniae*
- Streptococcus pyogenes*
What type of flu cause epidemics?
types A and B can cause epidemics
What is the cause of Avian influenza?
influenza A H5N1
What are the H antigen and N antigen and why are they imporant for the influenza virus?
H: hemagglutinins - required for binding the virus to the cell
N: neuraminidases - helps mature virus escape from the cell
Describe the difference between influenza shift & drift
- shift: major changes in H or N types
- drift: mutation in the H or N antigens that result in slight change
What is one way to differentiate between atypical pneumonia and influenza pneumonia?
atypical pneumonia is usually insidious
influenza pneumonia is rapid onset
What persons are recommended to receive influenza vaccination?
all persons over 6 months of age
What is the treatment for healthy persons who contract influenza virus?
supportive care
antipyretics and analgesics
antiviral drugs can be effective if given in the first 2 days of symptoms
What is the coloquial name for petussis?
What is the etiological cause of pertussis?
Whooping cough
Bordatella pertussis
What are the phases invloved in a pertussis infection?
- incubation period (7-10 days)
-
catarrhal phase (1-2 weeks)
- upper respiratory phase
- coryza, sneezing, low-grade fever, occasional cough
-
paroxysmal phase (2-4 weeks)
- episodic, sudden coughing, paroxysm of numerous rapid coughs
- inspiratory stridor causing “whoop”
- vomiting & exhaustion
What sign in pathognomonic for Pertussis?
high-pitched whoop at the end of a paroxysm of numerous, rapid coughs
What are the most important virulence factors of B. pertussis?
How does it work?
-
pertussis toxin
- enzyme that ribosylates guanine-nucleotide-binding protein with ADP, which affects regulatory mechanism in the ciliated cells of the host’s trachea
-
cytotoxin
- kills the cells that line the trachea
-
filamentous hemagglutinin
- important in the attachment to ciliated cells
What step can be taken to prevent pertussis among young infants?
Tdap vaccine durign pregnancy
What lab test provides a uniqe finding for children wtih pertussis?
elevated WBC with lymphocytosis
(unusual for bacterial infection)
What is the treatment for pertussis?
Antibiotics (erythromycin) if given before paroxysmal stage
Supportive care to preven hypoxia & pulmonary complications
What is the best method to prevent pertussis?
vaccination
DTap (given to children 6mo - 6 yrs)
What is the name for infections that cause diseases in the lower respiratory tract?
pneumonia
Identify the diagnosis based on the following presentation:
cough, dyspnea, sputum production, tachycardia, fever, abnormal breath sounds, dullness to percussion, wheezes, and crackles
pneumonia
Under what condition will pnemonia present without fever?
neonate with afebrile Chlamydia trachomatis pneumonia
What is the usual onset for typical pneumonia?
24-48 hrs
What is the usual onset for interstitial pneumonia?
several days to 1 week
What is the timeline for symptoms to fully develop with chronic pneumonia?
several weeks to a month
Identify the diagnosis based on the following presentation:
night sweats, low-grade fever, significant weight loss, productive cough with purulent sputum production, dyspnea
chronic pneumonia
What symptoms are uniqe to aspiration pneumonia?
recurrent chills rather than shaking chills
consolidations int he dependent lung segments
1/4 will produce foul smelling sputum
What is the etiological cause of Legionnaire’s disease?
What unique features are associated wtih Legionnaire’s disease opposed to other types of pneumonia?
Legionella sp.
- relative bradycardia
- abdominal pain
- vomiting
- diarrhea
- hematuria
- mental confusion
- abnormal liver/renal functional tests
- increases in serum creatinine phosphokinase
What is the etiological cause of Psittacosis?
What unique features are associated with Psittacosis opposed to other types of pneumonia?
Chlamydophila psittaci
- relative bradycardia
- epistaxis
- Horder spots
- splenomegaly
- normal - low leukocyte counts
- people who take care of psittacine birds
What is the etiological cause of Q fever?
What unique features are associated with Q fever opposed to other types of pneumonia?
Coxiella burnettii
- relative bradycardia
- tender hepatomegalyendocarditis
- abnormal liver function tests
- farmers who have recently birthed livestock
What etiological causes of pneumonia also cause erythema nodosum and hilar adenopathy?
Funal causes
- Histolasma capsulatum* (Ohio and Mississippi river valleys)
- Coccidiodes immitis* (San Joaquin valley)
- Coccidiodes posadasii* (Southwest US)
What is the most common fungal cause of pneumonia?
What symptoms are unique to this type of pneumoina?
Where is this fungus endemic?
Blastomyces dermatitidis
endemic in Southeast US
rough verrucous skin lesions
What unique features are associated with pneumonia caused by COVID-19?
- higehr fever (102 - 104)
- loss of taste and/or smell
- ground glass appearance of lungs on CT
- lymphopenia
- elevated lactate dehydrogenase & ferritin levels
What are the most common means of acquiring pneumonia?
Inhalation & aspiration
What time of year & in what age group is pneumonia most common?
winter
over 65
What conditions predispose persons to aspiration pneumonia?
- altered level of consciousness
- alcoholism
- seizures, anesthesia
- central nervous system disorder
- trauma
- dysphagia
- esophageal disorders
- nasogastric tubes
What are the 3 major ways that organisms are able to survive in the alveoli?
-
Capsule : prevents phagocytosis by alveolar macrophages
- S. pneumoniae, H. influenza, K. pneumoniae
- Viruses & Chlamydia invade host cells before alveolar macrophages can phagocytize them
- M. tuberculosis can survive in alveolar macrophages after being phagocytized
What is a “consolidation” as described on a chest x-ray?
acumulation of microorganisms, immune cells & serum components taht caue the alveolit ot fill and spread to othe ralveoli that are in close proximity
