Numbness and nerve pain

What neuropathy is

The peripheral nervous system consists of the nerves that connect the brain and spinal cord to muscles, skin and organs. It carries three kinds of signals: sensory (touch, pain, temperature, limb position), motor (commands to muscles) and autonomic (blood pressure, heart rate, digestion, sweating). When nerves are damaged these functions are disturbed, and this is called peripheral neuropathy.

Neuropathy can affect a single nerve (mononeuropathy, e.g. carpal tunnel syndrome, where the median nerve is compressed at the wrist) or many nerves at the same time (polyneuropathy). The most common form of polyneuropathy begins at the toes, because the longest nerves are damaged first, and spreads upward in a “stocking” distribution, later also reaching the hands (“glove” distribution). Numbness that comes from the neck or the back and runs down a limb may arise from compression of a nerve root by a disc (radiculopathy) and must be distinguished during examination.

What the symptoms are

• Numbness and tingling (paresthesia) in the hands or feet, like “pins and needles”.
• Neuropathic pain: burning, stabbing, like an electric shock, often worse at night; it can even be triggered by light touch (allodynia).
• Reduced sensation to touch, vibration and temperature, which makes stepping on hot or cold surfaces dangerous.
• Muscle weakness, difficulty with balance, falls, “foot drop”.
• When autonomic nerves are affected: dizziness on standing, digestive and urinary disturbances, changes in sweating.

One nerve or several may be affected, on one side or both; this helps the doctor sort the forms.

What the causes are

The most common cause of polyneuropathy is diabetes: high blood glucose over years damages nerves and the vessels that feed them (see type 2 diabetes). Other important causes are:

• nutritional deficiencies, especially vitamin B12, folate and vitamin B6 (in excess it also damages the nerve);
• excess alcohol;
• hypothyroidism, chronic kidney and liver disease;
• drugs (platinum and taxane chemotherapy, isoniazid, amiodarone, long-term metronidazole, nitrofurantoin) and toxins;
• compression of nerves by anatomical narrowing (carpal tunnel, ulnar nerve, peroneal nerve) or by a disc;
• inflammatory and autoimmune diseases, infections (zoster, HIV), plasma cell disorders;
• hereditary forms.

In a proportion of patients (about a quarter of cases) the cause remains unclear even after full investigation.

How they are diagnosed

The neurologist assesses sensation (touch, vibration with a 128 Hz tuning fork, temperature, pain), strength, reflexes and gait. Tests are chosen according to suspicion: glucose and HbA1c, vitamin B12, thyroid function, blood count, kidney and liver function, and, when features are atypical, serum protein electrophoresis. The results are interpreted together with the clinical examination.

Nerve conduction studies and electromyography (EMG) may be recommended at the relevant service; they show whether the damage affects the axon or the myelin, how widespread it is and whether there is focal compression. MRI of the spine or nerve is requested when a structural cause is suspected. These examinations are not requested automatically for every patient.

How they are treated

Treatment targets the cause when it is treatable: better glucose control, replacing vitamin B12 only when it is deficient, stopping alcohol, correcting the thyroid, stopping or changing a harmful drug, releasing a compressed nerve. In diabetic neuropathy, control of glucose, blood pressure and lipids slows progression.

Neuropathic pain is treated with specific drugs, because ordinary analgesics are often ineffective: amitriptyline, duloxetine, gabapentin or pregabalin, or, for localized pain, capsaicin creams. Doses are increased gradually and the effect is judged after a few weeks; opioids are not recommended for chronic neuropathic pain. Physiotherapy, balance exercises and aids (for example orthoses, a walking stick) are needed when there is weakness and unsteadiness. Do not use vitamins or “nerve” drugs without assessment.

Care at home

If sensation in the feet is reduced (especially in diabetes), check the skin of your feet every day, use suitable shoes and seamless socks, and do not walk barefoot. Avoid heat sources (hot-water bottles, heating pads) that can cause burns without being felt. Wounds, pus or new redness need prompt review. Make the home safe against falls (lighting, removing loose rugs). Regular check-ups, every 6 months to a year or sooner when the doctor considers it reasonable, follow the course and the effect of drugs.

Care at Tirana Polyclinic: we offer neurology consultation, interpretation of tests and outside examinations, and coordination with endocrinology and physiotherapy when needed.