Untitled Quiz

Upper Respiratory Tract and the Lung

• Course Objectives: Students will understand the pathologic changes in respiratory diseases, and the role of genetics, environment, and socioeconomic factors. Students will learn to diagnose likely causes of illness.

Respiratory Tract

• Structure: The respiratory tract includes the nasal cavity, pharynx, larynx, trachea, primary bronchi, and lungs, progressing from upper to lower respiratory portions.

Lung Diseases

• Categories: Obstructive and restrictive diseases, pulmonary vascular diseases, pulmonary infections, pulmonary neoplasia (tumors), and diseases of the pleura.

Lesions of the Upper Respiratory Tract

• Acute Infections: Acute rhinitis, acute sinusitis, acute tonsillitis, acute pharyngitis, acute epiglottitis, and acute laryngitis.
• Nasal Polyps: These are growths in the nasal passage.

Acute Rhinitis

• Definition: Inflammation of the nasal mucosa.
• Types: Common cold (caused by viruses like corona, rhinoviruses, influenza, &RSV) and Allergic rhinitis (type 1 allergic reaction).
• Viral Phase: Virus attaches to cell surfaces, enters cells reproducing, causing inflammation, edema, and congestion.
• Bacterial Phase: Invasion of bacteria leads to typical inflammation.

Acute Sinusitis

• Location: Inflammation of maxillary sinuses.
• Causes: S. pneumoniae or S. aureus.
• Complications: Excess mucous, purulent discharge, and potential spread to the brain.

Acute Tonsillitis

• Cause: Streptococcus hemolyticus (bacteria).
• Types: Catarrhal (enlarged and red tonsils). Follicular (pus over tonsil tissue). Membranous (pus forms a membrane).

Acute Pharyngitis

• Cause: EBV and adenovirus (most common, 70%). Beta-hemolytic streptococci (30%).
• Complications: Retropharyngeal abscess and Adenoid hyperplasia (enlarged adenoids), leading to an adenoid face (characteristic facial features).

Acute Epiglottitis

• Cause: H. influenzae.
• Symptoms: Rapid onset, pain, and airway obstruction (potentially fatal).
• Prevention: Vaccination reduces incidence.

Acute Laryngitis

• Causes: Inhalation of irritants (chlorine) or agents causing the common cold..
• Rare Forms: Tuberculous laryngitis (infected sputum) and diphtheric laryngitis (exotoxin-induced pseudomembrane formation).

Diphtheric Laryngitis

• Affects: Children (2-5 years)
• Rarity: Rare due to vaccination.
• Cause: Corynebacterium diphtheriae.
• Symptoms: Exotoxin causes mucosa necrosis and membrane formation, leading to potential life-threatening complications (like asphyxia).

Nasal Polyps

• Cause: Recurrent nose infections lead to mucosa thickening.
• Structure: Located in the middle turbinate, they're bilateral, rounded, gelatinous masses with a smooth surface, composed of loose edematous connective tissue covered by ciliated respiratory epithelium.

Upper Respiratory Tract Tumors

• Nose Tumors: Rare, can present at advanced stage. Benign (like sinonasal papilloma) or malignant (like squamous cell carcinoma and lymphomas).
• Nasopharyngeal Carcinoma: Viral oncogene (EBV, particularly in Chinese populations) is a contributing factor, more common in children and older adults.
• Laryngeal Tumors: Vocal cord polyps (in smokers and singers) are benign. Squamous papilloma (HPV) is benign but precancerous in adults. Carcinoma is malignant and common.

Laryngeal Tumors (more detail)

• Glottic Tumors: 70% of laryngeal cancers are in the glottis.
• Supraglottic Tumors: 25% are in the supraglottis.
• Subglottic Tumors: Only 5% are subglottic.
• Morphology: Appear as gray, rough plaques on the mucosa which may ulcerate.
• Most Common Type: 95% of laryngeal cancers are squamous cell carcinomas.
• Clinical Course: Tumors can interfere with vocal cord mobility, causing persistent hoarseness. Spread is less common in glottic tumors vs. supraglottic or subglottic cancers.
• Treatment: Surgery and radiation.

Causes of Epistaxis (Nosebleeds)

• Local: Trauma, tumors, nasal polyps.
• General: Hypertension, leukemia, hemorrhagic blood disorders, vitamin C/K deficiencies.

Normal Lung

• Right Bronchus: More vertical than left, so aspirated foreign bodies, vomit, and blood more often go to right lung first.
• Blood Supply: Pulmonary and bronchial arteries.
• Function: Exchange of gases in alveoli.

Alveoli

• Structure: Multiple, small air sacs.
• Wall Structure: Contain capillary endothelium, Type 1 pneumocytes (thin and covering 95% of surface),Type 2 pneumocytes (rounded, granular, surfactant producers), Pulmonary interstitium , and alveolar macrophages.
• Pores of Kohn: Perforations in alveolar walls, allow for fluid and bacteria passage.
• Surfactant: Layer beside alveolar cell membrane, crucial for normal lung function

Normal Respiratory Tree

• Bronchi to bronchioles to alveoli: The respiratory tree progresses in branching from larger to smaller airways.
• Bronchioles: Have no cartilage or submucosal glands.
• Epithelial changes: Becoming less columnar (simple, short, and thinner) as the airways branch to the smallest.

Atelectasis

• Types: Resorption (obstruction), Compression (passive collapse), Contraction (scarring).
• Causes of obstruction: Mucous plugs, foreign bodies, blood clots, and tumor blocks.
• Microatelectasis: Premature infants may suffer from weak respiratory action leading to atelectasis, due to surfactant deficiency.

Normal Structure:

• Diagrams and images included for structural understanding of the respiratory tract, lungs and associated elements

Historical notes

• There are mentions of vaccination contributing to reduced cases of some infectious forms.

Important Note:

This summary is based on the images provided. Medical professionals should be consulted for diagnosis and treatment.