VTNE Review: Common bird diseases

anatomy of the heart

• larger and is designed for rapid depolarization

• aortic arch is derived from the right not left

• designed for high performance

• heart disease is rarely recognized

clinical signs of heart disease

• listlessness

• ascites

• exercise intolerance

• cough

• dyspnea

• murmur or rhythm disturbance found on auscultation

• syncope

diagnosis of heart disease

• auscultation of the heart

• radiography

• ECG

• Echo

• ruling out any bacterial or viral causes of systemic disease

treatment of heart disease

• drugs used for other animals may be adapted for use in pet birds

• digoxin

• diuretics

• bronchodilators

• beta blockers

• ± pimobendan

• diet changes to prevent vitamin E, selenium, and amino acid deficiencies

hemorrhage

• related to trauma

• fractured beaks, broken nails, and injured blood feathers are the most common causes of bleeding in pet birds

clinical signs of hemorrhage

• bleeding (external)

• neurological dysfunction (if brain is involved)

• acute death

diagnosis for hemorrhage

• history of trauma to site of bleeding

• history of head trauma

• CBC and TP may indicate chronic blood loss from disease processes

treatment of external hemorrhage

• pressure to site will often be enough to stop the bleeding

• if bleeding is severe, electrocautery, chemical cautery, or ligation may be used once the bird arrives at the clinic

treatment of blood feather injury

• blood feathers are immature feathers that contain a large blood vessel that will bleed if broken or cut

• they will continue to bleed unless pulled from the feather follicle

• feather must be grasped close to the skin and pulled out to stop the bleeding

treatment for internal hemorrhage

• supportive measures including fluid therapy

• most cases of this type of hemorrhage will be found on necropsy

pericarditis and myocarditis

• seen infrequently in pet birds

• cause of both diseases is usually bacterial septicemia

arteritis

• reported in birds usually as a result of thrombosis from a resulting infection such as bumble foot

• not a common disease

anemia

• result of chronic disease or parasitism

• not common finding in pet birds

acute death related to stress

• seen especially in budgies or smaller birds

• related to excessive epinephrine release and in some cases of heart failure, aortic rupture, or both

describe digestive tract

• esophagus, found on right side of the neck contains the crop used for food storage

• from the crop, food passes to the proventriculus (glandular stomach), to the ventriculus (gizzard or grinding stomach), and then into the small intestine

• then the large intestine, the colon

• feces pass into the cloaca

signs of regurgitation (courtship behavior)

• seen regurgitating food

• usually a healthy appearing male bird

• no other signs of disease, normal appetite, normal feces

diagnosis of regurgitation

• gram staining of crop to rule out bacterial or fungal infection

• history of other breeding behavior

treatment of regurgitation

• frequent changes in toys and cage furniture

• avoidance of activities that stimulate behavior

• extending the daily period of darkness to reduce mating behavior

• hormone therapy

crop stasis

primary causes include:

• foreign objects

• infection

• atony from overstretching

• dehydrated food particles

• low environmental temperatures

• feeding food that separates in the crop

• overfeeding in older birds

clinical signs of crop stasis

• failure of the crop to empty in an appropriate time frame

• regurgitation of food

• history of ingestion of foreign body

diagnosis of crop stasis

• palpation of crop to rule out the presence of foreign bodies

• gram staining or culture and sensitivity for infectious agents

• ± radiology to rule out foreign objects

treatment of crop stasis

• stop feeding until crop motility returns to normal

• evacuate crop contents using a feeding tube and syringe

• lavage the crop by using warm saline and gentle massage to break down any impactions

• replace hand feeding diets with warm fluids to prevent dehydration until crop motility returns

• administer antibiotics based on culture and sensitivity

• foreign objects often may be removed with alligator forceps

crop burns

• occur in birds when owners feed diets that are heated to extreme temperatures

• primarily a result of using a microwave for heating the food

• if the food is not mixed well after heating, the very hot food may be placed into the crop, causing a severe burn

