Table 6

 Conditions that may present with generalised weakness

ConditionClinical clues
Guillain–Barré syndromeRapidly progressive ascending weakness
May involve respiratory muscles
Loss of reflexes
May have severe back pain
Respiratory or gastrointestinal illness two to four weeks prior to onset
BotulismSymmetric descending weakness
    Wound botulismCranial nerve weakness—for example, diplopia
    Food borne botulismNo sensory symptoms
Prodromal nausea, vomiting, diarrhoea
Suspect in intravenous drug users
Spinal cord diseaseBack pain
Sensory level
Sphincter disturbance
Motor neurone diseaseProgressive weakness over months
Fasciculation of muscles
Exaggerated reflexes
May have bulbar involvement
Vasculitic neuropathyPainful
Multiple peripheral nerves affected (mononeuritis multiplex)
Raised inflammatory markers
May be associated with rash, arthropathy, renal disease
Myasthenia gravisBulbar, ocular, and respiratory muscles affected
Viral myositisPainful muscles
Raised creatine kinase
Drug induced myopathyProgressive proximal weakness over weeks
 Drugs history—for example, statins
Metabolic disordersAlcoholism
    HypomagnesaemiaDrugs—for example, laxatives, diuretics
Polymyalgia rheumaticaElderly patient
Proximal pain and weakness
May be associated with weight loss, headache,
Raised ESR