Peripheral Neuropathy — A Painless Numb Foot is More Dangerous Than a Painful Foot and Examination Cannot Be Done Without Removing Shoes and Socks

A PAINLESS NUMB FOOT IS MORE DANGEROUS THAN A PAINFUL FOOT — CONTRARY TO INTUITION, THIS IS OFTEN OVERLOOKED BY BOTH THE PATIENT AND THE PHYSICIAN | Pain is a COMPLAINT, and the patient SEEKS HELP FOR PAIN; IF THERE IS NO PAIN, THE PATIENT THINKS THERE IS NO PROBLEM | HOWEVER, PAIN IS ALSO A PROTECTIVE MECHANISM: it alerts us and CHANGES OUR BEHAVIOR when we STEP WRONG, our SHOE HITS SOMETHING, or SOMETHING PIERCES US | WHEN THIS MECHANISM IS LOST, INJURY OCCURS SILENTLY and GROWS: the patient may find a DEEP WOUND under their shoe IN THE EVENING without knowing WHEN IT HAPPENED | WHAT THEY DO NOT NOTICE: A PEBBLE IN THE SHOE | BLISTER | BURN FROM HOT WATER | PRESSURE FROM TIGHT SHOES | The wound is only recognized by SMELL, DISCHARGE, or a STAIN ON THE SOCK (relevant protocol) | RULE: IN A PATIENT REPORTING NUMBNESS, THE LACK OF COMPLAINT IS NOT A REASSURANCE BUT A RISK INDICATOR → YOU CANNOT SAY "NO PAIN, NO PROBLEM" | EXAMINATION IS INCOMPLETE WITHOUT REMOVING SHOES AND SOCKS — THE MOST COMMON AND EASILY FIXED OMISSION | In outpatient clinics, TIME IS LIMITED, the patient may have difficulty REMOVING SHOES, and if the COMPLAINT SEEMS UNRELATED TO THE FOOT, this STEP APPEARS UNNECESSARY | HOWEVER, in a significant portion of these patients, there are FINDINGS THAT CANNOT BE SEEN WITHOUT LOOKING AT THE FOOT: A CORN | A CRACK BETWEEN TOES | AN INITIAL WOUND | NONE CAUSE COMPLAINTS because SENSATION IS REDUCED → THE WOUND IS ONLY NOTICED WHEN IT PROGRESSES and INFECTION DEVELOPS; BY THEN, TREATMENT IS MUCH MORE DIFFICULT | WHAT TO EXAMINE: BOTH FEET | SPACES BETWEEN TOES | SOLE AND HEEL | PROTECTIVE SENSATION (monofilament or equivalent) | VIBRATION SENSE | ACHILLES REFLEX | SKIN INTEGRITY AND COLOR | CORNS AND CRACKS | DEFORMITY AND PRESSURE POINTS | NAIL AND FUNGUS | FOOT PULSES | INSIDE OF THE SHOE — a FORGOTTEN OBJECT or A DAMAGED INSOLE CAN CAUSE THE WOUND | CORNS INDICATE PRESSURE POINTS ON A FOOT WITH REDUCED PROTECTIVE SENSATION AND SIGNAL A FUTURE WOUND

A painless numb foot is more dangerous than a painful foot because pain is a protective mechanism; when it disappears, injury occurs silently, and the patient finds the wound without knowing when it happened. Therefore, a lack of complaint is not reassurance but a risk indicator. Examination without removing shoes and socks is incomplete: corns, cracks, and initial wounds do not cause complaints because sensation is reduced, and the wound is only noticed when infection develops.

