A case report on Myasthenia Gravis in Golden Retriever presented to Animal Medical Centre, Kathmandu, Nepal.

1. A case presentation of
Myasthenia Gravis in Golden
Retriever at Animal Medical
Center (AMC)

2.  A 3 years and 17 days old male Golden Retriever named Mowgli, was
presented to Animal Medical Center (AMC) on Jan 25th, 2020 at around
7:30 pm
 Mowgli was brought in to AMC from Chapali Height by Nabina
Rajbhandari.
 Reason of visit : Swelling of both fore limbs and inability to bark
properly.

3. History of the presented case:
 Mowgli had a gradual loss of weight since last summer. He developed
inappetence and debility in the duration. Further inquiry revealed that he
had eye infection around 2 months ago which was treated with
Ciprofloxacin eye drop and suspension.
 H/o eczema was found which was treated at Advanced Pet Hospital on July
with Cephalexin (1st generation cephalosporin) and Prednisolone.
 H/o Ehrlichiosis, a tick-borne rickettsial disease, which was treated at
Kathmandu Veterinary Clinic (medication not mentioned)

4. Physical Examination of Mowgli:
 Vital Signs :
Temperature - 104 degree Fahrenheit
Body Weight- 16.8 kg
Heart Rate - 136 bpm
 Body Condition Score (BCS) : 2/5 revealing underweight condition
of the dog with raised bones and minimal tissue between skin and
bones.
 Slight bilateral ocular discharges were noticed.
 Blood sample was withdrawn from jugular vein, collected in EDTA
and SST vacutainer and dispatched to lab for General Health Panel
(GHP), Complete Blood Count (CBC), and Amylase test (Amy test).

5. Assessment Based on Hematology report of
Mowgli
S.N TEST RESULT NORMAL RANGE
1 Haemoglobin (gm/dl) 9 13-20
2 PCV(%) 28 35-60
3 WBC (K/uL) 11 05-17
4 Platelets count(K/uL) 138 148-484
5 Neutrophils (%) 88 60-77
6 Lymphocytes(%) 11 12-30
7 Eosinophils(%) 01 02-10
8 Monocytes(%) 00 03-10
9 Basophils(%) 00 00-01
10 ALT-SGPT(U/L) 45 10-125
11 ALP(U/L) 420 23-212
12 Total protein(gm/dl) 8.5 5.2-8.2
13 Albumin(gm/dl) 2.0 2.3-4.0
14 BUN (mg/dl) 6 07-30
15 Creatinine (mg/dl) 0.9 0.5-1.8
16 Glucose (mg/dl) 108 70-130
17 Amylase (U/L) 900 250-1000

6. Assessment Based on Blood
Examination:
 The blood report was highly suggestive of mild anemia, borderline platelets
count (Thrombocytopenia) and hypoalbuminea.
 The blood report analysis along with history of E. canis and clinical signs
like swelling of limbs, inappetence and weight loss were highly suggestive
of Ehrlichiosis.

7. Differential Diagnosis of Ehrlichiosis:
1. Rocky Mountain spotted fever (Rickettsia rickettsii)—usually seasonal
between March and October; serologic testing for diagnosis; responds to
same treatment as ehrlichiosis.
2. Immune-mediated thrombocytopenia—not usually associated with fever or
lymphadenopathy; serologic testing best distinguishes the disease; may treat
for both until results are known.
3. Systemic lupus erythematosus— Antinuclear Antibody (ANA) test usually
negative with ehrlichiosis; serologic testing for diagnosis.
4. Multiple myeloma—serologic testing to differentiate and determine cause of
that show hypercalcemia, anemia and prominent sign of bone lesions.
5. Chronic lymphocytic leukemia— differentiate by lymphocytosis and
cytology of bone marrow.

8. Line of treatment:
1. Doxycycline 100mg tab- 2 tabs p.o. once daily after food for 30 days.
2. Pantoprazole 40mg- 1tab p.o. once daily before food for 10 days
3. Planning and management: Revisit AMC for further evaluation after 2 weeks
if everything went as expected.

