Viral Pneumonia Flashcards
Tom is admitted to the ED at 2:00 pm for dyspnea and now at 2:00 am is experiencing flu-like symptoms.
- Is it likely that he contracted influenza while in the hospital?
- How would you most likely treat him?
- MOA of treatment options?
- Tom lives with his 96 year old grandma with SCID. What should you do for her?
NO - flu take 24-48 to incubate
Treatment: Oseltamivir or Zanamivir - both are neurominidase inhibitors
Grandma: Give Oseltamivir prophylactically
In 2002-2003 there was a pandemic in some asian countries of a disease causing fever, dyspnea, and hypoxemia. Patients were also more susceptible to bleeding during this infection.
- what were some potential reserviors of this disease?
- Why were patients susceptible to bleeding?
Reserviors:
• Masked palm civet
• Horseshoe Bat
Blood:
• Patients infected with SARS CoV (enveloped, single stranded, positive sense RNA virus) are THROMBOCYTOPENIC and LEUKOPENIC
• leukopenia should be noticable since you would expect WBCs to be increased
Jane is a 95 year old alcoholic that has been living at home by herself and presents with a pneumonia characterized by mononuclear infiltrates in the alveolar interstitium. The week prior she had suffered from an URTI.
• what risk factors did she have for the onset of this pneumonia?
• Other risk factors for this type of pneumonia?
Pneumonia - most likely is viral given histological findings
Risk Factors:
• Old Age
• Alcoholism
• Malnutrition - possible b/c she is living by herself
Other risks not seen here:
• Underlying debilitating illness = risk factor
How is Respiratory Syncytial Virus (RSV) transmitted?
- Respiratory Droplets
- Direct contact of contaminated hands with nose or mouth
- Community outbreaks every winter
What single stranded linear nonsegmented RNA virus is responsible for viral pneumonia?
• What are 3 virulence factors of this virus?
• How is this virus transmitted?
Parainfluenza Virus - enveloped single stranded nonsegmented RNA virus
3 Virulence determinants:
• Contain F (fusion protein)
• Contains H/N (hemogluttinin and neuraminidase)
Transmission:
• respiratory droplets
A child developes a seal-like, barking cough along with sore throat, and fever. What finding may be present on CXR?
• What is/are the etiologic agents?
• what causes this cough?
• What other respiratory sounds may be present?
Etiologic agents: hPIV1, 2, or 3 (remember only 2-3% of infections will progress this far)
Croup: associated with this cough, CXR is likely to show the steeple sign that results from inflammation around the larynx, trachea, and bronchi
Stridor: may be heard because it is caused by inflammation and obstruction of the larynx
Someone presents with atypical pneumonia following a flu infection. Onset of infection occured 24 to 48 hours after exposure to an infected friend. Onset was characterized by Fevers, Chills, and myalgia.
• explain how this virus was transmitted?
• What is the pathogensis of influenza?
• what causes the characteristic myalgias?
Transmission:
• airborne respiratory droplets
Pathogenesis:
• Inhalation => Neuraminadase degrades mucous layer gaining access to cells, Hemagluttinin attaches virus to cells => necrosis of respiratory epithelium
Myalgia:
• Myalgia of flu is caused by CYTOKINE release
In 2002-2003 there was a pandemic in some asian countries of a disease causing fever, dyspnea, and hypoxemia. Patients were also more susceptible to bleeding during this infection.
• what virus caused this outbreak?
• Why do you think it was pandemic?
• What is the structure of this bug and its genome?
Virus:
• SARS CoV (corona virus) is genetically distinct from other CoVs so caused more widespread disease.
• SARS CoV - is a single stranded positive-sense RNA virus
MERS
• what are some clinical presentation of MERS infection?
- Pneumonia
- ARDS
- Hemoptysis
- Myalgia
- Nausea/Vomitting/Diarrhea
(high mortality rate)
Differentiate what you would see in CBC and in pathological specimen in viral pneumonia and bacterial pneumonia.
Bacterial CBC/Pathology:
• Overall WBC very elevated
• Lots of PMNs
• PMN infiltrate would be seen
Viral CBC/Pathology:
• Overall WBC not insanely elevated
• Lots of Lymphocytes
• Mononuclear infiltrate
Who should get the flu vaccine and how long does it last?
- Anyone over 6 months of age should get the flu vaccine.
- Protection lasts 6 months
Dave is 3 months old when he is infected with a virus that causes pneumonia. He experiences lethargy, diarrhea, and vomitting. The infective virus is believed to be a non-enveloped double-stranded DNA virus.
• what virus is this?
• what are some problems that Dave may have down the road?
Virus: Adenovirus
Sequelae:
• Bronchiectasis
• Bronchiololitis obliterans- a rare andlife threateningNON-reversibleobstructive lung disease characterized byFIBROSISand scar tissue that causescollapse of broncioles
Someone is infected with viral pneumonia. The etiologic agent has a segmental genome consisting of 8 segemnts of helical negative sense RNA that is enveloped. One of the virulence factors for this bug is Neuraminidase.