• damaged tissue will become necrotic and slough, often leaving a fistula in the crop

clinical signs of crop burns

• discolored areas in the skin over the crop

• leakage of food or fluid from the crop onto skin

• pain on palpation of the crop

• reluctance to eat

diagnosis of crop burns

• good examination of crop an surrounding tissue

• demonstration of a fistula opening in the crop

treatment of crop burns

• for severe burns: perform surgical debridement of the damaged area, with repair of fistulous opening

• for mild burns:

  • withhold food for several feedings

  • replace food with a balanced electrolyte solution

  • treat with antibiotics if needed

beak deformities

• malformed beaks are the result of trauma, malnutrition, improper hand feeding techniques, mite infestation, bacterial or viral disease, or liver dysfunction

• may result in an inability to eat properly and digestive problems

• mite infestation with Knemidokoptes may result in damage to the beak

clinical signs of beak deformities

• observation of uneven wearing of the beak

• malocclusion of the beak

• overgrowth of the beak

• history of trauma or signs of trauma: bite wounds, bruising of beak soft tissues, or disruption of the horny surface

diagnosis of beak deformities

• clinical chemistries, CBC to rule out nutritional disorders

• gram staining with culture and sensitivity- choanal slit

treatment of beak deformities

• permanent deformities may be partially corrected by corrective grinding using a Dremel

• early correction of malnutrition or calcium deficiency may result in some improvement

• fractures or damage to the horny beak can be repaired with medical acrylics

proventricular dilation disease (Macaw wasting disease)

• characterized by inflammation of both central and peripheral nervous tissues, with migration of lymphocytes and plasma cells into the nerve ganglia located in the proventriculus and other parts of the digestive system

• affects adult birds more than juvenile

• cause is the Borna virus

• transmission is bird to bird contact, feces, feather dust, and contaminated environments

clinical signs of macaw wasting disease

• weight loss

• regurgitation

• depression

• swollen abdomen, diarrhea

• passage of undigested seeds in feces (most important sign)

• neurological signs: ataxia, abnormal head movement, seizures, motor problems

diagnosis of macaw wasting disease

• history and clinical signs

• radiography: dilated proventriculus

• increased creatine phosphokinase concentration

• increase in barium transit time as seen on radiographs

• pro-ventricular or crop biopsy for typical histopathologic signs

• PCR test

treatment of macaw wasting disease

• no cure

• cyclosporine may be of use

• cyclooxygenase-2 enzymatic anti-inflammatory drugs may decrease symptoms

• affected birds should be isolated

enteritis

• common in pet birds

• diet change may result in loose stools

• one of the most common causes of diarrhea in the pet bird is a bacterial infection which is usually caused by gram negative organisms commonly found in the environment

• viral infections as well

clinical signs of enteritis

• anorexia

• diarrhea

• soiling of feathers around. thevent

• polyuria or polydipsia

• tenesmus (straining)

• fluffing

diagnosis of enteritis

• gram staining; culture and sensitivity

• ruling out other systemic diseases with serum chemistries, antibody-antigen titers, tests for toxins such as lead

• ruling out mycotic infections

• history of diet change, excessive external temperatures, etc

treatment of enteritis

• depends on the cause

• antibiotics should be based on gram staining and culture and sensitivity tests

• yogurt or probiotics should be fed to normalize intestinal bacteria

• SQ balanced electrolyte solutions should be given if needed

• intestinal protectants such as kaolin and pectin may be of some use

cloacal prolapse

• can be caused by diarrhea, efforts by female birds to pass retained eggs

• eversion of the cloaca to the outside of the bird prevents urine and feces from being passed; allows the tissue to become contaminated, dry, and necrotic, and may become life threatening

clinical sign of cloacal prolapse

• tenesmus and diarrhea

• appearance of a pink to red blob of tissue from the cloaca

diagnosis of cloacal prolapse

physical exam and history

treatment of cloacal prolapse

• gently clean the exposed tissue

• reduce the swelling and lubricate the exposed tissue

• replace healthy tissue into the cloaca manually, and place a purse string suture around the vent to prevent recurrence

