Hyperhidrosis

Section: Skin and soft tissue Sub-section: Benign skin and soft tissue] Curriculum: Curriculum, page 55

Definition

• Abnormally increased perspiration
• Cause unknown -? focal dysfunction of ANS
• Usually onset in childhood
• Usually bilateral, intermittent, worse in summer

Incidence

• Primary hyperhidrosis affects 1-4% people
• M = F
• Often have family history
• Secondary Hyperhidrosis develops any time in life, due to disorder of:
  • Thyroid, Pituitary, Diabetes, Tumours, Menopause, Adrenal and Drugs
• Nearly all pts with palmar hyperhidrosis also have plantar sweating
• 50% also have axillary hyperhidrosis
• Leads to alteration of lifestyle
  • To avoid hand contact
  • Pts develop other coping mechanisms

Pathophysiology

• Sweat glands are coiled glands in the hypodermis
• Eccrine secretion
  • Regular sweat glands
• Apocrine Secretion
  • Modified sweat glands
• Holocrine Secretion
  • Sebaceous glands
• CNS control of extremity sweating

Type of glands

• Eccrine Secretion
  • Regular sweat glands
  • Present all over the body
    • Most on palms, soles, axilla & face
    • Except:
      • Vermillion border of lips, nipples, tympanic membrane, nail beds, labia minora and glans penis, and inner prepuce
  • Function for thermoregulation
    • Produce sweat that evaporates
  • The eccrine unit
    • Consists of coiled gland at the dermal-fat junction
    • Discharges into an intradermal duct, then to an intraepidermal portion then opens onto skin
  • Secretion is merocrine
    • Secretions excreted via exostosis from secretory vesicles into a gland’s acinus (an epithelial lined duct)
    • Secretion is initially isotonic, but salt and HCO3 actively reabsorbed in duct, and becomes hypotonic
  • SNS cholinergic supply

• Apocrine Secretion

  • Modified sweat glands
    • Axilla, areola, perineum, groin, breast, external auditory canal (ear wax)
  • SNS adrenergic supply
  • Secrete fluid rich in mucin by decapitation
    • Apical plasma membrane buds off to enter lumen of gland
  • Apocrine unit
    • Consists of a coiled gland in dermal-fat junction
    • Discharges into a duct through the dermis which empties into a hair follicle
  • Fluid initially milky, viscous and odourless
    • Then develops a strong odour after bacterial action on skin
    • Function probably as scent glands
  • Most axillary sweat
    • Eccrine sweat + small amounts of apocrine

• Holocrine Secretion

  • Sebaceous glands
    • Cell membrane ruptures and contents released into lumen
  • Includes
    • Meibomian glands of eyelid
  • Open into side of hair follicles & direct to hairless areas of lips, nipples, areolae, prepuce, glans penis & labia minora
  • Especially large on the face
  • No motor innervation
  • Androgens act locally on these glands

SNS Control of Extremity Sweating

• Palmar Sweating
  • Hypothalamic signals reach Preganglionic fibres with cell bodies in the Lateral Horn of the Spinal column at T3 - T6
  • Exit via the Ventral Root to join the Sympathetic Chain where they may synapse immediately or travel up or down chain before synapsing
  • Converge on T2 & T3 Ganglia, where Postganglionic fibres reach
    • Sympathetic Chain
    • Then Brachial Plexus
    • Then the hand
• Acetylcholine is released from the postganglionic neuron
  • Stimulates the eccrine sweat gland
  • NB: This is the exception to the rule that postganglionic sympathetic nerves release adrenaline or noradrenaline at the target synapse - in sweat glands ACh is released, acting on muscarinic receptors a la parasympathetic system
• Plantar sweating: L3 & L4 ganglia involved
• Sympathetic Chain descends in thorax over rib heads

Management

• Non-Surgical
• Surgical
  • T2-3 Sympathicotomy
  • Lumbar Sympathectomy

Non-Surgical Management

• Aluminium chloride hexahydrate 20% solution (Drysol)
  • Apply daily and cover in plastic wrap
  • Works in 3-5 days
  • Main side effect is skin irritation
• Iontophoresis
  • Placement of hands or feet in tap water through which an electric current flows
  • Mechanism unknown
• Botox injection
  • Block ACh release at end of Post-Ganglionic nerve end
  • Needs 20-30 intradermal injections
  • Effective for 6-9 months
  • Side effects include weakness in intrinsic muscles of the hand
• Anticholinergic e.g. Oxybutynin or glycopyrrolate
  • Effective but common side effects
  • Dry mouth, blurred vision, constipation

Thoracic Sympathectomy

• Indications

  • Raynaud’s
  • Hyperhidrosis
  • Reflex sympathetic dystrophy
  • PVD

• Interruption of sympathetic innervation to hand, axilla, or face by clipping, transection, or resection of ganglia

  • Exact level of ablation, and whether ganglia are resected or chain simply transected (sympathicotomy) controversial

• Palmar - Transect T2 and T3

  • Palmar probably best treated with Bilateral Endoscopic Thoracic Sympathicotomy

• Axillary - Transect T3 and T4

  • Isolated axillary best treated with Botox injection

• Lumbar Sympathectomy more controversial

• For surgical steps see: Thoracic Sympathectomy

T2-3 Sympathicotomy Results

• Virtually 100% cure for palmar
• 1-3% recurrence
• Less successful for facial or axillary
• Failure can be due to
  • Inability to visualise sympathetic chain
  • Misidentification
  • Incomplete nerve interruption
  • Nerve regeneration

T2-3 Sympathicotomy Complications

• Bleeding, pain
• Compensatory sweating - in up to 75% pts
  • In torso, thighs and legs
    • Most mild and annoying only
  • 3% patients may get severe symptoms and, once established, is permanent
  • Gustatory sweating is also often reported. Probably occurs due to thermoregulatory response
• Some authors propose interrupting more caudal segments (T3, T4) only and leaving T2 intact
• After T2 sympathicotomy
  • Heart rate reduces, but exercise tolerance unchanged
  • Horner’s < 1%
    • Due to damage to sympathetic nerves passing through stellate ganglia, due to misidentification of level, or diathermy injury
    • Ptosis is immediate and often permanent

Lumbar sympathectomy

• Done more to decrease vasomotor tone
• Indications
  • Non-reconstructable rest pain
  • Reflex Sympathetic Dystrophy
  • Raynaud’s
  • Visceral pain
• Contraindications
  • Small vessel disease
  • Poor collateral supply
• Excise or ablate Sympathetic Chain & Ganglia from L2 to L4
• Chemical
  • Patient lateral with lateral extension of affected side – kidney break
  • LA, Image intensifier
  • Localise L2-L4 by palpation
  • Spinal needle advanced to vertebral body then walked off tangentially under II control
  • 5ml aqueous phenol at 2 sites
• Surgical retroperitoneal approach - see Lumbar sympathectomy