פרק 46 Chapter 46: Disorders of the Neuromuscular Junction, Myotonias, and Persistent Muscle Fiber Activity

Question 1

איזו מהתעלות פגועה ב
myotonia congenita
א. נתרן
ב. סידן
ג. אשלגן
ד. gap junction (connexin)
ה. כלור

Answer 1

ה. כלור

Question 2

Table 46-4THE MAIN INHERITED MYOTONIAS AND PERIODIC PARALYSES (THE CHANNELOPATHIES)

Answer 2

Question 3

Table 46-2MAJOR DISORDERS OF THE NEUROMUSCULAR JUNCTION

Answer 3

Question 4

בת 16 פונה עקב עוויתות שרירים
(muscle spasms)
כואבות בגפיים המופיעות בעת ניסיון לתנועה רצונית, בעת מגע ובעת חשיפה לרעש פתאומי.
EMG - מדגימה יחידות מוטוריות עם מבנה תקין.
בבדיקת דם ימצאו נוגדנים ל:
א. Glutamic acid decarboxylase
ב. Voltage gated Calcium channels
ג. Muscle Specific Kinase
ד. Aquaporin 4

Answer 4

Anti GAD
stiff person syndrome

Question 5

Clinical grading To facilitate clinical staging of therapy and prognosis, the classification introduced by Osserman remains useful; it can be found in his monograph cited in the references and in previous editions of this book. This system has been replaced by a scheme suggested by a task force of the Myasthenia Gravis foundation

Answer 5

1. Class I- Any ocular muscle weakness (May have weakness of eye closure , All other muscle strength is normal)
2. Class II- Mild weakness affecting other than ocular muscles (May also have ocular muscle weakness of any severity)
   * IIa- Predominantly affecting limb, axial muscles, or both (May also have lesser involvement of oropharyngeal muscles)
   * IIb- Predominantly affecting oropharyngeal muscles, respiratory muscles, or both (May also have lesser or equal involvement of limb, axial muscles, or both)
3. Class III -Moderate weakness affecting other than ocular muscles (May also have ocular muscle weakness of any severity)
   * IIIa- Predominantly affecting limb, axial muscles, or both (May also have lesser involvement of oropharyngeal muscles)
   * IIIb- Predominantly affecting oropharyngeal muscles, respiratory muscles, or both (May also have lesser or equal involvement of limb, axial muscles, or both)
4. Class IV- Severe weakness affecting other than ocular muscles (May also have ocular muscle weakness of any severity)
   * IVa- Predominantly affecting limb and/or axial muscles (May also have lesser involvement of oropharyngeal muscles)
   * IVb- Predominantly affecting oropharyngeal muscles, respiratory muscles, or both (May also have lesser or equal involvement of limb, axial muscles, or both)
5. Class V- Intubation, with or without mechanical ventilation, except when employed during routine postoperative management. The use of a feeding tube without intubation places the patient in class IVb.

Question 6

Figure 46-1. A. Endplate from a patient with myasthenia gravis. The terminal axon contains abundant presynaptic vesicles, but the postsynaptic folds are wide and there are few secondary folds. The loose junctional sarcoplasm is filled with microtubules and ribosomes. The synaptic cleft (asterisk) is widened. (From Santa et al by permission.) B. Normal endplate for comparison. (Courtesy of Dr. A.G. Engel.)

Answer 6

Question 7

Table 46-1
DOSE-EQUIVALENTS FOR DRUGS USED IN THE TREATMENT OF MYASTHENIA GRAVIS

Answer 7

Question 8

Table 46-3
HEREDITARY AND CONGENITAL MYASTHENIC SYNDROMES

Answer 8

Question 9

תוארחולהעםספאזמיםשריריים קבועיםשלאנעלמיםבשינהמההטיפול?
1. -קלונזפאם
2. -בקלופן
3. -פניטואין
4. -/IVIGPLEX

Answer 9

פניטואין

ash loch- אשלגן
נתפס לי הגוף לא ישנתי כל הלילה- ספזמים שריריים לא עוברים בשינה
איפה- פניטואין
טגרטול- טגרטול
תימור- קשור לתימומה

Question 10

אישה בגיל אמצע החיים עם ספסטיות ברגליים, לא מצליחה להתכופף, הליכה רובוטית ולורדוזיס. ללא ערות החזרים, משתפר בשינה. מה המנגנון?
1. איטיות בקליטת סידן וכיווץ ממושך
2. ירידה בכמות הכללית של גאבאGABA
3. הפרעה בתעלות אשלגן
4. הפרעה בתעלות נתרן

Answer 10

ירידה בכמות גאבא
GABA

stiff person syndrome

Question 11

תינוקת עם תופעה של כיווץ ומיוטוניה (לא מצליחה לשחרר חפצים, לא מצליחה לפקוח עיניים בזמן בכי), משתפר בהליכה. בבדיקתה רואים היפרטרופיה של השרירים.
1. myotonia congenita
2. generalized myotonia
3. myotonic dystrophy
4. paramyotonia congenita

Answer 11

myotonia congenita

Question 12

מטופל מתלונן על התכווצות שרירים לפני מאמץ , מגושמות בפעילות גופנית , רגישות לקור. בבדיקתומבנה גוף שרירי .
1. מיוטוניהקונגניטה
2. היפוקלמיקפרלזיס
3. היפרקלמיקפריודיקפרליזיס
4. פרהמיוטוניה

Answer 12

מיוטוניה קונג’ניטה

היפרטרופיה של השרירים קיימת רק במיוטוניה קונג’ניטה ובבקר. קור משפיע על כל המיוטוניות, מגושמות אופייני למיוטוניה קונג’ניטה.

“על אף השרירים המוגדלים, הם אינם אתלטים ומתקשים בפעילות ספורטיבית, בד”כ יש מעורבות של כל שרירי הגוף אך בעיקר בולטת בגפיים תחתונות, ניסיון רציה גורם לנפילה, תתכן גם מעורבות שרירי ידיים או שרירי פנים”.

Question 13

מה לא נכון לגבי מיוטוניה?
1. ביטוי להיפראקסיטביליות שרירית
2. מחמירה עם פעילות גופנית
3. חלק מהמיוטוניות הינן בהורשה דומיננטית עם מוטציה בגן לתעלת כלור

Answer 13

מיוטוניה אינה מחמירה עם פעילות גופנית
warm up phenomenon

Myotonia, a tonic spasm of muscle after forceful voluntary contraction,.
This phenomenon reflects electrical hyperexcitability of the muscle membrane

myotonia congentia- chloride, autosomal dominant
(general myotonia- chloride- autosomal recessive)

Question 14

איזו תופעה שרירית מושפעת מקור?
1. מיוטוניה
2. מיקסאדמה
3. מיוקימיה

Answer 14

מיוטוניה

Question 15

מה ההגדרה של
paramyotonia

Answer 15

מיוטוניה פרדוקסלית- מופיעה במהלך פעילות ומחמירה ככל שהפעילות נמשכת

Question 16

בחור עם התקפי שיתוק ב4 גפיים שלא כוללים נשימה ופנים, אחרי התעמלות וארוחות כבדות. גם אבא שלו סובל מתופעה דומה.
1. hyperkalemic periodic paralysis
2. hypokalemic periodic paralysis
3. paramyotonia congenita

Answer 16

hypokalemic periodic paralysis

1. Hypokalemic
   * Calcium Channel
   * No associated myotonia
   * Onset late childhood to third decade
   * Appears after exercise
   * Not associated with fasting
   * Appears after carbohydrate load
   * Trigger – cold, pregnancy
   * Warm up phenomenon present
   * Does not involve cranial nerves
   * Serum CK during attack normal to slight increase
   * Serum K during attack decreased
   * Serum K between attacks normal

2.Hyperkalemic
* Sodium channel
* Associated with myotonia
* Onset first decade
* Appears after exercise
* Appears after fasting
* Appears after potassium load
* Trigger – cold, pregnancy
* Warm up phenomenon present
* Involves cranial nervers
* Serum CK during attack increased
* Serum K during attack increased
* Serum K between attacks normal

