Diabetic foot

Diabetic foot

by
Dr. Ammar Tlib Al-yassiri

objectives

definition
Epidemiology
Pathophysiology
Classification
Prevention
management

Definition

The complications of longstanding diabetes mellitus which often appear in the foot and, causing chronic disability.

Epidemiology

More than 30% of patient attending diabetic clinics have evidence of peripheral neuropathy or vascular disease
about 40% of non-trauma related amputations are for complications of diabetes.
nearly one in six patients die within one year of their infection


Pathophysiology
Factors predisposing diabetic patients to developing :diabetic foot are
1.Peripheral vascular disease
2.damage to the peripheral nerves
3.Reduced resistance to infection,
4. Osteoporosis

Peripheral vascular disease

atheroseclerosis affects mainly the medium sized vessels below the knee
The pt. may complain of claudication or ischemic changes and ulceration in the foot.
The skin feels smooth and cold the nails show trophic changes .
pulses are weak or absent
Superficial ulceration occurs on the toes
deep ulceration typically under the heel these ulcers are painful and tender

Digital vessels occlusion may cause dry gangrene of one or more toes.

proximal vascular occlusion resulting in extensive wet gangrene.

Peripheral neuropathy:

early on the pt usually unaware of the abnormality but clinical tests will discover
loss of vibration and position sense and
diminish of temperature
Diminish of discrimination in the feet


Symptoms : mainly due to
sensory impairment:
symmetrical numbness and parasthesia,
dryness and blistering of the skin,
superficial burns and skin ulcers due to shoe scuffing or localized pressure
Motor loss:
muscle weakness and intrinsic muscle imbalance usually manifests as claw toes with high arches and this may in turn predispose to plantar ulceration.

Neuropathic joint disease (Charcot joints)

it is chronic, progressive, destructive process affecting bone architecture and joint alignment in people lacking protective sensation.
the mid tarsal joints are most commonly affected followed by the MTP and ankle joints
There is usually provocative incident such as a twisting injury or a fracture following which joint collapses relatively painlessly
In late cases there may be severe deformity and loss of function. A rocker-bottom deformity from collapse of mid foot is diagnostic.

Osteoporosis

there is generalized loss of bone density in diabetes.
In the foot the changes may be severe enough to result in insufficiency fractures around the ankles and or in the metatarsals.

Infections

diabetes, if not controlled is known to have
adverse effect on the white cell function.
This combined with the
local ischemia,
insensitivity to skin injury and
localized pressure due to deformity,
• makes sepsis an ever recurring hazard.


Classification
Diabetic foot infection may be classified as:

superficial: often associated with ulceration.

Deep infection: may involve
soft tissues only with abscess formation or
can involve bones (osteitis or osteomylitis). This type of infection can also involve local joints (pyogenic arithritis).

Wagner classification system

most widely used and universally accepted grading systems for DFU
used to assess ulcer depth
0 Pre-ulcerative area without open lesion
1 Superficial ulcer (partial/full thickness)
2 Ulcer deep to tendon, capsule, bone
3 Stage 2 with abscess, osteomyelitis or joint sepsis
4 Localized gangrene
5 Global foot gangrene.

Prevention:

insist on regular attendance at a diabetic clinic.
full compliance with medication
examination for early signs of vascular or neurological abnormality.
advice on foot care and footwear and a high level of skin hygiene.


Foot care for the at risk patients
To do list:
*Inspect the foot daily using a mirror to see the sole and don’t forget between the fingers.
*Wash feet daily
*Apply lotion to avoid skin cracks and if present skin cracks should be kept clean and covered
*Use a comfortable shoe wear and change it often
*Inspect shoes before wearing it from inside and outside. *Great care is needed with nail trimming

Not to do list:

* Smoking
*Step into bath tub without checking the temperature of the water.
*use hot water bottles or heating pad.
*use keratolytic agent to treat the calluses or corn. *Wearing a tight shoes or stocking.
*walking with barefeet

Management of diabetic foot

For the management of diabetic foot there should be a multidisciplinary team comprising
a physician (or endocrinologist) ,
orthopaedic surgeon,
General surgeon,
chiropodist and orthotist


Evaluation of diabetic foot patient
Peripheral neuropathy:
Sensory: Examination for early signs of neuropathy should include the use of
Semmes-Weinstein hairs (for testing skin sensibility)
Biothesiometer (for testing vibration sense),
Thermal discrimination test,
And joint position sense.
Motor: examine for wasting, weakness, absent or diminished tendon reflex, and deformities (claw toes, hammer toes, pes cavus). This can be enhanced by the EMG & N/C study.

