Respiratory Diseases: CAP, Bronchiectasis, Abscess

Questions and Answers

What is the most common method for microorganisms to access the lower respiratory tract in cases of pneumonia?

Contiguous extension from infected pleural space

Inhalation of airborne pathogens

Aspiration from oropharynx (correct)

Hematogenous spread

What is a significant consequence of the capillary leak associated with pneumonia?

Decreased respiratory drive

Increased compliance of the lungs

Hypoxemia (correct)

Decreased heart rate

Which of the following is NOT a typical risk factor for Community Acquired Pneumonia?

Diabetes mellitus (correct)

Age greater than or equal to 70 years

Asthma

Alcoholism

Which inflammatory mediator is primarily responsible for fever during pneumonia?

IL-1 Signup and view all the answers

What type of cells primarily clears and kills pathogens in the lungs?

Resident alveolar macrophages Signup and view all the answers

Which phase of pneumonia pathology involves the presence of neutrophils and red blood cells?

Red Hepatization Signup and view all the answers

What physiological response is associated with systemic inflammatory response syndrome (SIRS) in pneumonia?

Respiratory alkalosis Signup and view all the answers

Which type of diagnostic method can be used to assess pneumonia with high accuracy?

History and physical examination Signup and view all the answers

What is the accuracy range of physicians’ clinical judgment in predicting community-acquired pneumonia (CAP)?

60-76% Signup and view all the answers

Which clinical feature is NOT associated with CAP?

Pulmonary embolism Signup and view all the answers

What is the value of a chest radiograph in the diagnosis of CAP?

It is essential for diagnosis and prognosis. Signup and view all the answers

What specific views of a chest radiograph are best for evaluating a patient suspected of having pneumonia?

Standing posteroanterior and lateral in full inspiration Signup and view all the answers

Which of the following statements about clinical prediction rules for pneumonia is true?

They combine history and physical examination findings. Signup and view all the answers

What is the yield for blood cultures in diagnosing pneumonia?

5-14% Signup and view all the answers

Which biomarker is useful for distinguishing between viral and bacterial infections?

Procalcitonin Signup and view all the answers

Is there a clinical feature that can distinguish pneumonia due to typical or atypical pathogens?

No, there is no reliable clinical feature for this. Signup and view all the answers

What is the recommended action for patients with moderate- and high-risk Community-Acquired Pneumonia (CAP)?

Hospital admission for monitoring Signup and view all the answers

Which of the following features best characterizes low-risk CAP?

Stable vital signs Signup and view all the answers

What is the role of microbiologic studies in low-risk CAP?

Optional, depending on the physician's discretion Signup and view all the answers

What indicates a high-risk category for patients with CAP?

Need for mechanical ventilation Signup and view all the answers

Which chest X-ray finding is typical for moderate-risk CAP?

Multilobar infiltrates Signup and view all the answers

What specific test is recommended for hospitalized patients with CAP?

Gram stain and culture of respiratory specimens Signup and view all the answers

Which vital sign abnormality suggests a moderate-risk status in CAP?

Respiratory rate (RR) > 30 breaths/min Signup and view all the answers

Which condition is NOT a characteristic of low-risk CAP?

Altered mental state Signup and view all the answers

Which procedure is NOT categorized as an invasive method for obtaining specimens in non-resolving pneumonia cases?

Sputum induction Signup and view all the answers

In patients with low-risk community-acquired pneumonia (CAP) without co-morbid illnesses, which antibiotic is recommended?

Amoxicillin 1 gm TID Signup and view all the answers

For moderate-risk CAP patients with the risk of aspiration, which combination of treatments is appropriate?

Ampicillin-Sulbactam + Azithromycin Signup and view all the answers

Which of the following pathogens is NOT associated with low-risk CAP?

Legionella pneumophila Signup and view all the answers

Which treatment option is used for high-risk CAP without risk factors for pseudomonas?

IV non-antipseudomonal β-lactam Signup and view all the answers

What is the treatment recommendation for low-risk CAP patients with stable co-morbid illness?

Co-amoxiclav 1 gm BID Signup and view all the answers

Which of the following antibiotics is NOT an extended macrolide used in the treatment of CAP?

Doxycycline Signup and view all the answers

Which pathogen is primarily targeted with IV non-antipseudomonal β-lactam treatments in moderate-risk CAP?

Moraxella catarrhalis Signup and view all the answers

What is the recommended duration of therapy for non-bacteremic MSSA community-acquired pneumonia?

7-14 days Signup and view all the answers

Which of the following patients might still require repeat chest radiographs after 72 hours?

