Uropygial Gland Disease Conditions

Basic Information

Definition

Disease conditions that affect the uropygial gland, a bilobed secretory gland located on the uropygium

Uropygial Gland Disease Conditions Normal appearance of the bilobed uropygial gland on this feather-picking parrot.

The uropygial area is located dorsally over the pygostyle, on the midline, at the base of the tail. Secretions of this gland are an important component in maintaining feathers’ condition.

Synonyms

Preen gland, oil gland

Epidemiology

Species, Age, Sex

All species that have a uropygial gland and all ages and both sexes can be affected by uropygial gland disease presentations.

Genetics and Breed Predisposition

None specific, but certain avian species (e.g., Amazon parrots, hyacinth macaws) do not have a uropygial gland; therefore, they would not be susceptible to disease conditions associated with this gland.

Risk Factors

• Trauma to uropygial gland

• Self-mutilation/feather/picking around the gland

• Impaction of the gland

• Infectious cause (e.g., bacterial)

• Glandular or ductular neoplasia

• Nutritional deficiencies (e.g., vitamin A)

Associated Conditions and Disorders

• Poor feather condition

• Inability of feathers to become water resistant

• Self-trauma and/or mutilation to the uropygial gland area

Clinical Presentation

Disease Forms/Subtypes

• Trauma to the gland

• Neoplasia of glandular and/or ductal tissue

• Impaction of the gland

• Granuloma/abscess of the gland

History, Chief Complaint

• Nonspecific

• Excessive preening over the caudal dorsal surface of the back

• Poor feather quality

• Water birds unable to maintain their bodies at proper level on the water surface

• Bleeding in area around uropygial gland

• Large mass in area around uropygial gland

Physical Exam Findings

• Asymmetric lobes of the uropygial gland

• Large mass incorporating all or part of the uropygial gland

• Necrotic tissue of the uropygial gland

• Feather loss and blood around the area of the uropygial gland

• Observation of the patient compulsively irritating and traumatizing the uropygial gland

Etiology and Pathophysiology

• The uropygial gland, often referred to as the oil or preen gland, is an epidermal holocrine gland localized on the uropygium of most birds. It is composed of two lobes separated by an interlobular septum and covered by an external capsule. A dorsocaudally oriented papilla contains one, two, or multiple ducts and a tuft of down feathers at the openings. The nerve supply of the gland has both a medullar and a sympathetic origin. The gland is vascularized by branches of the caudal artery.

• Composition of avian uropygial gland secretions is very complex and may vary with species, gender, season, diet, and hormonal regulation. The secretion is a complex mixture of ester waxes, fatty acids, lipids, and wax alcohols. Secretions are spread among the plumage by preening. Contact of the beak with the papilla induces a flow of secretion.

• Possible roles of uropygial gland secretions:

Antimicrobial activity against feather-degrading bacteria and fungi

Antiabrasive effects to prevent feather barbules from breaking and to maintain plumage in good condition when the feathers are drawn through the bill during preening

As protection against feather-degrading ectoparasites such as feather lice

Hydrophobic properties, which have a role in plumage waterproofing in some species

Conversion of provitamin D to vitamin D by ultraviolet light and ingestion by further preening

Sex-linked changes in the ultraviolet appearance of the plumage

Production of pheromones

Excretory functions of several pesticides and pollutants

The fact that some bird species lack a preen gland suggests that preen oil is not universally important, or that they may use alternative strategies for feather maintenance.

Diagnosis

Differential Diagnosis

• Glandular metaplasia and hyperkeratosis due to hypovitaminosis A

• Neoplasia: adenoma, adenocarcinoma, squamous cell carcinoma, papilloma

Uropygial Gland Disease Conditions Large tumor of the uropygial gland in a parakeet. Surgical excision often is incomplete and recurrence is common; aggressive radiation offers a good follow-up option after removal of the bulk of the mass.

