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Diabetic Foot Ulcer

Diabetic foot ulcers are painful sores appearing in the feet of people with type 1 and type 2 diabetes.


Presentation

Foot ulcers may appear long before they come in patient's notice. Elderly people may wrongly perceive signs and symptoms in lower limb as harbingers of senility and ignore a potentially correctable condition. Symptoms of peripheral neuropathy and arterial insufficiency precede ulcer formation. Ulcers most commonly occur on following sites:

  • Heel
  • Medial aspect of navicular bone 
  • Inferior aspect of cuboid bone
  • Medial or lateral malleoli
  • Tips of toes (hammer toes)
  • Any pressure points, e.g. area rubbing against shoe surface.

Any diabetic patient having following signs and symptoms is susceptible to develop ulcers. Peripheral neuropathy, when present, will present with symptoms of altered sensations in limb. These include paresthesia, hypreresthesia, hypoesthesia and dysesthesia. Loss of sweating and cold extremities is signs of autonomic neuropathy. Muscles may be atrophied and limb posture (in supine position) or shape may be abnormal due to earlier complications. Moreover, diabetic patients very frequently present with symptoms of arterial insufficiency that may be:

Increased demand of muscle during exercise or activity, when not adequately met, will cause accumulation of lactic acid, hence causing pain of intermittent claudication. Patients with atherosclerotic disease can be without symptoms while some people can have frank ischemia. History should be aimed at these signs and symptoms, which may also be helpful in early diagnosis and prevention of later complications and/or recurrent ulcers.

Examination is done to assess vascular perfusion, peripheral neuropathy, signs of osteoarthopathy and infectious ulcers. Examination of ulcer is also done taking into consideration its site, shape, margins, edges and tissue present in ulcer bed. General examination of limb may reveal hammer toes, calluses, fissures, previous scars or brittle nails. Special attention should be paid to interphalangial space that may sometimes show ulceration or microbial infection.