Question 17

מטופל עם סיפור של אירועים של חולשה הנמשכים מספר שעות. מה הטיפול המונע?
1. מקסילנטין
2. אצטזולאמיד
3. פרצטמול

Answer 17

אצטזולמיד

גם להיפוקלמיק וגם להיפרקלמיק

Question 18

בת 32 לאחר ניתוח כריתת תוספתן עם קבלת
halothane
במהלך הרדמה מפתחת
malignant hyperthermia
מה השינויים בשרירים הגורמים למחלתה?
1. עלייה בתקופה הרפרקטורית של הנוירונים המוטוריים מסוג אלפא
2. חוסר יכולת רפולריזציה של השרירים
3. בכיווץ שריר קיים שחרור יתר של סידן
4. שחרור של מרכיבים פירוגניים מהשריר
5. ירי רפטטיבי של הנוירונים המוטורים הפרה-סינפטטים מסוג אלפא

Answer 18

בכיווץ שריר קיים שחרור יתר של סידן

Malignant Hyperthermia
This dramatic syndrome is observed during general anesthesia in susceptible individuals, some of whom clearly have a channelopathy. It is characterized by rapidly rising body temperature, extreme muscular rigidity, and a high mortality rate.
in some cases to be a metabolic myopathy inherited as a dominant trait, rendering the individual vulnerable to any volatile anesthetic agent, particularly halothane, and to the muscle relaxant succinylcholine. The fundamental cause in a proportion of cases is an aberration in a component of the ryanodine calcium channel. Malignant hyperthermia has been estimated to occur approximately once in the course of every 50,000 administrations of general anesthesia.
Clinical Manifestations- As halothane or a similar inhalational anesthesia is induced, or succinylcholine is given for muscular relaxation, the jaw muscles unexpectedly become tense soon rigidity extends to all of the muscles. Thereafter, the body temperature rises to 42çC or 43çC and there is tachypnea and tachycardia. Blood pH may fall to 7 or below. There may be gross myoglobinuria and serum CK reaches extraordinarily high levels. Circulatory collapse and death may ensue in approximately 10 percent of cases, or the patient may survive with gradual recovery.
Electron microscope shows scattered segmental necrosis and phagocytosis of sarcoplasm without inflammation.
Patients with a particular congenital myopathy (central core myopathy), and those with King-Denborough syndrome, have a propensity to malignant hyperthermia.

MOA- It has been postulated that halothane acts in a manner similar to caffeine—that is, to release calcium from the sarcoplasmic reticulum and prevent its reaccumulation, thus interfering with relaxation of the muscle. The essential physiologic change is one of increased intracellular calcium.

Treatment
This consists of discontinuation of anesthesia at the first hint of masseter spasm or rise of temperature. The intravenous administration of dantrolene, which inhibits the release of calcium from the sarcoplasmic reticulum, may be lifesaving. An infusion of 1 mg/kg is given initially and increased slowly until symptoms subside, the total dosage not exceeding 10 mg/kg. Other measures should include body cooling, intravenous hydration, sodium bicarbonate infusion to correct acidosis, and mechanical hyperventilation to decrease acidosis. Thereafter, halothane and other volatile anesthetic agents and succinylcholine should be avoided in such individuals and surgical procedures, if necessary, should be done with other agents, such as propofol, nitrous oxide, fentanyl, thiopental (or other barbiturate), or local anesthesia. Intravenous dantrolene (2.5 mg/kg given slowly 1 h prior to anesthesia) prevents the syndrome, but this is not a preferred option in patients with the disorder.

Question 19

בן 58 עבר ארתקוסקופיה בהרדמה מלאה, במהלכה פיתח נוקשות בגפיים וחום מעל 40. מה הרצפטור המעורב במחלתו?

