This topic is under the Arterial Diseases of the Limbs. The MBBS students should know the Classification and Pathogenesis of Diabetic Foot. Also the different types of Gangrene and difference between Dry & Wet Gangrene....

1. Prof. U. Murali.
Gangrene &
Diabetic Foot

2. Learning Objectives
• Define gangrene. List the types & causes of gangrene.
• Describe the C/F & management of gangrene.
• Compare and contrast dry gangrene and wet gangrene.
• Explain the pathogenesis of diabetic foot.
• Mention the classification of diabetic gangrene.
• Outline the treatment options of diabetic gangrene.
• Discuss about – Frostbite.

3. Gangrene
Prof. U.Murali.

4. Definition
• It is macroscopic death of tissue
in situ (in continuity with
adjacent viable tissue) with
putrefaction (loss of function
also).
• It usually affects the most distal
part of a limb because of arterial
obstruction (from thrombosis,
embolus or arteritis).

5. 1/10/2024

6. Gangrene
Causes
• Sec – Emboli / A S
• Infective
• Traumatic
• Physical
• Venous
Sites
• Limbs
• Appendix
• Bowel
• Testes
• Gallbladder

8. Clinical Features
• Color changes – Greyish,
brownish black – due to
disintegration of Hb → iron
sulphide.
• Loss of pulsation / sensation /
function.
• Line of demarcation – viable &
dead tissue by – band of
hyperemia & hyperesthesia.
• Pre-gangrene features – rest
pain, color changes, hyperesthesia.

9. Differences between Dry / Wet Gangrene
Dry Gangrene Wet Gangrene (Moist)
1. Clean line of demarcation - seen Line of demarcation – vague
2. Dry / Shriveled / Mummified Oedematous / discolored / putrefied
3. Slow, gradual loss of blood supply Sudden loss of blood supply
4. Separation – by aseptic ulceration Septic ulceration – causes separation
5. Limited to demarcation Can extend proximally – rapidly – Skip areas
6. Causes – Atherosclerosis / TAO Emboli / trauma
7. Limited amputation - sufficient Major / higher amputation - often needed

10. Dry Gangrene Wet Gangrene

11. Gangrene
Investigations
• Hb %
• Blood sugar tests
• X-ray – affected part
• Doppler / Angiogram.
• U/S – abdomen
Treatment
• Drugs
• Care of toes & feet
• Cause is treated
• Amputation

12. • Drugs: Antibiotics, vasodilators,
pentoxiphylline, praxilene,
dipyridamole, small dose of
aspirin, ticlopidine.
• Cause is treated. If the patient is
Diabetic, it is controlled.
• Surgeries –
To improve the limb perfusion:
1. Lumbar sympathectomy
2. Omentoplasty.
Gangrene Treatment – Limb Saving Methods
Care of Feet

13. • Amputations may have to be done
often.
• Level of amputation is decided on
skin changes, temperature, line of
demarcation, Doppler study.
• Below-knee amputation is a better
option as BK prosthesis can be fitted
better and the movements of knee joint
are retained. There is no need of
external support and limp is absent.
• In above-knee amputation range of
movements are less, limp is present,
and often requires third (stick) support
to walk.
Gangrene Treatment – Life Saving Methods

14. Diabetic Foot
Prof. U.Murali.

15. Introduction
• Diabetes accounts for a substantial
number of the major foot infections.
• DF lesions are responsible for more
hospitalization than any other
complications of diabetes.
• Diabetes is the most common cause
of non-traumatic amputations of
lower limbs.

16. Definition
• Diabetes foot is a pathological
condition of the foot in diabetic patients,
comprised by skin & soft tissue lesions,
damage to joints & bones, presenting as
ulcers, deformities, necrotic &
gangrenous process.
• Among patients with diabetes, 15%
develop a foot ulcer and 12-25% of these
patients with a foot ulcer require
amputation.
• DF is by far the costliest complication
of diabetes mellitus {acc. To WHO}.

