Transcript PowerPoint - Megaesophagus

Practical Internal Medicine
Megaesophagus
Wendy Blount, DVM
Nacogdoches, TX
Megaesophagus
The most common
esophageal disorder
in dogs and cats.
Cats Are Not Little Dogs
Speed of Esophageal Transit
• Dog – 75-100 cm/sec
• Cat – 1-2 cm/sec
Why??
• Striated muscle is faster than smooth
So What??
Eating fast causes more vomiting in cats – tube
feeding must be slow
Cats Are Not Little Dogs
Muscle Type
• Dog – entirely striated
• Cat – cranial 2/3 striated, caudal 1/3 smooth
So What??
Cisapride works on smooth muscle
Will work better on cats with megaesophagus
when compared to dogs
Megaesophagus - Definition
• Part or all of the esophagus is enlarged.
• Food is not properly conducted from the
mouth to the stomach.
• Affected pets may not get adequate
nutrition.
• Affected pets are at risk for aspiration
pneumonia, which can be life threatening.
• It can be part of a more widespread
disease or muscle weakness.
Megaesophagus - Etiology
Generalized Megaesophagus
Entire esophagus is affected
Localized megaesophagus
Usually proximal to obstruction
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Esophageal Stricture
Causes
• trauma
• caustic substance swallowed
• doxycycline
(Oreo)
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Esophageal Stricture
Causes
• trauma
• caustic substance swallowed
• doxycycline
(Oreo)
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Foreign body
Where are they most common?
•
thoracic inlet
•
base of the heart
(Dr. Weatherly’s Case)
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Parasites
•
Spirocerca lupi
Spirocirca lupi
Localized megaesophagus
Usually proximal to obstruction
Spirocirca lupi
Localized megaesophagus
Usually proximal to obstruction
Spirocirca lupi
Localized megaesophagus
Usually proximal to obstruction
Spirocirca lupi
Who Gets It?
• Dogs
How Do They Get It?
• Eating a beetle
Where else can lesions be?
• Aorta
• Stomach
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Vascular Ring Anomaly
• persistent right aortic arch (PRAA)
• ring by left subclavian artery and
brachiocephalic trunk
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Neoplasia
• Esophageal neoplasia
• Mediastinal mass – which tumors?
– Lymphosarcoma
– Thymoma
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Neoplasia
• Esophageal neoplasia
• Mediastinal mass – which tumors?
– Lymphosarcoma
– Thymoma
Megaesophagus - Etiology
Localized megaesophagus
Usually proximal to obstruction
Congenital
• Esophageal diverticulum – where?
• Base of the heart - breed?
• English Bulldog
Megaesophagus
- Etiology
Generalized
Megaesophagus
Generalized Megaesophagus
Localized megaesophagus
Usually proximal to obstruction
Generalized Megaesophagus
Two Onsets
• Congenital
• Acquired
What’s the Difference?
Prognosis
• Congenital – guarded
• Acquired – short term guarded; long term
potentially good, depending on the cause.
Generalized Megaesophagus
Two Types:
• Megaesophagus alone
• ME as part of a generalized myopathy,
neuropathy or junctionopathy
Why Do We Care?
If the underlying cause of weakness is not
addressed, the animal will not do well
Generalized Megaesophagus
What is Junctionopathy?
Disease of the myoneural junction
Most Common Junctionopathy
Myasthenia gravis
Who has diagnosed a case of myasthenia
gravis?
Generalized Megaesophagus - Alone
The
most common esophageal disease in dogs
Esophagitis
and cats is megaesophagus
Causes – two most common
• Idiopathic
• Myasthenia gravis
Other Causes
• Esophagitis
• Congenital
Generalized Megaesophagus - Alone
Esophagitis
Chronic inflammation can result in ileus
Causes of esophagitis:
• Gastroesophageal reflux
• Hiatal hernia
• Chronic GDV
Generalized Megaesophagus
Myasthenia gravis
• Auto-immune disorder
• Autoantibodies against Ach receptors
There are four kinds of MG
–
–
Congenital
Acquired Focal
•
–
–
Esophagus, pharynx/larynx, facial nerve
Acquired Generalized
Acquired Acute Fulminant
Generalized Megaesophagus
There are four kinds of MG
Why do we care??
