Infections Flashcards
What is the difference between lobar pneumonia and bronchopneumonia?
LP - lobar pneumonia = entire lobe
BP - Scattered solid foci in the same/several lobes
What is community acquired pneumonia?
Pneumonia that arises outside the hospital in persons with no primary disorder of immune system.
What is nosocomial pneumonia?
Infection that develops in hospital environments and tends to affect compromised patients
What is opportunistic pneumonia?
Afflicts persons whose immune status is defective
Where are bugs that cause pneumonia normally acquired from?
They are normally commensals that are aspirated into the alveoli and set up shop
Describe the general route of S. pneumoniae infection
Mostly consequence of altered resp. tract defenses
Viral upper resp. infection -> mucous secretions (hospitable environment) -> aspiration of commensal S. pneumoniae
Describe the pathology commonly encountered in pneumococcal pneumonia
- Edema with organisms fill alveoli
- Capillary congestion with massive outpouring of PMNs and uhemorrhage (RED HEPATIZATION)
- Gray hepatization - Macros phago PMNs and inflamm debris
What are possible complications of pneumococcal pneumonia?
- Pleuritis
- Pleural Effusion
- Pyothorax - Infection of pleural effusion
- Empyema
- Bacteremia - Patients w/o spleen can die
- Pulmonary Fibrosis - Carnification - Rare alveolar fibrosis leading to a shrunken firm lobe
- Lung abscess - rare
A patient presents with fever, chills, chest pain, and produces a rusty sputum. Below is a lung biopsy. The alveoli are packed with exudate and PMNs. What is the Dx? What is the likely bug?
Pneumococcal pneumonia; Streptococcus pneumoniae
A patient presents with a lobar pneumonia. The lobe increases in size and the fissure bulges towards the unaffected region. What is the Dx? What other bug causes lobar pneumonia? What is a serious complication of this disease?
Klebsiella Pneumonia (Klebsiella pneumoniae); S. pneumoniae; Bronchopleural fistula (Connection betwixt bronchus and pleural space)
A patient with cystic fibrosis is admitted to the emergency room. The patient was found to have multiple foci of small abscesses throughout the lung. What is your Dx? What are common complications of infection with this organism?
S. aureus pneumonia; Cavitation and pleural effusion
An extremely debilitated patient dies in the hospital after a long battle with pneumonia. At autopsy, heavy bloody edema was observed. Dry consolidation is NOT observed. What is your Dx? What is a common complication?
Streptococcus pyogenes pneumonia; Empyema
A following birth, a newborn fails to thrive due to toxemia and dies within a few hours. What type of streptococcal pneumonia did this infant likely have?
Streptococcus agalactiae pneumonia
A patient presents with abrupt malaise, fever, muscle aches, and abdominal pain. A sputum sample was cultured but the organisms were not easily observed with conventional stains and required silver impregnation. The nurse was worried about the patient’s wife but you already know the Dx and know that this disease cannot be transmitted betwixt people. What is the Dx? In what settings is this bug acquired? What is a milder form of this disease?
Legionella pneumophila pneumonia; Aquatic environments such as water in A/C cooling towers, evaporative condensers, and construction sites; Pontiac fever
What two organisms typically cause pneumonia in immunocompromised hosts?
Escherichia coli and Pseudomonas aeruginosa
What scenarios predispose a person to pneumonia caused by anaerobes?
People with poor oral hygiene, swallowing disorders (alcoholics, anesthetized), people with seizures
A patient presents with fever, malaise, and muscle aches. His only respiratory Syx are cough. He says he eats bird poop. What type of pneumonia does this idiot likely have?
Psittacosis (Chlamydia psittaci pneumonia)
A patient rapidly declines and on autopsy, a whopping hemorrhagic, mediastinal mass is found. Hemorrhagic bronchitis and confluent areas of hemorrhagic pneumonia are found. What is the Dx?
Inhalation of Bacillus anthracis resulting in Anthrax pneumonia
What bug is plague caused by? Pathology?
Direct inhalation of Yersinia pestis; Hemorrhagic bronchopneumonia, pleuritis, rapid death
A patient with a history of insidiously progressive respiratory symptoms has seriologic testing performed to make the Dx. What is the Dx? If a lung biopsy was performed, what would a pathologist observe?
Mycoplasma Pneumoniae causing atypical pneumonia; Bronchiolitis with neutrophilic intraluminal exudate and lymphoplasmacytic infiltrate in bronchiolar walls
Why has there been a reemergence of tuberculosis?
AIDS endemic
Describe the lesions associated with primary tuberculosis and the pathologic progression of primary tuberculosis.
- Ghon lesion - peripheral parenchymal granuloma (often in upper lobes)
- Ghon complex - Ghon lesion + enlarged mediastinal lymph nodes
- Macrophages wall off organisms because they cannot kill them. Granulomas form.
What is a serious potential complication of primary tuberculosis? What population does this conditioin affect?
Progressive primary tuberculosis; Young children or immunocompromised
What are the typical Syx in primary tuberculosis?
There generally are no Syx
A patient presents with Syx of night sweats, weight loss, fevers, and hemoptysis. The patient expires shortly after presentation. The lung is shown. What is your Dx? What are other potential complications of this disease?
Secondary Tuberculosis;
- Milary tuberculosis
- Bronchopleural fistula
- Tuberculous laryngitis
- Intestinal tuberculosis
- Aspergilloma
A patient’s lung is shown below. What is your Dx? Describe the findings.