Answer 19

Ryanodine receptor

Malignant Hyperthermia
This dramatic syndrome is observed during general anesthesia in susceptible individuals, some of whom clearly have a channelopathy. It is characterized by rapidly rising body temperature, extreme muscular rigidity, and a high mortality rate.
in some cases to be a metabolic myopathy inherited as a dominant trait, rendering the individual vulnerable to any volatile anesthetic agent, particularly halothane, and to the muscle relaxant succinylcholine. The fundamental cause in a proportion of cases is an aberration in a component of the ryanodine calcium channel. Malignant hyperthermia has been estimated to occur approximately once in the course of every 50,000 administrations of general anesthesia.
Clinical Manifestations- As halothane or a similar inhalational anesthesia is induced, or succinylcholine is given for muscular relaxation, the jaw muscles unexpectedly become tense soon rigidity extends to all of the muscles. Thereafter, the body temperature rises to 42çC or 43çC and there is tachypnea and tachycardia. Blood pH may fall to 7 or below. There may be gross myoglobinuria and serum CK reaches extraordinarily high levels. Circulatory collapse and death may ensue in approximately 10 percent of cases, or the patient may survive with gradual recovery.
Electron microscope shows scattered segmental necrosis and phagocytosis of sarcoplasm without inflammation.
Patients with a particular congenital myopathy (central core myopathy), and those with King-Denborough syndrome, have a propensity to malignant hyperthermia.

MOA- It has been postulated that halothane acts in a manner similar to caffeine—that is, to release calcium from the sarcoplasmic reticulum and prevent its reaccumulation, thus interfering with relaxation of the muscle. The essential physiologic change is one of increased intracellular calcium.

Treatment
This consists of discontinuation of anesthesia at the first hint of masseter spasm or rise of temperature. The intravenous administration of dantrolene, which inhibits the release of calcium from the sarcoplasmic reticulum, may be lifesaving. An infusion of 1 mg/kg is given initially and increased slowly until symptoms subside, the total dosage not exceeding 10 mg/kg. Other measures should include body cooling, intravenous hydration, sodium bicarbonate infusion to correct acidosis, and mechanical hyperventilation to decrease acidosis. Thereafter, halothane and other volatile anesthetic agents and succinylcholine should be avoided in such individuals and surgical procedures, if necessary, should be done with other agents, such as propofol, nitrous oxide, fentanyl, thiopental (or other barbiturate), or local anesthesia. Intravenous dantrolene (2.5 mg/kg given slowly 1 h prior to anesthesia) prevents the syndrome, but this is not a preferred option in patients with the disorder.

Question 20

בחור עם
central core myopathy
ממה צריך להזהר?

Answer 20

שימוש בהלותן או סוקסינילכולין בניתוח שיכול לגרום ל
Malignant Hyperthermia
This dramatic syndrome is observed during general anesthesia in susceptible individuals, some of whom clearly have a channelopathy. It is characterized by rapidly rising body temperature, extreme muscular rigidity, and a high mortality rate.
in some cases to be a metabolic myopathy inherited as a dominant trait, rendering the individual vulnerable to any volatile anesthetic agent, particularly halothane, and to the muscle relaxant succinylcholine. The fundamental cause in a proportion of cases is an aberration in a component of the ryanodine calcium channel. Malignant hyperthermia has been estimated to occur approximately once in the course of every 50,000 administrations of general anesthesia.
Clinical Manifestations- As halothane or a similar inhalational anesthesia is induced, or succinylcholine is given for muscular relaxation, the jaw muscles unexpectedly become tense soon rigidity extends to all of the muscles. Thereafter, the body temperature rises to 42çC or 43çC and there is tachypnea and tachycardia. Blood pH may fall to 7 or below. There may be gross myoglobinuria and serum CK reaches extraordinarily high levels. Circulatory collapse and death may ensue in approximately 10 percent of cases, or the patient may survive with gradual recovery.
Electron microscope shows scattered segmental necrosis and phagocytosis of sarcoplasm without inflammation.
Patients with a particular congenital myopathy (central core myopathy), and those with King-Denborough syndrome, have a propensity to malignant hyperthermia.

