Microbiology Quiz on Respiratory Pathogens

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Questions and Answers

What percentage of cases are attributed to M. Catarrhalis?

20%

10-30%

15% (correct)

Which of the following organisms is most commonly associated with chronic otitis media?

M.Catarrhalis

S.pyogenes

P.aeruginosa (correct)

S.aureus

What is the main reason for undertaking empirical treatment?

Increased patient comfort

Rapid resolution of symptoms

Uncertainty of pathogen identification (correct)

Availability of targeted antibiotics

What is the prevalence of cases showing no growth?

10-30% (D) Signup and view all the answers

Which organism has the lowest percentage identified in cases discussed?

S.aureus (C) Signup and view all the answers

What type of pathogen is associated with pneumoniae?

Gram (-) bacteria (C) Signup and view all the answers

What is the maximum time allowed to start antibiotic treatment after pneumonia diagnosis?

4 hours (A) Signup and view all the answers

Which of the following is NOT a characteristic of Rhinovirus?

It is a Gram (-) bacteria (A) Signup and view all the answers

What duration of symptoms is indicated for the condition associated with Parainfluenzae?

More than 3 months (A) Signup and view all the answers

Which of the following bacteria is NOT commonly associated with community-acquired pneumonia?

Escherichia coli (A) Signup and view all the answers

Which of the following is known as Friedlander's bacillus?

K.pneumoniae (B) Signup and view all the answers

Which type of pathogen is primarily responsible for fungal infections?

Fungi (B) Signup and view all the answers

Which statement accurately describes the relationship between the pathogens mentioned?

Rhinovirus is a viral pathogen distinct from bacterial infections (A) Signup and view all the answers

What is a key reason for immediate antibiotic treatment in pneumonia cases?

Prevents complications (A) Signup and view all the answers

Which antibiotic is commonly used to treat community-acquired pneumonia caused by S.pneumoniae?

Amoxicillin (C) Signup and view all the answers

What is one function of the body's systems in regulating water and heat?

It aids in maintaining homeostasis. (D) Signup and view all the answers

How do the lungs respond in patients with metabolic acidosis?

They compensate quickly to restore balance. (A) Signup and view all the answers

What is a role of the body's systems regarding blood pH?

To assist in regulating blood pH levels. (B) Signup and view all the answers

In patients experiencing acid-base disorders, what characteristic is typically observed?

Compensation by the lungs occurs rapidly. (D) Signup and view all the answers

Which of the following is NOT a function of the body's system in relation to water and pH regulation?

Enhancing the production of metabolic waste (B) Signup and view all the answers

What is a key difference in treatment between atypical pneumonia and typical pneumonia?

Atypical pneumonia may require different antibiotics. (B) Signup and view all the answers

What is the typical time frame for a patient to present symptoms of pneumonia before seeking treatment in the emergency room?

Seven days after symptoms appear. (B) Signup and view all the answers

Which of the following statements accurately describes pneumonia treatment?

Atypical pneumonia treatment may vary based on the pathogen. (B) Signup and view all the answers

Which patient symptom timeline is most commonly associated with atypical pneumonia?

Symptoms that persist for more than a week. (B) Signup and view all the answers

Which statement regarding the urgency of seeking treatment for pneumonia is false?

All pneumonia cases need to be treated within hours of symptom onset. (D) Signup and view all the answers

What imaging technique is primarily used to visualize the airways when bronchitis is suspected?

Bronchoscopy (A) Signup and view all the answers

In the context of bronchitis, what is generally true about the use of antibiotics?

Antibiotics are often unnecessary. (C) Signup and view all the answers

Which of the following statements is correct about radiologic changes in bronchitis?

No radiologic changes are usually observed on chest X-ray. (C) Signup and view all the answers

What does the lack of radiologic changes on a chest X-ray imply about the condition of airways in bronchitis?

The airways can only be assessed through bronchoscopy. (C) Signup and view all the answers

What can be concluded about the visibility of bronchitis on imaging techniques?