Miliary tuberculosis; Presence of multiple, small tuberculous granulomas
Describe the process leading to intestinal tuberculosis. What is the common fungus that infects patient with secondary tuberculosis?
Patients swallow tuberculous material; Aspergillus species form a fungal mass in tuberculosis cavities
A patient with AIDS presents. The lung biopsy below shows extensive infiltrate of macrophages and innumberable acid-fast organisms. What is the Dx?
Mycobacterium Avium-Intracellulare (MAI)
A patient expires and at autopsy, the lung what found to have multiple, interconnecting, small abscesses. Clubbed basophilic filaments are noted at the margins of the bacterial colonies. What is your Dx? What do the clubbed basophilic filaments look like to the naked eye?
Actinomycetes (israelii) pneumonia; Sulfur granules
A lung biopsy of an immunocompromised patient is shown. The organisms are delicate, beaded, thin filaments branching at right angles. What is the Dx? What stain is used to visualize this organism?
Nocardiosis (Nocardia asteroides); Gomori methenamine silver
A patient that frequents the Mississippi River and Ohio River valleys shows Syx indicative of tuberculosis. On biopsy, it was found that the lung lesions were very fibrotic and there was very little if any cavitation. What is the likely Dx?
Histoplasmosis (Histoplasma capsulatum)
A patient who traveled to the San Joaquin Valley presents with Syx similar to tuberculosis. What is the likely infectious agent?
Coccidioidomycosis immitis
A patient was eating pigeon droppings and accidentally breathed in pigeon dropping dust. Luckily the patient wasn’t immunocompromised so the disease didn’t disseminate. What is the probably Dx?
Cryptococcosis (Cryptococcus neoformans)
A patient living in the Ohio river valley expires. On autopsy, Ghon complex-like lesions are observed but on histological analysis, central necrosis with a purulent reaction, surrounded by granulomatous inflammation is observed. What is the Dx?
Blastomycosis (Blastomyces dermatitidis)
A patient with AIDS experiences arterial thrombosis and infarction of his lung. A biopsy of lung tissue is shown below. What is your Dx? What is the treatment?
Invasive pulmonary aspergillosis; It is not amendable to Tx
A patient with bronchiectasis and a previous Hx of tuberculosis. On CXR, a large mass was found within an air space. What is the likely Dx? What are the typical clinical presentations?
Fungal ball aspergillosis; Generally asymptomatic but if become clinically evident, hemoptysis can occur.
An patient with asthmatic exacerbation shows signs on the CXR of transient pulmonary infiltrates, eosinophilia in his blood and sputum, skin sensitivity and increased serum IgE. What is the likely Dx? What typical markers would be found in the serum?
Allergic bronchopulmonary aspergillosis; Serum precipitins to Aspergillus fumigatus
A bronchial biopsy is performed and shown below. A dilated bronchus is filled witha mucous plug that has dense layers of eosinophilic infiltrates. What is your Dx? At higher magnification, what morphologies would be observed?
Allergic bronchopulmonary aspergillosis (ABPA); Eosinophils and Charcot-Leyden crystals
A transbronchial biopsy is performed on an AIDS patient and is shown below. An interstitial infiltrate of plasma cells and lymphocytes and hyperplasia of type II pneumocytes is observed. Foamy proteinaceous exudate is observed with organisms appearing as small bubbles. What is the Dx? What type of stain is used to observe the organism? What is the morphology observed? What other methods are used to Dx this disease?
Pneumocystis jiroveci; Silver impregnation to observe “cresent moon” bodies; Sputum analysis, bronchoalveolar lavage, needle aspiration, open lung biopsy
What pulmonary cells are typically affected in viral pneumonitis?
Type I pneumocytes
A lung biopsy from a patient is shown below. The biopsy shows cells with a single dark blue nuclear inclusion with a peripheral halo, and type II pneumocyte hyperplasia replacing the type I
Cytomegalovirus
A lung biopsy below shows multinucleated giant cells with single, eosinophilic, refractile inclusions and multiple irregular cytoplasmic inclusions. What is the Dx? What is the Px for this patient?
Measles infection; Good prognosis unless IC
What two viral lung infections show nuclear eosinophilic and refractile inclusions surrounded by a halo?
Varicella and Herpes simplex
A lung biopsy is shown below. The patient had necrotizing bronchiolitis and bronchopneumonia. By looking at the cell in the middle, what is the Dx? What is that cell? What other types of inclusions occur in this disease?
Adenovirus pneumonia; Smudge cell; Eosinophilic nuclear inclusions surrounded by a halo
An elderly patient with interstitial pneumonitis and bronchiolitis comes down with an acute fever and chills in december. The patient then gets a bacterial superinfection and expires. What is the likely Dx?
Influenza virus pneumonia
What is the most common cause of lung abscesses?
Aspiration of oropharyngeal anaerobic organisms
What are conditions/events that predispose a patient to aspiration?
Poor oral hygiene/Peridontal disease, depressed cough reflex, ALCOHOLISM, Drug OD, epilepsy, neurological impairment
What lung has a greater frequency of lung abscesses? Why?
Right because follows the path of the trachea closer than the left.
A patient present with a fever, cough and foul smelling sputum. Lung abscess is observed on CXR. What is your DDx? What is the most common Dx?
Aspiration of anaerobic organisms, cancer, cavitary TB; Cancer