MOA- It has been postulated that halothane acts in a manner similar to caffeine—that is, to release calcium from the sarcoplasmic reticulum and prevent its reaccumulation, thus interfering with relaxation of the muscle. The essential physiologic change is one of increased intracellular calcium.

Treatment
This consists of discontinuation of anesthesia at the first hint of masseter spasm or rise of temperature. The intravenous administration of dantrolene, which inhibits the release of calcium from the sarcoplasmic reticulum, may be lifesaving. An infusion of 1 mg/kg is given initially and increased slowly until symptoms subside, the total dosage not exceeding 10 mg/kg. Other measures should include body cooling, intravenous hydration, sodium bicarbonate infusion to correct acidosis, and mechanical hyperventilation to decrease acidosis. Thereafter, halothane and other volatile anesthetic agents and succinylcholine should be avoided in such individuals and surgical procedures, if necessary, should be done with other agents, such as propofol, nitrous oxide, fentanyl, thiopental (or other barbiturate), or local anesthesia. Intravenous dantrolene (2.5 mg/kg given slowly 1 h prior to anesthesia) prevents the syndrome, but this is not a preferred option in patients with the disorder.

Question 21

צעיר שפיתח בעבר היפרתרמיה מליגנית לאחר הרדמה מלאה. מאיזו מחלה הוא סובל בסבירות הגבוהה?
1. central core myopathy
2. nemaline myopathy
3. myofibrillary myopathy

Answer 21

central core myopathy

Malignant Hyperthermia
This dramatic syndrome is observed during general anesthesia in susceptible individuals, some of whom clearly have a channelopathy. It is characterized by rapidly rising body temperature, extreme muscular rigidity, and a high mortality rate.
in some cases to be a metabolic myopathy inherited as a dominant trait, rendering the individual vulnerable to any volatile anesthetic agent, particularly halothane, and to the muscle relaxant succinylcholine. The fundamental cause in a proportion of cases is an aberration in a component of the ryanodine calcium channel. Malignant hyperthermia has been estimated to occur approximately once in the course of every 50,000 administrations of general anesthesia.
Clinical Manifestations- As halothane or a similar inhalational anesthesia is induced, or succinylcholine is given for muscular relaxation, the jaw muscles unexpectedly become tense soon rigidity extends to all of the muscles. Thereafter, the body temperature rises to 42çC or 43çC and there is tachypnea and tachycardia. Blood pH may fall to 7 or below. There may be gross myoglobinuria and serum CK reaches extraordinarily high levels. Circulatory collapse and death may ensue in approximately 10 percent of cases, or the patient may survive with gradual recovery.
Electron microscope shows scattered segmental necrosis and phagocytosis of sarcoplasm without inflammation.
Patients with a particular congenital myopathy (central core myopathy), and those with King-Denborough syndrome, have a propensity to malignant hyperthermia.

MOA- It has been postulated that halothane acts in a manner similar to caffeine—that is, to release calcium from the sarcoplasmic reticulum and prevent its reaccumulation, thus interfering with relaxation of the muscle. The essential physiologic change is one of increased intracellular calcium.

Treatment
This consists of discontinuation of anesthesia at the first hint of masseter spasm or rise of temperature. The intravenous administration of dantrolene, which inhibits the release of calcium from the sarcoplasmic reticulum, may be lifesaving. An infusion of 1 mg/kg is given initially and increased slowly until symptoms subside, the total dosage not exceeding 10 mg/kg. Other measures should include body cooling, intravenous hydration, sodium bicarbonate infusion to correct acidosis, and mechanical hyperventilation to decrease acidosis. Thereafter, halothane and other volatile anesthetic agents and succinylcholine should be avoided in such individuals and surgical procedures, if necessary, should be done with other agents, such as propofol, nitrous oxide, fentanyl, thiopental (or other barbiturate), or local anesthesia. Intravenous dantrolene (2.5 mg/kg given slowly 1 h prior to anesthesia) prevents the syndrome, but this is not a preferred option in patients with the disorder.

