Myasthenia Gravis
Prevalence:
5 to 12 per 100, 000 in the population.
Myasthenia Gravis
Gender prevalance and how does this effect presentation?
disease is twice as common in women
Males have more rapid progression, fewer remission, and less improvement
Age:
Women: the second to third decade of life.
Men, sixth to seventh decade of life.
Myasthenia Gravis
Grading of Symptoms
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
Grade 1 Symptoms
Myasthenia Gravis
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
Grade II symptoms
Myasthenia Gravis
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
Grade III symptoms
Myasthenia Gravis
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
Grade IV symptoms
Myasthenia Gravis
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
Grading of Symptoms:
focal disease—ocular muscle weakness
Myasthenia Gravis
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
How to diagnose ?
Diagnosis
- a physical examination identifying the level of weakness
- an edrophonium (shortacting anticholinesterase) test is confirmatory if the patient shows improvement.
- Assay for AChR antibody is also available.
Myasthenia Gravis
Grading of Symptoms
generalized mild to moderate disease
Myasthenia Gravis
Grading of Symptoms
(I) focal disease—ocular muscle weakness
(II) generalized mild to moderate disease
(III) severe generalized weakness
(IV) life-threatening weakness—respiratory failure.
Myasthenia Gravis
Treatment - medical therapy
- Anticholinesterase therapy (pyridostigmine)
- corticosteroids if needed for immunosuppression.
- Plasmapheresis and IVIG are short-term
- for myasthenic crises
- preoperatively, or intermittently in patients with poor control of MG despite immunosuppression.
Myasthenia Gravis
Indications/contraindications for thymectomy
Thymectomy
indicated
- in patients with thymic hyperplasia or a thymoma.
- any MG patient with early, generalized, moderate to severe disease, especially if refractory to medical management.
Contraindications
should not be performed emergently for a myasthenic crisis/class IV disease.
Results of thymectomy for MG?
- % “some clinical improvement” ?
- % resolution of symptoms ?
- % improved symptoms ?
- % drug free remission ?
- 85% of patients will have some clinical improvement
- 25-30% will have resolution of sx
- 30-50% will have Improved symptoms
- 50-60% will have drug free remission
Age and symptomatology of mediastinal masses
Adults are more likely to be asymptomatic (60%)
Children are more likely to be symptomatic (60%)
Symptomatology of mediastinal masses
Anatomic location and symptoms
- Anterior / superior masses (75%) -most likely to be symptomatic
compared with:
- posterior (50%)
- Middle (45%)
symptomatology of mediastinal masses
which are more likely to have sx - benign or malignant?
Malignant masses are more likely to have symptoms
Mediastinal masses - by anatomic location what is the the most likely to be malignant?
- Anterior superior are most likely to be malignant (60%)
- Middle (29%)
- Posterior (16%)
Thymic carcinoid
Gender predominance
> 75% are male
Thymic carcinoid
- prevalance of symptoms?
- what are they?
- clinical implication?
Thymic carcinoid
- 2/3 are symptomatic
- Most commonly: cushing’s syndrome (33%)
- annother 15% may have ADH, MEN I, or PTH
- the presence of symptoms is a poor prognostic factor.
Pre-thoracic surgery testing & evaluation
- IS —> evaluate data… a reasonable cut-off for preoperative FEV1 and DLCO are 60% of predicted.
- If either value is less than 60% predicted, do predicted postoperative values
- If estimated postoperative FEV1 or DLCO is less than 40% predicted, do cardiopulmonary exercise .
- Maximal exercise oxygen consumption (VO2max) is a better patient-specific functional measure to establish a threshold for risk.
- VO2max < 10ml/(kg*min) correlates with high morbidity and mortality and such patients are generally considered inoperable.
Shuttle walk and MVO2 max
MVO2 Max
VO2max < 10ml/(kg*min) correlates with high morbidity and mortality and such patients are generally considered inoperable.
The inability to perform 25 shuttles has been correlated with a maximal oxygen uptake of less than 10 mL/kg/min and signifies prohibitive operative risk.
A healthy adult should be able to climb five flights of stairs. A drop in oxygen saturation of 4 percent or more during activity is considered significant.
Karnofsky and Zubrod score relationship with post operative outcomes
A high Karnofsky score (80–100%) or low Zubrod score (0–1) is associated with low mortality.
Cryptococcus: major related syndromes
Cryptococcus will go to the CNS
If serology or sputum cx are positive - patient should have CSF examined
Crytpcoccus
sp:
Endemic: Tropism:
Clinic:
Rx:
Histology:
Crytpcoccus
sp: Crytpcoccus neoformans
Endemic: World wide, Tropism - soil.
Clinic: Lungs forms a granuloma that can be confused with cancer. CNS Tropism for meninges can cause meningitis.
Need to check the CSF is serum or sputum are positive
Rx: Amphoteracin B for aggressive disease including mening itis
Histology: Budding yeast with THICK capsule