• sutures are removed in 5 to 7 days

• treat the diarrhea or cause for straining

• is tissue is necrotic when presented, surgical repair may be necessary

cloacal papillomas

• tend to occur most frequently in macaws, cockatoos, and some Amazon parrots

• can appear as protruding red masses from the vent or may be visualized only on internal examination of the cloaca

• should not be used for breeding

clinical signs of cloacal papillomas

• tenesmus

• soiled vent feathers

• hemorrhage in the vent area

• pasting of the vent area with feces, foul odor, and scalding of the area

diagnosis of cloacal papillomas

• visualization of the masses in the cloaca

• application of 5% acetic acid will turn abnormal tissue white

• biopsy

treatment of cloacal papillomas

• most will respond to cryosurgery, but rapid regrowth may occur

• autogenous vaccines may be prepared from removed tissues

hepatitis

• at least 80% of the liver must be damaged for clinical signs to occur, so can be difficult to diagnose

• do not experience jaundice

• some frequent causes are bacterial infections, chlamydial infections, viral infections, hepatic lipidosis, and toxins

clinical signs of hepatitis

• weight loss

• anorexia

• weakness

• Pu/Pd

• ascites

• coagulopathy

• melena or green urates

diagnosis of hepatitis

• CBC

• bacterial cultures (from liver biopsy)

• serum chemistries (AST is found in high concentrations; creatine kinase)

• bile acid level >120

• radiography: identify hepatomegaly and ascites

• US: may be useful in larger birds for localization of hepatic lesions such as granulomas or neoplasms

• liver biopsy

• chlamydia or viral serology

treatment of hepatitis

• lactulose is given orally to reduce ammonia levels

• colchicine may aid in limiting fibrosis of the liver

• eliminate the underlying cause of disease if possible

• supportive care:

  • oxygen therapy

  • fluids

  • removal of ascetic fluids to aid in breathing

  • IV dextrose

  • colloid administration

• diet therapy:

  • hand feeding with protein restricted diet

  • vitamin therapy, especially A, D, E, K, and B complex

clinical signs of intestinal parasites

• weight loss, depression

• diarrhea, melena

• bowel obstruction (Ascaridia)

• debility

• feather picking (giardia)

diagnosis of intestinal parasites

• fecal floatation

• direct smear, when it is necessary to identify the organism

• clinical signs

treatment of intestinal parasites

• Ivermectin

• Metronidazole

• Praziquantel

• cleaning up the environment

• removal of the bird from the source of infection

Ascaridia

Capillaria

Cestodes

Cryptosporidium

Eimeria

Giardia

Isospora

Sarcocystis falcatula

Sternostoma tracheacolum

what is the proper order for treating crop stasis in a baby bird?

flush the crop with warm saline, and then refill the crop with a balanced electrolyte solution

on finding papillomas in the cloaca of a blue and gold macaw, the veterinarian should tell the owners what?

this disease is treatable but they should not be used for breeding

what food is most likley to cause loose stools if added to a bird’s diet?

watermelon

what clinical chemistry test is useful for diagnosis of liver disease?

ALT, AST, and bile acids

the intestinal tract of the bird contains primarily what type of bacteria?

gram positive

true or false: cloacal polyps should be treated before using the bird for breeding

false, they should not be used for breeding

this organ is the glandular stomach of the bird

proventriculus

what is the most common disease associated with the thyroid gland?

iodine deficiency, resulting in formation of goiter

clinical signs of hyperthyroidism

• dyspnea

• characteristic squeaking noise on inspiration

• regurgitation or repeated swallowing when eating

diagnosis of hyperthyroidism

• history of a diet low in iodine (all seed diet)

• the enlarged thyroid is usually not palpable

treatment of hyperthyroidism

• increase the level of iodine in the diet by oral administration of a dilute Lugol iodine solution via the water

