PAS-501 Pulmonary Infections Pt. 2

Pneumonia and TB

An acute infection of the functional lung tissue (pulmonary parenchyma) acquired outside of a healthcare setting.

What is the definition of Community Acquired Pneumonia (CAP)?

S. pneumoniae.

Which pathogen is responsible for the majority of bacterial pneumonia cases in both adults and children?

50%.

In approximately what percentage of pneumonia cases is no specific pathogen isolated?

E. coli, Group B Strep, Klebsiella, and Staph aureus.

Which four specific pathogens are commonly acquired by neonates during birth from the mother's colon, GI tract, or skin?

A stabbing pain that worsens during deep breathing and coughing.

Describe the clinical characteristic of pleuritic chest pain associated with pneumonia.

When the diagnosis is in question or the patient has significant comorbid illnesses.

Under what clinical circumstances is a chest Xray required for the evaluation of CAP?

15,000 to 20,000.

What typical range is observed for the White Blood Cell (WBC) count in a patient with acute pneumonia?

Streptococcus and Legionella.

What specific pathogens can be identified using a urine antigen test, particularly in nursing home patients?

Presence of many WBCs and bronchoalveolar epithelial cells with few or absent squamous epithelial cells.

What are the characteristics of an adequate sputum specimen for pneumonia diagnosis?

Contamination of the sample with saliva from the buccal mucosa.

What does the presence of squamous epithelial cells in a sputum sample indicate?

500 mg on day 1 followed by 250 mg daily for 4 days.

What is the standard adult dosage and duration for Azithromycin when treating CAP?

100 mg twice daily for 7 to 10 days.

What is the adult dosage regimen for Doxycycline in the treatment of CAP?

Amoxicillin.

Which antibiotic is the first choice for treating pneumococcal pneumonia in children aged 6 months to 5 years?

It can cause permanent discoloration of adult teeth.

What is the primary reason Doxycycline is contraindicated in children under the age of 8?

Pneumonia Severity Index (PSI).

Which scoring system utilizes demographics, comorbidities, physical exam, and labs to determine adult pneumonia hospitalization?

Less than 90 mmHg.

According to the PSI, what systolic blood pressure threshold indicates a need for adult hospitalization?

Less than 35 decrees C (95 degrees F) or greater than 40 degrees C (104 degrees F).

What abnormal body temperatures serve as criteria for adult hospitalization in the PSI?

Grunting, nasal flaring, and retractions.

List three signs of respiratory distress that warrant hospitalization for pediatric pneumonia patients.

Streptococcus pneumoniae.

Which pathogen is associated with a "consolidated pattern" (complete white patch) on a CXR in 65% of bacterial pneumonia cases?

Staphylococcus aureus

Which organism often causes a necrotizing super infection following an influenza infection?

An interstitial pattern described as reticulated, lacy, or fish net

What radiographic pattern is characteristic of Mycoplasma pneumoniae infection?

Bullous myringitis, which presents as fluid

What physical finding on the eardrums is classically associated with Mycoplasma pneumoniae?

Mycoplasma typically results in a positive test, while viral pneumonia (influenza) results in a negative test.

How do the results of a cold agglutinins test typically differ between Mycoplasma and viral pneumonia?

Legionella.

Which atypical pneumonia pathogen is spread via water droplets and can cause epidemics?

The superior and posterior segments of the right lower lobe (RLL).

In cases of aspiration pneumonia, which specific lung segments are most commonly affected?

Circumferential consolidation with air

What radiographic finding suggests the presence of a lung abscess caused by anaerobic bacteria?

A compromise in airway defenses and an inoculum of sufficient size or toxicity.

What are the two primary requirements for the development of aspiration pneumonia?

Clindamycin

What is the first choice antibiotic for treating aspiration pneumonia?

Appearance 48 hours after hospital admission until 14 days after discharge.

What is the defining timeframe for a pneumonia infection to be classified as nosocomial?

Pseudonomas

Which gram negative organism is a common cause of nosocomial pneumonia in healthcare facilities?

6 to 8 weeks.

What is the recommended timeframe for a follow up chest Xray to document the resolution of a pneumonia infiltrate?

It is an indication for a CT scan to rule out underlying malignancy (cancer).

What is the clinical significance of a non resolving pneumonia infiltrate on a follow up CXR?

TMP-SMZ (Bactrim) or IV pentamidine.

What is the first line treatment for Pneumocystis jirovecii pneumonia in HIV patients?

Aspergillus.

Which fungal pathogen is associated with the formation of "fungus balls" on a chest Xray?

Cryptococcus.

Which fungal pneumonia is most common in organ transplant and HIV+ patients and frequently involves the CNS?

The Midwest states, specifically the Ohio and Mississippi river valleys.

In which geographic region of the United States is Histoplasma pneumonia most prevalent?

Inhalation of dust contaminated with bird or bat droppings.

