Arterial.2.Acute ischemia Flashcards

1
Q

DEFINITION of LIMB ISCHEMIA

A

Ischemia means diminished arterial blood sufficient to interfere with nutrition of the part.

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2
Q

ETIOLOGY of Ischemia

A

A) Acute Ischemia

B) Chronic Ischemia

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3
Q

All causes of acute ischemia

A
  1. Embolism “acute embolic ischaemia” : Commonest cause.
  2. Acute thrombosis “acute thrombotic ischaemia”
  3. Arterial injuries.
  4. Dissecting aneurysm.
  5. Phlegmasia cerulae or alba dolens.
  6. Arterial spasm due to ergot poisoning

7 : lntra-arterial injection.

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4
Q

All causes of chronic ischemia

A
  1. Atherosclerosis (commonest cause).
  2. Diabetic presenile atherosclerosis.
  3. Buerger’s disease.
  4. Vasospastic conditions
  5. Incomplete recovery after treatment of acute ischemia
  6. Aneurysm.
  7. Vascular compression : Thoracic outlet syndrome
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5
Q

Definition of acute ischemia

A

lt is SUDDEN decrease in arterial limb perfusion causing THREAT to limb vitality

No time for collaterals formation and gangrene occurs in 24 hours.

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6
Q

The Problem about acute ischemia

A

No time for collaterals formation and gangrene occurs in 24 hours.

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7
Q

Clinical picture of acute ischemia 6P

A
  1. Pain
  2. Paresis & muscle weakness “early” passing to paralysis “late”.
  3. Paraesthesia & numbness “early” followed by sensory loss “late”.
  4. Pulselessness : The distal pulsations are lost.
  5. Pallor “early”, then mottling & cyanosis “late”.
  6. Progressive coldness is an early symptom.
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8
Q

Pain in Clinical picture of acute ischemia

A
  • onset
  • character
  • site and radiation
  • what increase.
  • what decrease
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9
Q

onset of Pain in Clinical picture of acute ischemia

A

sudden onset.

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10
Q

character of Pain in Clinical picture of acute ischemia

A

Bursting or stabbing in character.

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11
Q

site and radtiation of Pain in Clinical picture of acute ischemia

A

Starts at the point of occlusion and shoots distalty

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12
Q

what increase.Pain in Clinical picture of acute ischemia

A

movement and warmth.

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13
Q

what decrease Pain in Clinical picture of acute ischemia

A
  • Pain may diminish in intensity by time if
  • collaterals open improving the circulation “as in cases of acute thrombotic ischemia”

OR

  • ischemia progresses causing ischemic sensory loss.
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14
Q

the reason why the pain in acute ischemia is bursting

A

Accumultion of metabolites ~~ V.D ~~ severe interstial edema ~~ bursting pain

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15
Q

collateral occur in which type of acute ischemia

A

acute thrombotic type

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16
Q

Paresis & muscle weakness “early” passing to paralysis “late” in Clinical picture of acute ischemia

A

1st muscle group affected by acute ischemia

The reason why detection of early muscle weakness is difficult in acute ischemia

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17
Q

1st muscle group affected by acute ischemia in Clinical picture of acute ischemia

A

intrinsic foot muscles followed by the leg muscles

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18
Q

the reason why detection of early muscle weakness is difficult in acute ischemia

A

because toes movements are produced mainly by leg muscles.

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19
Q

Paraesthesia & numbness “early” followed by sensory loss “late”. in Clinical picture of acute ischemia

A

order of frequency of sensory affection :

  1. Light (Crude) touch
  2. Vibration sense.
  3. Proprioception.
  4. Deep pain “late”.
  5. Pressure sense “late”
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20
Q

First to be affected from sensory due to acute ischemia

A

Light (Crude) touch

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21
Q

meaning of mottling

A
  • V.D of vessels by Accumulation of metabolites

* Extravasation of RBCs due to ischaemic endothelial damage

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22
Q

Complications of acute ischemia

A
  1. Extension thrombosis
  2. Muscle necrosis occurs after 6-12 hours.
  3. Moist aseptic gangrene :
  4. Chronic ischaemia in low level occlusion only.
  5. Reperfusion syndrome :
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23
Q

Pathogenesis of Extension thrombosis in Complications of acute ischemia

A

After circulatory arrest )> widespread distal intravascular thrombosis

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24
Q

Moist aseptic gangrene in acute ischemia

A

Pathogenesis

the reason why it’s moist

the reason why Development of collaterals may fail in acute ischemia

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25
Q

pathogenesis of Moist aseptic gangrene in acute ischemia

A

If occlusion is not relieved by surgical intervention or the collaterals are inadequate, the thrombosis extends further & the ischaemic changes progress to moist aseptic gangrene within 24 hours.