17. Risk Factors

18. Etiology
Classification
• Neuropathic foot – In which
peripheral neuropathy predominates
but the major arterial supply to the foot
is intact.
• Neuro-ischemic foot – Where
occlusive vascular disease is the main
factor by macro microangiopathy while
neuropathy is also present.
• Non-neuro-ischemic foot – No
significant neuropathy or ischemia.
Often follows a trauma and gets
infected because of uncontrolled /
undetected diabetes.
Severity of Ulcer

20. 1/10/2024

23. Pathogenesis
• ↑ blood level –
good culture
media
• Micro-
angiopathy –
hypoxia
• Neuropathy –
sensory/motor

24. Pathogenesis
• Atherosclrosis
– reduces
blood supply
• ↑ GHb –
hypoxia
• Immunosupp –
reduces phago-
cytic activity

25. Clinical Features
• Pain in foot.
• Ulceration.
• Absence of sensation.
• Absence of pulsations in
the foot.
• Loss of joint movements.
• Abscess formation.
• Color & Temp. changes
– gangrene.

26. Investigations
• Glucose Profile, urine – KB.
• Blood urea / Sr. creatinine.
• X-ray – affected part.
• Pus – C / S.
• Doppler study – patency.
• Imaging – CT / MRI.
• Angiogram – blockage.
• Tests – Sensation / Foot deformity.

31. Treatment
• Diabetes control– Insulin only.
• Diet control / Obesity control.
• Antibiotics – to pus C/S.
• Regular dressings.
• Surgical debridement.
• Pressure Off-loading.
• Care of feet – Important.
• Amputation when needed.

32. DFU - TRT
Ensuring Adequate Vascular Supply
Treat Underlying Disease Process - Insulin
Local Wound Care – Infection Control
Pressure Offloading

41. Frostbite
• It is due to exposure to cold weather
/ high altitude.
• More common in elderly people.
• Cold injury - damages the vessel wall
– swelling & leakage of fluid with
severe pain.
• Later the pain disappears, area
becomes waxy with blisters followed by
gangrene.
• Treatment is gradual rewarming,
analgesics & delayed conservative
amputation after demarcation of
devitalised tissue.

42. To Summarize
• Definition & Types of Gangrene.
• Causes & Treatment methods of gangrene.
• Differences between dry gangrene and wet gangrene.
• Pathogenesis of diabetic foot.
• Risk factors & Classification of diabetic foot.
• Investigative methods & treatment options of DFU.
• Features of frost bite.

43. References

44. Question Time
• Define Gangrene. Write the features of pre-gangrene.
• List the types, sites & causes of gangrene.
• Compare and contrast dry gangrene and wet gangrene.
• Explain the pathogenesis of diabetic foot.
• Name the classification and mention the treatments
options of diabetic gangrene.
• Enumerate the foot deformities in a person with diabetes.
• Mention the vascular assessments & sensory foot
examination in diabetic foot patients.
• What is a frost bite? Add a note on it.

45. Which of the following is true regarding
diabetic foot infections ?
• a) They are usually caused by infections with gram-positive
organisms only.
• b) Surgical debridement is unnecessary when pedal pulses are
present.
• c) Meggitt’s grading is very useful.
• d) Neuropathy is rarely a contributing factor in their development.

46. On comparing & contrasting dry gangrene with wet
gangrene, differentiate the features of dry gangrene
from the below statements ?
• a) Clear line of demarcation.
• b) Can extend proximally rapidly.
• c) Sudden loss of blood supply.
• d) Separation by septic ulceration.

47. A patient has a gangrenous limb, where the zone of
demarcation is developing. The distal part is becoming
discolored. At the region between the viable and the dead
or dying tissue, the clinician is most likely to find -
• a) Air bubbles below the viable skin.
• b) Hyperesthesia of the viable skin.
• c) Serous, enzyme rich discharge at the line of demarcation.
• d) A deep band of cleavage.

48. A doctor practicing in the hills encounters an elderly man who
presents with severe pain in the foot after a prolonged exposure to
snow. O/E the foot is cold, devoid of sensation and lacks venous
return. Which of the following should NOT be done as part of
management? -
• a) Administration of painkillers.
• b) Rapid warming of the patient with blankets / warm drinks.
• c) Rapid warming of the foot to 50°C.
• d) If gangrene develops, try to save limb length.

49. Which one of the following is not a foot
deformity in a patient with diabetes –
• a) Claw toe.
• b) Hammer toe.
• c) Metatarsal head prominence.
• d) Hallux varus.