Pathologist
  • The clinicians and pathologists should be aware of these combinations because only eradication of mucormycosis may not cure the ulcer, rather presence of squamous cell carcinoma may be ignored that may be an immediate threat to the patient's life.[ncbi.nlm.nih.gov]
Foot Disease
  • METHODS: A mathematical model was developed to simulate the onset and progression of diabetic foot disease in patients with type 2 diabetes managed with optimal care and usual care.[ncbi.nlm.nih.gov]
  • They can lead to much morbidity and some mortality, with foot disease the leading cause of non-traumatic lower-limb amputation in the developed world.[ncbi.nlm.nih.gov]
  • Magnus Löndahl, Katarina Fagher and Per Katzman, What is the Role of Hyperbaric Oxygen in the Management of Diabetic Foot Disease?, Current Diabetes Reports, 11, 4, (285), (2011).[doi.org]
  • Although the complex nature of diabetic foot disease presents particular difficulties in the design of robust clinical trials, and the absence of published evidence to support the use of an intervention does not always mean that the intervention is ineffective[ncbi.nlm.nih.gov]
Foot Pain
  • Better off-loading adherence was, in turn, predicted by larger and more severe baseline DFUs, more severe neuropathy, and NeuroQoL foot pain (P 0.05).[ncbi.nlm.nih.gov]
  • All people with diabetes can develop foot ulcers and foot pain, but good foot care can help prevent them. Treatment for diabetic foot ulcers and foot pain varies depending on their causes.[healthline.com]
  • Tendon lengthening may also be a helpful treatment for Charcot arthropathy, calluses and foot pain in patients with diabetes from other causes listed above. Dr.[podiatrytoday.com]
Foot Ulcer
  • RESULTS: Among the patients, 20 737 developed diabetic foot ulcers; 5.0% of people with new ulcers died within 12 months of their first foot ulcer visit and 42.2% of people with foot ulcers died within 5 years.[ncbi.nlm.nih.gov]
  • Diabetic foot ulcer was found to be 13.6%.[ncbi.nlm.nih.gov]
  • More research is needed on what can help prevent or relieve foot ulcers in diabetes.[doi.org]
  • Diabetic foot ulcer is a severe complication of diabetes, and most patients with diabetic foot ulcer require amputation. The incidence of Budd-Chiari syndrome is low; it is relatively rare.[ncbi.nlm.nih.gov]
  • BACKGROUND: The national clincial guidelines for diabetes recommend that diabetic foot ulcers be treated by interdisciplinary diabetic foot ulcer teams.[ncbi.nlm.nih.gov]
Skin Ulcer
  • Keratinocytes and dermal endothelial cells, excluding leukocytes that infiltrate wounds, are the main source of soluble factors regulating healing of skin ulcers.[ncbi.nlm.nih.gov]
  • ulcers Diabetic foot Categoria nascosta: Uses of Wikidata Infobox[commons.wikimedia.org]
  • Some patients predominatly get neuropathic pain, others skin ulceration and infection, many a combination of both. The classic neuropathic foot has warm dry skin and bounding pulses, but many patients have a combination of neuropathy and ischaemia.[foothyperbook.com]
  • Some large skin ulcers may have a hard time fully healing even with treatments above. They may need a patch of skin to help close the wound. This process is called a skin graft. Bioengineered skin graft or human skin graft may be used.[uvahealth.com]
  • Skin Graft TOP Some large skin ulcers may have a hard time fully healing even with the treatments above. They may need a patch of skin to help close the wound. This process is called a skin graft.[health.cvs.com]
Delayed Wound Healing
  • Molecular analyses of biopsies from the epidermis of patients have identified pathogenic markers that correlate with delayed wound healing. These include overexpression of c-myc and nuclear localization of β-catenin ( 13 ).[doi.org]
  • Percival, Proteases and Delayed Wound Healing, Advances in Wound Care, 10.1089/wound.2012.0370, 2, 8, (438-447), (2013).[doi.org]
  • PVD reduces blood flow to the extremity, which frequently leads to delayed wound healing and wound infection, putting the patient at risk for possible limb loss. 6 A prospective study 7 that examined patients with a history of a foot ulcer found that[o-wm.com]
  • […] as the primary cause for vascular impairment. [1] The risk of developing PAD is increased with diabetes and ischemia is considered the biggest culprit delaying wound healing. [1] Diabetic neuropathy and ischemia combined is called neuroischemia.[physio-pedia.com]
  • During this time the clinicians should also evaluate your overall blood glucose control because it is known that people with high blood glucose levels also demonstrate delayed wound healing.[diabetesselfmanagement.com]

Workup

Diabetic foot ulcer workup needs a good history along with complete general and local examination. History must involve questions regarding symptoms of neuropathy, vascular insufficiency and duration of diabetes. A detailed history of pain and redness must be taken. Foot ulcers and other complications are directly related to duration and severity of disease. Cold extremities, loss of sweating, brittle nails, fissures, hypertrophic calluses and history of past ulceration are very often described by patients. More often, physicians discover these signs in general physical examination. Patient may give a history of renal disease, eye problems or other diabetic complications. Medication history may also prove to be beneficial in certain cases. 

After general physical examination, peripheral vascular system and peripheral nerves are examined [9]. While examining peripheral vascular system, look for any change in color of limb, pigmentation, prominent veins, hair distribution, dryness, fissures, nail lesions, deformities of bones and ulcers or sinuses. While palpating, note temperature of skin and compare it with skin of opposite limb. An increased temperature is a sign of active inflammatory process, whereas dry, cold skin is indicative of ischemia and autonomic neuropathy in that area. Check and compare pulses in both limbs, including dorsalis pedis, posterior tibial, popliteal and femoral artery (note that during general physical examination, other pulses like radial, carotid etc are also checked). Tests for capillary refilling time, intermittent claudication and peripheral sensation should also be done. Interphalangial clefts should be looked for any hidden ulcers or lesions.