METFORMIN CAN LOWER B12 LEVELS — A CORRECTABLE CAUSE IS SYSTEMATICALLY OVERLOOKED | In a diabetic patient, when numbness occurs in the feet, the DIAGNOSIS IS ALMOST AUTOMATIC: this is a KNOWN OUTCOME of the disease and NO OTHER EXPLANATION IS SOUGHT | THIS INFERENCE IS OFTEN CORRECT BUT NOT THE ONLY POSSIBILITY | When Metformin is USED LONG-TERM, IT CAN REDUCE B12 ABSORPTION, and B12 DEFICIENCY CAN PRODUCE THE SAME PICTURE | THE DIFFERENCE IS IMPORTANT: THE PICTURE DUE TO B12 DEFICIENCY CAN BE CORRECTED WITH TREATMENT, WHILE THE PICTURE RELATED TO DIABETES IS ONLY MONITORED → IN A PATIENT USING METFORMIN LONG-TERM AND DEVELOPING NEUROPATHY, B12 IS ASSESSED; IT IS A SIMPLE TEST AND CAN REVEAL A REVERSIBLE CAUSE | OTHER CORRECTABLE CAUSES: ALCOHOL | THYROID | RENAL FAILURE | MEDICATIONS (especially chemotherapy) | VITAMIN D | CELIAC | MONOCLONAL GAMMOPATHY | RECURRENT PRESSURE | PATTERN IS AS IMPORTANT AS DIAGNOSIS | Typical neuropathy FOLLOWS A SPECIFIC PATTERN: STARTS SYMMETRICALLY IN BOTH FEET | SLOWLY PROGRESSES UPWARD IN THE SOCK DISTRIBUTION | SENSORY LOSS PROCEEDS BEFORE STRENGTH LOSS | ANY PICTURE THAT DOES NOT FIT THIS PATTERN INDICATES ANOTHER CAUSE: RAPIDLY PROGRESSING OVER DAYS-WEEKS | ASYMMETRIC or UNILATERAL (vasculitis) | STRENGTH LOSS FOREMOST | INVOLVING MUSCLES CLOSE TO THE TORSO | STARTING FIRST IN THE HANDS | STARTING SUDDENLY AND WITH SEVERE PAIN | ASSOCIATED WITH SYSTEMIC SIGNS | INCONTINENCE + NUMBNESS IN THE SADDLE AREA (SURGICAL EMERGENCY) | BREATHING DIFFICULTY (EMERGENCY) | EXPECTATION IN PAIN TREATMENT IS SET FROM THE BEGINNING | Patients RECOGNIZE THE EXPERIENCE OF PAIN RELIEF FROM OTHER PAINS: THEY TAKE ONE TABLET AND FEEL RELIEF QUICKLY | FOR THIS TYPE OF PAIN, DRUGS WORK DIFFERENTLY: EFFECT ESTABLISHES OVER DAYS AND WEEKS, and COMPLETE RELIEF IS OFTEN NOT ACHIEVED | When the patient does not know this, ONE OF TWO THINGS HAPPENS: EITHER THEY THINK THE DRUG DOES NOT WORK AND STOP, OR THEY INSIST ON INCREASING THE DOSE AND ENCOUNTER SIDE EFFECTS | REALISTIC GOAL: NOT ZEROING THE PAIN, BUT IMPROVING SLEEP AND RESUMING DAILY ACTIVITIES → when this goal is CLEARLY SET, PARTIAL IMPROVEMENT IS EXPERIENCED AS SUCCESS and TREATMENT IS MAINTAINED | START AT LOW DOSE, GRADUALLY INCREASE | OPIOIDS ARE NOT THE FIRST CHOICE | BALANCE RELIES ON VISION — FALLS INCREASE IN THE DARK | To stand, the brain needs to KNOW WHERE THE FEET ARE, and this information is NORMALLY PROVIDED BY SENSATION FROM THE FEET | When sensation decreases, the brain LARGELY STARTS TO RELY ON THE EYES, and THE PATIENT DOES NOT NOTICE IT because WHILE THE PATIENT SEES WELL DURING THE DAY, THERE IS NO BALANCE PROBLEM → WHEN LIGHT DECREASES or EYE IS CLOSED, SUPPORT DISAPPEARS: the patient STUMBLES WHEN GETTING UP TO THE BATHROOM AT NIGHT | MEASURES: NIGHT LIGHTING | REMOVAL OF OBSTACLES AND RUGS | GRAB BARS IN THE BATHROOM | SUPPORTIVE SHOES | BALANCE EXERCISES | WATER TEMPERATURE SHOULD NOT BE MEASURED WITH THE FOOT — A SEEMINGLY SMALL POINT THAT CAUSES SERIOUS BURNS | A person with reduced sensation evaluates the temperature of water WITH THE FOOT, AND THIS IS A NORMAL BEHAVIOR; HOWEVER, THE FOOT CAN NO LONGER ACCURATELY PERCEIVE HEAT AND A TEMPERATURE THAT SHOULD BE UNBEARABLE MAY FEEL COMFORTABLE → RESULTING IN A DEEP BURN THAT TURNS INTO A WOUND THAT HEALS POORLY IN A FOOT WITH REDUCED SENSATION | THE SAME MECHANISM APPLIES TO HOT WATER BOTTLES AND HEATERS: USED TO WARM COLD FEET, THEY CAN BURN UNNOTICED | FOOT CARE TRAINING (both written and with a close companion): DAILY VISUAL INSPECTION (if necessary, WITH A MIRROR OR THE HELP OF A COMPANION) | KEEP TOE SPACES DRY | DO NOT WALK BAREFOOT (even indoors) | CHECK INSIDE OF SHOES BY HAND | MEASURE WATER TEMPERATURE WITH HAND OR ELBOW | CUT NAILS STRAIGHT | DO NOT CUT CORNS YOURSELF

Metformin can lower B12 levels, and in diabetic patients neuropathy is directly linked to sugar, so this correctable cause is often overlooked; the distinction is important because B12 deficiency can be corrected with treatment. Pattern recognition is as important as diagnosis: anything that does not match a symmetrical and slowly progressing picture indicates another cause. Expectations in pain management should be set from the beginning; the goal is not zero pain but sleep and function. Since balance relies on vision, falls are concentrated in the dark, and water temperature should not be measured with the foot.