Q 1.4. Topical Sensory Syndromes

Topical sensory syndromes are distinct patterns of sensory abnormalities observed in neurological disorders. Understanding these syndromes is crucial for accurate diagnosis and management. 

1. Dermatomal Distribution:

   – Dermatomal sensory deficits result from lesions affecting specific spinal nerves.

   – Herpes zoster (shingles) exemplifies this pattern, causing a painful vesicular rash along a dermatome due to varicella-zoster virus reactivation.

   – Clinical studies highlight the importance of recognizing dermatomal distribution to promptly diagnose conditions like herpes zoster and differentiate them from other dermatological or systemic disorders.

2. Peripheral Nerve Distribution:

   – Sensory abnormalities occur along the distribution of a single peripheral nerve.

1.    Median Nerve Injury (Carpal Tunnel Syndrome):
   • Symptoms typically involve the thumb, index, and middle fingers.
   • Patients may complain of numbness, tingling, or burning sensations in the distribution of the median nerve, particularly at night or with activities involving wrist flexion.
   • Weakness in thumb abduction and opposition may also be present, leading to difficulties with grasping objects.

B.       Ulnar Nerve Injury (Cubital Tunnel Syndrome):

2. • Ulnar nerve injury often affects the ring and little fingers.
   • Patients may experience numbness and tingling along the ulnar aspect of the hand and forearm.
   • Weakness in grip strength and coordination, along with difficulty with fine motor tasks such as buttoning shirts or manipulating small objects, can occur.

C.      Radial Nerve Injury:

3. • Radial nerve injury may result in sensory and motor deficits in the posterior aspect of the arm, forearm, and hand.
   • Patients may report numbness and tingling along the dorsum of the hand and thumb.
   • Weakness in wrist and finger extension, along with a characteristic “wrist drop” due to paralysis of the extensor muscles, is often observed.

D.      Sciatic Nerve Injury:

4. • Sciatic nerve injury typically manifests as pain, numbness, and tingling along the posterior thigh, calf, and foot.
   • Patients may experience weakness in knee flexion and ankle dorsiflexion, leading to gait abnormalities such as foot drop and difficulty walking on tiptoes.

E.        Femoral Nerve Injury:

5. • Femoral nerve injury presents with sensory deficits in the anterior thigh and medial leg.
   • Patients may complain of numbness and tingling in the thigh region, along with weakness in hip flexion and knee extension.
   • Difficulty with activities such as climbing stairs or rising from a seated position may be evident.

F.        Peroneal (Fibular) Nerve Injury:

6. • Peroneal nerve injury results in sensory and motor deficits in the lateral leg and dorsum of the foot.
   • Patients may report numbness and tingling along the lateral aspect of the lower leg and dorsum of the foot, extending to the first web space.
   • Weakness in ankle dorsiflexion and toe extension can lead to foot drop and difficulties with walking, particularly on uneven surfaces.

G.      Brachial Plexus Injury (Erb’s and Klumpke’s Palsies):

7. • Brachial plexus injuries can affect multiple nerves and produce varied symptoms depending on the level and severity of the injury.
   • Erb’s palsy (C5-C6) may result in weakness or paralysis of the shoulder abductors, elbow flexors, and forearm supinators, known as the “waiter’s tip” posture.
   • Klumpke’s palsy (C8-T1) may lead to weakness or paralysis of the hand and wrist muscles, along with sensory deficits in the ulnar distribution of the hand.

3. Radicular Distribution:

   – Radicular sensory deficits emanate from spinal nerve root pathology, commonly due to disc herniation or foraminal stenosis.

4. Sensory Pathway Distribution:

   – Syndromes reflect disruptions in specific sensory pathways within the central nervous system.

   – Brown-Séquard syndrome, caused by unilateral spinal cord hemisection, demonstrates ipsilateral loss of proprioception and contralateral loss of pain and temperature sensation.

5. Peripheral Neuropathy Patterns:

   – Neuropathies exhibit characteristic patterns of sensory loss, often with distal, symmetric involvement.

   – Diabetic neuropathy frequently presents with a “stocking-and-glove” distribution of sensory deficits due to metabolic nerve damage.

6. Complex Regional Pain Syndrome (CRPS):

   – CRPS manifests as regional sensory abnormalities following trauma or injury.

   – Studies elucidate the role of neuroinflammation and neuroplasticity in CRPS pathogenesis, guiding targeted therapeutic approaches.

   – Multimodal interventions, including physical therapy, pharmacotherapy, and neuromodulation techniques, have demonstrated efficacy in managing CRPS-associated sensory disturbances.

References:

1. Gilden DH. Clinical practice. Herpes zoster. N Engl J Med. 2015;372(16):1539-1544.

2. Cohen JI. Clinical practice: Herpes zoster. N Engl J Med. 2013;369(3):255-263.

3. Atroshi I, Gummesson C, Johnsson R, Ornstein E, Ranstam J, Rosén I. Prevalence of carpal tunnel syndrome in a general population. JAMA. 1999;282(2):153-158.

4. Visser LH, Ngo Q, Groeneweg SJ, Brekelmans G. Long-term effect of local corticosteroid injection for carpal tunnel syndrome: a relation with electrodiagnostic severity. Clin Neurophysiol. 2012;123(4):838-841.

5. Modic MT, Masaryk TJ, Boumphrey F, Goormastic M, Bell G. Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography. AJR Am J Roentgenol. 1986;147(4):757-765.

6. Carreon LY, Djurasovic M, Glassman SD, Sailer P, Johnson R. Diagnostic accuracy and reliability of fine-cut CT scans with reconstructions to determine the status of an instrumented posterolateral fusion with surgical exploration as reference standard. Spine (Phila Pa 1976). 2007;32(8):892-895.

7. Lee JH, Lee SH, Kim ES, Eoh W. Clinical analysis of 59 patients with Brown-Séquard syndrome. J Korean Neurosurg Soc. 2011;49(5):259-263.

8. Ellingson BM, Salamon N, Holly LT. Advances in MR imaging for cervical spondylotic myelopathy. Eur Spine J. 2015;24 Suppl 2(Suppl 2):197-208.

9. Boulton AJ, Malik RA, Arezzo JC, Sosenko JM. Diabetic somatic neuropathies. Diabetes Care. 2004;27(6):1458-1486.

10. Callaghan BC, Little AA, Feldman EL, Hughes RA. Enhanced glucose control for preventing and treating diabetic neuropathy. Cochrane Database Syst Rev. 2012;6(6):CD007543.

11. Uçeyler N, Eberle T, Rolke R, Birklein F, Sommer C. Differential expression patterns of cytokines in complex regional pain syndrome. Pain. 2007;132(1-2):195-205.