A 70-year-old woman was admitted to our department with bilateral lower-limb numbness and unsteady walking for 1 month. In January 2020, she was diagnosed with anxiety disorder at another hospital, due to loss of appetite and bilateral lower-limb numbness for 3 months. She received Deanxit treatment, without improvement.
At our hospital in February 2020, she reported a 1-month history of weight loss, diarrhea alternating with constipation, and multiple episodes (>10/d) of irradiative, electric shock-like pain in both lower limbs, which lasted for several seconds and then subsided. She denied a history of nitrous oxide abuse or anesthesia.
Physical examination showed normal consciousness, slow reactions, low emotions, and skin desquamation at multiple sites of the hands and feet. We found normal muscle tension and slightly reduced muscle strength in the limbs (upper, grade V-; lower, grade IV-), with positive tendon reflexes (upper limbs, ++; lower limbs, +++). Pinprick and vibration sensations were decreased in both lower limbs. The Babinski sign was detected in both lower limbs; the Chaddock sign was present in the left lower limb. The Romberg sign was positive. Blood tests showed the following: RBCs, 2.7x1012/L (NR 4.3-5.8*1012/L); Hb, 81 g/L (NR 130-175 g/L); HCT, 29.90% (NR 37-50%); MCV, 114.5 fL (NR 82-100 fL); MCH, 35.2 pg (NR 27-34 pg); RDW, 69.4% (NR 11.9-14.5%); VitB12, 61 pM (NR 138-652 pM); FA, 45.3 nM (NR 7.0-46.4 nM); serum copper, 16.31 muM (NR 7.12-21.29 muM); serum anti-intrinsic factor antibody, positive; HCY, normal; ANA, ACA, ANCA, and RF, negative; syphilis and HIV, negative.
Thoracic vertebral MRI showed long T1 and T2 signals in both dorsal and lateral columns of T5-T6, i.e., the "small character" sign (Figure 4). Electromyography showed substantially decreased amplitude and conduction velocity of the tested sensory and motor nerves, multiple peripheral nerve injuries, motor and sensory nerve axonal damage, and myelin injures. Thyroid tests showed the following: free thyronine, 4.0 pM (NR 3.1-6.8 pM); free thyroxine, 11.24 pM (NR 12-22 pM); thyroid-stimulating hormone, 5.97 muIU/mL (NR 0.27-4.2 muIU/mL), and thyroid peroxidase antibody, 93.96 IU/mL (NR 0-34 IU/mL). Thyroid ultrasonography showed bilateral heterogeneous texture of the thyroid with a hypoechoic nodule. Fine needle aspiration cytology showed benign nodules.
The patient was diagnosed with SCD, malignant anemia, and autoimmune thyroiditis (AITD). Daily intramuscular injection of mecobalamine (1 mg/) and oral FA, VitB12, and VitB6 were administered for 2 weeks. The VitB12 level returned to normal. Lower-limb muscle strength (grade IV+ to V-) and deep sensation improved, tendon reflexes were bilaterally positive (++), and urination/defecation were normal. The patient could stand without help. She was referred to the Endocrine Department for AITD treatment.