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26
Q

the reason why gangrene in acute ischemia is moist gangrene

A

Accumultion of metabolites ~~ V.D ~~ severe interstial edema

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27
Q

Development of collaterals may fail in acute ischemia due to

A

a. Reflex vasoconstriction of collaterals.

b. Spreading thrombus in the collaterals.

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28
Q

the reason why Chronic ischaemia complicates acute ischemia in low level occlusion only.

A

Infra popliteal region is supplied by 3 vessels

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29
Q

Etiology of Reperfusion syndrome in complication of acute ischemia

A

a. compartmental syndrome
b. cardiac arrhythmia or cardiac arrest
c. crush syndrome

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30
Q

compartmental syndrome in complication of acute ischemia

A
  • Definition
  • in a phrase
  • pathogenesis
  • Treatment
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31
Q

Definition of compartmental syndrome in complication of acute ischemia

A

Means increased pressure in a closed fascial compartment (e.g, the anterior compartment of the Ieg) more than pressure needed for tissue perfusion.

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32
Q

compartmental syndrome in a phrase

A

acute ischemia with a pulse as the capillary bed is occluded

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33
Q

pathogenesis of compartmental syndrome in complication of acute ischemia

A
  • Released inflammatory mediators as a result of muscle ischemia causes vasodilatation of the blood vessels & damage of the endothelial lining.
  • Later on after perfusion, severe edema occurs raising the pressure in the closed compartment
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34
Q

Treatment of compartmental syndrome in complication of acute ischemia

A

Fasciotomy

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35
Q

cardiac arrest and cardiac arrhythmia in complication of acute ischemia

A

pathogenesis

Treatment

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36
Q

pathogenesis of cardiac arrest and cardiac arrhythmia in complication of acute ischemia

A

Due to flooding the circulation with:

  • excess acid metabolites (resulting from anaerobic metabolism of the tissues)
  • excess potassium from cell damage.
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37
Q

Treatment of cardiac arrest and cardiac arrhythmia in complication of acute ischemia

A

with NaHCO3 + Glucose-insulin infusion to stimulate intracellular shift of K+

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38
Q

crush syndrome in complication of acute ischemia

A

Pathogenesis

Treatment

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39
Q

Pathogenesis of crush syndrome in complication of acute ischemia

A

Acute tubular necrosis due to release of myoglobin from ischaemic muscles which the blocks renal tubules leading to acute renal failure.

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40
Q

Treatment of crush syndrome in complication of acute ischemia

A

mannitol infusion & dialysis if anuria developed

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41
Q

Definition of acute embolic ischemia

A

Embolism means sudden impaction of an embolus in a relatively healthy arterial tree causing obstruction & loss of function.

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42
Q

sources of Embolism

A

(A) cardiac:

(B) Arterial wall :

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43
Q

cardiac sources of Embolism

A
  1. Left atrium in atrial fibrillation.
  2. Left ventricle after recent myocardial infarction
  3. Thrombi may form on prosthetic valves
  4. The valves in S.B.E
44
Q

Arterial wall sources of Embolism

A

The aorta from an aneurysm

45
Q

Site of impaction of an embolus is Bifurcation of vessels due to :

A
  • Decrease in diameter.
  • Slowing of the circulating blood.
  • Turbulence.
46
Q

Commonest site of impaction of an embolus ; In order of frequency

A

Common femoral bifurcation

Aortic bifurcation.

Popliteal bifurcation.

47
Q

Saddle embolus

A

Embolus impacted at aortic bifurcation.

