Introduction
Diseases of the head and neck affect organs around the head and neck. These organs include: the teeth & supporting structures; nose; pharynx; larynx; ear; salivary glands. We shall begin by discussing these diseases one after the other.
The teeth have several parts including the enamel; dentin; pulp chamber; cementum; periodontal ligament. While the teeth anchors to the jaw bones, the gingiva mucosa surrounds the teeth and the jaw bones.
The enamel-the outermost & visible part of tooth, is densely mineralized and acellular, hence, making it the most mineralized tissue in the body. The dentin is a fairly hard & special form of connective tissue below the dentin. The pulp chamber contains the nerve tissues, lymphatic vessels, and capillaries.
Between the outer wall of the pulp chamber and dentin are the odontoblasts, which help produce new dentin. Cementum-within the root of tooth anchors the periodontal ligament to the tooth. The periodontal ligament, therefore anchors the alveolar bone to the tooth.
Dental caries
This is the localized mineral breakdown of tooth structure by acid metabolic end products from bacteria in the mouth.
The mode of prevention include: standard oral hygiene & fluoridation of drinking water.
Gingivitis
Gingivitis is the inflammation of gingival mucosa surrounding the tooth. The cause includes build up of dental plaque (complex of oral bacteria, saliva protein, desquamated epithelium) & calculus (mineralized plaque).
Plaque containing bacteria ferment sugar-rich foods, which then releases acid metabolic by products that damage the enamel. Surrounding squamous epithelium becomes affected resulting in gingivitis.
Signs/symptoms: gingival erythema; edema; bleeding; abnormal soft tissue changes.
Therapy/prevention: brushing; flossing; regular dental visits.
Periodontitis
An inflammation of the cementum, periodontal ligament, & alveolar bone that may destroy the periodontal ligament and lead to loss of teeth.
Causes: poor oral hygiene, dental plaque; aggregatibacter actinomycetemcomitans; Porphyromonas gingivalis; prevotella intermedia; AIDS; Crohn disease; leukemia; neutropenia.
Complications: Pulmonary and brain abscesses; infective endocarditis.
Buccal mucosa fibroma
This is nodular lesion along the bite line or gingivodental margin of the mouth. It is the commonest tumor-like lesion of the oral cavity.
Histologically, it consists of a surrounding fibrous tissue lined by squamous mucosa, with a few inflammatory cells.
Treatment: surgical excision
Aphthous ulcers (Canker sores)
These are painful single, multiple superficial erythematous ulcerations with a pale central exudative membrane. They may heal spontaneously within a few days, persist for weeks or become recurrent.
Recurrent attacks may be either due to celiac disease or inflammatory bowel disease.
Glossitis
This is the inflammation of the tongue or atrophic changes seen during vitamin deficiencies. In atrophic changes, tongue papillae under atrophy with thinning of mucosa, thereby exposing underlying capillaries; macroscopically the tongue is diffusely red.
Atrophic changes are seen in association with Plummer Vinson or Paterson-Kelly syndrome (iron-deficiency anemia + esophageal dysphagia+ glossitis); vitamin deficiencies including B12, B3, B2, B6; iron deficiency anemia.
Inflammation with ulceration may occur due to: corrosive chemicals; inhalation burns; syphilis; dental carries; ill-fitting dentures.
Acute herpetic gingivostomatitis
This is an inflammation of the oral cavity caused by herpes simplex virus -1 infection. It occurs in children 2 to 4 years of age.
Signs/Symptoms: vesicles/bullae and ulcerations throughout oral cavity; lymphadenopathy; fever; anorexia; irritability.
Macroscopically, the vesicles contain serous fluid which may rupture into painful shallow ulcers. Microscopically, Tzanck test on vesicle fluid reveals eosinophilic intranuclear viral inclusions or multinucleate polykaryons.
Recurrent herpetic stomatitis
This occurs by reactivation of the HSV-1 at site of primary infection, or neighboring mucosa. It affects areas including: gingiva; buccal mucosa; hard palate; nasal orifices and common among adults with milder symptoms and short duration.
Signs/symptoms: group of small vesicles with ulcerations in a particular area of oral cavity.