9. Follow up on 27th Jan,2020
 History:
Mowgli had chronic loss of body weight and dysphagia. Significant changes
in the pitch, generalized weakness and debilitated condition was observed.
Blood test on the 25th of Jan showed hypoalbuminea with mild anemia.
He was started on Doxycycline medication but the condition was not
improving.
 Physical examination : BAR, BCS 1.5/5 (emaciated than before), high
pitch voice and dysphagia observed on the exam table during food intake.
 Assessment: Suspect Myasthenia Gravis (MG) ??
 Line of treatment: a. Warmed Ringer Lactate SC 500ml once
b. Ranitidine 1.7ml SC once c. Dexamethasone 2ml SC once

10. Differential diagnosis
 Rabies: Occurs as dumb and furious form. Symptoms include pica,
frothy salivation, seizures, difficulty in swallowing, change in tone of
bark, unusual aggression, muscular Inco-ordination, case fatality 100%.
Pathognomic cell inclusions (Negri bodies)observed on brain tissue on
microscopy.
 Pharyngeal paralysis: Difficulty in swallowing, regurgitation,
hypersalivation, vomition, choking etc. Endoscopy can be performed to
assess the condition of throat (pharynx).
 Megaesophagus: Dysphagia, hypersalivation, regurgitation, inappetence
and general body weakness. Lateral radiograph shows dilated esophagus.
Usually it occurs as a sequelae to Myastheina Gravis, polymyositis,
obstruction of esophagus by foreign body etc.

11.  Rhabdomyolysis: Severe muscle weakness, pain, muscle swelling and
marked elevation in serum Creatine kinase. Urinalysis shows Coca-
cola appearance.
 Polymyositis: Generalized inflammatory muscle disease seen with
infectious organisms as well as auto immune disorders. Tetraparesis
with stilted gait, dysphagia, fever etc are observed. Elevated creatine
kinase in blood serum and muscle biopsy provides definitive diagnosis.
Contd..

12. Follow up on 28th Jan,2020
 Physical examination: Willingness to eat but severe dysphagia
was observed. Froth seen on chewing of dry food.
 Line of treatment:
a. Warmed R/L SC 500 ml once
b. Ranitidine 1.7ml SC bid
c. Dexamethasone 2ml SC once
d. Doxycycline 200mg once (Noon, after food)

13. Follow up on 29th Jan, 2020
 Mowgli, was boarded at AMC.
 He was sent for diagnostic imaging of chest cavity by X-ray with the aid of
two staffs from AMC.
 Assessment: Radiograph of chest cavity indicated no pleural effusion/
pneumonia and megaesophagus. Cardiac silhouette appeared smaller than
normal (Microcardia)
 Suspected illness : Myasthenia Gravis (MG) based on differential
diagnosis from history, clinical signs and radiographs.
 It can further be differentiated from other myopathic disorders by the
elevation of Creatine kinase which is not seen in MG

14. Diagnostic Imaging
Lateral Radiograph of chest cavity of Mowgli showing Microcardia
Average Vertebral Heart Score : 9.7±0.5v
Photo Source : ANIMAL MEDICAL CENTER
Contd..

15. Line of treatment
 Warmed RL 500ml SC therapy, once
 Ranitidine 1.7ml SC bid
 Doxycycline 200mg once p.o (pm)
 Dexamethasone 2ml SC once
Contd..

16. Follow up on 30th Jan 2020
 Mowgli, is boarded at AMC for further treatment.
 Physical examination: Better control over food chewing, and slight
improvement noticed in dysphagia. Appetite is normal
 Treatment: .
Dexamethasone 2ml SC once (pm)
Ranitidine 1.7ml SC bid
Doxycycline 200mg once p.o(pm)
Pantoprazole 40mg- 1tab p.o. once daily before food for 10 days

17. Prednisolone instead of Dexamethasone from 31st of Jan 2020 in the
following order
a. One and a half tab of 10 mg tablet p.o bid daily after food for 10 days
b. One and a half tab of 10 mg tablet p.o sid daily after food for 7 days
c. One tab of 10 mg tablet p.o every alternating day after food for 14 days
 Plan: Mowgli was ready to be discharged. Follow up was to be made
after a month for further clinical evaluation
Contd..

18. Follow up on 13th February,2020
 As per the phone call of the owner the health status of
Mowgli was found to be progressive and improving.
 He was eating well and tone of barking had also improved.