48
Q

Clinical picture of acute embolic ischemia

Very important

A

6P + clinical features suggestive of acute embolism

49
Q

clinical features suggestive of acute embolism

A
  1. Sudden onset of symptoms.
  2. Known source of emboli.
  3. No previous history of claudication pain & chronic ischaemia.
  4. Normal pulse in the other limb or A.F.
50
Q

D.D of acute embolic ischemia

A

Commonly, acute thrombosis arises in an artery previously narrowed by atherosclerosis

51
Q

Difference between acute embolism and acute thrombosis is done by

A

Age

Past history

Commonest site.

Radial pulse.

Pulse in other limb.

Arteriography.

52
Q

Age of acute embolism

A

Commoner in young age

53
Q

Age of acute thrombosis

A

Commoner in old age

54
Q

Past history of acute embolism

A

Cardiac troubles

55
Q

Past history of acute thrombosis

A

Intermittent claudication

56
Q

Commonest site of acute embolism

A

Bifurcation of common femoral artery

57
Q

Commonest site of acute thrombosis

A

Lower end of femoral artery.

58
Q

Radial pulse of acute embolism

A

A.F (commonest cause).

59
Q

Radial pulse of acute thrombosis

A

Usually regular.

60
Q

Pulse in other limb of acute embolism

A

Normal.

61
Q

Pulse in other limb of acute thrombosis

A

Weak.

62
Q

Arteriography of acute embolism

A

Minimal collaterals

63
Q

Arteriography of acute thrombosis

A

Exlensive collaterals

64
Q

commonest cause of acute emoblism

A

A.F

65
Q

Investigations of acute embolic ischemia

A
  1. Arterial duplex scanning.:
  2. ECG, echocardiography.
  3. Arteriography usually not needed better to be done intraoperative
66
Q

Arterial duplex scanning in Investigations of acute embolic ischemia, show

A

Inaudible arterial signals at the level of obstruction.

67
Q

Postgraduate note : The presence of pedal signals in Arterial duplex scanning in Investigations of acute embolic ischemia, usually indicates

A

that there is time for conventional arteriography & proper patient preparation.

68
Q

Arteriography in Investigations of acute embolic ischemia

A

indications

value of Pre-operative arteriography

69
Q

Indications of Arteriography in Investigations of acute embolic ischemia

A
  • usually not needed better to be done intraoperative
  • Pre-operative arteriography in acute ischemia is done ONLY If differentiation between acute embolic ischemia & acute thrombotic ischemia is not clear clinically provided that the condition of the limb permits
70
Q

value of Pre-operative arteriography in Investigations of acute embolic ischemia

A

a) Localizes the exact site of obstruction.
b) Visualizes the arterial tree & distal run-off.
c) Can diagnose an embolus by:

71
Q

Pre-operative arteriography in Investigations of acute embolic ischemia can diagnose an embolus by :

A

1) Sharp cut-off
2) Reversed meniscus sign
3) Clot silhouette.

72
Q

Reversed meniscus sign

A

Crescentic filling defect in arteriography of actue ischemia

73
Q

Clot silhouette.

A

Its Shadow

Filling defect in arteriography of actue ischemia

74
Q

Treatment of acute embolic ischemia

A

(A) General rules

(B) Immediate Embolectomy

(C) prevention of complications

(D) Prevention of further emboli

(E) Delayed embolectomy

(F) Amputation

75
Q

General rules in treatment of acute embolic ischemia

A
  • Immediate heparinisation : (most important)
  • Appropriate analgesia.
  • Start TTT of associated cardiac condition as A.F
  • Simple measures to increase existing perfusion :
76
Q

the reason why we do immediate heparinisation in General rules in treatment of acute embolic ischemia

A

To prevent propagation of thrombosis

77
Q

Simple measures to increase existing perfusion in General rules in treatment of acute embolic ischemia

A

i) Keep the foot dependant.
ii) Avoid extremes of temperature (cold induces vosospasm & heat raises the metabolic rate
iii) Maximum tissue oxygenation

78
Q

most important General rule in treatment of acute embolic ischemia

A

Immediate heparinisation

79
Q

Immediate Embolectomy in treatment of acute embolic ischemia

A

Procedure

Indications

Signs of adequate embolectomy

Complications

Prognosis:

80
Q

Procedures of Immediate Embolectomy in treatment of acute embolic ischemia

A

Using Fogarty balloon catheter:

It is done under local anesthesia.