Ulcer examination is done with a sterile stainless steel probe. Look for site, color, any discharge (blood/pus), margins and edges of ulcer. Check the ulcer base for any granulation tissue, pus or bone showing from it. Sinus tracts progress from ulcer to underlying tissue and sometime into bones. Depth of sinus tracts must be assessed using stainless steel probe [10].

Laboratory investigations include routine investigations of complete blood count, Erythrocyte Sedimentation Rate (ESR), leukocytosis, blood and urine sugar and urine ketone bodies, electrolytes and creatinine levels. Hemoglobin A1C levels are monitored in order to check glycemic control in patients. Other tests, for renal and hepatic function, should also be done to ascertain patient’s metabolic status. Culture examination from samples taken from ulcer is not that much valuable as all ulcers harbor microorganisms. However, in case of secondary infection, that may help in identification and medical treatment.

Special investigations involve:

  • Imaging techniques like X-ray, MRI 
  • Thermoregulatory sweat testing, quantitative sudomotor axon reflex testing and quantitative direct and indirect axon reflex testing or heart rate variability rate (these tests are to ascertain degree of autonomic/sensory/motor neuropathy).
Albuminuria
  • AIM: To determine the diabetic foot ulcer incidence and examine its association with microangiopathy complications, including diabetic retinopathy (DR) and albuminuria (Alb), in type 2 diabetes patients.[ncbi.nlm.nih.gov]
Multiple Ulcerations
  • Participants with a single ulcer on their index foot had a higher incidence of healing than those with multiple ulcers (hazard ratio 1.90, 95% CI 1.18 to 3.06).[ncbi.nlm.nih.gov]
  • Unit of analysis issues We recorded whether trials measured outcomes in relation to an ulcer, a foot, a participant or whether multiple ulcers on the same participant were studied.[doi.org]
  • Unit of analysis issues We recorded whether trials measured outcomes in relation to an ulcer, a foot, a participant or whether multiple ulcers on the same participant are studied.[doi.org]
  • Multiple ulcers were seen on one foot in eight (5.9%) patients. The forefoot involving the toes was commonly affected in 60.3% of cases. Neuropathic ulcers were the most common type of DFU accounting for 57.4% of cases.[bmcresnotes.biomedcentral.com]

Treatment

An infected wound may contain foreign particles, microorganisms, dead and necrosed tissue that hinder cell migration and inhibit healing. Debridement is removal of dead, damaged or infected tissue in order to promote healing in rest of tissue that is normal. It can be done in DFU using a sharp scalpel, ensuring effective removal of all the damaged tissue and, if necessary, some portion of surrounding tissue, since necrosis can extend beyond ulcer bed. This procedure is called surgical (sharp) debridement. Debridement can also be achieved through mechanical, medical, chemical, enzymatic or autolytic (self debridement) methods. In self debridement (used often), dead tissue is allowed to slough off while ensuring adequate care i.e., keeping it dry and infection free. Debridement is followed by dressing and topical wound coverage. The basic principle for topical wound management is to provide a moist, but not wet wound surface. Choice of dressing should be appropriate. Dressing may be wet or dry, depending upon the material used. Following types of wound dressing can be used:

  • Hydrocolloid
  • Hydrofibre
  • Hydrogel
  • Transparent films
  • Alginates
  • Antiseptic dressings (e.g silver dressings or cadexomer)

Medical treatment aims at:

