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Myasthenia gravis in resource-poor setting
Case Study and Case Report 2013; 3(4): 147 - 150.
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LIVING WITH MYASTHENIA GRAVIS FOR 18 YEARS IN A RESOURCE
LIMITED COUNTRY: CASE REPORT
Oluwayemi IO1*, Oduwole AO1, Oyenusi E1, Fakeye-Udeogu OB1, Onyiriuka AN1,
Abdullahi M1, Achonwa CJ1, Kouyate M1
1. Paediatric Endocrinology Training Centre for West Africa, Lagos University Teaching
Hospital, Idi-araba, Lagos, Nigeria
Correspondence
Dr. Isaac Oludare Oluwayemi. Paediatric Endocrinology Training Centre for West
Africa, Lagos University Teaching Hospital, Idi-araba, Lagos, Nigeria
Email: dareoluwayemi@yahoo.co.uk
Oluwayemi IO, Oduwole AO, Oyenusi E, Fakeye-Udeogu OB, Onyiriuka AN, Abdullahi
M, Achonwa CJ, Kouyate M . Living with myasthenia gravis for 18 years in a resource
limited country: a case report. Case Study and Case Report 2013; 3(4): 147 - 150.
ABSTRACT
Myasthenia gravis (MG) is an autoimmune neuromuscular disorder resulting in
fluctuating muscle weakness and fatigability. We report a case of myasthenia gravis
diagnosed at the age of 5 years in a 20 year old young adult. He presented with 3 years
history of drooping of both upper eye lids which worsens as the day progresses and has
been successfully managed for fifteen years despite challenges of getting needed
medication on regular basis. Tensilon test was positive; Computerized tomography (CT)
of the chest showed a normal study; Patient is doing very well as an undergraduate in one
of the leading Nigerian University. He is clinically stable on daily Pyridostigmine and
low dose Prednisolone. Myasthenia gravis in children can be readily diagnosed and
managed effectively despite limited resources, if parents and doctors are willing and
committed enough.
Key words: Myasthenia gravis, resource-poor setting
INTRODUCTION
Myasthenia gravis (MG) is an autoimmune neuromuscular disorder resulting in
fluctuating muscle weakness and fatigability1. The weakness is caused by circulating
antibodies that block acetylcholine receptors at the postsynaptic neuromuscular junction
inhibiting the excitatory effects of the neurotransmitter acetylcholine on nicotinic
receptors in neuromuscular junctions2. The incidence of myasthenia gravis is 3-30 cases
per million per year3. Myasthenia gravis occurs in both genders and affects all races. All
age groups can be affected but most commonly people from 50 to 70 years. In females
incidence of MG peaks in the third decade of life, whereas it peaks in the 6th and 7th
decades in males4.
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CASE REPORT
JH was 5 years old when he first presented with a 3 years history of drooping of both
upper eye lids. Eyes were usually widely opened on waking up from sleep but weakness
and difficulty in keeping the eyes opened set in and worsened as the day progresses.
There was no family history of myasthenia gravis. However, child also had asthma.
Examination revealed a boy who was well nourished, not pale, afebrile, anicteric.
Significant findings were on ocular examination. He had bilateral ptosis, other systems
were essentially normal.
A diagnosis of myasthenia gravis was made.
Investigations: Tensilon test was supportive of the diagnosis of myasthenia gravis; PCV
35%, total WBC 6,800; Hemoglobin electrophoresis AS, Erythrocyte sedimentation rate
10mm/hr; Electrolyte and urea within normal limit; Computerized tomography of the
chest revealed a normal study.
Child was initially commenced on oral Neostigmine 7.5mg 8 hourly and later increased
to 15mg 12 hourly. He was very stable on this dosage for 4 years when parents could no
longer get Neostigmine to buy and because of this Pyridostigmine was given at a dose of
7mg/ kg/ day (30mg 4hourly). This was later increased to 60mg 8hourly and he was
stable on this for 5 years when parents again could not find Pyridostigmine to buy!
Patient had to be returned to Neostigmine which has then become available. However,
while on Neostigmine he was noticed to be getting weaker despite adequate dose of
Neostigmine; prednisolone was added with no remarkable improvement and child had to
be returned to Pyridostigmine with prednisolone and he subsequently became stable
clinically. Patient had sustained clinical improvement and Pyridostigmine was maintained
at 10mg once daily and prednisolone at 10 mg 8 hourly. Since the time of diagnosis 15
years earlier he has been growing steadily and performing well in school. He is a third
year undergraduate in a Nigerian University at the time of this report. He never had
severe myasthenia crisis necessitating intensive care during these 15 years of follow up.
