DM Foot problems Flashcards
What are the three major complications that arise from DM?
- Peripheral neuropathy
- Autonomic Neuropathy
- PVD
What are the arteries that are classically associated with PVD?
Tibial
Peroneal (fibular)
What are the three major contributing factors of PVD in DM?
- Smoking
- HTN
- Hyperlipidema
What happens to bone with autonomic dysfunction of the foot?
Dilation of vessels, causing increased bone resorption
charcot foot
What happens to the skin of the foot with autonomic dysfunction of the foot?
Dry, cracked skin
What are the immune consequences of PVD?
Impaired wound healing
What are the components of metabolic syndrome?
- Hyperinsulinemia
- Hypertriglyceridemia
- HTN
- Central obesity
What are the ssx of PVD?
- Atrophic skin
- Rest pain
- Claudication
- Pallor on elevation
What happens to the aorta and medium sized vessels with PVD?
Accelerated atherosclerosis
What are the major PE findings of PVD?
- Diminished pulses
- Cap refill time
- Skin atrophy
What is the inexpensive test that can be used to evaluate for PVD?
Ankle brachial index
Greater than 0.50
What is the minimum value of the ABI and transcutaneous oxygen that is needed for healing in the foot?
More than 0.5
More than 30 mmHg
What is a normal ankle brachial index? Moderate obstruction?
Above 0.9
Moderate = 0.5-0.8
At what level of obstruction does loss of the arterial rebound with occur? What about loss of the reversal of blood flow
Mild obstruction
Moderate obstruction
What can cause an inaccurate ABI? Why?
Calcified vessels will lower the ratio, since they will not compress as readily
What happen to the waveform of the doppler US as you progress from normal to severe obstruction?
Normal = triphasic Mild = biphasic Moderate = monophasic Severe = loss of peaks
What is transcutaneous oxygen pressure measurement?
O2 levels in the arteries through the skin
Why may someone with a poor ABI have a normal transcutaneous oxygen pressure?
Collateral circulation
What are the invasive vascular exam that may be performed to assess for arterial oxygen? (3)
Arteriography
MRA
DSA
What are the causes of the increased ulceration risk with peripheral neuropathy, beside the loss of sensation and increased blood flow?
More pressure on the toes and bony prominences
What is “neuro-traumatic” theory of Charcot foot osteoarthropathy?
Exaggerated overuse injury coupled with loss of protective sensation
Allows for continued tissue destruction in
What is “neurovascular” theory of Charcot foot osteoarthropathy?
AV shunting leads to excessive bone resorption, contributing to fractures
What is stage 1 Charcot neuropathy?
The acute destructive phase, characterized by inflammation, joint effusion, and degradation of bone
What is stage 2 Charcot neuropathy?
Coalescence phase:
-Further bone/cartilage destruction, but initiation of sclerosis where cartilage has degraded, and fusion of bone fragments
What is stage 3 Charcot neuropathy?
Reconstruction phase:
- Remodeling of joint surfaces
- Sclerosis
What is the treatment for the acute stage of Charcot foot?
- Reduce weight bearing
- Cast immobilization
- Drugs to inhibit bone resorption
- Manage ulcers
What is the major issue with immobilization of one foot for charcot?
Will favor the other foot, causing Charcot on the other
How do you follow Charcot?
Weekly foot x-rays
When is surgery for Charcot indicated?
If causing pressure ulcers d/t bone remodeling
What happens to the bones with Charcot foot?
“Rocker-bottom” foot d/t loss of midfoot
What are the four major types of ulcerations?
Arterial
Venous
Neuropathic
Pressure
What are the molecular stages of chronic wound healing?
Constant inflammatory cytokines increases proteases and MMPs, and a loss of GFs and TIMPs
What is grade 0 Wagner’s foot?
No evidence of ulcer or infx
What is grade 1 Wagner’s foot?
Superficial ulcers
What is grade 2 Wagner’s foot?
Ulcers that have not yet penetrated to the bone or fascial plane
What is grade 3 Wagner’s foot?
Ulcers extend to bone, or have invaded fascial plane
What is grade 4 Wagner’s foot?
Feet have gangrene of the forefoot
What is grade 5 Wagner’s foot?
Gangrene of the entire foot that will likely require amputation
What are the general principles of ulcer wound management (3)
- Increase vascular supply
- Debride/wound management
- Offload
What are the most common infections seen in DM Pts?
Bacterial and fungal skin infx
How do you collect a good culture of the foot?
Deep swab and collect purulence
What is the definitive diagnostic modality for osteomyelitis?
Bone biopsy
What are Tc-99m scans used for?
Collects on osteoapatite
very sensitive, but not specific
What can indium scans detect?
WBCs with:
Acute osteomyelitis
Acute cellulitis
What can ceretec scans detect?
WBCs with:
Acute osteomyelitis
What can Tc-99 scan detect? (4)
- Acute/inactive osteomyelitis
- Acute cellulitis
- Charcot joint
Why is it that the indium scan no detect inactive chronic osteomyelitis?
No WBCs present
