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Induction can be achieved with either prednisone or cyclophosphamide ( oral / pulsed IV ) followed by low-dose prednisone and / or steroid sparing agents such as azathioprine , mycophenolate mofetil or methotrexate as maintenance . IVIg , plasmapheresis and rituximab may be helpful in refractory cases . ⁶⁸

Use a multidisciplinary approach including a rheumatologist and haematologist for optimal monitoring and outcomes , especially in patients with systemic involvement . ⁶⁸

CASE STUDY

ANDREW , a 35-year-old electrician with type 1 diabetes presents with a 10-day history of tingling that started in his toes and fingertips . This started about a week after he returned from a holiday in Bali where he had experienced a sore throat and taken an overthe-counter antihistamine . He also reports altered taste sensation and mild difficulty in gripping his tools .

Examination reveals mild weakness of finger extensors and sluggish supinator and ankle jerks . He has mild weakness of orbicularis oculi bilaterally .

Nerve conduction studies reveal prolonged latencies and reduced persistence of F waves in the peroneal and ulnar nerves with mildly prolonged motor latencies . A subsequent CSF examination reveals raised CSF protein with two white blood cells .

Andrew is diagnosed with GBS- AIDP variant and admitted to hospital , where he receives IV immunoglobulin

2g / kg during his week-long admission . He is discharged to inpatient rehabilitation . Three months later he returns to his regular work , and apart from mild paraesthesia in his feet , for which he takes 50mg per day of nortriptyline , he remains asymptomatic .

This case illustrates the typical

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1 . Which THREE statements regarding the epidemiology of the neuropathies are correct ? a The prevalence of neuropathic pain can be as high as 7-10 % in the general population . b Fewer than 15 % patients with diabetes are aware of their neuropathy . c There is difficulty in accurately estimating the prevalence of the hereditary neuropathies . d About 65 % of patients have neuropathy at the time of diagnosis of diabetes .

2 . Which ONE best describes the term paraesthesia ? a Increased sensitivity to stimulus . b Loss of pain sensation c Abnormal painless sensation either spontaneous or provoked . d Pain in response to a nonpainful stimulus .

3 . Which TWO statements regarding neuropathies are correct ? a Tingling and numbness are common in metabolic and nutritional deficiency neuropathies . b Acquired demyelinating neuropathies are mostly toxin related . c Sensory symptoms in the hands preceding the onset of lower limb symptoms confirm a

Table 7 . Vasculitic neuropathies

Disorder Vessels affected Presentation Other neurological and systemic features Comments

Rheumatoid arthritis ( RA )

Systemic lupus erythematosus ( SLE )

Wegener granulomatosis ( WG )

Churg-Strauss syndrome / eosinophilic granulomatous angiitis ( CSS / EGA )

Cryoglobulinaemia

Sjogren syndrome

demyelinating neuropathy . d Exclude immune and inflammatory causes in demyelinating neuropathy .

4 . Which THREE statements regarding the investigation of neuropathies are correct ? a Genetic testing can allow for diagnosis and , at times , disease-specific intervention . b Consider CSF analysis in patients with a polyradiculopathy or polyradiculoneuropathy pattern . c A two-hour glucose tolerance test is more sensitive than blood sugar and HbA _1c at detecting glucose intolerance in its early stage . d Nerve biopsy is a first-line investigation , often providing a definitive diagnosis .

5 . Which THREE statements regarding the medications for neuropathic pain are correct ? a Pregabalin needs thrice-a-day dosing . b Topical lidocaine may cause local erythema and rash . c Use amitriptyline with caution in the elderly , patients with cardiac conditions or glaucoma . d Nortriptyline is better tolerated than amitriptyline .

6 . Which TWO may be features of distal symmetric polyneuropathy ? a Slowly progressive sensory symptoms that start distally and ascend proximally . b Tingling and numbness c Persistently warm feet . d Symptoms appear in the hands and feet at the same time .

7 . Which THREE nutritional deficiencies may cause a neuropathy ? a Vitamin B12 . b Lead . c Folate . d Copper .

8 . Which THREE are features of carpal tunnel syndrome ? a More common in women . b Sensory loss on the dorsal aspect of the thumb , index and middle fingers and lateral fourth digit .

