2.1.3 Infectious Disease of the Lung Flashcards
What is the difference between these two images?
Left - Normal ciliated columnar epithelium
Right - rhinovirus infected epithelium
What is the most common way that organisms are introduced to the lower respiratory tract?
Aspiration of flora from the oropharynx
What is the most likely population to aspirate?
Institutionalized (nursing home patients) patients are more likely to aspirate
They also have an altered oral flora, which can include many gram negative and anaerobic organisms
What can be used to make a diagnosis of pneumonia?
Most Important - Presentation of clinical symptoms and/or the presence of infiltrate on CXR or CT Scan. Blood cultures are also helpful
Less important - sputum culture
What are the types of pneumonia?
Community-Acquired pneumonia
Atypical pneumonia
Bronchial pneumonia
Lobar pneumonia
What are the characteristics of community-acquired pneumonia?
Community-acquired acute pneumonia refers to lung infection in otherwise healthy individuals that is acquired from the normal environment (in contrast to hospital acquired pneumonia). It may be bacterial or viral.
Rarely seen either resolves or progresses to cause lobar pneumonia
Neutrophilic reaction and abundant sputum
RLL is the most common area affected
What are the characteristics of atypical pneumonia?
Low grade fever, patchy consolidation and has a non-productive cough
What is the difference between these two images?
Left - bronchopneumonia
Right - Lobar pneumonia
How would lobar pneumonia show up on a CXR?
It would show up as a tissue density on a chest X-Ray.
What are the stages of lobar pneumonia?
What is this an image of?
This is a CXR of a lobar pneumonia
What is the most common organism to cause pneumonia?
Streptococcus pneumoniae
What is this an image of?
S. pneumoniae - sputum gram stain
What is this an image of?
Lobar pneumonia
What is this an image of?
Lobar pneumonia - notice how nearly every alveoli is filled with pus.
How could you distinguish between lobar pneumonia and bronchopneumonia on a histologic slide?
If the bronchi were filled with pus, it would be called bronchopneumonia. If it is in the alveoli, it is lobar pneumonia, by definition.
Why is it important to get a patient with pneumonia on antibiotics as soon as possible?
To prevent scarring of the lung tissue
What are the clinical features of Haemophilus influenzae?
Gram-negative
Mainly a problem with children
Common cause of COPD exacerbation
What is the most frequent cause of gram-negative bacterial pneumonia?
Klebsiella pneumoniae
What population does Klebsiella pneumoniae most often afflict?
Debilitated and malnourished people, particularily alcoholics
What is this an image of?
Klebsiella pneumoniae
Notice the abcess formation
What are the important characteristics of legionella pneumophilia?
It is an intracellular organism, requiring antimicrobial drugs with good cytoplasmic penetration. Biochemical abnormalities may seem more severe than patient presents. Requires special media to grow
What is this an image of? (Hint: Lab studies make this disease worse than the patient is presenting)
Legionella CXR - affecting the RUL
What is this an image of?
Legionella - IF sputum staining
What is this an image of and what is the stain?
Legionella - Dieterle stain
What are some of the complications of pneumonia?
What is this an image of?
Lung that has a hole in it after infection and liquefactive necrosis.
Patient has a Staphylococcus aureus infection, and presents with this CXR. What is a common cause that he got it?
This is bilateral Staph pneumonia. It is most likely cause by IV drug abuse
What is the difference between primary TB and secondary TB?
What are complications associated with TB?
What is this an image of?
TB - gross finding
Notice - Caseous necrosis and cavitation in advanced TB
What is this an image of?
CXR of TB - Miliary TB
What is this an image of?
Interstitial pneumonia - CT Scan
What are these images of?
Hemorrhagic Tracheobronchitis - Influenza A
What is this an image of?
Cytomegalovirus - Owl eye inclusion in the nucleus. Immunocompromised host
In a patient with pneumocystis jirovecii infection and a normal immune system, how will the infection present?
It will tend to be asymptomatic in a patient with normal immune system
Who is at risk for Pneumocystis jirovecii infection?
HIV patients with <200 CD4 count
What is this an image of?
Pneumocystis jirovecii
Also know that a BAL can be a good diagnostic test for this
What is this an image of?
Pneumocystis jirovecii - silver stain
What are the different clinical classifications of aspergillosis? *Important
What is this an image of?
This is an aspergilloma - it exists within a previously existing space, most likely an old abcess
What is circled in this image?*
Aspergilloma - There is no invasion of tissue by the fungus. It respects the boundaries of the previously existing abscess cavity.
What is this an image of?*
Aspergillus niger
What is this an image of and what caused it? *Very important
Invasive Aspergillosis that caused a lung infarct -
What is this an image of?*
Aspergillosis (Blood vessel invasion/thrombosis)
Aspergillus will invade blood vessels, and cause thrombosis and infarction, and those infarcts can occur anywhere in the body, not just the lung