Predisposing factors: allergies, pregnancy; immunosuppression; cold; trauma; upper respiratory tract infection; menstruation.
Thrush (oral pseudo-membranous candidiasis)
A fungal infection of the oral cavity, especially by Candida albicans.
Signs/symptoms: superficial, gray to white inflammatory membrane. This membrane can be scrapped off to reveal an erythematous inflammatory base.
Predisposing factors: broad-spectrum antibiotics; AIDs; neutropenia; bone marrow transplant recipients; chemotherapy; diabetes mellitus.
Hairy Leukoplakias
These are white, hairy patches of thick mucosa epithelium, usually on the lateral border of the tongue. Unlike candidiasis, this oral lesion can’t be scrapped off.
Predisposing factors: HIV infection (80% of cases); chemotherapy; transplant patients.
Leukoplakia and erythroplakia
These are premalignant lesions identified after pathologically excluding other potential differential diagnosis. Leukoplakias appear as white patches or plaques with defined borders in the oral cavity. Erythroplakia are red, velvety eroded lesions within the oral cavity.
Predisposing factor(s): tobacco use. Both lesions are found commonly in men between 40 & 70 years.
Head and Neck Squamous Cell Carcinoma (HNSSCs)
This is the most common malignant cancer of the head and neck. Its locations include: ventral surface of tongue; gingiva; floor of the mouth; lower lip; soft palate.
Predisposing factors: family history; tobacco use; HPV; sunlight; chronic mucosa irritation; chewing of beta quid and paan (in India & parts of Asia).
Signs/symptoms: firm, pearly plaques or irregular, rough mucosal thickening. Overtime the lesion expands in mass with ulcerations and irregular border.
Local metastasis is to the cervical lymph nodes, while distant metastases are to the mediastinum, lungs, liver, bones.
We now turn to discuss diseases of the upper airways, affecting especially the nose, pharynx & larynx.
Infectious rhinitis (common cold)
This is the inflammation of the nasal mucosa, resulting in the production of profuse catarrhal discharge. Remission occurs in a week.
Causes: adenoviruses; rhinoviruses; echoviruses.
Signs/symptoms: red, edematous and thick nasal mucosa; narrow nasal cavities; enlarged nasal conchae.
Complication: nasopharyngeal tonsilitis (suppurative exudate) due to secondary bacterial infection.
Allergic rhinitis (hay fever)
An IgE-mediated immune reaction affecting the nasal mucosa triggered by allergens.
Predisposing factors: plant pollens; animal furs; dust mites; fungi.
Signs/symptoms: red, edematous nasal mucosa; mucus hypersecretion; intermittent sneezing.
Nasal polyps
These are protrusions on the nasal mucosa in length of up to about 4cm. The cause includes recurrent rhinitis.
Microscopically, polyp mucosa is edematous, with hyperplastic enlarged mucosa gland; stroma infiltration of neutrophils, eosinophils, plasma cells.
Complication: impairment of sinus drainage when multiple and large, with secondary bacterial infections.
Chronic rhinitis
A consequence of recurrent attacks of acute nasal mucosal infection by microbes or allergens.
Microscopically, mucosa is ulcerated or desquamated with variable amounts of neutrophils, lymphocytes, and plasma cells.
Complications: secondary bacterial infection, especially in those with deviated nasal septum or large/multiple polyps.
Sinusitis
An inflammation of the paranasal sinuses either following an acute rhinitis or chronic rhinitis. Sinusitis may be acute or chronic, and both processes impair mucus drainage contributing to further complications.
Predisposing factors for severe chronic rhinitis include diabetes. Diabetes exposes the patient to recurrent fungal infections (mucormycosis).
Complications: osteomyelitis of cranial vault; thrombophlebitis of dural venous sinus.
Nasopharyngeal carcinoma
It is the cancer of the Nasopharyngeal epithelium. In some African countries manifestation is in childhood, in contrast to southern China where it occurs in adulthood.
Predisposing factors: EBV infection; smoking; fermented foods; salted fish; inhaled chemicals.
Microscopically, squamous epithelium may show well differentiated/poorly differentiated squamous cancer cells, or undifferentiated cancer cells surrounded by lymphocytes.