• improvement in diet can be achieved by addition of vegetables that contain iodine through formulated pelleted diets that contain iodine

clinical signs of diabetes mellitus

• polyuria/ polydipsia

• weight loss in the presence of a voracious appetite

• depression, lethargy

diagnosis of diabetes mellitus

• persistent glycosuria

• serum glucose levels are persistently increased to >600 mg/dL

• serum glucagon levels should be obtained

treatent of diabetes mellitus

• supportive care: fluids, hand feeding, correction of electrolyte disorders

• a serial blood glucose curve should be performed

• insulin therapy should be instituted; twice daily injections

• addition of a high fiber diet to decrease postprandial hyperglycemia should be considered

goiter is a common problem in parakeets because of what?

a seed diet low in iodine

compared with mammalian thyroid glands, which type of cell is missing from the avian thyroid gland?

C cells

lack of the hormone glucagon in the avian patient may result in what?

hypoglycemia

filoplumes

modified feathers present at the margins of the lids and function like eyelashes, for protection and tactile stimulation

Cryptophthalmos

• abnormal fusion of skin over globe and orbit

• seen in cockatiels

• reduces the palpebral fissure in both length and width

treatment of cryptophthalmos

• surgical removal of excess tissue has not been successful in curing this condition

• topical application of cortisone-containing eye ointment may help after surgery

periocular swelling

• may result from disorders of the eyelids, the infraorbital sinuses, or less commonly, the conjunctiva

• trauma to the periocular tissue may also cause swelling

clinical signs of periocular swelling

• eyelids or periocular tissue will appear swollen and red or scaly

• palpebral fissure may be reduced and the nictitans may be prolapsed

• feather loss around the eye may be present

• facial swelling may be present with evidence of rubbing

• ± scabbing of tissues is seen

diagnosis of periocular swelling

• complete ocular exam

• skin scraping to rule out Knemidokoptes infection

• skin biopsy of necessary

• good dietary history

• gram staining or culture and sensitivity of the infraorbital sinuses to rule out bacterial infection

treatment of periocular swelling

• maintain adequate corneal lubrication with the use of ophthalmic ointments

• repair eyelid laceration is present

• vitamin A therapy may help some birds

• flush the sinuses; some may have to be trephined to remove debris

conjunctivitis

• caused by trauma, bacterial infections, viral infections, and vitamin A deficiencies

• organisms capable of causing it include Chlamydia, Mycoplasma, E. coli, Pseudomonas, Bordatella, Mycobacterium, and Streptococcus

signs of conjunctivitis

• hyperemia

• blepharospasm

• photophobia

• ocular discharge

• swelling

diagnosis of conjunctivitis

• culture and sensitivity of the conjunctiva and cornea

• corneal staining

• cytology of the conjunctiva

• viral serology or cultures to rule out systemic causes

treatment of conjunctivitis

• broad spectrum topical ophthalmic antibiotics

• oral or systemic antibiotics if respiratory disease or systemic disease is involved

• corticosteroids if conjunctivitis is nonsuppurative and if no corneal ulceration is present

cataracts

• frequently noted in long living psittacines

• may also be seen in response to trauma, nutritional deficiencies, and other ocular disorders

clinical signs of cataracts

• lens opacity identified visually

• owner may report vision loss

treatment of cataracts

• surgical removal of the lens if other intraocular disease is absent

• treatment of any related ocular disease if present

otitis externa

• diagnosed in pet birds

• usually related to a bacterial infection

clinical signs of otitis externa

• pruritus

• serous or purulent discharge with or without soft tissue swelling

treatment of otitis externa

topical antibiotics applied into the ear canal after cleaning (3 to 4 times daily)

“eyelashes” in the bird are actually what?

feathers

the color of a female cockatoo’s eye is what?

red

what is a vascular structure involved in nutritional support of the retina and may be seen using an ophthalmoscope?

pecten

bacterial isolates from most normal birds will contain mostly what type of bacteria?

gram positive