Introduction
Diabetes mellitus has deleterious effects on many systems of the body especially the immunity and the nervous systems. This article focuses on effects of diabetic neuropathy on the foot, its signs and symptoms and treatment.
Effects on the foot
The effects of diabetic neuropathy can be explained using parameters such as the thickness, Power Ratio (PR), which is “the ratio of high-frequency power to the total power in the power spectrum of the walking-foot pressure image distribution obtained from the optical pedobarograph” (Charanya et al. 431) and the Shore level, which is a measure of the foot sole hardness. High values of both PR and Shore level are seen in patients with diabetic neuropathy of the foot and all parts of the sole ranging from 0.92 to 0.99. The power ratio is generally higher in upper shore regions than lower shore regions consequently the upper shore regions are more prone to plantar ulcers since PR is related to vertical and shear forces which are made worse by loss of sensation.
Thickness of the sole is inversely related to PR. Loss of sensation makes the patient exert a lot of pressure which triggers the compensatory thickening and hardening to prevent damage to tissues. The thickening areas require more blood supply which can not be provided due to the hardening leading to formation of ulcers. The three parameters, the shore value, the PR and thickness increase by 30-80% in the lateral heel (foot sole area 2), 20-34% in the second metatarsal (foot sole area 6), and by 16-32% in the big toe (foot sole area 8). Increases in the power ratio by 1.2-2.5 times the lower shore ranges have increased incidence of ulcers especially when accompanied by the sensory loss (Charanya et al. 441).
Signs and symptoms
Patients with diabetic neuropathy can be recognized by ulcers especially on the plantar aspect of the foot. These ulcers may become infected since due to loss of sensation they may take long to heal. Wound healing is also decreased in diabetic patients. These wounds serve as a pathway for the entry of bacteria, which may cause sepsis, which may become clinically apparent by its symptoms like fever. Severe ulceration and sepsis may cause the foot to die leading to foot loss. Sensory and motor functions are impaired and they may be elicited by diminished Achilles’ tendon reflex (Teelcksingh et al. 289).
Slipping slipper sign
Patients with diabetic neuropathy affecting the foot have been said to lose their footwear while walking without even noticing. Assessing the patient with the slipping slipper sign involves asking the patient to sit on a raised place and asking them to say if their slippers are still on or if they are fallen. Diabetic patients have impaired neurosensory and neuromuscular integrity and in severe cases they are not able even to tell if the slipper is fallen or not. Normal controls recognize a fallen slipper immediately and it rarely falls accidentally unlike in the patients. This test has a very high degree of sensitivity and specificity, 83% and 91% respectively. It is not just a simple qualitative test but somehow quantitative since it is positive in patients with severe neuropathy (Teelcksingh et al. 290).
Management
Management of these patients has two approaches which should be used together to achieve optimum results. These are surgical and pharmacological.
Surgical management
After carefully assessing the ulcer wound, debriding and growing cultures, surgical repair is started by first considering the remaining part of the foot after debridement. Muscle and bone are rearranged using skeletal manipulation, shortened tendons are lengthened, and amputations in specific areas as necessary. Microsurgical flaps are used in soft tissue replacement to aid healing of the wound by secondary intention. Skin grafts are laid to prevent wound associated tumors when the ulcers are large. Local blood flow must be maintained to prevent gangrene (Clemens & Attinger 54).
Pharmacological treatment
Insulin is especially important as it has many beneficial effects as it reduces hyperglycemia. Injections of insulin decrease the disease progression. C-peptide improves peripheral nerve conduction and pain sensation in the extremities. It improves the conduction in myelinated nerves and c-fiber. Studies have shown similar effects with acetyl-L-carnitine.
Aldolase Reductase Inhibitors (ARI) like tolrestat, sorbinil and zenarestat are beneficial in decreasing symptoms of this disease by decreasing the rate of cofactor turnover. Other drugs which are of benefit include Benfortiamide, which is a soluble form of vitamin B1, Aspirin which inhibits AGE formation, N-phenacylthiazolium bromide (PTB), (alpha)-Lipoic acid which is an antioxidant and Resveratrol which improves heat and cold sensation. Pain can be managed with tricyclic anti-depressants like Amitriptyline and desipramine and Serotonin-Norepinephrine reuptake inhibitors like Duloxetine. Antiepileptics like gabapentin, carbamazepine, Topiramate have been used. Opioids, Tramadol, and topical lidocaine also reduce pain (Smith & Argoff 1).
Effects on quality of life
Diabetic neuropathy of the foot has many negative effects on patients. In some hospitals, most of the amputations done are associated with diabetic foot. Amputation decreases mobility of the patient, thereby reducing the level of activity which impairs daily chores. Basic activities like cleansing the body, going to the toilet, etc are left to the caregivers. Patients usually develop a negative attitude in this condition. The chronic and severe pain affects the patients’ emotions and sleep and this may cause clinical depression. These factors also affect the caregivers and the costs involved in treatment reduce the quality of life of the affected population (Morales et al. 8).
Works cited
Charanya et al. Effect of foot sole hardness, thickness and footwear on foot pressure distribution parameters in diabetic neuropathy. Indian Institute of Technology, Chennai: India, 2004. Print.
Clemens, Mark and Attinger, Christopher. Functional Reconstruction of the Diabetic Foot. Seminars in plastic surgery. New York: Prentice Hall, 2010. Print.
Morales et al. Impact of Diabetic Foot Related Complications on the Health Related Quality of Life (HRQol) of Patients – A Regional Study in Spain. New York: Sage publications, 2009. Print.
Smith, Howard and Argoff, Charles. Pharmacological Treatment of Diabetic Neuropathic Pain. New York: Adis Data Information BV, 2011. Print.
Teelcksingh et al. The slipping slipper sign: a marker of severe peripheral diabetic neuropathy and foot sepsis. New York: Bmj, 2009. Print.