Only a bronchoscopy provides visibility of bronchitis. (A) Signup and view all the answers

Study Notes

Internal Medicine Topics

Increased blood cholesterol was noted as a potential concern (17).
History of heart problems, hernia, or asthma was also noted (18).

Respiratory Infections

Respiratory infections are a subject of study.

Respiratory Tract Outline

Anatomy is a key component.
Upper respiratory tract infections are discussed.
Lower respiratory tract infections are also discussed.

Respiratory Anatomy

Nasal cavity, including sinuses, is detailed.
Pharynx, nasal conchae, nose, tongue, hyoid bone, trachea, bronchus, right lung, left lung diaphragm, bronchioles and alveoli and capillary network are featured.

Upper Respiratory Tract Anatomy

The nose and nasal cavity, paranasal sinuses, pharynx, larynx are components.
These comprise the conducting portion of the respiratory system.
Air is transported to the alveoli.
No gas exchange occurs here.
Important: Patients with upper respiratory tract infections are not hypoxic.
Diagnosing pharyngitis or bronchitis when hypoxic is incorrect; look for other causes (mostly lower respiratory tract infections).

Upper Respiratory Tract Structures

Sphenoidal sinus,
Superior meatus,
Middle meatus,
Pharyngeal tonsil,
Opening of the pharyngotympanic (auditory) tube,
Nasopharynx,
Posterior nasal aperture,
Uvula,
Palatine tonsil,
Fauces,
Oropharynx,
Laryngopharynx,
Vestibular fold,
Vocal fold,
Esophagus,
Frontal sinus,
Cribriform plate of the ethmoid bone,
Superior concha,
Middle concha,
Inferior concha,
Vestibule,
Inferior meatus,
Nostril,
Hard palate,
Soft palate,
Tongue,
Lingual tonsil,
Epiglottis,
Hyoid bone,
Thyroid cartilage,
Laryngeal cartilages,
Cricoid cartilage,
Thyroid gland,
Trachea.

Paranasal Sinuses

Frontal,
Ethmoidal,
Sphenoidal,
Maxillary

Respiratory System Functions

Oxygen supply and carbon dioxide removal.
Air filtration (mucosal membrane, cilia).
Sound production.
Smell detection.
Water and heat release.
pH regulation (lungs compensate quickly for acid-base disorders, unlike the kidneys which take 3-5 days).

Upper Respiratory Tract Infections

Acute tonsillitis,
Acute pharyngitis,
Acute otitis media,
Acute sinusitis,
Common cold,
Acute laryngitis,
Otitis externa,
Acute epiglottitis, are common types.

Upper Respiratory Tract Infections (Viral)

Rhinovirus is the most common cause in adults.
Parainfluenzae and RSV are common in children.
The infection involves the upper respiratory tract, starting in the nasal cavity, and spreading throughout the airways.
Often self-limiting, resolvng without specific treatment.
Secondary bacterial infections can occur.

Pathophysiology of URIs

Direct invasion of the mucosa lining the upper airway.
Viruses are the most common cause.
Bacterial infections can complicate viral URIs.
Inoculation occurs when secretions touch exposed surfaces or inhaled from infected individuals.

Terminology

Rhinitis: Nasal mucosa inflammation.
Rhinosinusitis/Sinusitis: Inflammation of nares and paranasal sinuses.
Pharyngitis: Pharynx inflammation.
The pharynx, hypopharynx, uvula, and tonsils are involved.
Diagnoses are made clinically due to inability to directly visualize these structures.

Epiglottitis and other upper airway inflammations

Epiglottitis (Supraglottitis ): Inflammation of the superior portion of the larynx and supraglottic area.
Laryngitis: Inflammation of the larynx.
Laryngotracheitis: Inflammation of the larynx, trachea, and subglottic area.
Tracheitis: Inflammation of the trachea and subglottic area.
These are significant because they can cause upper airway obstruction.

