1. CRITICAL ILLNESS NEUROMYOPATHY

2. Abbreviations CIP critical illness polyneuropathy
CIM critical illness myopathy
CMAP compound muscl action potentials
SNAP sensory nerve action potential
EMG electromyogram
SIRS systematic inflammatory response syndrome

3. HISTORICAL REVIEW
In observed a polyneuropathy after shock or cardiac arrest
In 1961 described “coma-polyneuropathies”
In 1971 described a polyneuropathy in patients with burns
in severe polyneuropathy about septic patients

4. By 1983 the term “critical illness polyneuropathy”（CIP） was applied
Recently the termed “critical illness myopathy ”（CIM） was applied

5. Studies about Aetiologyvariously
The various factors associated with the SIRS CIP and CIM (Fig. 1)
A simplified depiction of theoretical mechanisms of dysfunction in CIP and CIM.(Fig. 2 )
Disorder of microcirculation（Fig. 3)

6. Figure. 1
Adapted with permission from Bolton.

7. Adapted with permission fromBolton25.
Figure. 2

8. Figure Schematic, theoretical presentation of disturbances in the microcirculation to various organs, including brain, peripheral nerve, and muscle, in SIRS.

10. Incidence
50%–70% SIRS
20%–50% ICU

11. Clinical Features • Tendon reflexes absent or decrease
• Weakness of limb and respiratory muscle
• Tendon reflexes absent or decrease
•Distal loss to pain, temperature, and vibration

12. Diagnosis
The diagnostic criteria for CIP are shown in following Table

13. Diagnostic criteria for CIP
The patient is critically ill (sepsis and multiple organ failure,SIRS)
Difficulty weaning patient from ventilator afternonneuromuscular causes such as heart and lung diseasehave been excluded
Possible limb weakness
Electrophysiologic evidence of axonal motor and sensory polyneuropathy

14. Electrophysiologic Features
Decline in the CMAP amplitude firstly (Fig. 4)
Dcline in the SNAP amplitude
Motor unit potentials may be reduced in number
Single-fiber EMG indicate dysfunction of terminal motor axons

15. Measurement of compound thenar muscle action potentials at the onset of sepsis (A) and 3 weeks later (B).
FIG.4

16. Morphologic Features Peripheral axonal degeneration.
Moderate loss of dorsal root ganglion cells
Central chromatolysis of anterior horn cells
No inflammation in the peripheral nervous system

17. Muscle biopsy
Acute and chronic denervation
Occasional myopathic changes

18. Pathology of critical illness polyneuropathy
Pathology of critical illness polyneuropathy. There is chromatolysis of anterior horn cells (A); severe axonal degeneration in this cross-section of superficial peripheral nerve (B) and longitudinal section of deep peroneal nerve (C); and acute and chronic denervation of intercostal muscle (D)

19. Differential Diagnosis
Axonal variants of Guillain–Barre′ syndrome
Develop earlier
Often associated with CJ infection
Abnormal cerebral spinal fluid

20. Transient neuromuscular blockade
Repetitive nerve stimulation
Measurement of anti-MuSK (muscle specific receptor tyrosine kinase) antibodies

21. Treatment Treatment of sepsis and multiple organ dysfunction syndrome
Management of difficulty in weaning from the ventilator
Attempts at direct treatment of CIP (still unproven)
Physiotherapy and rehabilitation

22. Two newer research approaches are being explored
Intensive insulin therapy
The administration of recombinant human activated protein C

23. Prognosis Recovery depends on the distance
Recovery for weeks in mild cases and months in severe cases
Slowing of nerve conduction may have a poor prognosis

25. Incidence
At least one-third of ICU patients（ treated for status asthmaticus）
In 7% of patients after transplantation

26. Clinical Features Major feature is flaccid weakness
Tendon reflexes depressed
Ophthalmoplegia may be present
Myalgias are uncommon

27. Diagnosis Diagnostic criteria of CIM
● SNAP amplitudes 80% of the lower limit of normal
● Needle EMG with short-duration, low-amplitude MUPs with early or normal full recruitment, with or without fibrillation potentials
● Absence of a decremental response on repetitive nerve stimulation

28. ● Muscle histopathologic findings of myopathy with myosin loss
● CMAP amplitudes 80% of the lower limit of normal in two or more nerves without conduction block
● Elevated serum creatine kinase (CK）
● Demonstration of muscle inexcitability
*For a definite diagnosis of critical illness myopathy, patients should have all of the first five features.

29. Electrophysiologic Features
Nerve conduction studies
Low-amplitude CMAPs
Long duration CMAPs
Normal SNAPs
Phrenic nerve conduction normal latencies diaphragm CMAP amplitudes reduce

30. EMG Fibrillation potentials and positive sharp
Motor unit potentials low amplitude and short duration
Electrical inexcitability by direct needle stimulation

31. Morphologic Features
Features of the histopathology in thick filament myosin loss (Fig. 5)
Electron microscopy reveals selective loss of thick (myosin) filaments (Fig. 6)
Inflammatory changes are conspicuously absent

32. Figure Muscle histopathology in a critically ill patient with thick filament myosin loss. (original magnification, 100) (courtesy of Dr. Andrew Engel).

33. Figure. 6 Electron microscopy of muscle in CIM
Figure. 6 Electron microscopy of muscle in CIM. (original magnification, 44,000) (courtesy of Dr. Andrew Engel).

34. 6. Differential Diagnosis
CIP
Direct needle stimulation of the muscle
Electrical inexcitability in CIM
There is a response in CIP (Fig. 7)
Serum CK
Muscle biopsy

35. FIGURE. 7 Results of direct and indirect muscle stimulation
FIGURE. 7 Results of direct and indirect muscle stimulation. CMAPs from the anterior tibial muscles of a patient with critical illness polyneuropathy (left) and critical illness myopathy (right).

36. Subtypes of CIM
Muscle morphologic
Differentiating feature of neuromuscular disorders in critical illness Table 1.

38. Treatment No specific therapy available as to now
Positioning to avoid additional nerve damage by pressure
Avoid administering muscle relaxants and corticosteroids

39. Thank you!