Different Prognoses
• Congenital – poor
• Acquired Acute Fulminant – dismal
• Acquired Focal and Generalized
–
–
–
–
Long term potentially good
Most cases of acquired MG resolve within a year
Short term guarded
50% die of aspiration pneumonia during therapy
Generalized Megaesophagus
ME as part of generalized weakness
Causes:
• Congenital myopathy, neuropathy,
junctionopathy
• Hypothyroidism
• Hypoadrenocorticism
• Muscular dystrophy
• Dysautonomia – more common in cats
Generalized Megaesophagus
ME as part of generalized weakness
Causes:
• Immune mediated disease
– Systemic Lupus Erythematosis
– Dermatomyositis
– Polymyositis
•
•
Giant axonal neuropathy - GSD
Congenital myasthenia gravis
Generalized Megaesophagus
ME as part of generalized weakness
Causes:
• Hereditary myopathy of Labradors
• Lead toxicity
• Thallium toxicity
• Organophosphate toxicity
Vomiting, Regurgitation, Coughing
Time with respect to eating
Vomiting
•
Minutes to hours after eating
Regurgitation
•
Minutes to hours after eating
Coughing & gagging
•
•
Not related to eating
But can be precipitated by drinking water
Vomiting, Regurgitation, Coughing
Expulsion Process
Vomiting
•
Active – abdominal contractions
Regurgitation
•
More passive
•
Can be confusing – regurgitation can cause gagging and then
retching, and then vomiting
Coughing & gagging
•
After coughing
•
Can be confusing – productive cough can cause gagging and
then retching, and then vomiting
Vomiting, Regurgitation, Coughing
Premonitory signs
Vomiting
•
Salivation, pacing, licking lips, anxiety
Regurgitation
•
Salivation, exaggerated swallowing
Coughing & gagging
•
Elevated respiratory rate
Vomiting, Regurgitation, Coughing
Vomiting
Regurgitation
Coughing
Hardly digested to
liquid
Hardly digested to
liquid
White and foamy
Smell variable
May smell sour and
fermented
Not usually foul
smelling
Rarely has mucus
Often is slimy with
mucus
May contain mucus
or pus
Digested blood
suggests vomiting
Blood is rare
May be blood tinged
May contain bile
Never bile stained
Never bile stained
Clues in the History - ME
Signs of Aspiration Pneumonia
Coughing
Fever
Dyspnea
Cyanosis
Can have coughing without regurgitation
Coughing can be due to pressure of enlarged esophagus
on the trachea
SUSPECT MEGAESOPHAGUS IN AN OLDER DOG
WHO IS BOTH “VOMITING” AND COUGHING
Clues in the History - ME
Weight loss
Can be severe
Neurologic deficits – LMN Signs
Depressed spinal and cranial nerve reflexes
Large, easily expressed bladder
Constipation
Muscular abnormalities
Muscle atrophy with generalized weakness
Muscle pain with polymyositis
Clues in the History - ME
Signs of myasthenia gravis
Weakness worsens with exercise
Change in barking
Difficulty eating or swallowing
Weak or absent palpebral reflex – fatigues
Signs of hypoadrenocorticism
Vomiting and diarrhea (especially with blood)
Lethargy and weakness
Shock if severe
Clues in the History - ME
Signs of hypothyroidism
Obesity
Symmetrical alopecia
Dry eye
Pyoderma
Signs of lead toxicity
Vomiting and diarrhea
Seizures, dullness, behavior changes, apparent
blindness
Clues in the History - ME
Signs of immune mediated disease
Muscle pain - polymyositis
Joint pain or swelling - polyarthritis
Anemia - IMHA
Thrombocytopenia – ITP
Skin or mucous membrane lesions
Fever
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs
• Survey rads may be normal
• Survey rads may show a gas filled
esophagus
• You may need to do both right and left
laterals to see air in the esophagus
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Barium Esophagram
• Normal esophagram shows lines only
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Barium Esophagram
• Normal esophagram shows lines only
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Barium Esophagram
• Normal esophagram shows lines only
• Barium will pool in the esophagus if ME
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Barium Esophagram
• Normal esophagram shows lines only
• Barium will pool in the esophagus if ME
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Barium Esophagram
• Normal esophagram shows lines only
• Barium will pool in the esophagus if ME
• Can assess wall thickness
• May see filling defect of radiolucent foreign
body, ulcer, or mass
• Can sometimes see a herringbone pattern in
the distal feline esophagus, due to mucosal
folds
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Barium Esophagram
Procedure:
• Administer 5-20 ml barium paste, liquid or
barium coated food
• Paste gives the best coating, but can be
dangerous if aspirated
• If motility problem with good tone, it may take
barium coated food to see abnormalities
***WARN OWNER OF DANGER OF THIS
PROCEDURE***
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Radiographs – Survey Abdominal
• May see radiopaque foreign body if
heavy metal poisoning
• May see a gas filled stomach if
generalized GI motility disorder
• May see displaced pylorus of chronic
gastric volvulus.
