amy@totalfootrepair.co.uk
Foot health care practitioners need to know when there is a possibility that their diabetic client may have neuropathy as it means that they will be high risk in terms of infection and diabetic foot ulcers. Neuropathy is a nerve problem that causes pain, numbness, tingling, or weakness in the body. To assess neuropathy, a neurovascular assessment involving sensation testing can be conducted.
Sensation testing can be a number of examinations used to identify a patient’s ability to feel pain, touch, vibration, temperature and position. It is used to assess sensory motor and neurone responses as part of a neurological exam. Both reflexes and monofilament exams may be included. The results will show any problems with the central nervous system. Monofilament testing is known as the ‘gold standard,’ for identifying possible neuropathy in diabetic clients. Further tests may include lumbar punctures and neuroimaging.
Monofilaments are nylon threads made from one fibre. The size and weight of each denotes a different amount of force needed for them to buckle when the tip is placed against the client’s foot in specific areas. Monofilaments are used to diagnose peripheral neuropathy even when there are no outwards signs of ulcers.
At Total Foot Repair we use the Neuropen for neurovascular tests which has a sharp end with a neurotip and a monofilament at the other end. We may also use Neuropads where patients may be unable to communicate – a Neuropad is stuck to the sole of the patient’s feet for ten minutes. This does not cause any pain – it feels as if a plaster is being stuck on the feet. After ten minutes, the Neuropad is removed and the colour checked. Any abnormal findings can then be reported to the GP or a Podiatrist for further investigation.
A Neuropen – the white object is a Neurotip which is a small needle used for sensation testing
What happens during a neurovascular test?
After showing the patient the Neuropen and allowing them to have a close look at the different ends, we ask the patient to close their eyes and say ‘yes,’ when they feel the monofilament/neuro tip touch. The clinician should vary the order and timing of the test points so the client is unable to guess when the monofilament/neurotip is applied.
If a client is unable to feel the pressure of the monofilament when it buckles, this shows a significant loss of sensation.
Other sensation testing
Vibration testing uses a 128Hz tuning fork with the practitioner holding it by the stem and striking it against a solid surface. The stem is then placed on the top of the joint of the big toe whilst the practitioner puts their fingers on the bottom part of the joint, asking the client if they can feel the vibration. As the practitioner can also feel the vibration at the same time, when they ask the client to identify the exact moment they can no longer feel the vibration, it can be compared to the practitioner’s feeling. If the feelings are not felt at the same time, it indicates that the sensation is impaired.
Practitioners should test both feet but where an impairment is identified, further testing on nearby joint is needed.
Temperature testing is when a tuning fork is run under hot and cold water and the fork is then pressed to the patient’s skin in similar places. The client will need to identify if the fork is warm or cool.
Position sense testing is when the practitioner holds the client’s big toe by the sides and lifts or lowers the toe. The client needs to identify if their toe is up or down. Both feet should be checked and the results compared.
Effective sensation testing allows foot health practitioners to help their clients avoid foot ulcers, gangrene and possible amputations.
Reflex testing
A reflex action is the involuntary reaction of the body in response to a stimulus. Involuntary means that the body does it automatically. It is a test used to check whether a specific muscle will contract and allows the tester to see if a patient’s reflexes are working correctly. Neuropathy testing is useful in a variety of scenarios, not just for diabetic clients. Abnormal reactions may provide clues to an unknown illness which may otherwise have been missed. Where foot healthcare practitioners notice abnormalities, a referral to a GP should be made.
Reflex actions work when a stimulus is detected by a pain receptor. The main detector sends a signal along a sensory neurone, this then sends a signal to the relay neurone which passes it to a motor neurone as well as to the brain. The brain then tells the body that it feels pain. The motor neurone passes the signal to the effector muscles or tendon which contracts moving the affected area of the body away from the stimulus.
When testing reflexes, a small hammer is used to strike a tendon. The tendon joins muscle to bone so when the tendon is struck, the muscle contracts, the tendon ‘pulling’ the bone and thus the limb moves. It is important to hit the tendon in the exact place needed to cause a reaction as otherwise the reaction will not take place. If there is excess tissue around the tendon, the hammer’s impact will be spread and may not cause the reflex action. The best way to ensure the correct place is hit is by finding the spot with a finger first.
Reflex actions occur as a set of responses but they only work if every stage of the process is functioning correctly. There are some disorders of the limb that can slow or prevent a normal response. This is because the transmission of the signal may be delayed or prevented. Peripheral neuropathy that occurs as a result of diabetes is a common factor in developed countries for a loss of reflexes.