• what is the function of neuraminidase?
• what are 2 other virulence factors for this pathogen?
• What causes the endemic nature of this virus?
• What causes the pandemic nature of this virus?
Infleunza virus (could be A or B)
Neuraminidase: cleaves neuraminic acid to release viral progeny. ALSO, it degrades the protective mucous layer in the respiratory tract. (2 major subtype N1 and N2)
2 other:
- *Hemagglutinin**: allows the virus to grab onto to cell surface recptors and infect human cells
- *M2 ion channel:** essential for infectivity of flu virus
Endemic nature:
• Less severe - caused by mutations that make it different enough to evade immune response
Pandemic nature:
• More severe - caused by reassortment human genes and animal genes. The virus becomes antigenically new.
What the structural and genomic characteristics of adenovirus?
• How is it transmitted?
• Non-enveloped, double-stranded, linear DNA virus
• Transmitted via aerosol droplet, fecal-oral, or direct inoculation
Beisides Upper Respiratory Tract infection and pneumonia. What other diseases are caused by Adenovirus?
Adenovirus Diseases:
• Febrile Pharyngitis
• Conjunctivitis
• Hemorrhagic Cystitis
• Gastroenteritis (less than 2 years old)
• Disseminated infection in immunocompromised
Jack is a 34 week old infant who is suffering from a presumed viral pneumonia. He is experiencing persistent cough, wheezing, fever, tachypnea, and is turning blue. Labs indicate that it is likely RSV.
• what put this kid at a high risk of RSV infection?
• How could you treat him?
• What should have been given to this kid to prevent this disease?
• MOA of preventative measure?
High Risk:
• Infants get pneumonia from RSV, especially those born under 35 weeks of gestation
Treatment:
• ONLY treatment option is supportive care with hydration, albuterol, and O2.
• Ribavirin - reserved for adults (particularly stem cell transplant pts)
Prevention:
• Kid should have been given Palvizumab a monoclonal antibody against F-protein - PREVENTS VIRUS INFECTIVITY
What pathogen is clinically indistinguishable from RSV? what other virus is also often mistaken for?
• How is this virus transmitted?
• Diseases caused?
• Human Metapneumovirus - member of the same Paramyxoviridae family, its also sometime mistaken for Influenza.
Route of Transmission:
• Respiratory Droplets
Diseases:
• causes upper respiratory tract infections and pneumonia.
What is the most common cause of respiratory tract infections that results in physician and hospital visits in the U.S?
• what groups of people are most likely to die from these infection?
- Influenza Virus
- Children under 2 and the Elderly are the most likely to Die as a result of infections.
- ~36,000 death/year from flu
In 2002-2003 there was a pandemic in some asian countries of a disease causing fever, dyspnea, and hypoxemia. Patients were also more susceptible to bleeding during this infection.
• what are you likely to see on CXR of these patients?
- Range from normal to diffuse interstitial infiltrates
- Bilateral peripheral infiltrates common usually in middle or lower lung lobes
An infant succombs to a pneumonia characterized by diffuse interstitial infiltrates on CXR. Mononuclear infiltrates are seen on lung biopsy along with mutlinucleated giant cells.
- what are key characteristics to determine the etiologic agent as given here?
- Describe the reason we see these characteristics?
Key Characteristics:
• Viral b/c of interstitial infiltrates with MONONUCLEAR cells, since it was an infant start thinking RSV
• GIANT CELLS - SYNCYTIA - key - caused by surface spikes on RSV that are fusion proteins that cause fusion of respiratory epithelium.
What type of pneumonia is caused by viruses?
• what characterizes this type of pneumonia on CXR?
Atypical Pneumonia - characterized by patchy inflammatory changes in the lungs, largely confined to the alveolar septa pulmonary interstitium (aka NO CONSOLIDATION)
Differentiate the progression of a case of RSV in infants and adults?
• what are some risk factors of getting RSV?
• How would you diagnose this disease?
Infants:
• Persistent cough, wheezing, fever, tachypnea, hypoxemia
• Often involes the lower respiratory tract and turns into pneumonia
Adults:
• Typical Upper repiratory tract infection
• Lasts 4-5 days then resolves
Diagnosis:
• RT-PCR on nasal swab or washings
• Rapid antigen test on nasal swab or washings
How do we keep military recruits from getting Adenovirus?
Vaccine:
• LIVE oral enteric-coated vaccines directed aginst adenovirus serotypes 4 and 7.
How do you treat a child with a parainfluenza virus infection?
• What do you do to diagnose?
• what is the prognosis?
• What are the chances that the same kid will be back in your office with a seal-like cough in the future?
Dx:
• Clinical
Tx:
• Supportive
Prognosis:
• good - most children recover after a few days but reinfection is common