81
Q

Indications of Immediate Embolectomy in treatment of acute embolic ischemia

A

Done as long as the limb is viable.

  • no fixed mottling.
  • No muscle turgor.
  • Intact capillary circulation.
82
Q

indications of viable limb in cases of acute embolic ischemia

A
  • no fixed mottling.
  • No muscle turgor.
  • Intact capillary circulation.
83
Q

Signs of adequate embolectomy in Immediate Embolectomy in treatment of acute embolic ischemia

A
  1. Back bleeding. .
  2. Pulses are felt during the operation.
  3. Intraoperative angiography.
84
Q

Complications of Immediate Embolectomy in treatment of acute embolic ischemia

A
  1. Rupture of the artery.
  2. Dissection.
  3. Distal embolization
85
Q

Prognosis of Immediate Embolectomy in treatment of acute embolic ischemia

A

Removal of embolus within 6-10 hrs of onset of symptoms can result in saving the limb completely

86
Q

Prevention of complications in treatment of acute embolic ischemia

A

Fasciotomy

NaHCO3 + Glucose-insulin infusion

mannitol infusion & dialysis if anuria developed.:

87
Q

the reason why we do Fasciotomy

A

To prevent compartmental syndrome

88
Q

the reason why we give NaHCO3 + Glucose-insulin infusion

A

To stimulate intracellular shift of K+ :

To prevent cardia arrest and cardiac arrhythmia

89
Q

the reason why we give mannitol infusion & dialysis if anuria developed

A

to prevent crush syndrome

90
Q

Prevention of further emboli in treatment of acute embolic ischemia

A
  1. Long term anticoagulants e.g. warfarin.

2. Treatment of the underlying cause whenever possible.

91
Q

indication of delayed embolectomy

A

If the patient is presented after 24 hours

It’s done to save the profunda femoris artery & hence a safe AKA.

92
Q

Amputation in treatment of acute embolic ischemia

A

indications

Rule

93
Q

indications of Amputation in treatment of acute embolic ischemia

A

irreversible ischemia with permanent tissue damage

94
Q

Permanent tissue damage in acute embolic ischemia is known by

A

turgid muscles
or
fixed mottling & cyanosis

95
Q

turgid muscles

A

Like rigor mortis

96
Q

Pathogenesis of fixed mottling in Permanent tissue damage in acute embolic ischemia

A

Thrombosis reached vasodilated skin blood vessels

97
Q

Rule of amputation in treatment of acute embolic ischemia

A

Palpable popliteal pulse)> Below knee amputation “BKA”.

Absent popliteal pulse)> Above knee amputation “AKA”.

98
Q

ETIOLOGY of acute thrombotic ischemia

what changes the condition from chronic to acute

A
  • Atherosclerosis.
  • Typhoid fever.
  • Polycythaemia.
  • Dehydration e.g. with diarrhea.
  • Prolonged immobilization.
99
Q

Clinical picture of acute thrombotic ischemia

A

6Ps + previous history of chronic ischaemia.

100
Q

the reason why acute thrombotic ischemia is less severe than acute embolic ischaemia.

A

Collaterals are more developed in patients with preexisting chronic ischemia

101
Q

Investigations of acute thrombotic ischemia

A
  1. Arterial duplex scanning.
  2. Urgent arteriography is a MUST.
  3. ECG, echocardiography.
102
Q

the reason why Urgent arteriography is a MUST in case of acute thrombotic ischemia

A

To detect run off

If present )> by pass surgery

103
Q

Treatment of acute thrombotic ischemia

A

Acute arterial thrombosis is an emergency.

  1. Bypass graft
  2. lntra-arterial thrombolysis by streptokinase, urokinase or TPA is another option of treatment:
104
Q

indications of Bypass graft in Treatment of acute thrombotic ischemia

A

if there is good run-off.

105
Q

Indications of lntra-arterial thrombolysis by streptokinase, urokinase or TPA

A
  • if there is no run-off.

* High risk patient for bypass graft.