• Abscessation, adenitis

• Impaction

• Granulomas: fungi, foreign bodies

• Trauma, rupture of the gland, chronic ulcerative dermatitis of the uropygial and periuropygial area

Initial Database

• Complete blood count (CBC): in most cases unremarkable; slight leukocytosis or monocytosis may be observed in cases with inflammation or secondary infection

• Plasma biochemistry panel: no specific biochemistry abnormalities noted

• Cytologic examination/cultures: Cytologic examination can be performed on gland secretions or ulcerations. The main purpose is to determine whether an infection is present with inflammatory cells and bacteria (monomorphic intracellular) or neoplasia (neoplastic cells present). Culture and sensitivity should be performed as appropriate.

Advanced or Confirmatory Testing

Histopathologic examination: tissue biopsy is essential to confirm neoplasia and to characterize the tumor type (see Tumors). Biopsy is useful to differentiate neoplasia from infectious or granulomatous processes.

Treatment

Therapeutic Goal

Resolution of the disease condition and return of normal function of the uropygial gland

Acute General Treatment

• Treatment of a uropygial gland problem will depend on the diagnosis.

• Nursing care

Digital pressure in cases of impacted, abscessed, or metaplastic glands may be helpful in exuding the contents. Application of hot compresses may help in liquefying the content before expulsion.

Wound care and cleaning are necessary if ulceration or erosion is noted. Adherent dressings (e.g., 3M Tegaderm, 3M Tegaderm-Foam-Adhesive-Dressing, 3M Tegaderm-Hydrocolloid-Thin-Dressing [3M, St Paul, Minn]) should be considered whenever possible with an infected or extensive wound in this area. Treatments that can be used alone or in combination with surgery are described later.

• For impacted uropygial glands, an incision over the affected lobe(s) with subsequent removal of the impacted material; the incision should be left to heal by secondary intention

Chronic Treatment

• Systemic chemotherapy

• Topical chemotherapy (e.g., 5-fluorouracil application)

• Intratumoral chemotherapy (e.g., carboplatin, cisplatin)

• Radiation therapy involves administration of ionizing radiation to tumor cells. Strontium 90 ophthalmic applicator therapy has been used to apply 100 Gy in the treatment of uropygial tumors.

• Cryotherapy has several advantages: minimal systemic effects, minimal postoperative bleeding, and safe repeat treatments.

Drug Interactions

• Any chemotherapy and radiation therapy should be administered by a trained oncology specialist. Chemotherapeutic and radiation therapeutic agents present a serious health hazard for people around the patient during treatment application.

• If chemotherapeutic and radiation therapy is not administered correctly and at the proper dose, the patient may die or suffer permanent injury.

Possible Complications

• Death from blood loss during surgery to remove the uropygial gland

• Lack of treatment response

• Recurrence of uropygial disease condition

• Death or permanent injury due to selected treatment protocol

Recommended Monitoring

• Monitor diseased uropygial gland for treatment response.

• Repeat CBC and plasma chemistry panel when radiation or chemotherapy is being used.

• Analgesic/antiinflammatory medication is required in cases of suspected pain and inflammation.

• Monitor appetite, fecal output, and behavior during treatment period, until the disease condition has resolved.

Prognosis and Outcome

• Uncomplicated cases have a good prognosis.

• The prognosis degrades as the number of complications increases, especially in cases in which neoplasia has been diagnosed or severe trauma to the gland has occurred.

Pearls & Considerations

Comments

• Some avian species (e.g., some macaw species, Amazon parrots) do not have a uropygial gland.

• With many avian species, the uropygial gland may be removed without adverse consequences.

• The uropygial gland is very important for water birds to maintain the health and condition of their feathers while swimming.

• The uropygial gland is vascular; care should be taken when excising the gland to reduce hemorrhage associated with removal.

• A definitive diagnosis is necessary to establish a proper treatment protocol for the patient.

Prevention

• Routinely check the uropygial gland as part of the physical examination.

• Provide a well-balanced diet.

Client Education

• Inform the owner of the location and function of the uropygial gland.

• Discuss that it is normal for birds to preen and rub their head in the area of the gland.

• Bleeding, loss of feathers, and gross enlargement of the gland or areas around the gland are abnormal.

Cross-References to Other Sections

Tumors

AUTHORS: HUGUES BEAUFRÉRE and W. MICHAEL TAYLOR

EDITOR: THOMAS N. TULLY, JR.