Causative Organisms

Children (<3 years): >100% viral infection
Children (5-15 years): 15-30% GABHS (group A beta-hemolytic Streptococcus)
Adults: ≈10% GABHS
Most common streptococcus bacterium.

Streptococcal Infections—Signs and Symptoms

Sore throat is a key symptom.
Anterior cervical lymphadenopathy is frequent.
Fever is often present (≥ 38 °C), especially if bacterial.
Difficulty swallowing is typical.
Headache and fatigue occurs.
Muscle pain, nausea, and vomiting
Tonsillar hyperemia and exudates, soft palate petechiae, and absence of coughing and nasal discharge are common presentations that distinguish bacterial from viral infection.
Absence of hoarseness occurs because the infection occurs in the tonsil area.

Viral vs. Bacterial tonsillitis/pharyngitis

Viral tonsillitis/pharyngitis may also have rhinitis, hoarseness, conjunctivitis, and cough.
Oral vesicles or ulcers might be present in viral infections.
Bacterial infections in the upper respiratory tract (tonsils and pharynx) are localized.
Viral infections tend to be more widespread.

Exudates

GABHS
Presence of white discharge indicates a need for antibiotics.

Lymphadenopathy

GABHS or other infections (Epstein-Barr virus, adenovirus, human herpesvirus type 6, tularemia, HIV) can create lymphadenopathy
Important to note lymphadenopathy as a symptom for diagnosis purposes

Laboratory Diagnostic Tests for Tonsillitis/Pharyngitis

Throat swabs are helpful.
Rapid antigen tests.
Antistreptolysin titer tests for streptococcal infections.
White blood cell counts.
Peripheral smears.

Tonsillitis and Pharyngitis due to Streptococci

Supurative complications (abscess, neck stiffness, photophobia).
Sinusitis, otitis, and mastoiditis are potential complications.
Cavernous sinus thrombosis and toxic shock syndrome can arise.
Cervical lymphadenitis is noted.
Septic arthritis and osteomyelitis are severe possibilities.
Repeat infections may occur.
Nonsupurative complications
- Acute rheumatic fever.
- Acute glomerulonephritis.

Antibiotics for GABHS

Oral: Penicillin V or Cefuroxime. Dosing and duration for children and adults are detailed.
Parenteral: Benzathine penicillin is an injection method of treatment.
Consider alternative antibiotics for penicillin allergy.

Acute Otitis Media

S. pneumonia(30%), H. influenzae (20%), and M. catarrhalis (15%) are the common causes. Other bacteria include S. pyogenes (3%) and S. aureus (2%).
No growth is present in 10-30% of cases.
Treatments are typically empirical because accurately identifying the cause proves difficult.
Chronic otitis media is complex.
Requires culture identification to determine the correct treatment.

Acute Otitis Media (Symptoms)

Symptoms are reviewed, including otalgia, ear pain, hearing loss, ear drainage, fatigue, fever, irritability and tinnitus/vertigo.

Acute Otitis Media (Frequency)

85% of children up to 3 years will experience at least one episode of acute otitis media.
50% experience at least two episodes.
Most cases resolve spontaneously.
Antibiotics are rarely necessary.

Acute Rhinitis/Sinusitis

Acute sinusitis is commonly caused by S. pneumoniae (41%), H. influenzae (35%), M. catarrhalis (8%).
Other causes include streptococcal pyogenes, S. aureus, rhinovirus, parainfluenzae.
Chronic sinusitis is different.
Caused by anaerobic bacteria (Bacteroides, Fusobacterium), S. aureus, streptococcal pyogenes, Gram-negative bacteria, and fungal organisms.
Symptoms last for more than three months.

Acute Bronchitis

Typically viral in origin.
Rhinovirus, parainfluenzae, RSV, and flu are common causes.
Chest pain, expectoration, fever, dyspnea, wheezing, and fatigue are symptoms.
Adenovirus may cause bronchitis and gastrointestinal issues.
Coughs can last for up to three weeks after other symptoms resolve.

