Nervous system Dan Flashcards
How is Post herpetic neuralgia defined?
Pain lasting more than 4 weeks after zoster vesicles healed
T/F
older pts are more at risk of Post herpetic neuralgia
True
almost 50% of over 60s
can be disabling - tends to be more severe and longer lasting in older age
worth immunising older people to reduce zoster risk
vaccine reduces the incidence of both zoster reactivation and post herpetic neuralgia
T/F
Pain of Post herpetic neuralgia is worsended with stress
True
has an autonomic component – worse when stressed, eases with relaxation
T/F
compression can relieve pain of Post herpetic neuralgia even when allodynia present
True
T/F
Post herpetic neuralgia can cause anaesthesia dolorosa
True
sensory loss in area of pain
Treatment ladder for Post herpetic neuralgia
Simple analgesia can be helpful esp if mild – paracetamol, NSAIDs
Firm compression
Relaxation techniques
Topical capsaicin 0.025-0.077% applied 3-4x per day is effective but can cause burning pain and hyperalgesia
Topical 5% lignocaine patches
Amitryptaline (TCA) 70mg daily – effective in 60% - cholinergic AEs; sometimes other TCAs e.g. nortryptaline
Gabapentin, Pregabalin (GABA analogues) – at least as effective as the antidepressants above but fewer side effects
Opioids – oxycodone, tramadol – try after the above
Clonidine (central α2 agonist)
lamotrigine (antiepileptic)
Baclofen (GABA analogue, antispasmodic)
Intrathecal methylprednisolone weekly
TENS
Spinal cord stimulators
Refer to pain clinic or neurologist
T/F
treating zoster with antivirals up to 10 days after onset can reduce risk of and severity of Post herpetic neuralgia
False
Can reduce pain/severity and duration but not incidence of PHN
but works best in first 72 hrs
T/F
TCS during zoster reduce risk of and severity of Post herpetic neuralgia
False
no effect
T/F
acupuncture is proven to help Post herpetic neuralgia
False
T/F
Surgical techniques are last line but effective treatment for Post herpetic neuralgia
False
high morbidity
not recommended
What are causes of neuropathic ulcers?
T2 Diabetes – vast majority Peripheral neuropathy Leprosy Alcoholism Vitamin deficiency Tabes dorsalis (tertiary neurosyphylis) Spinal dysraphism Spinal cord injury Hereditary sensory and autonomic neuropathies
T/F
In neuropathic ulcers cellulitis or palpable bone using a wound probe indicate high risk of osteomyelitis and the foot should be X-rayed
True
can show osteomyelitis, foreign body, gas in tissues or bony abnormality
How do you care for neuropathic feet to prevent ulcers?
Inspect feet daily and keep clean and dry
Have regular podiatry for callous removal etc
Should be taught correct toe nail cutting
Need shoes with round or square toe box and low heel to prevent excess pressure on forefoot
Urea products may help callus
Stop smoking, control HTN and diabetes, may need aspirin
What is total contact casting (TCC)?
a way to make a plaster of paris boot that completely encompasses the foot and lower leg and redistributes pressure to completely off-load the usual pressure points
boots applied weekly initially then every 3 weeks
How do you manage established neuropathic ulcers?
Surgical debridement
Dressing with hydrogel or hydrocolloid dressings (hold a lot of water)
Offload pressure eg contact casting or Aircast walkers boot
T/F
neuropathic ulcers develop in areas of injury or highest pressure
True
T/F
50% of diabetics get a foot ulcer
False
15-25%
T/F
50% of pts with diabetes don’t know they have it
True
T/F
treated diabetic ulcers have a 50-70% recurrence risk in the next 5 years
True
T/F
Diabetic foot ulcers are often preventable with early recognition and intervention
True
T/F
diabetic foot ulcers are always neuropathic
False May be; Neuropathic Ischaemic Combined (neuroischaemic)
T/F
Ischaemic diabetic ulcers have the best prognosis
False
Purely neuropathic ulcers have better prognosis than other 2 types
T/F
Most diabetic ulcers will eventually heal with good care
False
Only 1 third of diabetic foot ulcers will heal even with best care and those that do are slow, often more than 2 months
T/F
diabetics with foot ulcers have a higher mortality than those without
True
50% higher
T/F
T/F
50% of lower limb amputations follow a diabetic foot ulcer
False
85%
T/F
Diabetics have a 15-45x increased risk of lower limb amputation
True
How common is a contralateral amputation after a first lower limb amputation for diabetic complications?
50% risk of contralateral lower limb amputation within 5 years of first side amputation
What are the pathological factors in diabetic foot ulcers?
Neuropathy – motor, sensory and autonomic. Due to;
• Nitric oxide inhibition – increased ROS/superoxides
• Maillard reaction – results in advanced glycation end products
Vascular disease
- Macrovascular disease
- Microvascular disease
- Thickening and loss of elasticity of capillary walls prevents vasodilatation
Inflammation & susceptibility to infection
What deformities can ocur in neuropathic feet?
‘cocked-up’ toe, claw toes and hammer toes - due to motor neuropathy displaced plantar fat pads due to toe deformitys halux valgus (bunions), hallux rigidus or equinus deformity of the ankle Charcot or ‘rocker bottom’ foot and charcot ankle
What makes diabetic feet prone to infection and prolonged inflammation?
Loss of barrier when an ulcer forms allows entry of microbes
Bacteria grow in colonies surrounded by a biofilm
Diabetics have reduced chemotaxis and function
Reduced bactericidal and phagocytic capacity in the presence of hyperglycaemia
Sustained inflammation and delayed re-epithelialization contribute to slow healing
T/F
In diabetic foot disease callus indicates increased local pressure and portends an ulcer
True
Must examine both feet carefully with shoes and socks off
for callus neuropathy, pulses and deformity as well as ulcers
What are the International working group on the diabetic foot (IWGDF) risk categories and management recommendationd for diabetic foot disease?
Risk of ulcer and amputation goes up with category except 1 and 2 have zero risk of amputation
Should educate patient at all stages
0 - no sensory neuropathy
- Ulcer 2-6%, Amputation 0%
- revew annually
1 - Sensory neuropathy
- Ulcer 6-9%, Amputation 0%
- podiatry every 6 months + OTC shoes/ insoles
2 - Sensory neuropathy w/ deformity or PVD
- Ulcer 8-17%, Amputation 1-3%
- podiatry every 2-3 months + therapeutic shoes/ insoles
3 - Previous ulcer or amputation
- Ulcer 26-78%, Amputation 10-18%
- podiatry every 1-2 months + therapeutic shoes/ insoles
What are the 3 trongest risk factors fo diabetic ulcers?
Previous ulcer or amputation
Arterial disease
Neuropathy
presence of any 2 of these increases the risk by 32%
What are the most important things on examination of diabetic foot?
Ulcer Callus or blister Deformity Pulses (DP or PT) Neuropathy
How do you assess for neuropathy?
use sterile 10g monofilament on 10 areas – 4 insensate areas = positive test
128Hz tuning fork for vibratory perception
Test JPS in usual way