For surgical management, patient should first be evaluated by a vascular/podiatric/orthopedic surgeon. Perioperative management, especially a strict glycemic control in patients before and after operation, is both an imperative as well as a complicated procedure. Objectives of surgery in these patients are debridement, vascular reconstruction, revisional surgery for bony architecture or providing soft tissue coverage with grafts, such as skin grafts. Wound closure is done when maximum antiseptic milieu and sufficient granulation tissue is available in wound. It may require grafting healthy skin flap or artificial graft materials, while in case of small wounds, primary closure is also possible. Osteomyelitis and cellulitis requires debridement, reconstruction and revisional surgery. Purpose of revisional surgery may be to remove pressure points in bones that may prone patient to future ulcerations. Vascular reconstruction, in the form of angiography and by-pass surgery, is done to tackle impending ischemia of tissues. Adequate blood supply and nutrition is also necessary for effectiveness of other treatments such as grafting. Amputation is considered when other medical and surgical procedures are of no value, to avoid long term morbidity, and when long-term wound care is not possible.
Offloading of ulcerated area is done to treat and prevent future injuries to foot. Custom designed shoes, soft heeled shoes, padded socks and shoe inserts, contact casts and removable cast walkers are used. These aids help to redistribute pressure over a comparatively larger surface area and prevent excessive pressure at one point. They also accommodate deformities of Charcot foot and avoid friction.

Uncontrolled diabetes correlates with a proportionate early onset of complications. Concurrent hyperlipidemia and hypertension further increase the risk. A regulated glycemic control can help protect patient from microangiopathy, neuropathy, retinopathy and nephropathy. Treatment of diabetic foot ulcer is along following lines:

  • Offloading 
  • Wound debridement
  • Wound coverage
  • Antibiotics and other drugs
  • Vascular reconstruction and other surgical options
  • Control of blood glucose level

Prognosis

DFU can develop infection or can turn into chronic ulcer if treatment is inappropriate or delayed. Patient must consult a physician on noticing an ulcer or sore area in foot. If pressure points have developed symptoms i.e., areas that repetitively come under pressure show change in color or are painful, they should not be ignored. Fractures, osteomyelitis or sepsis are frequent complications. If treatment is sought early, foot ulcers can be treated effectively and complications can be avoided, which, once developed, cause significant morbidity; sometimes amputation of foot may be the only treatment option. In some cases, a benign looking ulcer may turn out to be a grievous danger to health of patient. Treatment of DFU may be protracted over several weeks due to impairment of healing mechanism. 

Etiology

Diabetes is the most common cause of non-traumatic lower limb amputation. Risk factors and etiologies for diabetic foot ulcers are peripheral neuropathy [3], vasculopathy [4], excessive pressure at certain points in foot [5] and deformities of foot [6]. Peripheral neuropathy, a common complication of persistent high glucose level in blood, is found to be present in 60% of diabetic patients. It can present with motor, sensory or autonomic neuropathy, involving a single nerve or multiple peripheral nerves. In the face of vascular insufficiency, ischemia of tissues, including nerves, occurs. Charcot foot, also known as Charcot osteopathy/Neuropathic osteoarthropathy/Neuropathic osteopathy is a term given to a collection of bone and soft tissue abnormalities in foot with unique clinical presentations. It is present in about 2% of diabetic patients. Bone and joint deformities that occur in a patient with peripheral vasculopathy and neuropathy gives rise to this condition. Foot assumes a characteristic shape, in which dorsum is dome-like and bottom is more concave than normal, while toes are splayed out (in most cases). Ankle mortise may also be displaced. Charcot foot is often accompanied by ulceration in foot (commonly involving toe and medical or inferior aspect of foot). Foot ulceration is the most common cause of hospitalization in diabetic patients.

Epidemiology

In the United States, 16 million people suffer from diabetes mellitus. Diabetes is the major contributor to morbidity in Western world and its incidence is increasing throughout the world due to changes in lifestyle, diet and habits of people. Prevalence of DFU is highest in Native Americans, Latino communities of the Eastern United States, and in African Americans [7]. With increasing incidence and prevalence of obesityhyperlipidemia and hypertension, non-familial incidence of diabetes is increasing, even in children and young adults. In United States, 10% people have type 1 diabetes, called insulin dependent diabetes mellitus and they are usually diagnosed before 40 years of age. However, genetic predisposition is higher in non-insulin dependent diabetes mellitus. Among patients with diabetes, foot ulceration is seen in 15% of patients.