Question 22

Answer 22

anti musk

Question 23

Answer 23

anti musk

Question 24

חולת מייסטניה גרביס מזה חצי שנה, עם נוגדנים חיוביים שמסתדרת רק חלקית על אצטילכולין אסטרז אינהיביטור וסטרואידים. איזה טיפול נוכל להציע לה שבסבירות גבוהה ישפר את מצבה לתקופה ארוכה?
1. פלסמה פרזיס
2. טיפול בIVIG
3. מיקופנולט מופטיל
4. תימקטומיה

Answer 24

תימקטומיה

Question 25

Answer 25

החולה תזדקק לעלייה במינון פירידוסטיגמין

The weakness and atrophy of chronic thyrotoxic myopathy may be added to that of the myasthenia without appearing to affect the requirement for or response to anticholinesterase medications.
By contrast, hypothyroidism, even of mild degree, seems to aggravate the weakness of myasthenia gravis, greatly increasing the need for pyridostigrnine and at times inducing a myasthenic crisis.

Question 26

תיאור של חולה עם חולשה פרוקסימלית, קושי בבליעה ודיפלופיה. לפני שבוע טופל באמפיצילין בשל דלקת ריאות וכעת הגיע עם החמרה. מה הטיפול?
1. פלזמה פרזיס
2. הפסקת האנטיביוטיקה שגרמה למצבו
3. אדרופוניום
4. נאוסטיגמין

Answer 26

פלזמה פרזיס-

מדובר בהחמרה אקוטית של מיאסטניה לאחר מחלה ריאתית.

Question 27

Answer 27

נוגדני אנטי מאסק

Question 28

. מה מהבאים יוצר פגיעה פוסט-סינפטית?
א. ניאומיצין
ב. מגנזיום
ג. בוטוקס
ד. פניצילאמין
ה. אורגנופוספאטים

Answer 28

פניצילאמין

There are more than 30 drugs in current clinical use (other than anesthetic agents) that may, under certain circumstances, interfere with neuromuscular transmission in otherwise normal individuals. Of these, the most important are the aminoglycoside and quinolone antibiotics.
Myasthenic weakness has been reported with 18 different antibiotics but particularly neomycin, kanamycin (less so with gentamicin), colistin, streptomycin, polymyxin B, and certain tetracyclines. It has been shown that these drugs impair transmitter release by interfering with calcium ion fluxes at nerve terminals (Presynaptic). The fluoroquinolones—typified by ciprofloxacin—affect both pre and postsynaptic activity Other agents—particularly the organophosphate insecticides and nerve gases—cause paralysis by binding to cholinesterase and blocking the hydrolysis of Ach. The endplate remains depolarized and is refractory to neural stimuli. The most notable of these agents are
(1) botulinum toxin, which binds to cholinergic motor endings, blocking quantal release of Ach;
(2) black widow spider venom, which causes a massive release of Ach, resulting in muscular contraction and then paralysis from a lack of Ach;
(3) d-tubocurarine, which binds to AChR;
(4) suxamethonium and decamethonium, which also bind to AChR;
(5) organophosphates, which bind irreversibly to AChE;
(6) malathion and parathion, which inhibit AChE.
The actions of all these agents except for the organophosphate “nerve gases” are transitory.

• The administration of d-penicillamine has also caused an unusual type of myasthenia- induced autoimmune myasthenia gravis seropositive.

Rarely, typical autoimmune myasthenia gravis develops as part of a chronic graft-versus-host disease in long-term (2- to 3-year) survivors of allogeneic marrow transplants.
A large group of naturally occurring environmental neurotoxins are known to act at the neuromuscular junction and to induce muscle paralysis of a pattern like that of myasthenia gravis. Venoms of certain snakes, spiders, and ticks are common and well-known animal poisons, as are ciguatera and related toxins (from fish that have ingested certain dinoflagellates), curare (from plants), and Clostridium botulinum

Question 29

בחורה עם מיאסטניה, איזה ממצא מתאים?
1. התכווצות שרירי העפעפיים בזמן תנועות הוריזונטליות של העיניים
2. בעת הרמת עפעף צנוח, תהיה צניחה של העפעף הקונטראלטרלי