20.  Myasthenia gravis in dogs is a neuromuscular disease contributed by
autoimmune disorder in which antibodies are produced that attack and
destroy Acetylcholine Receptors (AChR) and post-synaptic molecules.
 This then results in impaired signal transmission resulting muscle
weakness and fatigue in canines who suffer from it.
 Derived form Latin and Greek words:
Myasthenia : Weakness
Gravis : Serious
That literally means “ serious muscle weakness”

21.  Myasthenia gravis can be congenital and detectable in puppies at 6 to
8 weeks of age, or it can be acquired and appear in dogs at bimodal
age distribution.
 The bimodal age distribution for acquired MG are:
1 to 4 years of age or,
9 to 13 years of age.
However, it rarely starts to appear in dogs at any age in between.
Contd..

22. Predisposed breed of dogs to
Myasthenia Gravis:
Akita Scottish Terrier Great Dane
Golden Retriever Labrador Retriever Newfoundland
German Shepherd

23. Symptoms associated with MG are:
 Dilation and weakened contractility of esophagus (aka Megaesophagus )
 Dysphagia and Regurgitation
 Trouble swallowing food or drinks
 Retching
 Abdominal contractions similar to those associated with vomiting
 Weight loss
 Aspiration pneumonia (on inhaling of vomitus, edibles or liquids) is a
deadly common sequelae to MG

24. Changes are not only limited to esophagus. Other associated symptoms are
 Voice changes
 Weakness or cramping that gets worse with exercise and better with rest
 Inability to close the eyes or blink
 Sleeping with eyes open
 Absent gag reflex
 Excessive drooling
 Difficulty breathing or aspiration pneumonia
 Tumor in the chest cavity called a thymoma
Contd..

25. Diagnosis of MG
TENTATIVE DIAGNOSIS
 Based on the history and clinical signs
 Based on radiographs of chest cavity. For example:

26.  IV administration of Tensilon® (edrophonium chloride): A short
acting anti-cholinestarase which provides transient muscle
weakness resolution when administered IV at 0.1 to 0.2 mg/kg
body weight
Contd..

27. DEFINITIVE DIAGNOSIS
 Based on serological evaluation of antibody titers against Ach
receptors by immunologic precipitation
An antibody titer > 0.6 nmol/L is diagnostic for acquired
Myasthenia Gravis in dogs. This assay provides confirmative
diagnosis in 98% in dog cases.

28. Differential diagnosis
 Rabies: Occurs as dumb and furious form. Symptoms include pica,
frothy salivation, seizures, difficulty in swallowing, change in tone of
bark, unusual aggression, muscular Inco-ordination, case fatality 100%.
Pathognomic cell inclusions (Negri bodies)observed on brain tissue on
microscopy.
 Pharyngeal paralysis: Difficulty in swallowing, regurgitation,
hypersalivation, vomition, choking etc. Endoscopy can be performed to
assess the condition of throat (pharynx).
 Megaesophagus: Dysphagia, hypersalivation, regurgitation, inappetence
and general body weakness. Lateral radiograph shows dilated esophagus.
Usually it occurs as a sequelae to Myastheina Gravis, polymyositis,
obstruction of esophagus by foreign body etc.

29.  Rhabdomyolysis: Severe muscle weakness, pain, muscle swelling and
marked elevation in serum Creatine kinase. Urinalysis shows coca-cola
appearance.
 Polymyositis: Generalized inflammatory muscle disease seen with
infectious organisms as well as auto immune disorders. Tetraparesis
with stilted gait, dysphagia, fever etc are observed. Elevated creatine
kinase in blood serum and muscle biopsy provides definitive diagnosis.
Contd..

30. Line of Treatment for MG
Symptomatic and life-long therapy is indicated for proper management and
prognosis of MG:
 Anti-cholinestarase drugs viz. Pyridostigmine traded as Mestinon.
 Immuno suppressant drugs viz. Dexamethasone, Prednisolone to supress
auto-immune antibody production.
 Anti-bacterial drugs viz. Doxycycline to prevent secondary bacterial
infection.
 Protein-pump inhibitors viz. Ranitidine and Pantoprazole to inhibit stomach
ulcer and esophagitis.
 A holistic approach is to be made for proper management of MG in dogs viz.
proper nutrition by feeding smaller meals (pellets) more frequently, arranging
pet food-dish at a certain height to avoid bending of dog for feeding and
drinking, holding the dog for 10-20 minutes to minimize the chances of
regurgitation and aspiration pneumonia etc.

31. Thank you!!