Peripheral neuropathy open link, a complication of diabetes, occurs in 60% diabetics, as described above, and it usually follows within 10 years of onset. About 80% patients with this complication come up with ulceration. Throughout the world, 12 to 24% of the patients of diabetes undergo amputation (incidence of 1% every year).

Sex distribution
Age distribution

Pathophysiology

Diabetic foot ulcer is characterized by a classical triad of vasculopathy, neuropathy and infection. Wound healing is a normal process that may be hampered by some physiological insult, resulting in persistence of wound. An ulcer is a break in the continuity of epithelial lining. Persistent high glucose levels in blood presumably prolong healing process and delay the formation of granulation tissue. Diabetes mellitus also prolongs inflammatory phase in wounds, retards the formation of granulation tissue and causes a parallel reduction in wound tensile strength [2].

High blood glucose can cause hypertension and atherosclerosis with resultant arteriolar hyalinosis, endothelial proliferation and increased thickness of basement membrane. Tunica media may also be involved, which undergoes thickening and calcification (Monckeberg sclerosis). Decreased nutrition supply disrupts myelin synthesis in nerves and hampers the function of sodium potassium ATP-ase. Increased amounts of sorbitol and fructose are also detrimental and hyperosmolar state also causes edema in nerve trunks, and together these changes lead to neuropathy of diabetes, which can involve one or more sensory, motor or autonomic nerves [8]. Thus, hyperglycemia induced by microangiopathy causes metabolic, ischemic and immunological injury to motor, sensory and autonomic nerves.

Sensory neuropathy is manifested as reduced sensations in foot; patient may not notice an injury or trauma to foot. Sometimes persistent trauma that occurs with the use of ill fitting foot wear produces ulceration in foot that may not be noticed by patient. Motor neuropathy in patient causes weakness of intrinsic muscles of foot, while osteoarthropathy weakens bones. All these effects together cause splaying. Upper part becomes convex, dome shaped and foot has a rocking bottom, this characteristic shape is called Charcot foot. Weakness of bones can cause bending or fractures; pressure points are produced inside foot, which if present in weight bearing regions or undergoing repetitive trauma can give rise to ulceration. Fractures usually go unnoticed until marked foot deformity becomes apparent. Sometimes sinus tracts form that lead to underlying bone.

Prevention

80% of foot ulcers can be prevented through following measures:

  • Meticulous podiatric care
  • Early and proper management of minor injuries
  • Use of appropriate foot wear
  • Patient education
  • Tight glycemic control and avoidance of other risk factors e.g., smoking, high (saturated) fat diet.

Podiatric care is essential. By routine inspection, regular follow up and with patient education, physician can help patient develop good foot-care habits. Routine inspection and examination of feet, by a physician in a clinic, is preferable, although patient or a caretaker can also carry out inspection at home. Foot care should include regular, gentle cleansing of feet with water and afterwards application of a mousturizer. Patient's foot should be inspected for any pressure sore, minor ulcers, skin dryness, pigmentation, change in color or any of other deformities described above. Custom shoes can be utilized, particularly by those in whom a risk factor has been identified by physician. Purchase of custom foot wear is covered for patients by Medicine Part B, provided an ulcer risk factor has been identified by a certified physician and appropriate documentation has been submitted. A moist foot environment and use of topical antibiotics can help prevent foot ulcers. Minor injures should not be ignored. Patients should be educated to avoid use of home remedies, which can sometimes exacerbate an injury in immunocompromised patients of diabetes.

Summary

Diabetes mellitus (DM) is a complex and serious disease with high rates of morbidity and mortality in patients. This pathological condition involves almost all the vital organ in the human body. DM accounts for around 40-60% of lower extremity amputations and most of these amputations result from deterioration of foot ulcer. Extracellular matrix forms largest part of dermal skin [1] and defects in its repair can result from various physiological insults, a well as pathological and aberrant metabolic processes; Diabetes mellitus being one of them. Diabetes mellitus disturbs normal healing mechanism by causing delay in granulation tissue formation and reduction in wound tensile strength [2].