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NEUROPATHIES

Renal / cerebral ischemia , cardiomyopathy

non-length-dependent evolution of symptoms that clinches the diagnosis of demyelinating neuropathy in a patient with diabetes ( which

c Motor symptoms indicate an advanced stage . d Decompressive surgery is indicated for severe cases .

9 . Which TWO statements regarding Guillain-Barré syndrome are correct ? a Progression occurs for

4-8 weeks . b There is initial acral paraesthesia followed shortly by ascending motor symptoms . c IV steroids are first-line treatment . d Plasma exchange and IV immunoglobulin ( IVIg ) are the mainstay of treatment .

10 . Which THREE statements regarding the acquired neuropathies are correct ? a Chronic acquired demyelinating polyneuropathies respond extremely well to immunomodulation . b Multifocal motor neuropathy and motor neuron disease present with asymmetric pure motor involvement . c Painful mononeuropathies at sites prone to compression should raise suspicion of a vasculitic neuropathy d Neuropathy occurs after at least five years of systemic rheumatoid arthritis .

Screen for hepatitis B

Lung and GI ANCA / MPO ( myeloperoxidase ) antibodies

Medium-small Polyneuropathy , mononeuropathy , cranial neuropathies

Small-medium Polyneuropathy , mononeuropathy , cranial neuropathies

Small vessel

Small vessel ( rarely large vessels )

Small-medium ( rarely large vessels )

Similar to WG including polyneuropathy , mononeuropathy , cranial neuropathies

Painful mononeuropathies , aggressive polyneuropathy

Small fibre neuropathy , sensory ataxia from ganglionopathy , trigeminal neuropathy

Non-systemic vasculitis of peripheral nervous system

Any Painful polyneuropathy , mononeuropathy

Neuropathy often coexists with CNS involvement and systemic features of SLE

Renal , upper and lower respiratory

Similar to WG including involvement of paranasal sinuses

Purpura , skin hyperpigmentation / ulcerations , renal and hepatic involvement , lymphoproliferative disease including malignancies

Enlarged salivary glands , sicca syndrome

Lung disease , uveitis , parotid enlargement , fever

No systemic features although some constitutional features may be present

HIV , hepatitis B , hepatitis C , CMV , Lyme disease

Exclude RA in patients with relatively aggressive form of axonopathy

Usually with CNS involvement

Upper ( paranasal sinuses ) and lower respiratory involvement is the often the clue

Eosinophilia ( more than 10 %) plus ANCA / MPO antibodies , fleeting pulmonary infiltrates

Screen for hepatitis C

SSA , SSB antibodies

Facial palsy is often the clue Raised ACE levels

Accounts for 25 % of vasculitic neuropathies ; slow progression compared with systemic vasculitis

Tissue confirmation of vasculitis preferred prior to immunosuppressive therapies

usually causes axonal neuropathy with length-dependent evolution of symptoms ). The prodrome of a respiratory illness and the presence of facial weakness further allude to this being an immune-mediated acquired polyneuropathy .

The timing of CSF examination and neurophysiological assessment is crucial in obtaining ancillary support to the diagnosis that is mostly a clinical one .

CONCLUSION

NEUROPATHIES are common and often easy to diagnose and differentiate from other neurological presentations . Given the myriad potential presentations of peripheral neuropathies , a high index of suspicion is required to diagnose the treatable and potentially curable neuropathies such as GBS , which if not diagnosed early may have significant consequences . A high index of suspicion and focussed clinical assessment are the cornerstone of management .

History of evolution of symptoms and length-dependent versus non-length-dependent features are the starting point to avoid missing cases of demyelinating neuropathies . Diabetic and entrapment neuropathies , carpal tunnel syndrome in particular , are among the common neuropathies seen by a GP . These are amenable to timely diagnosis and treatment .

Pharmacotherapy of neuropathies can be painstaking and frustrating ; one needs to be intimately familiar with the adverse effect , ceiling doses and the time required before patients may experience any benefit . Perseverance is the key to avoid short trials of inadequate dosing before labelling a treatment ineffective .

References Available on request from howtotreat @ adg . com . au