Rosen & Barkin's 5-Minute Emergency Medicine Consult (528 page)

• Open dislocation, presence of multiple trauma, or other, more serious, injuries
  
• Inability to reduce dislocation or maintain reduction
  
• Neurovascular compromise
  

• Closed injuries
  
• Adequate reduction
  
• No neurovascular involvement
  
• Orthopedic follow-up within 2–3 days
  

All patients with perilunate dislocations should be referred to a hand surgeon for surgical stabilization and ligament repair.

• All patients with a perilunate dislocation must follow-up with a hand surgeon for surgical stabilization and ligament repair.
  
• Follow-up should be within 2–3 days.
  

• Up to 25% of these injuries are missed on initial presentation.
  
• In a patient with wrist pain, swelling, and limited range of motion, it is important to obtain adequate x-rays of the wrist and make sure that the lunate and capitate are located in their fossa on the lateral wrist x-ray.
  
• Late presentation of these injuries leads to a very poor outcome and often requires a salvage operation.
  
• Complications include median nerve injury, tendon problems, complex regional pain syndrome, wrist instability, and post-traumatic arthritis.
  
• Even with appropriate treatment, there is a high incidence of post-traumatic arthritis and loss of grip strength.
  

• Budoff JE. Treatment of acute lunate and perilunate dislocations.
  J Hand Surg Am.
  2008;33A:1424–1432.
  
• Forli A, Courvoisier A, Wimsey S, et al. Perilunate dislocations and transscaphoid perilunate fracture-dislocations: A retrospective study with minimum ten-year follow-up.
  J Hand Surg Am
  . 2010;35:62–68.
  
• Kardashian G, Christoforou DC, Lee SK. Perilunate dislocations.
  Bull NYU Hosp Jt Dis
  . 2011;69(1):87–96.
  
• Melsom DS, Leslie IJ. Carpal dislocations.
  Curr Orthoped
  . 2007;21:288–297.
  
• Stanbury SJ, Elfar JC. Perilunate dislocation and perilunate fracture-dislocation.
  J Am Acad Orthop Surg
  . 2011;19(9):554–562.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Carpal Fractures
  
• Lunate Dislocation
  
• Scaphoid Fracture
  

CODES

• 814.01 Closed fracture of navicular [scaphoid] bone of wrist
  
• 833.09 Closed dislocation of wrist, other
  

BASICS

• Periodic paralysis (PP): Disorder of muscle metabolism usually inherited that leads to flaccid extremity weakness. Exacerbated by hyperkalemia, hypokalemia, thyrotoxicosis
  
• Primary: Familial AD mutation skeletal muscle calcium, sodium, or potassium channel
  
• Secondary: Thyrotoxic, hypokalemia, hyperkalemia
  

• Hypokalemic PP (HypoPP):
  
  • MC, 1:100,000 prevalence
    
  • 1/3 new AD mutations
    
• Hyperkalemic PP (HyperPP):
  
  • 1:200,000 prevalence
    
  • 90% of people with mutation will have clinical symptoms
    
• Thyrotoxic PP (ThyroPP):
  
  • Incidence 2% in patients with thyrotoxicosis
    
  • Higher in Asians
    
  • Subset of HypoPP, clinically identical
    
• Andersen–Tawil:
  
  • Subset of HypoPP
    
  • Rare
    
  • Prevalence unknown
    

• Mutation of skeletal muscle Na channel gene:
  
  • SCN4A
    
  • HypoPP, HyperPP:
    
    • AD inheritance
      
    • Spontaneous mutation
      
• Mutation of skeletal muscle calcium channel gene CACN1AS:
  
  • HypoPP
    
• Mutation of KCNJ2 gene:
  
  • Andersen–Tawil:
    
    • AD inheritance
      
    • 50% spontaneous
      
• M>F
  
• Age of onset:
  
  • HypoPP:
    
    • 1st or 2nd decade
      
  • HyperPP:
    
    • 1st decade
      
  • Andersen–Tawil:
    
    • 1st or 2nd decade
      
  • ThyroPP:
    
    • 2nd–5th decade
      

DIAGNOSIS

• Intermittent weakness:
  
  • Can be isolated
    
  • Rapid onset
    
  • Common for attacks to recur and for weakness to persist between attacks
    
  • Frequency from single isolated to daily attacks
    
• Type of attack:
  
  • Spontaneous
    
  • At night or early morning
    
  • Provoked:
    
    • History of thyroid disease
      
    • Recent carbohydrate rich meal
      
    • Rest after strenuous exercise
      
    • Illness
      
    • Lack of sleep
      
    • Medications: Insulin, epinephrine, corticosteroids, β-agonists, diuretics
      
    • Cold environment
      
    • Menstruation
      
    • Reduced sleep
      
    • Pregnancy
      
    • Medications that induce thyroid disease
      
• Length of attack:
  
  • HypoPP: 1 hr–days
    
  • HyperPP: 15 min–4 hr
    
  • ThyroPP: Same as HypoPP
    
  • Andersen–Tawil: Variable
    
• Family history of episodes of weakness
  

• General:
  
  • ThyroPP:
    
    • Hyperthermia
      
• HEENT:
  
  • HypoPP and HyperPP:
    
    • Lid lag: Rare
      
    • Difficulty swallowing: Rare
      
  • ThyroPP:
    
    • Exophthalmos
      
    • Goiter
      
  • Andersen–Tawil:
    
    • Dysmorphic features: Short stature, low set ears, broad based nose, micrognathia
      
• Cardiac:
  
  • HypoPP and HyperPP:
    
    • Dysrhythmias possible
      
  • ThyroPP:
    
    • Tachycardia, dysrhythmia
      
  • Andersen–Tawil:
    
    • Cardiac dysrhythmia
      
• Pulmonary:
  
  • HypoPP:
    
    • Can affect respiratory muscles, rare
      
  • Severe hypokalemia
    
• M/S:
  
  • HypoPP, HyperPP, ThyroPP:
    
    • Symmetrical muscle weakness in 1 or more extremity
      
    • Legs > arms
      
  • Andersen–Tawil:
    
    • Periodic flaccid muscle weakness <1 hr
      
    • Proximal > distal
      
• Neuro:
  
  • Alert, conscious
    
  • Sensation intact
    
  • DTR reduced or absent
    
  • Skeletal muscle weakness, symmetrical
    
  • Sphincter normal
    
• Skin:
  
  • ThyroPP:
    
    • Warm, moist
      

Lab tests and EKG

• EKG:
  
  • HypoPP:
    
    • Sinus bradycardia
      
    • Flattened T-wave
      
    • ST-segment depressions
      
  • HyperPP:
    
    • Rarely peaked T-waves
      
  • ThryoPP:
    
    • Tall P-waves, wide QRS, decreased T-wave, AV block, ventricular fibrillation or asystole
      
  • Andersen–Tawil:
    
    • Long QT, ventricular arrhythmias
      
    • U-waves, prolonged T-wave downslope
      
    • Differentiates Andersen syndrome from other long QT syndromes
      
• Electrolytes:
  
  • Potassium:
    
    • HyperPP: Normal or increased
      
    • HypoPP: Normal or decreased
      
    • ThryoPP: Decreased during attacks
      
    • Andersen–Tawil: Decreased, normal, or increased
      
  • Calcium:
    
    • ThryoPP: Decreased during attacks
      
  • Phosphorus:
    
    • ThryoPP: Decreased during attacks
      
• Thyroid Studies:
  
  • ThyroPP:
    
    • TSH: Low
      
    • T4: Elevated
      

Not necessary for diagnosis

None in ED but specialists may consider the following: