Dx Testing & Treatment
Virulence Factors
Signs & Symptoms
Misc
100
A 6-month-old male presented to the ED with his parents for a 3-day hx of nasal congestion, cough, and low-grade fever. The infant has become increasingly fussy and has been breathing more rapidly. He has no significant PMH, and his vaccinations are UTD. On exam the pt is irritable, tachypneic, respiratory rate of 60, O2 sat is 92% on RA, lung exam reveals intercostal retractions, wheezing and crackles at the bases.
Question: You are suspicious for bronchiolitis and order a CXR to investigate further. What findings would support your suspicion?
Peribronchial cuffing with lung hyperinflation. peribronchial cuffing of the soft tissue around the bronchi results from peribronchial edema secondary to inflammation. Ths inflammation also causes thickening of the bronchial walls making it more difficult for air to flow out of the lungs. The air becomes trapped inside the alveoli resulting in lung hyperinflation and rapid breathing in an attempt to compensate.
100
This mode of viral transmission involves the spread of infectious particles when an infected person coughs, sneezes, or talks and releases respiratory droplets. These droplets can be inhaled by individuals in close proximity. It is a common way for respiratory viruses like the flu and COVID-19 can be spread.
Airborne transmission
100
A patient comes into the doctor’s office with a sore throat, headache, fatigue, and a cough that have all developed over the past three days. The patient believes they have COVID-19 since they saw on the news that there has been an increase in COVID cases nationwide. They want Paxlovid, and to be sent on their way. What is an appropriate response to this question?
Empathize with patient, explain that their symptoms are generalized with many types of infections, and talk with them ways to determine what infection is occurring (i.e. COVID test, PCR, etc.)
100
Patient comes in with fever, chest pain, and shortness of breath. Resident diagnose bronchiolitis, and recommend treatment to you, the attending physician. The resident believes she should immediately be treated with a wide spectrum antibiotic and begin albuterol, a vasodilator. Since you are the chairman of the AAP, do you agree with this treatment plan?
NO! Antibiotics should not be given unless bacterial infection is evident. Albuterol should not be given due to adverse effects and cost.
Bonus: Why would you not want to give antibiotics unless you are almost certain it is a bacterial infection? How should the resident change their treatment plan?
200
Given the patient's presentation and symptoms, what viral illness do you suspect the pt has contracted?
RSV. Lung hyperinflation with bronchiolitis is a common presentation of RSV in young children. This virus is more common in children than adults due to their less developed immune system and frequent possibility of exposure in setting such as daycare and school.
200
This surface glycoprotein of RSV is crucial for both attachment to host cells and immune cell evasion by mimicking the CX3C chemokine motif. This influences the recruitment of immune cells to the site of infection and thereby modulates the immune response.
What is the G protein?
200
What kind of infection became a pandemic during 2020, and what is one niche symptom that can help differentiate this infection from others?
Viral infection, loss of taste and smell
200
A patient presents 1 day s/p sustaining a laceration to the right hand from a kitchen knife. The exam is normal other than mild erythema and tenderness to palpation at the wound site. What division of the immune system is likely at play at this stage of the immune response to any microbes the wound may have been exposed to? Specifically what cells are involved.
Your skin is part of the innate immune system as it works to keep a barrier between you and pathogens in the environment. When the skin is breached, macrophages, dendritic cells, mast cells, granulocytes and natural killer cells are the first line of defense. The response is generalized and acts the same towards any given pathogen.
Bonus: If the innate immune response fails to clear the pathogen and the infection persists, after how many days will adaptive immunity kick in?
300
Case continued: A nasopharyngeal swab confirms Respiratory Syncytial Virus (RSV) infection. The medical team decides to administer palivizumab (Synagis) as part of the management plan.
Question: What is the mechanism of action of palivizumab in the prevention and treatment of RSV, and how does it help mitigate the severity of RSV-induced respiratory illness in high-risk infants?
Palivizumab is a monoclonal antibody that binds to the fusion (F) protein of RSV thereby preventing RSV from attaching and penetrating host cells. As a result, RSV cannot replicate or spread deeper into the respiratory tract
Bonus: What are monoclonal antibodies?
300
A young child with confirmed RSV is experiencing symptoms of severe bronchiolitis. The immune response is initiated but there is a delay before antigen presenting cells (like dendritic cells) can activate B cells to differentiate into plasma cells.
What is the typical time frame for the immune system to produce specific antibodies following an RSV infection? What is the significance of this delay in regard to disease progression?
It takes approximately 7-9 days for B cells to produce antibodies against a particular antigen. This delay is significant because the body is solely reliant on the innate immune response which is non-specific and may be unable to control viral proliferation.
Note, RSV is able to evade the innate immune system via NS1/NS2 proteins and the CXC3 motif on cell-surface G proteins.
300
A 32-year-old woman presents to the clinic with a 5-day history of fever, cough, body aches, and nasal congestion. She was diagnosed with influenza two days ago and has been taking over-the-counter medications for symptom relief. Today, she reports that her nasal discharge has changed from clear to colored. Upon examination, she has mild fever, and her vital signs are stable. She describes the nasal discharge as initially green but now turning yellow. She is concerned that this change might indicate severe bacterial infection.
Does this indicate severe bacterial infection?
No!
Yellow = acute infection, not as severe
Green = More severe infection, potential spread to more than one area
Green to yellow indicates infection is decreasing. While this is good news, mucous color alone is not indicative of condition. Make sure to ask follow up questions and make sure other symptoms are not worsening.
300
3 week old patient comes in for a routine physical and check-up. Physicality is normal, except for a few things: abnormally shaped eyes, brushfield spots, sandal gap deformity and lack of suck reflex. What is the suck reflex and how did the physician determine that the baby is not exhibiting?
Suck reflex helps the baby to feed by sucking on breast or bottle. When the roof of the mouth is stroked, the baby will start to suck.
Bonus: What condition does this baby have? What test would confirm the diagnosis of the baby? What are some other abnormal findings that may come up in a physical for a patient with this condition?
400
In an acute care setting, what is the quickest way to confirm the presence of a RNA virus?
When dealing with an RNA virus like RSV, an RSV antigen test can provide results within half an hour. A nasal or oral swab is collected and used to detect the presence of viral antigens. In this case, typically the F fusion protein or N nucleoprotein are detected in the lab.
Note, rapid antigen tests are less sensitive than RT-PCR and can result in false negatives if the viral load is low. RT-PCR is the gold standard to detect viral infection because it has high specificity and sensitivity.
Bonus: What step is added to detect RNA?
400
A 2-year-old child is brought to the emergency department with a high fever, cough, and difficulty breathing. Nasopharyngeal swab testing is positive for RSV. Which of the following best describes the genome and classification of the virus responsible for this infection? Where is the replication site of RSV replication and what enzyme does it use for replication?
RSV is a single-stranded negative-sense RNA virus that is enveloped. It replicates in the cytoplasm of the host cell. It relies on its own RNA-dependent RNA polymerase to synthesize mRNA and replicate its genome.
400
Use VINDICATE to help identify zebras with a patient experiencing the common cold symptom of chest pain:
V - Pulmonary embolism, myocardial infarction
I - Pneumonia, pericarditis
N - Lung cancer
D - Arthritis, osteoarthritis
I - Exposure to CO, alcohol-related GI inflammation
C - Hypertrophic cardiomyopathy, congenital heart defect
A - Lupus, Rheumatoid arthritis
T - Rib fracture
E - Electrolyte imbalance (i.e. hypokalemia)
Bonus: Why would hypokalemia cause chest pain?
400
A child presents with a runny nose, fever, and cough. A rapid antigen test comes back for RSV. How many days has it likely been since the pt was exposed to the initial RSV virion?
Pt 2: The patient received the Nirsevimab RSV vaccine 10 months ago. Given this information, how did their immune system likely respond initially to the infection?
Symptoms typically appear 4-6 days after exposure to a virus. The vaccine Nirsevimab provides acquired immunity that lasts for about 5 months. Therefore, the child does not have any persisting acquired immunity and will have a normal innate immune response followed by the adaptive immune response several days later.
Bonus: How could you check to see if this patient has any residual acquired immunity from their prior vaccination?
500
Besides the two diagnostic tests discussed for RNA viruses, what are 3 other methods used for microbe detection?
PCR: Useful for microbes with DNA. Amplifies specific DNA sequences of the pathogen, allowing for its identification even in small amounts.
Titer/ Serology: detects the amount of antibodies you have in your body against a specific antigen. Best for providing information about a previous exposure.
3. Culture: Involves growing pathogens from respiratory samples, such as sputum, nasal swabs, or bronchoalveolar lavage fluid, in specific media under controlled laboratory conditions. This method is more time consuming but provides definitive results.
500
28-year-old man presents to the emergency department with a 2-day history of high fever, severe myalgias, headache, and a nonproductive cough. He reports that several of his coworkers had similar symptoms in the past week. Physical examination reveals a temperature of 39.5°C (103.1°F), tachycardia, and diffuse muscle tenderness. A rapid influenza diagnostic test (RIDT) is positive for Influenza A. Draw out the pathway an Influenza A virion takes as it attaches to a cell, replicates, and releases. Note the mechanism of action of neuraminidase inhibitors like Oseltamivir.
500
A 3-day-old newborn is admitted to the neonatal intensive care unit (NICU) with worsening lethargy, poor feeding, and a pale grayish appearance. The infant's mother reports that she took antibiotics during her pregnancy for a urinary tract infection.
The following vital signs are recorded:
Temperature: 98.2°F (36.8°C)
Heart Rate: 90 beats per minute
Respiratory Rate: 25 breaths per minute
Blood Pressure: 45/25 mm Hg
Oxygen Saturation: 90%
Physical examination reveals a grayish discoloration of the skin, hypotonia, and signs of respiratory distress.
What abnormal symptoms indicate that the baby is experiencing adverse effects to mom’s use of antibiotics?
Low HR, low RR, low BP, low O2
500
A patient presents with 4 days of a mild non-productive cough without any exertional tachypnea. A CXR is ordered. You are a radiologist assigned to read the following CXR. What reading would you provide?
Normal lol
Bonus: What would you look for to identify hyperinflation and peribronchial cuffing?