Diagnosis of Megaesophagus
The test that most often diagnoses ME
Fluoroscopy
• The best way to evaluate mild to moderate
esophageal hypomotility
• 5-20 cc liquid barium per bolus first
• Then liquid barium mixed with canned food
• Then liquid barium coated kibble
• Strictures may show no abnormalities with
liquid barium bolus
Diagnosis of Megaesophagus
Minimum database for ME
CBC
General health profile
Electrolytes and venous blood gases
Urinalysis
Fecal flotation and direct wet mount
Thoracic and cervical radiographs
Diagnosis of Megaesophagus
Patterns in Minimum database
CBC
Aspiration pneumonia
• Neutrophilia with left shift
• Activated lymphocytes and monocytes
Immune mediated disease (rare)
• Absolute reticulocute count 300,000
• HCT 16%
• Spherocytes
Diagnosis of Megaesophagus
Patterns in Minimum Database
Serology
Hypothyroidism
• Elevated triglycerides
• Elevated cholesterol
Hypoadrenocorticism
• Azotemia (elevated BUN, creat, phos)
• Hypercalcemia
• Hyperkalemia
Diagnosis of Megaesophagus
Patterns in Minimum Database
Diagnosis of Megaesophagus
Patterns in Minimum Database
Fecal Examination
Standard sugar and salt flotation solutions
will not give great yields of Spirocerca
lupi larvated eggs
Sodium nitrate or direct wet mount is often
more sensitive
Diagnosis of Megaesophagus
Tests indicated in every dog and cat with ME
Thyroid panel
•
Dog – TSH, T4, freeT4
•
freeT4ED is indicated if T4 is low, to rule out antithyroid antibodies
ACTH stimulation test
•
**Different protocols for dogs and cats**
Myasthenia gravis titer
•
Comparative Neuromuscular Laboratory, UC-Davis
Getting a positive test result on one of the above should not
preclude testing for the others.
A significant number of ME patients have 2 or even all 3 of these
problems concurrently
Diagnosis of Megaesophagus
Ancillary tests for ME
Abdominal ultrasound
Electrodiagnostics – EMG, NCV
Muscle and nerve biopsy **RISKY**
Blood Lead level
Organophosphate toxicology screen
Tensilon test
ANA (rarely helpful)
Treatment of Megaesophagus
Elevated Feedings
THE PRIMARY TREATMENT IF THE
ANIMAL IS TO BE FED BY MOUTH
MAKE SURE YOU SPEND ENOUGH TIME
WITH THE OWNER TO FULLY
EXPLAIN THIS, AS THEIR PET’S LIFE
CAN DEPEND ON IT
Treatment of Megaesophagus
Elevated Feedings
• Upper body should be elevated 45-90 degrees.
• Hold this position for 10 minutes after eating
• Do this also prior to periods of known
prolonged lateral recumbency (sedation,
sleeping)
• Small frequent meals (2-4 or more a day)
• Avoid feeding for several hours before bedtime
• Experiment with food type to determine which
works best for the patient
• Lots of how to videos on www.youtube.com
• “Bailey Chair”
Treatment of Megaesophagus
Elevated Feedings
•
•
•
•
•
•
Upper body should be elevated 45-90 degrees.
Hold this position for 10 minutes after eating
Do this also prior to periods of known
prolonged lateral recumbency (sedation,
sleeping)
Small frequent meals (2-4 or more a day)
Avoid feeding for several hours before bedtime
Experiment with food type to determine which
works best for the patient
Treatment of Megaesophagus
Elevated Feedings
•
•
•
•
•
•
Upper body should be elevated 45-90 degrees.
