What are paraneoplastic syndromes?     

Neurological paraneoplastic syndromes are side effects that are caused by cancer, but are not directly caused by the disease or associated treatment.

Paraneoplastic syndrome is an umbrella term which covers a number of diseases, such as Lambert-Eaton myasthenic syndrome, a rare autoimmune disorder that weakens the immune system and causes limb weakness, especially in the legs. This type of weakness, which is most active in the morning, may be accompanied by dry mouth, muscle pain, and diarrhoea. Patients who have previously suffered from a paraneoplastic syndrome are most likely to be affected by another, including encephalomyelitis, subacute sensory neuropathy, and limbic encephalitis.    

Paraneoplastic syndromes can affect many areas of the body and are classified as such:

• General paraneoplastic syndrome
• Cutaneous paraneoplastic syndrome
• Endocrine paraneoplastic syndrome
• Digestive paraneoplastic syndrome
• Haematological paraneoplastic syndrome
• Neurological paraneoplastic syndrome
• Renal paraneoplastic syndrome
• Rheumatologic paraneoplastic syndrome

Prognosis

The prognosis for paraneoplastic syndromes depends on the particular type of condition. Diagnosing these diseases can be a difficult process as symptoms often mimic other conditions. In some patients, altered biochemical parameters may be observed in a routine blood test, but this is not always the case and other tests may be required. Often  further blood tests or cerebrospinal fluid examination, along with CT and MRI scans can help to give a more specific diagnosis.

What are the symptoms?

Symptoms will vary depending on the syndrome, and they may be haematological, gastrointestinal, cutaneous, cardiovascular, renal, or neurological, depending on the organ affected. Fever is a common symptom in all these conditions, although symptoms can be vary varied. Nervous system conditions include dementia, confusion, weakness, double vision, and altered sensitivity.   

Medical tests

The specialist will carry out a thorough general and neurological check-up which may include testing osteotendinous reflexes, muscular balance, sensitivity, eyesight, hearing, coordination, and balance. Some lab tests, such as blood tests, lumbar puncture and CT or MRI scans may also be performed. 

What causes paraneoplastic syndromes?

The causes remain unknown, but experts believe that pyrogens can cause fevers and metabolic alterations of copper and zinc, which causes a bad taste in the mouth. Patients who have lymphoma, lung, ovarian, breast, or testicular cancers, are more likely to develop this condition. Tumoural cells can generate bioactive molecules that can cause specific tissue or organ injury which may be linked to the onset of paraneoplastic syndromes. 

How can paraneoplastic syndromes be prevented?

Unfortunately prevention is not possible, but an early diagnosis can help avoid major complications.

How are paraneoplastic syndromes treated?

Symptoms may diminish depending on the treatment given for the underlying cancer. Surgical treatment aims to remove the tumour, although it is sometimes not necessary to resort to surgery.

Which type of doctor treats paraneoplastic syndromes?

Neurologists treat paraneoplastic syndromes, while other specialists including oncologists treat associated cancers and associated symptoms.