Acute Flaccid Paralysis


  • duration of weakness (ie. hours to days to weeks/months)
  • classify as rapidly progressive, acute, subacute or chronic
  • mode of progression (eg. onset in arms, “ascending paralysis”)
  • sensory involvement (numbness, tingling, loss of balance esp. in dark, pain/burning)
  • bulbar involvement (change in voice or swallowing)
  • facial weakness (trouble chewing, sucking with straw, blowing)
  • extraocular muscle weakness (diplopia) or ptosis
  • respiratory involvement (dyspnea, orthopnea)
  • bladder or bowel involvement
  • autonomic involvement (diarrhea, orthostatic dizziness, urinary retention, palpitations)
  • systemic symptoms (fever, weight loss, rash, joint pain)
  • recent illness or immunization (diarrheal or respiratory tract infection, oral polio vaccine)
  • recent travel (out of the country, to woods [tick bites])
  • precipitating factors (exertion, carbohydrate loading – with periodic paralyzes)
  • fluctuation in weakness (eg. diurnal variation, fatiguability in myasthenia)
  • drug or toxin exposure (canned or ‘bad’ food, pesticides, ‘statins’, lead exposure)
  • family history (porphyria)

Physical Examination

Distribution and Degree of weakness
– MRC grading (0 to 5 out of 5)
– Examine extraocular muscles (? ptosis), facial muscles, neck, arms & legs
– Describe the pattern of weakness (eg.paraparesis, faciobrachial, multifocal) if possible
– Assess for fatiguability

Sensory loss
– to particular modality (vibration / proprioception vs. pain / temperature)
– is there a sensory level?

– are the DTRs lost (ie. areflexic), depressed preserved, or brisk

Autonomic testing
-postural vitals, abnormal sweating, pupillary response, ileus

– the rash of Lyme disease (erythema chronicum migrans), lines on nails with arsenic poisoning (Mee’s lines), ticks, photosensitivity, Gottron’s papules (on extensor surfaces) & heliotrope discoloration over eyelids,

Spinal tenderness (with epidural abscess or hematoma, spinal tumor)

Straight leg raise (radiculopathy)

General Patterns

  1. Flaccid symmetric quadriparesis (+/- bulbar and respiratory involvement) with areflexia and minimal to profound sensory loss (but often sensory symptoms)- Acute neuropathy or polyradiculopathy (esp. Guillain-Barre syndrome)
  2. Symmetric proximal muscle weakness without sensory symptoms or signs and with preserved reflexes:- Acute myopathy (eg. polymyositis)
  3. Fatiguable muscle weakness with diplopia, ptosis and bulbar dysfunction- Myasthenia gravis (and other neuromuscular disorders)
  4. Flaccid Paraparesis with sensory level (often with reduced lower limb reflexes & bladder dysfunction)- Cauda equina syndrome
    – Thoracic spinal cord lesions (eg. transverse myelitis, spinal cord infarct)
  5. Bulbar predominant involvement- Botulism
    Myasthenia gravis
    – Motor neuron diseases (ALS,)
    – Pontine lesions
  6. Ophthalmoplegia with motor weakness:- Miller-Fischer variant of GB syndrome (areflexia)
    – Botulism & Tick paralysis
    Myasthenia gravis
  7. Prominent autonomic dysfunction- Guillain-Barre syndrome
    – Paraneoplastic Syndromes
    – Organophosphate toxicity
    – Botulism