Hold this position for 10 minutes after eating
Do this also prior to periods of known
prolonged lateral recumbency (sedation,
sleeping)
Small frequent meals (2-4 or more a day)
Avoid feeding for several hours before bedtime
Experiment with food type to determine which
works best for the patient
Treatment of Megaesophagus
Elevated Feedings
•
•
•
•
•
•
Upper body should be elevated 45-90 degrees.
Hold this position for 10 minutes after eating
Do this also prior to periods of known
prolonged lateral recumbency (sedation,
sleeping)
Small frequent meals (2-4 or more a day)
Avoid feeding for several hours before bedtime
Experiment with food type to determine which
works best for the patient
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Treatment of Megaesophagus
Tube Feeding
Temporary gastrostomy
• can help stabilize until megaesophagus can be
improved, it the cause is treatable
• Often required for 1-3 months
• Medications given by tube are more assured of
absorption
• NEVER GIVE DOXYCYCLINE BY MOUTH TO
A PATIENT WITH ME
• extremely helpful for aspiration pneumonia
Treatment of Megaesophagus
Tube Feeding
Permanent gastrostomy
• Place a Pezzar tube first
• When stoma is well healed, replace with low
profile gastrostomy tube
• Medications given by tube long term
• Owners have to be vigilant to keep their pets
from taking in food by mouth
• If they do take food PO, they need to keep the
pet’s front end elevated for 10 minutes.
Treatment of Megaesophagus
Prokinetics
•
•
Metoclopramide and cisapride - empty
the stomach faster to minimize GER and
regurgitation
Cisapride – may actually improve
esophageal function
– Seems to work more consistently in cats
– Response in dogs varies from dramatically
positive to no response
Treatment of Megaesophagus
Treat aspiration pneumonia
•
Broad spectrum antibiotics – gram negatives,
positives and anaerobes
–
–
•
•
•
•
•
Long term therapy might be needed for chronic recurring
aspiration pneumonia
Choose 3-4 that work and rotate q6-8 weeks
IV fluid therapy – overhydration to keep respiratory
secretions coming up
Coupage
+ Nebulization
Gastrostomy tube
NPO – including medications
Treatment of Megaesophagus
Treat esophagitis – 2 weeks after resolution of
clinical signs
•
Sucralfate - PO
–
•
•
•
Do not give within 2 hours of any other PO meds
Prokinetics
H2 blockers
Proton pump blockers
Treatment of Megaesophagus
Immunosuppression – SKEERY!!
•
Might be indicated for:
–
–
–
•
•
•
Myasthenia gravis
SLE
Polymyositis
Only when IM disease has been confirmed,
or as a last resort.
Dangerous for those with aspiration
pneumonia
Some patients with MG can decompensate
when immunosuppressed
Treatment of Megaesophagus
Immunosuppression – SKEERY!!
•
Drugs:
–
Prednisone
•
–
Azathioprine
•
•
Start at 0.25 mg/lb/day and gradually increase to
immunosuppression if tolerated
Start at 0.5 mg/kg PO SID, and then double if tolerated
Eventually wean down to the lowest effective dose
over 2-3 months
Those who respond to immunosuppression may
be able to be weaned off Mestinon
Use MG titer to know how long to continue therapy
•
•
–
–
Begin the weaning process when titer negative
Check monthly to make sure not weaning too fast
Megaesophagus - Prognosis
Severe dilation often carries a poor prognosis, no
matter the cause
Spirocerca – rarely can be effectively treated
Acquired idiopathic megaesophagus carry a variable
prognosis, depending on:
•
Use of permanent gastrostomy
•
Response to cisapride
•
Tendency to develop aspiration pneumonia
Congenital megaesophagus
•
Guarded in general
•
Occasionally a puppy will have resolution at 6-12
months
All patients with ME are at risk for sudden death due to
aspiration and respiratory obstruction
Handouts
•
•
PowerPoint Presentation – behind the white tab
Instructions for Adrenal Testing in Dogs and
Cats
Lab Submission Forms
•
–
–
•
TAMU GI Lab Endocrine Submission Form
Comparative Neuromuscular Laboratory Submission
Form and submission instructions
Client Drug Handouts
–
–
–
•
Azathioprine
Prednisone
Pyridostigmine
Client Information Handout
–
–
Hiatal Hernia
Megaesophagus