What are they?
Neurological paraneoplastic syndromes are side effects that are caused by cancer, but they are not directly caused by the disease or the treatments used to treat it. These cancer side effects include diseases such 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. It normally affects patients who already had these kinds of conditions before. Examples include; encephalomyelitis, subacute sensory neuropathy, and limbic encephalitis.
There are different types of paraneoplastic syndromes depending on the affected area:
- 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 depends on the condition. Diagnosing these diseases can be a difficult process as symptoms often mimic other conditions. Sometimes there are altered biochemical parameters in a routine blood test, however sometimes they are normal and other tests will need to be carried out, which can be further blood tests or testing the cerebrospinal fluid. CT and MRI scans can help 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.
The specialist will carry out a thorough general and neurological check-up: osteotendinous reflexes, muscular balance, sensitivity, eyesight, hearing, coordination, and balance tests.
They may also carry out some lab tests, such as blood tests and a lumbar puncture. Other tests include a CT scan and MRI scan.
What causes them?
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 it has affinity for (tropism).
How can they be prevented?
Prevention is not possible, but an early diagnosis can help avoid major complications.
What is the treatment?
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 specialist should I see?
The specialist who studies, prevents, diagnoses, and treats this condition is a neurologist. They specialise in all issues that may arise in the central nervous system (brain, cerebellum, brainstem, and spinal cord) and the peripheral nervous system (roots, plexuses, nerves, neuromuscular junction, and muscles).