Metastasis is to the cervical lymph nodes and radiation therapy is a standard treatment offered to affected patients.
Laryngoepiglottitis and laryngotracheobronchitis (croup)
These are inflammatory reactions affecting the larynx, and require special attention because they are common among children.
Laryngoepiglottitis affects the epiglottis and vocal cords. Causes include: respiratory syncytial virus; β-streptococci bacteria; Haemophilus influnzae. mucosal exudates and edema cause laryngeal obstruction that requires emergency care.
Laryngotrachobronchitis affects both the larynx and trachea. An important cause includes the parainfluenza virus. Patients present with stridor due to airway inflammation.
Other predisposing factors for laryngitis in adults include reflux esophagitis; chemical fumes; microbial infections & allergies.
Acute and chronic otitis media
These are infections affecting the middle ear and common among children. Acute otitis media occur following viral infections. Secondary bacterial infections by Moraxella catarrhalis, S. pneumoniae, H. influenzae are also complicit.
Chronic otitis media occur following recurrent acute infections, & infections by other bacteria such as S. aureus, P. aeruginosa, fungus,
signs/symptoms: fever, ear irritability, conductive hearing loss
Complications of chronic otitis media: ear drum perforation; necrotizing otitis media (by P. aeruginosa in diabetics); temporal cerebritis & abscess.
Cholesteatoma
A cystic lesion of about 4cm in diameter, containing cell debris and lined internally by keratinizing squamous epithelium, or metaplastic mucus secreting epithelium. It may also contain cholesterol, & is a sequela of chronic otitis media and eardrum perforation.
Otosclerosis
This is a fibrous ankylosis and bony overgrowth of the stapes footplate anchoring the oval window, resulting in immobilization. This condition usually affects both ears and common in young and middle age groups.
Causes: familial (autosomal dominant pattern); uncoordinated processes of bone resorption and formation.
Signs/symptoms: conductive hearing loss
Branchial cyst, Thyroglossal duct cyst
Branchial cyst is a benign cyst between 2 to 5cm in diameter, on the upper lateral region of neck along the sternocleidomastoid muscle. These cysts are remnants of the second branchial arch, & are usually seen in young adults btw 20 & 40 years of age.
It is covered by a fibrous wall which contains lymphoid tissues and lined by stratified squamous or pseudostratified columnar epithelium. The cyst may contain cell debris or fluid. Treatment requires excision.
The thyroglossal duct cyst is benign cyst, lined by either stratified squamous or pseudostratified columnar epithelium. It is a remnant of the thyroglossal duct, & located at the anterior region of neck. The diameter of the cyst is btw 1 and 4cm. Treatment requires excision.
Xerostomia
This condition refers to dry mouth due to decreased production of saliva.
Causes: radiotherapy; Sjogren syndrome (+ dry eyes); anticholinergics; antipsychotics; antidepressants; diuretics; muscle relaxants; analgesics; antihypertensive and sedative agents.
Signs/symptoms; dry oral mucosa; atrophy of tongue papillae; tongue fissuring, & ulceration; dysphagia and difficulty speaking.
Complications: candidiasis; dental caries.
Sialadenitis, mucocele
Sialadenitis is the inflammation of the salivary glands. Causes may include virus, bacterial, trauma, or autoimmune.
Mucocele is a cystic lesion resulting from blockage or rupture of the salivary gland. It is usually caused by trauma and found in all age groups. Lesion is lined by fibrous connective tissue and filled with mucus and macrophage. It presents as a fluctuant lower lip swelling and blue translucent hue.
Sialolithiasis & nonspecific bacterial sialadenitis
These are disorders that affect the tissues of the major salivary glands. Sialolithiasis is the obstruction of the salivary gland ducts by stones in the form of food debris or edema from an injury. This obstruction eventually results in a nonspecific bacterial sialadenitis.
Nonspecific bacterial sialadenitis is a complication of sialolithiasis and causes include Streptococcus viridans & S. aureus. Other predisposing factors include dehydration caused by the use of phenothiazine (antipsychotic).
Signs/symptoms: painful, unilateral salivary gland enlargement; purulent ductal discharge.