DISCUSSION
Myasthenia gravis is idiopathic in most patients1,4. In children, three types of myasthenic
syndrome can be distinguished:1 1. Neonatal: Pregnant mothers with myasthenia gravis in
12% of cases pass the antibodies to the infant through the placenta, causing neonatal
myasthenia gravis. The symptoms will start in the first two days and disappear within a
few weeks. 2. Congenital: this occurs very rarely in children of healthy mothers with
symptoms beginning at birth. It is not caused by an autoimmune process but due to
synaptic malformation, which in turn is caused by genetic mutations and the inheritance
pattern is typically autosomal recessive 3. Juvenile myasthenia gravis: it occurs in
children but after the peripartum period. The hallmark of myasthenia gravis is
fatigability1. In most cases, the first noticeable symptom is weakness of the eye muscles;
in a few others difficulty in swallowing and slurred speech may be the first presentation.
The muscles become progressively weaker during periods of activity and improved after
periods of rest. The muscles controlling movement of the eyeballs and eye lids, facial
expressions, chewing, talking, and swallowing are particularly susceptible.1 Often,
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Case Study and Case Report 2013; 3(4): 147 - 150.
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physical examination yields normal finding5. The degree of muscle involvement varies
raging from localized form limited to the eye muscles (ocular myasthenia) to a
generalized, severe form affecting many muscles, sometimes including respiratory
muscles. Symptoms varies including; asymmetrical ptosis, diplopia (due to weakness of
muscle that control movement of the eyeballs), unstable/ waddling gait, weakness in
arms, hands, fingers, legs, and neck, a change in facial expression, dysphagia, shortness
of breath and dysarthria. Up to 75% of myasthenia gravis patients have an abnormality of
the thymus and 10% have a thymoma1,4. In myasthenic crisis there is paralysis of the
respiratory muscles necessitating assisted ventilation to sustain life. Crisis is often
triggered by infection, fever, adverse drug reaction or emotional stress in patients whose
respiratory muscles are already weak6. Cardiac muscle is generally not affected by MG
since it is regulated by autonomic nervous system1. Myasthenia gravis is an autoimmune
channelopathy featuring antibodies directed against the body’s own proteins. It has been
proposed that sensitization to a foreign antigen which has cross reactivity with
acetylcholine receptor could be a cause of MG but there is yet no known infective agent
that could account for this4,7. Various drugs may also induce or exacerbate symptoms of
MG which often resolve after discontinuance of the drugs4. Other findings associated
with MG includes: female, and people with certain human leucocyte antigen types (HLA-
BB, HLA-DRw3, and HLA-DQw2). MG is also associated with various autoimmune
diseases like Hashimoto’s thyroiditis, Grave’s disease, rheumatoid arthritis, diabetic
mellitus type I, Lupus and demyelinating CNS diseases1,4. Our patient did not have any
autoimmune disease.
Diagnosis of myasthenia gravis can be difficult as the symptoms can be subtle.5 A
thorough physical examination can reveal easy fatigability, with the weakness improving
after rest and worsening again on repeat exercise1,4. In suspected cases serology can be
performed to detect antibodies against the acetylcholine receptor. This test has a
sensitivity of 80-95% in generalized severe cases but may be negative in up to 50% of
ocular myasthenia gravis5. Patients who are negative for anti-acetylcholine receptor
antibodies may be seropositive for antibodies against MuSK protein1,4. Electromyography
considered to be the most sensitive test is not very specific for MG5. Endrophonium test
is limited to situation where other investigations do not yield a conclusive diagnosis.4,8 In
this test intravenous endrophonium chloride or Neostigmine is administered; these drugs
block the breakdown of acetylcholine by cholinesterase and temporarily increase the
levels of acetylcholine at the neuromuscular junction thereby relieving weakness
temporarily in ocular myasthenia gravis8. At the time of diagnosis of our patient
endrophonium test was used for diagnosis because other earlier mentioned tests were not
available. A chest X-ray may identify widening of mediastinum suggestive of thymoma,
but CT or MRI are more sensitive ways to identify thymomas which are closely
associated with MG4,9. MRI of the cranium and orbits is also performed to exclude
compressive lesions of the cranial nerves and ocular muscles.4
Treatment involves use of cholinesterase inhibitors such as Neostigmine or
Pyridostigmine1,4. Corticosteroids are typically used in moderate or severe cases of MG
that fail to respond adequately to acetylcholine inhibitors and thymectomy4. Our patient
was managed with cholinesterase inhibitors and low dose corticosteroids only. There
were no identified complication of prolonged steroid use: blood glucose, blood pressure
and growth were within normal range. Thymectomy is the standard treatment for all
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Case Study and Case Report 2013; 3(4): 147 - 150.
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patients with thymoma and for patients aged 10-55years without thymoma but
generalized MG1,4. Immunoglobulin is useful during myasthenia crisis in patients with
severe weakness poorly controlled with other agents. The effect is rapid but transient and
the same is true for plasmapharesis1,4,6.
CONCLUSION
In conclusion, we report this case of MG diagnosed at the age of 5 years and followed up
for 15 years with good response to Pyridostigmine and prednisolone in a resource poor
setting to exemplify the challenges physicians encounter in the management of similar
cases and ways of getting round it for the benefit of the patients while working towards
the ideal.
COMPETING INTERESTS
The authors declare that they have no competing interests.
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3. McGrogan A, Sneddon S, deVries CS. The Incidence of myasthenia gravis: a
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