You lift the deadweight. Nothing. Then “tingling” starts, several thousand microscopic acupuncturists needling your flesh. As you shake the arm vigorously, your partner wakes, delighted you are not dying but irritated at your lack of consideration.
We call this pins and needles. Doctors, in pointed fashion, style it paraesthesiae, principally because “my arm has gone all weird” is too simplistic to publish in medical journals.
The plural, paraesthesiae, includes tingling, prickling, burning, buzzing, crawling, electric-shock sensations, and numbness. Most are harmless and temporary. Some are not. So, what gets on your nerves? There are numerous causes, so rather than needle you with every possibility, let’s stick to the salient points.
Mechanical: By far the most common cause is pressure. Sit cross-legged, sleep on an arm, or spend hours wedged into an airline seat designed for an anorexic lawn ornament and you may compress a peripheral nerve. Pointedly, remove the pressure and normal service usually resumes, accompanied by pins and needles as the nerve wakes up and complains to management.
Persistent symptoms can arise at anatomical pinch-points. Imagine a snagged electric cable: pressure damages insulation, wire, or both, impairing transmission.
Carpal tunnel syndrome compresses the median nerve at the wrist, causing tingling or numbness predominantly in the thumb, index and middle fingers, and part of the ring finger, often worse at night. The affected digit points to the culprit!
At the elbow, ulnar nerve compression produces tingling in the little and ring fingers. Hitting your “funny bone” actually whacks this nerve, demonstrating that anatomists have a peculiar understanding of comedy.
Then there is the spine. Bulging or prolapsed discs, arthritis, or spinal canal narrowing can cause pain, tingling, numbness, and weakness extending into an arm or leg. In the lumbar spine this may produce sciatica (“A Broken Record,” AOPA Pilot, April 2011, page 36). This can cause consternation when a patient complains of strange knee sensations and the doctor says their back needs sorting; one might say numb and number, but pinpointing where the tingling travels helps identify where the nerve is pinched.
Pilots are particularly accomplished at provoking back trouble: prolonged sitting, vibration, awkward cockpit entry, and lifting heavy luggage all contribute.
Metabolism: Persistently elevated blood glucose in diabetes damages nerves, commonly beginning in the feet. Tingling, burning, or numbness develops in a “stocking” distribution, sometimes later involving the hands in a “glove” pattern. Sensory loss matters: unnoticed injuries may deteriorate into ulcers and, in severe cases, amputation.
Kidney disease, thyroid disorders, and disturbances of calcium or other electrolytes can also cause strange sensations. Nerves are sophisticated electrical cables but, like complex electrical equipment, become temperamental in the wrong chemical environment.
Chronic excessive alcohol consumption can cause peripheral neuropathy directly and through nutritional deficiencies.
Diet: Nerves are fussy eaters, and vitamin B12 deficiency is an important, treatable cause. B12 is essential for neurological function; deficiency can cause tingling, numbness, weakness, balance problems, and permanent neurological damage. Because reliable natural sources are predominantly animal-derived, strict vegans may need fortified foods or supplementation. This is a nutritional deficiency that is worth catching early to prevent harm.
Sometimes the problem isn’t what enters your mouth but what your gut does with it. Pernicious anaemia, stomach surgery, Crohn’s, and celiac disease can impair B12 absorption.
Vitamin B6 offers a nutritional paradox: deficiency causes problems, but excessive supplementation also provokes sensory neuropathy—relevant when swallowing handfuls of supplements apparently constitutes breakfast. This punctures the notion that if one vitamin tablet is good, twelve must be better.
Other substances cause problems too. Cocaine can cause formication—not a typo, the $100 word for feeling insects crawling on your skin. Chemotherapy, anticonvulsants, antibiotics, and other drugs can produce neuropathy, as can withdrawal from certain medications. Heavy metals including lead, mercury, and arsenic are also culprits.
Victorian ladies used arsenic-containing cosmetics to achieve fashionable pallor, occasionally with unfortunate consequences. Mercury exposure among felt hat makers caused neurological and psychiatric symptoms; hence “mad as a hatter,” as in Lewis Carroll’s Alice stories.
Neurologic causes: Consult Dr. Google about a tingling finger at 11:47 p.m. and you will invariably self-diagnose a brain tumor, multiple sclerosis (MS), or something previously reported only in Norwegian elk.
And yes, MS can produce paraesthesiae. Stroke and transient ischemic attack (TIA) can also alter sensation, typically suddenly and with other neurological abnormalities.
Migraine can produce sensory disturbances, while shingles—reactivation of the chickenpox virus—can cause tingling or burning before its characteristic rash. Some develop persistent post-herpetic neuralgia, where even clothing touching skin becomes exquisitely painful.
