Diffuse body rigidity

Specialty: General.

• general numbness of the muscles
• generalized body rigidity
• rigid body

Why it occurs

• Early or atypical extrapyramidal disorders (refractory Parkinson's disease or Parkinson Plus syndromes such as progressive supranuclear palsy)
• Stiff person syndrome (autoimmune neurological disorder characterized by progressive muscle rigidity and painful spasms, mediated by anti-GAD antibodies)
• Hypocalcemic or hypomagnesemic tetany (neuromuscular hyperexitability due to low levels of divalent cations that generates generalized tonic contracture)
• Chronic metabolic myopathies or severe hypothyroidism (which slow the relaxation phase of the muscle contraction cycle due to ATP deficiency or slowing of the SERCA pump)
• Spasticity due to lesions of the pyramidal tract in the generalization or decompensation phase.

Initial workup

Serum levels of total calcium, ionic calcium, magnesium, phosphorus, creatine phosphokinase (CPK), anti-glutamic acid decarboxylase (anti-GAD) antibodies, needle electromyography of paravertebral and proximal muscles, and high-resolution brain MRI.

Standard management

• Diazepam — 2 to 5 mg orally every 8 to 12 hours, useful for reducing excessive muscle tone by facilitating central GABAergic transmission
• Baclofen — 5 to 10 mg orally every 8 hours, titrated progressively, to modulate the myotatic reflex at the spinal level
• Calcium gluconate (10 mL at 10% by slow intravenous route, indicated urgently if the rigidity is secondary to proven acute symptomatic hypocalcemia).