GANGRENOUS TOE SPECIMEN

Question 1

OUTLINE THE VARIETIES AND AETIOLOGY OF A GANGRENOUS TOE SPECIMEN

Answer 1

a) 2˚ to arterial obstruction
-Thrombosis
-Embolus
-Arteries with neuropathy in DM
-Buegers disease due to vasculitis
-Raynaud‘s
-Arterial infection- drugs
b) Infective
-Abscesses
-Gas gangrene
-Fournier gangrene (tissue necrosis/infection of perineum in pts. with DM)
c) Traumatic
-Direct injury (knife, bullet)
-Crashing injury (compression)
-Physical- pressure sores, burns
-Heat, irradiation, electrical
-Constructed grove of strangulated bowel
d) Venous
-Venous gangrene

Question 2

WHAT ARE THE CAUSES OF LIMB ISCHEMIA?

Answer 2

1. Atherosclerosis
2. Embolism (acute presentation)
3. Arteropathies – Buerger’s disease, Raynauds disease, takayasu’s disease
4. Diabetes
5. Scleroderma
6. Physical agents: trauma, tourniquet, radiation injury

Question 3

OUTLINE THE CLINICAL FEATURES OF LIMB ISCHEMIA

Answer 3

Clinical features of limb ischaemia
 Symptoms and signs depend on the site of occlusion, duration of ischaemia and degree of collateral circulation.
 Embolus more likely if severe, features are of sudden onset and potential source identifiable, e.g. atrial fib.
 Thrombosis usually if less severe (collaterals present), history of claudication
 Look for
-Arterial pulsation
-Venous return
-Capillary refilling
-Marked pallor, cyanotic appearance
-Brittle nails with transverse ridges
-Pulsation - Absent popliteal and lower pulsations
-Sensation - Decreased sensations
-Warmth/Cold and tenderness
-Functionality of the limb- Inability to move toes
-Ulceration on the foot and digits
-Muscles waisting
-Color changes: dark brown due to Hb disintegration and iron sulphides formation

Question 4

EXPLAIN THE FEATURES OF POOR CIRCULATION

Answer 4

Other features of poor circulation
1. Cold with numbness, paraesthesia and colour changes.
2. Ulceration, gangrene, decreased sensation and movements.
3. Delayed capillary filling: Blanched nails or pulp of fingers, on pressure, show delay in refilling.
4. Delayed venous refilling: place 2 fingers over the vein. Finger nearest to heart is moved away so as to empty the vein. Distal finger is released to observe the venous refilling. Delay in filling is called Harvey’s sign, signifies ischaemia. It’s increased in AV fistulas.
5. Crossed leg test (Fuchsig’s test): ask pt to sit with legs crossed one over the other so that popliteal fossa of one leg will lie against the knee of other leg. Oscillatory movements of foot can be observed synchronous with popliteal artery pulsation and is absent with blockage of popliteal artery.
6. Disappearing pulse syndrome: Exercise limb after feeling the pulse, which disappears once pt develops
claudication (unmasking the arterial obstruction).
7. Buerger’s postural test: Pt lying down on his back is asked to raise the leg above. Ischaemic limb (on
plantar aspect of foot), when elevated shows marked pallor and empty veins remains pink even after raising
above 90° in normal individuals. Buerger’s angle of vascular insufficiency is the angle at which pallor
develops and an angle of < 30°, indicates severe ischaemia.
8. Systolic bruit may be heard over stenosed artery like subclavian artery, femoral artery, carotid artery, iliacs,
renal artery.
9. Adson’s test (Scalene manoeuvre): radial pulse is felt with pt sitted on a stool, then asked to take a deep
breath (to allow rib cage to move upwards to narrow the cervicoaxillary channel) and turn the face to same
side (to contract scalenus anterior muscle to narrow the scalene triangle). If radial pulse disappears or
become feeble it signifies cervical rib or scalenus anticus syndrome.
10. Elevated arm stress test (EAST), or modified Roos test: With both arms kept in 90° abduction and external
rotation position, ask pt to make a fist and release repeatedly for 5 minutes. Pt will continue to do the
manoeuvre in normal side whereas in diseased (Thoracic outlet syndrome) side pt gets pain and
paraesthesia with difficulty in continuing the manoeuvre and drops the arm down to relieve the symptoms
11. Costoclavicular compression manoeuvre (Falconer test): Radial pulse becomes absent when patient draws
his shoulders backwards and downwards in excessive military position because at the subclavian artery is
compressed between first rib and clavicle, leading to feeble or absent radial pulse.
12. Hyperabduction manoeuvre (Wright test): radial pulse becomes absent or feeble when affected arm is
hyperabducted, due to compression of artery by pectoralis minor tendon.
13. Allen’s test: done to find out the patency of radial and ulnar arteries. Compress both arteries near the wrist
and allow to blanch completely in one minute (while pat closes and opens the fist several times for further
venous outflow). When palm appears pale and white, one of the arteries is released and colour of hand is
noted. Normally hand will become pink and flushed in no time; whereas in obstruction, the area will still
remain pale. Then release the other artery and looked for changes in hand.
14. Examine for presence of abdominal aortic aneurysms. Presents as pulsatile mass above the umbilicus,
vertically placed, smooth, soft, nonmobile, not moving with respiration, resonant on percussion. Confirm
expansile pulsation by placing the patient in knee elbow position.
15. Auscultate for arterial bruit over femoral artery, abdominal aorta, subclavian and carotid arteries