Peripheral vascular damage: examine for

the pulses,
skin temperature,
trophic changes in the skin and nails
Peripheral vascular examination is enhanced by using
Doppler ultrasound probe,
ankle brachial index measurement,
Absolute toe pressure,
transcutaneous oxygen measurement,
angiography.

Infection:

the local and systemic signs of infection.
Ulcers must be swabbed for infecting organisms.
Magnetic resonance imaging (MRI) is the most specific
and sensitive non-invasive test to evaluate
Osteomyelitis
probable abscess
sinus tract formation.
Bone scans, such as the white blood cell labeled Indium-111, Technetium-99m HMPAO and Sulfur Colloid Marrow Scan,
distinguishing acute and chronic infections,
identifying OM from Charcot neuroarthropathy

Osteopathy:

Examine for Charcot deformities
flatening of the foot arches,
rocker-bottom deformity,
prominent metatarsl heads.
X-ray examination may reveal
periosteal reactions,
osteoporosis,
cortical defects near the articular margins and
osteolysis - often collectively described as 'diabetic osteopathy

Laboratory investigations :

WBC elevated in 50% of patients.
renal function,
electrolytes,
acidosis,
blood glucose level.
Hemoglobin A1C levels provide a barometer of glycemic control averaged over the previous 2-3 months.
Acute phase reactants ESR &CRP (baseline and post-treatment CRP, ESR and WBC were significantly elevated in patients who ultimately required amputation).
Total serum protein and albumin→nutritional status.


treatment
According to wagner classification:
Grade 0 (skin intact): calluses should be trimmed so as not mask active ulcer, advise the patient how to do daily foot care and apply the preventive measures.(extra depth shoes and pressure relieving insole)
Grade 1&2(superficial & deep ulcer but without infection ): the aim here is to heal the skin, after desloughing the ulcer and removing the hyper keratotic skin the ulcer can be dressed locally, the application of a skin - tight POP(total contact cast) changed weekly will allow most of the ulcers to heal. It also allows the patient to be mobile

Grad 3 (grade2 with infection):

deep infection without abscess formation can be treated by strict rest, elevation, soft tissue support and AB.
Occasionally, septicemia calls for admission to
hospital and treatment with intravenous antibiotics.
Any form of abscess formation needs to be drained urgently and the deeper tissues thoroughly debrided.
Deep ulcers in certain sites are more problematic than elsewhere . Once an ulcer is healed the use of appropriate insoles and shoes can prevent further ulceration.

Grade 4(localized gangrene):

Ischaemic changes need the attention of a vascular surgeon who can advise on ways of improving the local blood supply. Arteriography may show that bypass surgery is feasible.
Dry gangrene of the toe can be allowed to demarcate before local amputation.
With diabetic gangrene septic arithritis is not uncommon , the entire ray(toe+metatarsal bone ) should be amputated.
In More extensive gangrene partial foot amputation done e.g. through the midtarsal joints(Chopart),thruogh tarsometatarsal joints(lisfranc), thruogh metatarsal bone, syme’s amputation

Grade 5(Global foot gangrene) :

severe occlusive disease with wet gangrene may call for immediate amputation.
This should be undertaken at a level where there is a realistic chance of the wound healing.


Treatment of special problems
Ischaemic changes : need the attention of a vascular surgeon who can advise on ways of improving the local blood supply. Arteriography may show that bypass surgery is feasible.
Insufficiency fractures: should be treated, if possible, without immobilizing the limb; or, if a cast is essential, it should be retained for the shortest possible period.
Fixed foot deformities : corrective surgery should be considered.

Neuropathic joint disease : is a major challenge.

Arthrodesis is fraught with difficulty,
very poor union rate,
sometimes is simply not feasible.
'Containment' of the problem in a weight-relieving orthosis may be the best option.

Home message

Diabetic foot is the complications of longstanding diabetes mellitus.
common problem and can lead to serious consequences.
Four major predisposing factors: ischemia, neuropathy, immunopathy and osteopathy.
insist on regular attendance at a diabetic clinic and apply preventive measures.
multidisciplinary team is required for the management of diabetic foot.