Patient Information

Diabetic foot ulcer, a complication of diabetes mellitus, affects about 15% of patients of diabetes mellitus. Persistent high level of glucose in blood interferes with normal metabolic and healing processes in our body. It results in an abnormal blood supply to body organs, accumulation of harmful products and delayed healing of wounds. Ill fitting shoes, smoking and other risk factors like cardiovascular diseases, hyperlipidemia, hypercholesteremia, hypertriglyceridemia, hypertension and certain hereditary conditions, if concurrently present, may increase the chance of developing these ulcers by many folds. Diabetic foot ulcers account for 80% of leg amputations in the United States.
DFU develops when blood supply to lower extremities has been compromised to such an extent that it causes damage to nerves, bones and soft tissue. Due to altered nerve function, patient does not notice a blister or sore that, if not detected, can lead to infection and aggravation of condition. A limb that is prone to ulcer development may present with one of following symptoms:

Moreover patient can have difficulty in walking. Ulcers and blisters may come into patient's notice late, when signs and symptoms of infection appear. Diagnosis is made by physicians on examination. Further investigations may be required in order to identify the cause/causes of ulcer formation e.g., X-ray, CT, MRI or Doppler's Ultrasound studies. Specimen from a wound will be required for prescription of an antibiotic. Blood glucose and HbA1C are tested for assessing glycemic control in patients.

Treatment is through wound debridement, antibiotics, regular dressing change, offloading of foot and surgery, if other strategies are not sufficient. Skin grafting, hyperbaric oxygen therapy, arterial reconstruction and revisional surgery for bones and joints may also be suggested depending upon the condition of limb and prognosis after treatment. DFU can be prevented by maintaining foot hygiene, meticulous wound management and care, and control of diabetes.

References

Article

  1. Iakovos NN, Constantinos M, Nicholas CV. Protective and Damaging Aspects of Healing: A Review, Wounds 2006; 18 (7) 177-185.
  2. McLennan S, Yue DK, Twigg SM. Molecular aspects of wound healing, Primary intention. 2006; 14(1) 8-13.
  3. Boulton AJ, Kirsner RS, Vileikyte L. Clinical practice. Neuropathic diabetic foot ulcers. N Engl J Med. 2004 Jul 1. 351(1):48-55.
  4. Arora S, Pomposelli F, LoGerfo FW, Veves A. Cutaneous microcirculation in the neuropathic diabetic foot improves significantly but not completely after successful lower extremity revascularization. J Vasc Surg. 2002 Mar. 35(3):501-5.
  5. Boulton AJ. Pressure and the diabetic foot: clinical science and offloading techniques. Am J Surg. 2004 May. 187(5A):17S-24S.
  6. Jeffcoate WJ, Harding KG. Diabetic foot ulcers. Lancet. 2003 May 3. 361(9368):1545-51.
  7. Marshall MC Jr. Diabetes in African Americans. Postgrad Med J. 2005 Dec. 81(962):734-40.
  8. Tomic-Canic M, Brem H. Gene array technology and pathogenesis of chronic wounds. Am J Surg. 2004 Jul. 188(1A Suppl):67-72.
  9. Gentile AT, Berman SS, Reinke KR, et al. A regional pedal ischemia scoring system for decision analysis in patients with heel ulceration. Am J Surg. 1998 Aug. 176(2):109-14.
  10. Grayson ML, Gibbons GW, Balogh K, Levin E, Karchmer AW. Probing to bone in infected pedal ulcers. A clinical sign of underlying osteomyelitis in diabetic patients. JAMA. 1995; 273: 721-723.

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Last updated: 2019-07-11 21:17