Session 23 Upper Respiratory Tract Pathology

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Lecture Notes

Session 23: Upper Respiratory Tract Pathology

Alex Simon (MD)

Learning tasks

At the end of this session, students are expected to be able to:

Explain acute infections of the upper respiratory tract.

Explain chronic infections of the upper respiratory tract.

Explain tumors of the upper respiratory tract.

Introduction

Acute infections of the upper respiratory tract are among the most common infections of humans.

Most frequently manifesting as the “common cold.”

Most of these infections occur in the fall and winter.

They are self-limiting.

The clinical features are

Nasal congestion accompanied by watery discharge.

Sneezing.

Scratchy, dry sore throat.

A slight increase in temperature (˃ young children).

Introduction cont…

The most common pathogens are rhinoviruses.

Other pathogens are

Coronaviruses.

Respiratory syncytial viruses.

Parainfluenza & influenza viruses.

Adenoviruses.

Enteroviruses.

Secondary bacterial infection particularly bacterial otitis media and sinusitis can occur.

Staphylococci, Streptococci, and Haemophilus influenzae are the commonest causative bacteria.

Rhinitis

An inflammation of the nasal mucosa

It is the most common nasal disorder.

The condition may be either acute or chronic.

Aetiology of acute rhinitis are

Infective.

Allergic.

Acute rhinitis

Infectious rhinitis

It is usually of viral origin.

Rhinoviruses, adenoviruses.

Inflammation of surface epithelial cells.

Followed by exudation of fluid and mucus from the damaged surface (‘runny nose’).

Later, submucosal oedema occurs.

Lead to a partial blockage of the nasal airways.

Acute rhinitis cont…

Allergic rhinitis (‘hay fever’)

It is a type I (IgE-mediated) hypersensitivity reaction to inhaled materials such as grass and pollens.

Producing a mixed serous-mucous exudate and submucosal oedema leading to nasal blockage.

Eosinophils are prominent in the inflammatory infiltrate.

Chronic rhinitis

Caused by repeated attacks of acute rhinitis,

Often develop a secondary bacterial infection.

It may result in the development of nasal polyps.

Microscopically: Oedematous tissue with scattered infiltrate of chronic inflammatory cells.

Nasal polyps

Pedunculated grape-like masses of tissue.

Prolonged chronic inflammation causing polypoid thickening of the mucosa.

May be allergic or inflammatory.

Frequently bilateral.

Middle turbinate is the common site.

Macroscopically

Smooth surfaced, creamy, semi-translucent, ovoid masses.

Sinusitis

It is an inflammation of the paranasal sinuses.

Maxillary sinuses are the commonest site.

Usually secondary to acute or chronic rhinitis.

Rhinitis usually results in the inflammation of the sinus linings.

Swelling of the mucosa around the drainage foramen.

Sinuses are filled with mucus secretions (mucocele).

Secondary bacterial infection causes alteration of the static fluid from seromucous to purulent (empyema).

Sinusitis cont…

In severe cases, the infection may spread to the meninges causing meningitis.

Orbital cellulitis may also complicate acute sinusitis.

Acute sinusitis may become chronic due to

Incomplete resolution.

Damage to the mucous membrane.

Thickened & inflamed mucosa and persistent fluid accumulation in the sinuses seen in chronic sinusitis.

Acute pharyngitis

Manifests as a sore throat.

Mild pharyngitis with minimal physical findings frequently accompanies a cold.

It is the most common form of pharyngitis.

Marked hyperemia and exudates is seen in severe form.

Caused by β-hemolytic streptococcal and adenovirus infections.

Acute pharyngitis cont…

Infectious mononucleosis caused by Epstein-Barr virus is an important cause of pharyngitis (kissing disease).

Severe form of acute pharyngitis is associated with Streptococcal tonsillitis.

Tonsillitis

Caused by Staphylococci or Streptococci.

May be acute or chronic.

There is an enlargement and redness of tonsils.

Acute tonsillitis may progress to acute follicular tonsillitis.

Acute tonsillitis is associated for development peritonsillar abscess (quinsy).

Chronic tonsillitis is caused by repeated attacks of acute tonsillitis.

Tonsils become small and fibrosed.

Peritonsillar abscess (Quinsy)

Peritonsillar abscess or quinsy occurs as a complication of acute tonsillitis.

The causative organisms are Staphylococci or Streptococci .

Acute pain in the throat, trismus, difficulty in speech and inability to swallow.

Glands behind the angle of the mandible are enlarged and tender.

Retropharyngeal abscess

An abscess in the soft tissue between the posterior wall of the pharynx and the vertebral column.

Occurs due to infection of the retropharyngeal lymph nodes.

It is more common in debilitated children.

A chronic form of the abscess in the same location is seen in TB of cervical spine (cold abscess).

Acute bacterial epiglottitis

Predominantly affecting young children.

Caused by Haemophilus influenzae.

Pain and airway obstruction are the major findings.

The onset is abrupt.

Failure to maintain an open airway for a child with this condition can have fatal consequences.

Vaccination against Haemophilus influenzae has greatly decreased the incidence of this disease.

Acute laryngitis

It is an acute inflammation of the larynx.

May be caused by

Infectious agents (viruses, bacteria).

Inhalation of irritants (cigarette smoke)

Mechanical factors (endotracheal intubation)

Overuse of the voice.