Secondary Bacterial Infections in Bronchitis

Secondary bacterial infections are rare (5-10% of bronchitis cases).
H. influenzae, S. pneumoniae, and S. aureus are common bacterial causes of secondary infections.

Bronchitis Diagnosis

Usually clinical.
Chest X-rays are typically normal.
Antibiotics are typically not needed.
Use if secondary bacterial infection is present and tested as such.

Pneumonia

Inflammation of alveoli of lung parenchyma with consolidation and exudation.
Symptoms include cough (at first dry, later with sputum), pleuritic chest pain, and purulent sputum production; Fever.

Community-Acquired Pneumonia

An infection of the lung parenchyma in non-hospitalized or long-term care facility residents.
Common causes include S. pneumoniae (60-70% of CAP cases), H. influenzae, Moraxella, K. pneumoniae (Friedlander's bacillus), chlamydia pneumonia, and S. aureus.

Nosocomial Pneumonia

Hospital-acquired pneumonia that arises 48 to 72 hours after endotracheal intubation.
Risk factors include mechanical ventilation.
Bacterial causes are varied. More frequent use of anaerobes, enterobacteriaceae, gram-negative rods, acinetobacter, or pseudomonas species and MRSA.

Streptococcus pneumoniae

Gram-positive diplococci.
Often causes CAP.
“Typical” symptoms include malaise, shaking chills, fever, rusty sputum, pleuritic chest pain, cough.
Lobar infiltrate on chest x-ray.
25% develop bacteremia.

Atypical Pneumonia

Caused by atypical microorganisms (mycoplasma, chlamydia, legionella).
Usually less severe symptoms than typical pneumonia.
Usually non-productive cough without consolidation.
Often occurs at the initial stages.
Distinguishing features include time of onset or presence of extra-pulmonary symptoms (e.g. anemia, rashes, headache, sore throat).

Other Bacterial Pneumonia

Causative bacteria such as anaerobes, klebsiella, morexella catarrhalis, and Staph are possible causes.
Often associated with aspiration pneumonia, skin disease, and IVDU.

Viral Pneumonia

Common in children (viral causes most common).
RSV, influenza, and parainfluenzae infections are common causes in all ages; with flu being most common in adults.
Secondary bacterial infections can occur (post-influenza pneumonia).
Common bacterial causes are S. pneumo and staph aureus.

Investigations for Pneumonia

Blood cultures, respiratory specimens (for viruses, chlamydia, mycoplasma), urine tests for legionella and pneumococcal antigen testing, sputum culture with gram stain, bronchoalveolar lavage, and pleural fluid analysis.

Infiltrate Patterns

Lobar, patchy, or interstitial patterns on chest X-ray.
Certain patterns are strongly indicative of specific diseases.

COVID-19

Novel coronavirus causing a global pandemic.
Symptoms include fever, dry cough, tiredness, aches, pains, sore throat, diarrhea, conjunctivitis, headache, loss of taste or smell which often occurs without accompanying nasal congestion and runny nose, rash on skin, or discoloration of fingers or toes.
Serious symptoms can be rapid deterioration, shortness of breath, chest pain, pressure, or speech and movement loss.
Laboratory features such as lymphopenia and elevated D-dimer may occur with Covid19 pneumonia.

Pneumonia Management

Based on patient characteristics, including comorbidities and whether they have been previously hospitalized or are immunocompromised.
Choice of antibiotic can depend on various factors.

Pneumonia Prevention

Smoking cessation.
Influenza vaccination per ACIP recommendations, including inactivated vaccine for people over 50 and those at risk for influenza complications, and intranasal live, attenuated vaccine for people 5–49 years old without chronic underlying disease.
Pneumococcal vaccination for those at high risk.

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Description

Test your knowledge on the various microorganisms associated with respiratory infections. This quiz covers key facts about pathogens such as M. Catarrhalis, as well as their roles in chronic otitis media and community-acquired pneumonia. Understand the importance of timely antibiotic treatment and the characteristics of different viral and bacterial agents.