Patients showing no improvement Signup and view all the answers

What is the minimum duration of therapy for non-bacteremic Pseudomonas aeruginosa pneumonia?

14-21 days Signup and view all the answers

What criteria must be met for hospital discharge within the last 24 hours?

Pulse <100/min Signup and view all the answers

Which vaccination is recommended for the prevention of community-acquired pneumonia?

Influenza vaccination Signup and view all the answers

What is the maximum duration of antibiotic therapy for bacteremic MSSA community-acquired pneumonia?

21 days Signup and view all the answers

Which of the following is NOT a discharge criterion for a patient?

Respiratory rate <16/minute Signup and view all the answers

Which antibiotic duration is recommended for Mycoplasma pneumonia?

10-14 days Signup and view all the answers

Study Notes

Community Acquired Pneumonia (CAP)

Infection of the pulmonary parenchyma, leading cause of death worldwide, and 6th overall in death rates.
Most common cause of morbidity and mortality, primarily caused by microbial pathogens at the alveolar level.
Pathogen access through aspiration (from oropharynx), hematogenous spread, or contiguous extension from infected areas.

Host Response and Inflammatory Pathophysiology

Resident alveolar macrophages play a key role in clearing pathogens.
Inflammation mediators like IL1 and TNF trigger fever, while IL8 and GCSF cause leukocytosis and increased secretions.
CAP presents with symptoms like dyspnea, hypoxemia, and increased respiratory drive.

Pathological Stages

Edema phase involves bacteria and neutrophils.
Red hepatization marks red blood cell accumulation.
Gray hepatization shows neutrophil dominance.
Resolution phase is characterized by macrophage engagement.

Risk Factors

Significant risk factors include alcoholism, asthma, immunosuppression, institutionalization, and age ≥70 years.

Clinical Diagnosis

Physician judgment accuracy for diagnosing CAP is 60-76%, using clinical prediction rules.
No specific clinical feature can reliably distinguish between typical and atypical pneumonia.

Clinical Manifestations

Symptoms include fever, tachycardia, cough (with possible hemoptysis), chills, dyspnea, pleuritic chest pain, gastrointestinal symptoms, fatigue, headache, myalgia, and arthralgia.

Differential Diagnosis

Conditions to differentiate from CAP include acute bronchitis, chronic bronchitis exacerbation, heart failure, pulmonary embolism, hypersensitivity pneumonitis, and radiation pneumonitis.

Etiologic Diagnosis

Gram stain and culture yield ≤50%; blood culture yield is 5-14%.
Urinary antigen tests have a sensitivity of 70% and specificity of 99% (Legionella and pneumococci).
Serology tests indicating a fourfold rise in IgM titer confirm infection.
Biomarkers like CRP help identify disease progression; Procalcitonin aids in differentiating viral vs. bacterial infections.

Imaging and Diagnosis

Chest X-ray crucial for diagnosing CAP, assessing severity, and prognostication.
Posteroanterior and lateral views in full inspiration are optimal for evaluating suspected pneumonia.

Hospital Admission Criteria

Risk stratification based on clinical presentation and co-morbid conditions determines care site.
Low-risk CAP can be managed outpatient, while moderate to high-risk patients require hospitalization.

Risk Categorization in CAP

Low-risk features: Stable vital signs, no altered mental state, localized infiltrates.
Moderate-risk features: Increased respiratory rate, altered mental state, possible aspiration.
High-risk features: Severe sepsis, need for mechanical ventilation, multilobar involvement.

Microbiologic Studies

Optional for low-risk CAP; needed for moderate/high-risk cases.
Invasive procedures for special microbiologic studies are considered for difficult cases.

Treatment by Risk Category

Low risk: Amoxicillin or extended macrolides for common pathogens.
Moderate risk: IV non-antipseudomonal β-lactams paired with macrolides or fluoroquinolones.
High risk: Combination of treatments to cover resistant pathogens.

Duration of Antibiotic Therapy

Duration varies by pathogen; most bacterial pneumonias require 5-7 days.
Specific durations range from 7 days for non-bacteremic MSSA to up to 28 days for bacteremia in certain pathogens.

Hospital Discharge Criteria

Patient stability indicators include normal temperature, pulse <100 bpm, respiratory rate 16-24/min, systolic BP >90 mmHg, and blood oxygen saturation >90%.

Prevention

Vaccination against influenza and pneumococcal disease is recommended.
Smoking cessation is advised for all patients with CAP.

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Description

This quiz delves into Community Acquired Pneumonia (CAP), Bronchiectasis, and Lung Abscess. Explore definitions, diagnoses, and management strategies for these common respiratory conditions. Test your understanding and knowledge in this essential area of medicine.