And then there are rarer delights.
Anxiety and hyperventilation produce tingling, particularly around the mouth and fingers. Rapid breathing lowers blood carbon dioxide, altering nerve excitability. Tingling causes anxiety, more hyperventilation, more tingling, and eventually an expensive visit to the ER.
Guillain-Barré syndrome occurs when the immune system attacks peripheral nerves; tingling may precede rapidly progressive weakness and, severely, paralysis.
Meralgia paraesthetica, a splendidly grand name, is compression of a sensory nerve supplying the outer thigh, provoked by tight belts, obesity, pregnancy, or tight clothing. If fashionable trousers make your thigh numb, your nervous system may simply be reviewing your wardrobe.
Porphyria, once proposed to explain King George III’s illness, can present with neuropathy, abdominal, and psychiatric symptoms. Amyloidosis deposits abnormal proteins in tissues including nerves. Paraneoplastic neuropathy results when an immune response triggered by cancer attacks nerves, occasionally revealing an otherwise hidden tumor.
And leprosy, or Hansen’s disease, still exists and is treatable. Mycobacterium leprae, the causative bug, particularly enjoys peripheral nerves, causing patches of numb skin, paraesthesiae and weakness. Rare, certainly, but difficult to beat for a trivia question. Lyme disease and HIV can also affect nerves.
Location, location, location: Where symptoms occur provides clues. One hand suggests something different from both feet; one finger may identify a particular nerve. Tingling from neck to arm suggests cervical nerve irritation; down a leg, think lower spine. Both feet suggest systemic neuropathy such as diabetes or B12 deficiency.
Doctors ask: where, when, how long, and what else? Pain, weakness, or loss of balance? Does position provoke it? Is it progressing? New medication or supplement? If fingers change colour and tingle in cold weather, in a case of nerve jingle all the way, perhaps Raynaud’s phenomenon is responsible.
When tingling isn’t funny: Sudden altered sensation on one side, especially with facial drooping, weakness, speech difficulty, visual disturbance, severe headache, or poor coordination, may indicate stroke. Get to the ER immediately.
New leg weakness with numbness around buttocks or genitals, or loss of bladder or bowel control, may indicate cauda equina syndrome, compression of nerves at the bottom of the spinal canal. This too is an emergency. Progressive tingling with increasing weakness also needs prompt assessment as does persistent or worsening paraesthesiae.
After chatting with your doctor, examination assesses sensation, strength, reflexes, and circulation. Blood tests might include glucose, B12, thyroid and kidney function, and electrolytes. Depending upon the suspected cause, nerve-conduction studies, electromyography, or brain or spinal imaging may follow.
Treatment addresses the cause: relieve a trapped nerve, control diabetes, replace B12, modify drug regimens, and treat underlying neurological conditions. Sometimes nerve pain/tingling merits medications to block or moderate signals.
What the FAA thinks: Pins and needles do not automatically mean grounding; paraesthesia is a symptom, so the aeromedical issue is its cause and whether it impairs your ability to safely act as PIC.
FAA AME guidance addresses peripheral neuropathy through its disposition process. Sciatica interfering with function or likely to become incapacitating may require FAA review, including documentation of strength, range of motion, pain, and medication effects. An occasional grumble from your sciatic nerve is one thing; inability to reliably operate rudder pedals is another.
The underlying diagnosis matters. For medication-treated diabetes, FAA assessment considers complications including peripheral neuropathy; MS has its own evaluation pathway. Significant neurological conditions may require FAA review rather than straightforward AME issuance.
Medication matters too. Something that suppresses neuropathic pain beautifully but makes you resemble a tranquillized sloth is not compatible with aviation.
Practically, occasional tingling with preserved strength, sensation, and function is aeromedically less interesting than progressive symptoms with weakness, numbness, poor coordination, or impaired function. Discuss persistent symptoms with your AME rather than concealing them; adding an administrative problem to a medical one will get on your nerves.
A final prick: Many silly things jangle someone’s nerves: loud music from cars, pretentious restaurants, interactive voice-response systems, and emails asking you to rate a bill-paying service. But sometimes something serious gets on your nerves. Pay attention to new or progressing strange sensations, weakness, balance problems, or other neurological symptoms.
Our nerves carry an astonishing torrent of information, allowing us to feel, move, and interact with the world—and, importantly, determine whether the rudder pedal is where we left it.
Usually, they perform this task silently. So when your nerves start talking to you, listen.
Unless you’ve been sitting on your foot for twenty minutes. In which case, get off it…and fly well!
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