Neurological disorders

A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain and altered levels of consciousness. There are many recognized neurological disorders, some relatively common, but many rare. They may be revealed by neurological examination and studied and treated within the specialities of neurology and clinical neuropsychology. 

Neurological disorders are very frequent during palliative care.

They can concern all parts of nervous system:

Spinal cord compression,
Leptomeningeal metastases,
Skull base invasion,
Radiculopathies,                                                        Brain metastases.

 Spinal cord compression:

Spinal cord compression is a genuine therapeutic emergency.

Living the last months of life bedridden, motionless and completely dependent upon carers, is a terrible agony for patients that we should endeavour to avoid through early diagnosis and rigorous treatment.

Spinal cord compressions may be due:

• either to an extrinsic compression of epidural space (by a bone metastasis or invasion of adjacent soft tissues),
• or less often by intradural invasion (tumour-like carcinomatous meningitis),
• or even less often by intramedullary invasion.

The differential diagnoses are other compressive cord lesions: abcess, haemorrhage, discal lesion, lipomatosis, narrow lumbar spinal canal, all of them also representing emergencies.

Clinical diagnosis

Clinical diagnosis requires expertise and alertness on the part of caregivers (particularly home caregivers and general practitioners): most often, the revealing symptoms of this neurological catastrophe are present a few weeks before it occurs.

The following symptoms may appear (not necessarily all of them or in the following order):

• onset of vertebral pain or its modification (in location and/or occurrence circumstances),
• appearance of Lhermitte's sign (lightning pain in limbs provoked when the neck is bent forward),
• onset of belt-like pain,
• onset of sensitive deficiency below the pain with an evocative level,
• onset of sphincter modifications (urine retention, recently appeared constipation),
• appearance of minor (then increasing) motor palsies typical of cord lesion.

A rigourous neurological clinical examination should be regularly performed in order to diagnose cord compression:

• more or less important motor weakness,
• hypertonicity,
• positive Babinski's sign,
• sensitive deficiency (research of a precise level).

This is a genuine emergency for which the best paraclinical examination is RMI (probably THE rare emergency indication which should be performed before all others).

Treatment

It should be administered as quickly as possible.

A unique lesion, in most cases, is a good indication of neurological decompression surgery.
The quicker the surgical intervention, the larger patient's chances of recovering normal function. Even if long term prognosis is unknown, such surgery should be performed.
 
After 12 to 18 hours of complete palsy, the patient has lost most of his/her chances of function recovery.
Localised radiotherapy associated with corticosteroid therapy may be very efficient in association with surgery, or when surgery is not feasible..

Leptomeningeal metastases:

They are caused by the dissemination of cancer cells into the subarachnoid space. Cancer cells reach the meningeal spaces:

• via the general circulation,
• by infiltrating perineural spaces along nerve roots,
• by direct invasion of epidural spaces,
• by diffusion from brain metastases.

The invasion may be diffuse or provoke visible meningeal tumour nodes.

Clinical symptomes

They are very diverse:

• various neurological disorders,
• radicular-type pain,
• headache and hydrocephalus (in relation to spinal fluid circulation disorders).

Diagnosis is generally made by lumbar puncture: cytology reveals cancer cells in cerebrospinal fluid (with frequent increased fluid protein and decreased glucose concentration).

RMI with contrast enhancement may reveal localised menigneal tumours which can be irradiated.

Treatment

Treatment involves high dose general corticotherapy and, if feasible, general chemotherapy.
Local intrathecal chemotherapy remains a subject of controversy (particulary due to its meningeal toxicity), but it may provide very impressive remissions.

Radiotherapy of the whole spine has been proposed, however, generally speaking, more localised radiotherapy is prescribed in zones where tumour development is more intense.

Prognosis

Prognosis remains severe.

Without treatment, patient survival is limited to a few months.
When the aetiological treatment is efficient, impressive remission may be obtained with a mean duration of 20 months.

