what causes extreme muscle weakness
Many chronic diseases commonly cause muscle weakness. In some conditions this is due to reduced blood and nutrient supply to muscles: Peripheral arterial disease: this is caused by narrowing of the arteries, usually due to the build-up of cholesterol. It's linked to smoking and diet.
Less commonly-used medicines which can cause muscle weakness and damage to muscles include: 1  Some heart medicines (for example, amiodarone). 2  Chemotherapy medicines. 3  Anti-HIV medications. 4  Interferon - used in some cancers and for multiple sclerosis (MS). 5  Medicines used to treat an overactive thyroid.