Answer 29

בעת הרמת עפעף צנוח תהיה צניחה של העפעף הקונטראלטרלי

Particular ocular signs are highly characteristic of myasthenia. For example, sustained upgaze (for 30 or more seconds) will usually induce or exaggerate ptosis and may uncover myasthenic ocular motor weakness, thereby marking it as “fatigable.”
twitching of the upper eyelid that appears a moment after the patient moves the eyes from a downward to the primary position (“lid-twitch” sign). one or more twitches may be observed upon closure of the eyelids or during horizontal movements of the eyes. Repeated ocular versions when tracking a target or by an optokinetic stimulus may disclose progressive paresis of the muscles that carry out these movements. Unilateral painless ptosis without either ophthalmoplegia or pupillary abnormality in an adult will most often prove to be due to myasthenia. Usually, there is subtle ptosis of the other eye that can be revealed by manually elevating the more affected eyelid. Attempts by the patient to overcome ptosis may impart a staring expression of the opposite eye. Bright sunlight is said to aggravate the ocular signs and cold to improve them. The application of an ice pack over the eye often relieves the ptosis for a brief period.

Question 30

בת 34 פונה עקב הפרעה בדיבור. בבדיקתה, מיד לאחר מבט מטה ולאחר חזרה למבט פרימארי, מופיע
ריצוד של העפעף העליון .איזה מצב מאופיין על ידי ממצא זה?
(twitching)
א. חולשה היקפית של עצב הפנים (פציאליס)
ב. הפרעה בעצבוב הסימפטטי של העפעף
ג. פגיעה בעצב קרניאלי 3
ד. הפרעה בתפקוד חיבור עצב שריר

Answer 30

הפרעה בתפקוד חיבור עצב שריר

Particular ocular signs are highly characteristic of myasthenia. For example, sustained upgaze (for 30 or more seconds) will usually induce or exaggerate ptosis and may uncover myasthenic ocular motor weakness, thereby marking it as “fatigable.”
twitching of the upper eyelid that appears a moment after the patient moves the eyes from a downward to the primary position (“lid-twitch” sign). one or more twitches may be observed upon closure of the eyelids or during horizontal movements of the eyes. Repeated ocular versions when tracking a target or by an optokinetic stimulus may disclose progressive paresis of the muscles that carry out these movements. Unilateral painless ptosis without either ophthalmoplegia or pupillary abnormality in an adult will most often prove to be due to myasthenia. Usually, there is subtle ptosis of the other eye that can be revealed by manually elevating the more affected eyelid. Attempts by the patient to overcome ptosis may impart a staring expression of the opposite eye. Bright sunlight is said to aggravate the ocular signs and cold to improve them. The application of an ice pack over the eye often relieves the ptosis for a brief period.

Question 31

מה לא נכון לגבי
neonatal myasthenia gravis
1. מופיע אצל עד 20% מהתינוקות לאימהות עם מיאסתניה
2. מועבר בתורשה דומיננטית
3. חולפת תוך כחודשיים
4. חשודה אצל ילודים
5. מגיבה לטיפול ע”י
plasma exchange

Answer 31

neonatal myasthenia gravis
אינה מועברת בתורשה דומיננטית.

An estimated 10 to 20 percent of babies born to mothers with myasthenia show transient signs of myasthenia (hypotonia, weak cry and suck). This transitory phenomenon is apparent at birth and has a mean duration of about 2 to 5 weeks; recovery is usually complete within 2 months of birth (rarely longer), without later relapse.
Uncommonly, the mother with myasthenia reports reduced intrauterine movements, suggesting a dangerous degree of myasthenia in the fetus. A few of these children will be born with arthrogryposis, the result of a sustained period of intrauterine immobility, and this complication tends to recur in subsequent births.
It has long been assumed that neonatal myasthenia is a result of the passive transplacental transfer of AChR antibodies. This explanation is not entirely satisfactory
insofar as maternal AChR antibodies are transferred from mother to fetus in all AChR antibody-positive pregnancies and the incidence and severity of neonatal myasthenia gravis do not correlate with the severity or duration of the mother’s illness or with the serum level of the maternal AChR antibody. In fact, neonatal myasthenia may occur when the mother is in remission.
Administration of plasma exchange and anticholinesterase drugs to the infant may be useful in hastening recovery from neonatal myasthenia.

