Guillain–Barré syndrome | Initial proximal weakness, some distal sensory symptoms, absent reflexes | Lumbar puncture, nerve conduction studies |
Myopathies (eg, acid maltase) | Proximal weakness, no sensory changes | Raised serum creatine kinase, electromyography, muscle biopsy |
Cervical myelopathy (structural or inflammatory) | Usually subacute onset, sensory level, urinary retention | MR scan, lumbar puncture |
Motor neuron disease | Usually with clear preceding history, muscle fasciculation and wasting, brisk reflexes | Electromyography |
Brainstem stroke/inflammation | Cranial nerve signs, altered consciousness, brisk reflexes, sensory signs | MR scan, lumbar puncture |
Botulism | History of intravenous drug abuse, weakness spreading caudally, autonomic disturbances (sluggish pupillary responses, dry eyes) | Electromyography |
Lambert–Eaton myasthenic syndrome | Rare; subacute proximal leg weakness, autonomic symptoms | Electromyography, voltage gated calcium channel antibodies |
Organophosphate poisoning | History of pesticide use, chemical warfare, symptoms similar to cholinergic crisis | Red cell acetylcholinesterase levels |
Cholinergic crisis | Salivation, lacrimation, diarrhoea, urinary incontinence, bradycardia, miosis, bronchospasm (in addition to muscle weakness and respiratory failure) | Drug history and clinical signs |