Flashcards in CRRAB Respiratory Micro - Get in my brain! Deck (44):
Most common viral infection of common cold
2 most common bacterial pathogens in sinusitis?
Most important pathogens in laryngitis/croup?
Respiratory Synctial Virus (RSV)
Key Points for common cold:
-Winter most common
-Hundreds of immunologically distinct varieties
-Rhinovirus most common (also adeno,corona)
-stuffiness, headache, sneezing, rhinorrea, sore throat, fever
How does Rhinovirus infect cells of nasal passages and pharynx?
attaches to ICAM-1
Key Features of Sinusitis:
-Common pathogens are Strep Pneumo and H. Influenza
-Sneezing, rhinorrhea, congestion, post-nasal drip, facial pressure and headache, sore throat, fever, muscle aches
-Aspergillis fumigatus is fungal sinusitis, rare
How do you differentiate between viral and bacterial sinusitis?
-Bacterial is likely when moderate symptoms persist over 7 days (or there is facial swelling/tooth pain)
-In kids moderate symptoms must last longer than 10-14 days (or a fever over 102 with facial swelling/pain)
How do you treat bacterial sinusitis?
Strep Pneumonia is a common cause of pneumonia in adults. Name the key feature:
Gram ( + )
catalase ( - )
What virus is common in military recruits and boarding schools? How does it present?
Acute Respiratory Disease
Fever, sore throat, edema, and hyperemia of tonsils and pharyngeal walls in common i both viral and bacterial pharyngitis.
What additional symptoms might suggest viral cause?
Inflammation of mucus membrane
Fever and sudden-onset severe swallowing pain
Do rapid-step test for S. Pyogenes
How would you treat pharyngitis caused by Strep pyogenes?
Penicillin, or erythromycin for those with penicillin allergy
Strep pyogenes special test:
sensitive to what?
Child with flushed face and strawberry tongue following a strep pyogenes infection.
What's the disease?
What is causing it?
Strep pyogenes exotoxins SpeA, SpeB, SpeC, and SpeF
(actually encoded by the bacteriophage, not the bacteria, weird.)
So you know that Scarlet Fever needs genes from a bacteriophage. What other bacterial pathogen requires bacteriophage genes to cause virulence.
Where are two places that diptheria can affect outside of the pharynx?
Neuritis (temporary paralysis of limbs, palate, diaphragm)
"A disease of the heart and the mind too"
Bark-like cough, respiratory stridor, general cold sx, fever 38-39C (100-102 F)
What are you thinking?
I am thinking croup/laryngitis!
Cyanosis is late-stage and dangerous
Cool air seems to relieve some symptoms...
What is one of the important virulence factors in RSV?
F proteins on viral surface cause cell membranes to merge into one another. (Synctial)
IMPORTANT: Also seen in parainfluenza virus
You are surprised to see that one of the partners at your practice has just ordered a potassium tellurite culture. You rush over to talk to him about the case. Why?
Diptheria! Don't see that too often. I'd want to talk to him anyway.
Which viral genome that can cause the common cold has a segmented genome?
Which virus can cause sever complication o fhemorrhagic cystitis?
Patient with COPD gets bacterial pneumonia. Test reveal the causal bacteria hydrolyzes tributyrin, produces DNase, reduces nitrate and nitrite, and does NOT ferment sucrose, glucose, maltose, or lactose
It's moraxella Cattarrhalis!
(top two for pneumonia after COPD = Non-typeable H. Influenza and M. catarrhalis)
How is protein synthesis halted in diptheria?
Ribosylation of EF-2 through diptheria toxin
This bacteria is:
-a major cause of CAP
-Potentially dangerous for asplenic patients
-Systemically causes meningitis
IF you are asplenic you better get a pneumovax vaccine!
(they can't clear capsuled bacteria)
We know strep pneumo is dangerous for asplenic patients, what other organism also is?
HINT: especially causes meningitis in kids!
Hemophilus Influenza B
Capsule means it is quelling(+)
Special way to culture HiB?
Chocolate agar with X,V
If you are particularly worried about a high-risk premature infant getting RSV, what should you do?
Synagis (f-antigen) vaccine
Child present with hacking cough, fever, and chest pain after a typical cold presentation.
CXR reveals no consolidation and no infiltrates.
Tx: Erythromycin, or azithromycin
Violent coughing spasms that are severe and uncontrollable.
Special culture for pertussis?
Bordet Gengou agar
Gram ( - )
Which virus undergoes antigenic drift?
at which site?
Usually at antobidy binding site
Most common pneumonias in 40-65 yo adults:
Most common pneumonia in elder 65+ adults
Gram - rods
A 66-year-old man was brought ED for abrupt onset of shaking chills, high fever, and pain on the right side of his chest since prior evening. In the last 24 hours he had experienced sob and a cough that was productive of rust-colored sputum. Diabetic/smoked two ppd, 20 yrs. Had not received any vaccinations in last 20 years.
Sounds like pneumonia. Most common pathogens are Strep Penumo, gram(-) rods, and H. influenza.
(without CXR, can't tell if it's just bronchitis)
If CXR shows upper lobar pneumonia we know strep pneumo (likes making lobar pneumonia)
In December, 73-year-old man from nursing home in acute respiratory distress. Usual health until 10AM yesterday when he suddenly developed fever, chills, muscle aches, cough, and prostration. Several others at nursing home developed a similar illness last week. Past hx unremarkable and he did not see a physician in the past year.
Culture is optochin sensitive!
Strep pneumoniae is definitely what we are seeing on the culture.
The history sounds a lot like a Influenza C leading to a secondary pneumonia infection.
Differentiate flu from common cold by higher fever. (he aslo didnt get vaccinated!)
Bronchiolitis usually affects what patient population, with what pathogen?
-infants under 1yo
-self-limiting disease usually, like bronchitis
Classic pneumonia symptoms:
-sudden onset chills, fever, dyspnea, productive cough, purulent (sometimes blood-tinged) sputum.
-tachypnea, tachycardia, lung crackles
Method of infection fro parainfluenza virus:
-Infect larynx mucosa through viral hemagluttinin (HA) protein attaching to sialic acid
-Viral neuroaminidase protein permits viral spread by cleaving HA bound to sialic acid
Leads to croup!
Infections caused by Coxsackie A and B?
Coxsackie A – herpangina and hand-foot-and-mouth disease
Coxsackie B – pleurodynia, myocarditis, and pericarditis.
Coxsackie A and B – aseptic meningitis, paralysis, and URI cold
What kinds of infections caused by step agalactiae?
meningitis in newborns
gram+, beta-hemolytic, bacitracin resistant!
Tx with penicillin
How do you treat mycoplasma pneumoniae?
erythromycin or tetracycline
how do you treat chlamydia pneumoniae?
How does legionella avoid destruction by macrophages?
It actually survives and proliferates despite being phagocytosed by macrophages.
Chemoattractants secreted by the infected macrophages is what causes the symptoms seen in Pontiac fever and legionnaire's disease.