Neurology. Myasthenia gravis

Guillain-Barre
Acute paralytic polyneuropathy
Triggered by infection :
Campylobacter Jejuni
Cytomegalovirus
Epstein-Barr virus
HIV/AIDS, HSV, Mycoplasma, H. influenzae
Vaccines (Influenza, polio)
Symptoms: occurs post infection, begins in lower limbs, symmetrical ascending weakness, reduce reflexes, peripheral loss of sensation, neuropathic pain, facial nerve weakness,
Acroparesthesia - tingling, pins-and-needles, burning or numbness or stiffness in the hands and feet
Autonomic disfunction: blood pressure dysregulation, urinary retention, cardiac arrythmias and sinus tachycardia

Guillain-Barre syndrome
Diagnosis:
Clinical
The most accurate is Electromyography (EMG) and Nerve conduction test
(reduced signal)
Lumbar puncture
(Albuminocytological dissociation)
Treatment:
IV immunoglobulins
Plasma exchange
Supportive care
VTE prophylaxis
Respiratory failure: intubation and ventilation; admission to ICU (daily monitoring of vital capacity)

An 11-years-old boy is brought to your practice with progressive difficulty climbing stairs, walking, or running for the past few days. On examination, bilateral lower limb weakness is noted. All lower limb deep tendon reflexes are lost, the sensation is, however, intact. Which one of the following tests is most likely to confirm the diagnosis?
A) CSF analysis
B) Forced vital capacity
C) MRI
D) Nerve conduction studies
E) X-ray

A child was recently vaccinated for polio, now presents with 1-week history of fever, flaccid paralysis of both lower limbs with no reflexes. The most likely diagnosis is?
A) Infection with wild poliomyelitis
B) Complication of the polio vaccine
C) Guillain-Barre syndrome
D) UMN lesion

Infection with wild poliomyelitis
Initial symptoms are fever, fatigue, headache, vomiting, stiffness of the neck and pain in the limbs.
Complication of the polio vaccine
Myocarditis, hypertension, pulmonary edema, pneumonia, UTIs
UMN lesion
Spasticity, weakness, hyper-reflexia

A 32-year-old woman suddenly develops abdominal pain and diarrhea. The abdominal pain is periumbilical and crampy, and she has had about 10 episodes of diarrhea per day over the past 3 days. She has no past medical or surgical history. She reports no sick contacts or recent travel, and no abdominal exposure. About 3 days ago she ate chicken at a barbecue that she thought might have been undercooked, but denies any other unusual exposure. Stool studies are positive for fecal WBCs and fecal occult blood; stool culture eventually grows out Campylobacter jejuni. She is treated with IV fluids and ciprofloxacin and is discharged home. About 2 weeks later, she develops weakness and absent deep tendon reflexes involving the lower extremities bilaterally.
All of the following are also triggers for this complications, EXCEPT:
(A) Chlamydia trachomatis infection
(B) Influenza-like illness
(C) HIV
(D) Vaccination

Myasthenia gravis
Autoimmune disease affecting skeletal muscles
Affects young women 20-30 and older men 60-70
Associated with:
Thymic tumors
Other autoimmune diseases: RA, SLE, ect.

Myasthenia gravis
Symptoms:
Weakness neck, face, arms
Eyelid drooping “Ptosis”
Appearance mask-like (very sleepy look)
Keep choking/gagging when eating
No energy
Extraocular muscle involvement
Slurred speech
Shortness of breath
Limbs (proximal and distal)
Painless fatigue with exercise
“Thinker” – hand used to hold the mouth closed and the head up

Myasthenia gravis
Complications:
Myasthenic Crisis
Severe muscle weakness and respiratory failure
Cholinergic Crisis
Severe muscle weakness and respiratory failure
Diagnosis
Serum anti-acetylcholine receptor antibodies
Electrophysiological tests if antibody test negative
CT scan/x-ray of the chest to detect thymoma
Edrophonium test still useful but potentially dangerous (atropine is the antidote)

Myasthenia gravis
Management
Thymectomy is recommended early for generalised myasthenia, especially in all younger patients with hyperplasia of the thymus
Plasmapheresis – in acute crisis
Anticholinesterase inhibitor drugs (e.g. pyridostigmine, neostigmine or distigmine) should be used only for mild-to-moderate symptoms
Corticosteroids are useful for all grades of MG

A 38-year-old woman presented to hospital with history of gradually increasing fatigue over last 6 months. She reported more fatigue in the evening than in the morning. Now she developed double vision, ptosis and, weakness of chewing and swallowing. She occasionally becomes breathless due to fatigue. Serum anti-acetylcholine receptor antibodies are positive.
Which ONE of the following treatment is useful for all grades of this clinical condition?
a. Thymectomy
b. Plasmapheresis
c. Neostigmine
d. Corticosteroids
e. Physiotherapy

A 42-year-old woman presents with progressive fatigue over the past few weeks. She reports muscle fatigue, occasional double vision, and some difficulty breathing. She has no relevant past medical history and takes no medications. On examination, sustained upward gaze leads to muscle fatigue and bilateral ptosis. Pulmonary function testing is performed and is shown below.
Which of the following is responsible for this patient’s pattern on pulmonary function testing?
(A) Chronic obstructive pulmonary disease
(B) Neuromuscular disease
(C) Pulmonary fibrosis
(D) Pulmonary hemorrhage

Neuromuscular disease. Myasthenia gravis is a neuromuscular disease caused by autoantibodies directed against postsynaptic acetylcholine receptors. Neuromuscular diseases can show a restrictive pattern (decreased FEV1 and FVC but normal/increased FEV1/FVC ratio) on pulmonary function testing that is extrinsic to the lung itself and therefore will have a normal DLCO.
Examples include lower motor neuron disease (e.g., polio and Guillain– Barre syndrome), myasthenia gravis, Lambert–Eaton syndrome, muscular dystrophies, chest wall deformities (e.g., scoliosis and pectus carinatum), and obesity.
COPD will present with an obstructive pattern on spirometry (decreased FEV1/FVC ratio) with a decreased DLCO (if there is a prominent component of emphysema).
(C) Pulmonary fibrosis is a type of interstitial lung disease, which will show a restrictive pattern on spirometry as well as a decreased DLCO from parenchymal destruction and scarring.
(D) Pulmonary hemorrhage would present with normal spirometry but an increased DLCO, since the presence of red blood cells within the airways will cause a rapid consumption of carbon monoxide during the test.

A 75 year old lady is admitted in an acute confusional state secondary to a urinary tract infection.
Despite antibiotic therapy, reassurance and environmental modification she remains agitated. You are considering prescribing haloperidol. Which one of the following condition may be significantly worsened If haloperidol is prescribed?
A) Myasthenia gravis
B) Parkinson’s disease
C) Essential tremor
D) Epilepsy
E) Depression

Which ONE of the following condition causes ptosis and dilated pupil?
a. Myasthenia gravis
b. Mitochondrial myopathy
c. Horner’s syndrome
d. Third cranial nerve palsy
e. Chronic fatigue syndrome