Question 5

HOW IS LIMB ISCHEMIA CLASSIFIED?

Answer 5

Classification of limb ischaemia
1. Functional Limb Ischaemia - blood flow is normal when limbs are at rest; but presents with claudication
with increased during exercise.
 It as. It is defined as, “Muscle discomfort in the limb reproducibly produced by exercise and relieved by rest
within 10 minutes.
2. Critical Limb Ischaemia: It is persistently recurring ischaemic rest pain for 2 wks, which requires regular
analgesics for > 2 wks or ulceration or gangrene of foot or toes with an ankle SBP < 50 mmHg or toe SBP <
30 mmHg. Ankle brachial pressure index (ABPI) will be less than 0.3

Question 6

OUTLINE THE FONTAINE CLASSIFICATION OF LIMB ISCHEMIA

Answer 6

Fontaine classification of limb ischaemia
Stage 1: No clinical symptoms
Stage 2: Intermittent claudication
– 2a: Well-compensated—can walk > 200 metres
– 2b: Poorly compensated—walk only < 200 metres
Stage 3: Rest pain
Stage 4: Gangrene, ischaemic ulcer

Question 7

WHAT IS CLAUDICATION?

Answer 7

Claudication: crampy aching pain in the calf muscles appearing with fixed level of exercise (claudication distance)
and relieving promptly (2-3 mins) on rest

Question 8

OUTLINE BOYD’S CLASSIFICATION OF CLAUDICATION

Answer 8

Boyd’s classification of claudication
Boyds 1: pain- walk- relief- pain after walking, relieved with persistence
Boyds 2: pain- walk- no relief-Pain persists on continuing walk; but can walk with effort
Boyds 3: pain- stop- relief- Pt has to take rest to relieve pain
Boyds 4: rest pain

Question 9

DIFFERENTIATE BETWEEN GANGRENE AND PREGANGRENE

Answer 9

 Gangrene- It is macroscopic death of tissue in situ with putrefaction.
 Pregangrene- It is the changes in tissue which indicates that blood supply is inadequate to keep the tissues alive
and presents with rest pain, colour changes, oedema, hyperaesthesia with or without ischaemic ulceration.

Question 10

DIFFERENTIATE BETWEEN THE CLINICAL TYPES OF GANGRENE

Answer 10

1. Dry gangrene- It is dry, desiccated, mummified tissue caused by gradual slowing of bloodstream. There is a
   line of demarcation and is localised
   a) Tissue desiccation by gradual slowing of the blood stream
   b) Due to atheromatous occlusion of arteries
   c) Affected part is
   -dry
   -Wrinkled
   -Discolorized from Hb disintegration
   -Greasy to touch
2. Wet gangrene- due to both arterial and venous block along with superadded infection and putrefaction. It
   spreads proximally and there is no line of demarcation. It spreads faster
   a) Venous and arterial obstruction present
   b) When artery is suddenly occluded e.g. ligature or embolus and in diabetes
   c) Infection and putrefaction are always present
   d) Affected part becomes swollen and discolored
3. Gas gangrene

Question 11

WHAT INVESTIGATIONS DO YOU CARRY UT IN A PT PRESENTING WITH GANGRENE?

Answer 11

1. Bloods: FBC, U&Es, coagulation profile, thrombophilia screen, WBC count to r/o infection; raised platelet count may precipitate thrombosis (of arteries and veins both);
2. Blood sugar (RBS, FBS, OGTT and glycosylated haemoglobin (HbA1C) r/o diabetis;
3. Lipid profile;
4. Peripheral smear;
5. Renal function tests (serum creatinine) and liver function test
6. Imaging: CXR, Doppler or duplex scanning of blood flow, arteriography to demonstrate the site of occlusion and plan intervention if limb viable.
   a. Angiography: appropriate investigation for arterial diseases
   b. CT angiogram/MR angiogram.
   c. Ultrasound abdomen- exclude aneurysm/aorta and its anatomical changes/other vessels
7. Plethysmography: measures blood flow in limbs. Segmental plethysmography using occlusion cuffs of 65mmHg pressure is placed at thigh, calf and ankle levels and then quantitative measure of pulsation is done.
8. Ankle-brachial pressure index: It is cornerstone of diagnosis.
9. ECG: Looking for atrial fibrillation.
10. Treadmill test/ECG/echocradiography to assess cardiac/coronary status
11. Transcutaneous oximetry: By placing polarographic electrodes over the skin over thigh, leg and foot of oxygen tension (tcPO2) can be measured

Question 12

OUTLINE THE ANKLE-BRACHIAL
PRESSURE INDEX IN GANGRENE

Answer 12

Ankle-brachial pressure index: It is cornerstone of diagnosis. Takes the ratio of systolic pressure at the ankle to that in the arm. The highest pressure in the dorsalis pedis, posterior tibial or peroneal artery serves as the numerator, with the highest brachial systolic pressure being the denominator. ABPI is checked in supine position with a proper cuff; SBP in upper and lower extremities (2 upper and 2 lower) is checked and higher value of each extremities is taken; ABPI is calculated. Results—>0.90 is normal; 0.70–0.89 is mild disease; 0.50–0.69 is moderate; <0.50 is severe, >1.3: Arteriosclerosis. Resting ABPI is normally about 1.0, values below 0.9 indicate some degree of arterial obstruction (claudication), less than 0.5 suggests rest pain and less than 0.3 indicates imminent necrosis

Question 13

IN SUSPECTED GANGRENE, WHAT QUESTIONS DO YOU NEED TO ASK TO FORM A DIAGNOSIS?

Answer 13

Ask the following questions on the diagnosis
* Is this ischaemia?
* Is this an embolism or thrombosis? clinical features include:
 Rapidity of onset of symptoms
 Features of pre-existing chronic arterial disease
 Potential source of embolus- emergency treatment. Embolic disease - embolectomy or intra-arterial
thrombolysis
 Embolic disease - embolectomy or intra-arterial thrombolysis
 State of pedal pulses in contralateral leg
 Is this limb viable? If not amputate the limb

Question 14

OUTLINE THE MANAGEMENT OF GANGRENE

Answer 14

 Immediate: ABCs, analgesia, heparin anticoagulation to prevent thrombus propagation. Immediate admin of
5000 U of heparin IV can reduce this extension and maintain patency of the surrounding (particularly distal)
vessels until embolus can be treated.
 Treat associated cardiac disease
 Surgical: Revascularisation within 6 hours in order to salvage limb. Operative risk is often high due to
underlying heart disease. Postoperative anticoagulation is essential
 If acute or chronic thrombosis: The limb may remain viable for a longer time due to collateral formation,
and percutaneous intervention is an option, e.g. aspiration, intraarterial thrombolysis with local infusion of,
e.g., t-PA, and angioplasty of underlying stenosis
 Intra-arterial thrombolysis; Arteriogram and catheter advanced into thrombus and give Streptokinase
5000u/hr + heparin 250u/hr
* Alternative thrombolytic agents include Urokinase or tissue plasminogen activator (tPA)
* Repeat arteriogram at 6 -12 hours
* Advance catheter and continue thrombolysis for 48 hours or until clot lyse
* Contraindications to thrombolysis; recent stroke, bleeding diathesis, pregnancy, and results in those over
80 years old