Skull base lesions :


Lesions of the base of the skull are most often combined with carcinomatous meningitis (particularly metastases from breast or prostate carcinoma).

However, a continuous local head and neck cancer invasion may be observed.

Symptomatology is generally dominated by more or less localised headache and a neurological syndrome in relation to the cranial nerve concerned.

Diagnosis is generally performed by TDM using both bone and brain windows.
Treatment is mainly localised radiotherapy of the tumour lesion.

Most frequent syndromes

Orbital syndromes are characterised by retro-orbital pain, blurred vision, diplopia, ocular palsy, exophtamos.  

Cavernous syndromes also provoke ocular disorders, particularly hemianopsia and papilloedema. 

Middle crania fossa syndrome associated diffuse headache, facial pain and numbness along the distribution of trigeminal nerves, with paroxysmal episodes of lancinating pain. 

Jugular foramen syndrome provokes hoarseness and dysphagia, and various palsies (IXth , Xth, XIth , XIIth nerves) or Horner's syndrome (myosis, palpebral ptosis, enophtalmia, unilateral sweating). 

Occipital condyle syndrome with frequent nuchal stiffness and palsy of XI th and XII th nerves. 

Glossopharyngeal nerve infiltration (by head and neck cancer) provokes pharyngeal pain, with severe irradiation to ear (aggravated by swallowing and associated with syncopes). 

Trigeminal nerve infiltration provokes dull, constant facial pain with paroxysmal episodes of throbbing or lancinating pain.

Treatment

When feasible, radiotherapy may bring relief, although, in most cases, it has already been adminstered and repeated doses may become dangerous.

Patients concerned should request specialised pain consultations since their relief is most often difficult to obtain.

Radiculopathies:

General remarks

Radiculopathies are generally provoked by a leptomeningeal invasion or by a metastatic bone compression of nerve roots (or other paravertebral lesions).

Pain is generally focalised on the compression zone and irradiates according to the neurological distribution. If necessary, an electrophysiological study may be performed in order to better distinguished polyradicular lesions from plexic lesions. TDM and RMI are also useful imaging examinations.

Sometimes, herpes zoster may be considered, particularly in immunodeprived patients after chemotherapy. Looking for typical vesicles is good clinical practice. A good knowledge of clinical history may help to detect post-herpetic neuralgia in elderly patients.

Cervical plexopathy 

Frequent in head and neck cancer or in relation with metastatic nodes,

They provoke intense local pain, with very severe irradiations in the retroaurical region, the back of the neck, the shoulder or the jaw.

They often complicate severe skin and soft tissue sclerotic disorders related to previous surgery and radiotherapy.

CT and RMI should detect potential local relapse.

Their treatment is difficult (frequent severe and relapsing neuropathic pain).

Brachial plexopathy 

Frequent, brachial plexopathy is often related to breast carcinoma, lung cancer or lymphoma.

The nerve may be compressed either in the axilla or in the supraclavicular region.

Pain is typically neuropathic, with anaesthetic zone, paresthaesia and hyperesthaesia.

A precise study of pain or anaesthesia location enables the precise determination of the incriminated root.

Specific serial TDM sections are necessary to study the incriminated zone.

When plexic pain is due to a tumour progression, irradiation (when feasible) brings good relief. However, in post-radiotherapy or post-surgical pain, treatment is difficult and should be entrusted to specialized pain team.

Lumbosacral plexopathy 

Frequent during rectum carcinoma, cervix uteri cancer, bladder or prostatic cancer.

It provokes pain located in the back, buttock, perineum and lower limbs.

Pain is lancinating with excruriating paroxysms but rarely a burning sensation.

Other neurological disorders are often associated: perineal saddle sensory loss, motor and sphincter disorders, lower limb oedema.

Most often, this pain is related to cancer progression (rarely a complication of the treatment like for cervical or brachial plexopathy).

Precise radiological study with TDM or RMI sometimes enables further irradiation if possible.

If not, these patients need to be entrusted to a specialised pain team.