Question 32

אישה עםמיאסטניה, נולד לה תינוק חלש עם קושי ביניקה,היפוטוניה. מה הסיבה?
1. העברת נוגדנים
2. תגובה לטיפול בסטרואידים
3. תגובה לטיפול אנטיביוטי קווינולון לפני הלידה
4. בעיה גנטית

Answer 32

העברת נוגדנים

An estimated 10 to 20 percent of babies born to mothers with myasthenia show transient signs of myasthenia (hypotonia, weak cry and suck). This transitory phenomenon is apparent at birth and has a mean duration of about 2 to 5 weeks; recovery is usually complete within 2 months of birth (rarely longer), without later relapse.
Uncommonly, the mother with myasthenia reports reduced intrauterine movements, suggesting a dangerous degree of myasthenia in the fetus. A few of these children will be born with arthrogryposis, the result of a sustained period of intrauterine immobility, and this complication tends to recur in subsequent births.
It has long been assumed that neonatal myasthenia is a result of the passive transplacental transfer of AChR antibodies. This explanation is not entirely satisfactory
insofar as maternal AChR antibodies are transferred from mother to fetus in all AChR antibody-positive pregnancies and the incidence and severity of neonatal myasthenia gravis do not correlate with the severity or duration of the mother’s illness or with the serum level of the maternal AChR antibody. In fact, neonatal myasthenia may occur when the mother is in remission.
Administration of plasma exchange and anticholinesterase drugs to the infant may be useful in hastening recovery from neonatal myasthenia.

Question 33

בת 30 , הסובלת ממיאסתניה גראביס ומטופלת בפירידוסטיגמין וקורטיקוסטרואידים, פונה למיון עקב
קשיי נשימה, בחילות, הזעה והחמרה של חולשת השרירים. בבדיקתה: דופק 45 , לח”ד 80/50 . מיוזיס,
פטוזיס דו”צ וחולשה פרוקסימלית. לאחר ייצוב המודינמי והנשמה איזה טיפול יש לתת?
א. Neostigmine IV
ב. Prednisone .
ג. Plasmapheresis
ד. Atropine sulfate IV

Answer 33

הטיפול הוא אטרופין סולפאט- מדובר ב
cholinergic crises

.
If the response to anticholinesterase drugs is poor and progressively larger doses are not relieving symptoms, there is consideration of a cholinergic crisis. In our own experience with more than 80 patients of severe myasthenia in an intensive care unit, we have been persuaded of the occurrence of a cholinergic crisis only rarely. This consists of a relatively rapid increase in muscular weakness, usually coupled with the adverse muscarinic effects of the anticholinesterase drug (nausea, vomiting, pallor, sweating, salivation, bronchorrhea, colic, diarrhea, miosis, bradycardia). An impending cholinergic effect is betrayed by constriction of pupils. If the blood pressure falls with bradycardia, 0.6 mg atropine sulfate may be given slowly by the intravenous route. Neostigmine or repetitive stimulation may be used to determine whether or not weakness is to the result of an excess of anticholinesterase medications.

Question 34

בן 50, סובל מזה מספר שבועות מכאבי שרירים , חולשה פרוקסימלית , עם התעייפות , יובש בפה וקושי בשליטה על סוגרים . תמונה בבדיקה אלקטריופיזיולוגית שמראה עלייה עם אינקרמנט. שאלו מההפתופיזיולוגיה
1. הפרעהפרהסינפטיתבשיחרוראצטיל כולין
2. הפרעהפרהסינפטיתבכמותהוזיקולותשלאצטיל כולין
3. הפרעה פוסט סינפטית – חסימת רצפטורים לאצטיל כולין
4. חסר באצטיל כולין אסטרז

Answer 34

הפרעה פרה-סינפטית בכמות הוזיקולות של אצטיל כולין