What environmental exposure is most commonly linked to Histoplasma infection?

Blastomycosis.

Which fungal pneumonia is caused by inhaling spores found in moist soil and wooded areas?

Mucormycosis.

Which fungal infection is more common in summer/fall and resides in soil with decaying organic matter like compost or feces?

Tuberculosis (TB).

What is the most common infectious cause of death worldwide after HIV?

Immune suppression (HIV/AIDS), substance abuse, and silicosis.

Identify three predisposing conditions for the development of active Tuberculosis.

It is a dormant infection that is not contagious and is characterized by granuloma formation.

What characterizes Latent TB in terms of contagion and pathology?

It occurs years after the primary infection, has a more acute onset, and is often more severe.

How does Secondary TB typically differ from Primary TB infection?

At the lung margins near visceral pleura/fissures and in the middle 2/3 of the lungs.

Where do inhaled TB bacilli typically deposit within the lungs during a primary infection?

Calcified hilar lymph nodes and granulomas (Ghon focus).

What are the two anatomical components of a Ghon Complex in primary TB?

Tuberculomas.

What term describes the mass like opacities formed when calcified TB tubercles coalesce?

The hematogenous dissemination of TB infection throughout the lungs or to extrapulmonary sites.

What is the clinical definition of Miliary tuberculosis?

2 years.

Within how many years do 2/3 of primary TB survivors typically achieve radiographic resolution?

AIDS.

Which condition represents the highest risk factor for a patient progressing to active TB disease?

Erythema multiforme.

What is the target rash associated with Mycoplasma pneumoniae called?

The posterior segment of the upper lobes.

If a patient aspirates while in a supine position, which lung segment is the most likely site of infection?

2 to 6 weeks.

What is the specific timeframe for the development of a cell mediated immune response to wall off a TB infection?

Cryptococcus.

Which fungal pathogen is treated primarily with Fluconazole and lives in the soil?

Marked hypoxemia, dyspnea, and cough.

What are the common clinical features of Pneumocystis jirovecii pneumonia despite potentially absent radiologic findings?

Chemical pneumonitis.

Which pulmonary condition results from the aspiration of gastric acid and predisposes to secondary bacterial infection?

Sunken fontanelle, absence of tears when crying, and fewer than 3 wet diapers.

List three specific signs of dehydration in an infant with pneumonia.

Homogenous parenchymal consolidation, particularly in the lower to middle lobes.

What specific radiographic finding in primary TB is often indistinguishable from bacterial pneumonia?

To ensure the best possible chance of isolating and identifying the specific causative organism.

Why is it optimal to obtain a sputum specimen for Gram stain prior to the administration of antibiotics?

They receive macrophages carrying bacilli and initiate the cell mediated immune response.

What is the primary role of hilar lymph nodes during the initial phase of TB infection?

Neoplastic disease, heart failure, cerebrovascular disease, renal disease, and liver disease.

In the PSI, which coexisting medical diseases are considered risk factors for pneumonia severity?

Poor prognosis.

What is the prognosis for patients diagnosed with Miliary tuberculosis?

Anaerobes from the mouth (e.g., Peptostreptococcus, Fusobacterium).

Which group of bacteria is specifically associated with lung abscesses and air fluid levels on CXR?

A lacy, fish-net, or reticulated appearance of the lung tissue.

What defines the "Interstitial" pattern seen on a CXR?

Macrolides (Azithromycin, Erythromycin, or Clarithromycin).

What is the first line antibiotic for children over age 5 when covering for Mycoplasma and Chlamydophila?

The degree of illness or severity of disease.

What is the medical definition of "morbidity"?

To counteract bronchospasm that may occur during the recovery phase.

Why might bronchodilators be prescribed during follow up for a patient recovering from pneumonia?

Cefdinir.

What is the first choice cephalosporin alternative for children with pneumonia?

It acts as a predisposing condition for the development of active TB disease.

How does malnutrition, specifically low Vitamin D, affect the risk of Tuberculosis?

Patients residing in nursing homes.

Which specific population should always have urine tested for Streptococcus and Legionella antigen if pneumonia is suspected?

95% of cases.

What percentage of primary TB cases successfully heal through immune clearance or entry into a latent phase?

Systolic blood pressure less than 90 mmHg.

What physical exam finding involving blood pressure is part of the adult PSI for hospitalization?

Mycoplasma pneumoniae.

Which atypical bacterial pathogen is most common in adolescents and young adults?

It indicates an anaerobic infection, typically resulting from aspiration of oral flora.

What is the clinical significance of finding Peptostreptococcus in a lung specimen?

Doxycycline.

If a patient with CAP is allergic to penicillins, what is a standard oral alternative for outpatient treatment?

Hilar adenopathy on the same side as the pneumonia.

What CXR finding is commonly seen alongside the pneumonia infiltrate in Histoplasma infections?