Two uncommon but important forms of laryngitis

Tuberculous.

Diphtheritic.

Acute laryngitis

Tuberculous laryngitis occurs when infected sputum is coughed up.

Diphtheritic laryngitis occurs when Corynebacterium diphtheriae is inhaled and implants on the mucosa of the upper airways.

Sequelae of acute laryngitis

Resolution.

Spread of infection may occur throughout the respiratory tract.

Airway obstruction due to laryngeal oedema.

Acute laryngeal edema

It is an acute inflammatory condition causing swelling of the larynx.

Acute laryngeal oedema may occur due to

Trauma.

Inhalation of irritants.

Drinking hot fluids.

Infective in origin.

May lead to airway obstruction and death by suffocation.

Chronic laryngitis

Commonly seen in heavy cigarette smokers.

Permanent thickening of the laryngeal mucosa and submucosa.

With associated excess production of keratin (‘smoker’s keratosis’).

Dysplastic change in the basal layer can occur.

This is a predisposing factor in the development of squamous carcinoma of the larynx.

Laryngotracheobronchitis (Croup)

Life-threatening acute inflammation and obstruction involving the larynx, trachea and bronchi.

It usually affects young children aged 6 months to 3 years.

Typically caused by viral infection.

Parainfluenza virus is the most common cause.

Respiratory syncytial virus also may precipitate this condition.

Laryngotracheobronchitis (Croup) cont…

It is self-limited.

May cause frightening inspiratory stridor and harsh, persistent cough, a rising pulse rate, restlessness and cyanosis.

Occasionally, laryngeal inflammatory reaction may narrow airway resulting in respiratory failure.

Tumors of upper respiratory tract

Nasopharyngeal carcinoma.

Laryngeal tumors.

Benign tumors

Vocal cord nodules.

Laryngeal papillomas.

Malignant tumors

Squamous cell carcinomas of the larynx.

Nasopharyngeal carcinoma

Rare neoplasm that strong links to Epstein Barr Virus.

EBV replicates in the nasopharyngeal epithelium and causes transformation of epithelial cells into malignancy.

The three (3) histologic variants are

Keratinizing squamous cell carcinoma.

Nonkeratinizing squamous cell carcinoma.

Undifferentiated carcinoma

Most common and the one most closely linked with EBV.

Laryngeal tumors

These includes

Vocal cord nodules.

Laryngeal papillomas.

Squamous cell carcinomas of the larynx.

The most common presenting feature is hoarseness.

Vocal cord nodules (“polyps”)

Smooth, hemispherical protrusions.

Located most often on the true vocal cords.

Composed of fibrous tissue and covered by stratified squamous mucosa.

Can ulcerate from contact trauma.

These lesions occur commonly in

Heavy smokers.

Singers (singer’s nodes).

Result of chronic irritation or abuse.

Laryngeal papilloma

Squamous papilloma of the larynx is a benign neoplasm.

Usually located on the true vocal cords.

Caused by human papillomavirus (HPV) types 6 and 11, do not become malignant.

Forms a soft, raspberry-like excrescence.

Papilloma on the free edge of the vocal cord can ulcerate.

Laryngeal papilloma

Histologically

Multiple, slender, finger-like projections supported by central fibrovascular cores.

Covered by an orderly, typical, stratified squamous epithelium.

Carcinoma of the larynx

It most commonly occurs after age 40 years.

More common in men than in women.

Environmental influences are very important in its causation

Smokers

Alcohol

Asbestos exposure.

Human papillomavirus.

Carcinoma of the larynx cont…

Most of laryngeal cancers are typical squamous cell carcinomas.

Rarely, adenocarcinomas are seen (arising from mucous glands).

Usually the tumor develops directly on the vocal cords.

Squamous cell carcinomas of the larynx begin as in situ lesions.

Carcinoma of the larynx cont…

Later appear as pearly gray, wrinkled plaques on the mucosal surface, ultimately ulcerating and fungating.

Carcinoma of the larynx manifests itself clinically with persistent hoarseness.

The usual cause of death is infection of the distal respiratory passages or widespread metastases and cachexia.

Key points

The most common pathogen for common cold is rhinovirus.

Chronic rhinitis is associated with development of nasal polyps.

Peritonsillar abscess or quinsy occurs as a complication of acute tonsillitis.

Parainfluenza virus is the most common cause of laryngotracheobronchitis.

Vocal cord polys are seen in chronic smokers and singers.

Nasopharyngeal carcinoma is linked with Epstein-Barr virus (EBV).

Review questions

List five (5) microorganisms which cause common cold.

What are the features of acute tonsillitis?

Explain two (2) types of acute rhinitis.

What is croup?

List (4) risk factors for laryngeal carcinoma.

References

Kumar V. ; Abbas A. K. ; Aster J. C.;(2013): Robbins and Contran Pathologic Basis of Disease (9th Ed.) Elsevier Saunders, USA. Pg. 512-514.

Mohan H.;(2010): Text book of Pathology (6th Ed.) Jaypee Brothers Medical Publishers, India. Pg. 515-520.

Xiu P.;(2012): Crash Course Pathology (4th Ed.) Elsevier Saunders, USA. Pg. 87-89.

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Session 23 Upper Respiratory Tract Pathology

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