NMJ DISORDERS

NMJ DISORDERS

1- MYASTHENIA GRAVIS
2- LAMBERT EATON SYNDROME
3- INFECTIVE NMJ DISORDERS
PERIODIC PARALYSES SYNDROMES

Myasthenia Gravis:

Autoimmune inflammatory
fluctuating
(diurnal rhythm & relapse & remission),
fatigueable &
painless weakness disorder
affecting particularly, ocular, masticator, facial, neck, deglutition, lingual muscles & extremity & respiratory muscles.

Epidemiology:

1st Peak:

2nd peak

Pathologically
AChR Ab

AntiMusk Ab

Thymus Gland

HLA & other CTD

Clinical Presentation

INVESTIGATIONS:
Clinically (Provocative Tests):
Tensilon Test
EMG




Ix
AchR Ab 80%&if negative AntiMusk Ab 40% & Anti skeletal muscle
CXR & Contrast chest CT
: Thyroid function test & Antinuclear Ab.s
Serial follow up

TREATMENT:

Aim: - Symptomatic treatment

- Immune Modulation

AntiCholinestrase Drugs


Pyridostigmine Bromide

Immune Modulators:

Corticosteroids

AZATHIOPRIME

Mycophenolate Mofetil

Cholinergic Crisis Treatments

EMERGENCY TREATMENTS

Plasmapharesis PE

Immunoglobulin IgG

Thymectomy

should be offered in any:
Seropositive


<45yr old

not confined to ocular

Disease duration not more than 7 years.

MYASTHENiC CRISIS= ICU

Profound weakness Cn affected muscles in myasthenic :
1- withdrawal of anticholinestrase drugs.
2- Withdrawal or decreasing dose or acute administration of high dose of steroid.
3- Infection.
4- Bad choice of contraindicated drugs.

Cholinergic Crisis

ACheI Overdose:

Weakness in unaffected muscles too.

+

Course is extremely variable

Fatality
Course

Lambert Eaton Myasthenic Syndrome LEMS:

Autoimmune NMJ Disorder, VGCC Ab

Malignancy Association

Clinically
- spares:
- lower limbs
- ED
- Sphincter dysfunction
- Dry mouth
- Postural hypotension

Investigations

EMG
LOOK FOR MALIGNANCY

Treatment:

Treatment of associated cancer
Symptomatic:
3,4 Diaminopyridine DAP or
Guanidine

Infective NMJ Disorder:

Botulism:

PERIODIC PARALYSIS SYNDROMES

characterised by :
Recurrent,
Episodic,
Generalised,
Painless,
fairly Rapid onset of muscle weakness
coincidental changes in serum electrolyte level, and reversal to norm in between attacks.

Hypokalaemic Periodic Paralysis:

AD
Association with THYROTOXICOSIS


TYPICAL ATTACK
Time & provokation

Pattern

Spare

Duration

Investigations:
Serum K

ECG

TFT

EMG

Muscle Biopsy

Treatment:
1-Acute Attack
oral or IV potassium
Prophylaxis
- Acetazolamide
- Dichlorphenamide
- Spironolactone


Course & Prognosis:
Descending Recovery

Recurence: every few weaks

Improve with age

Mortality: rarely, respiratory or cardiac

Hyperkalaemic Periodic Paralysdisis (HyperKPP)
AD, Na Chanelopathy

TYPICAL ATTACK:

MYOTONIA

Acute Attack:

Prophylaxis

Investigations

K Level


ECG.

Treatment:

Acute Attack:
- IV Ca Gluconate
- IV Glucose or Glucose & Insulin
- -Diuretics
Prophylaxis
- Acetazolamide
- Dichlorphenamide
- Chlorthiazide. 0.5 mg/day
- Mexilitine
Myotonia

NormoKalemic Periodic Paralysis (NormoKPP)