Thyroid metabolism can be disrupted secondary to a primary disease. A common comorbidity of the metabolic myopathy McArdle disease (Glycogen storage disease type V) is hypothyroidism. It is also a comorbidity of late-onset Pompe disease (Glycogen storage disease type II). As both hyper- and hypothyroidism disrupts muscle glycogen metabolism, it is important to keep in mind differential diagnoses and their comorbidities when trying to determine whether signs and symptoms are either primary or secondary disease.
thYrOiD mETAbOLisM cAN be DiSruPTed seCoNDary to a prImary diseaSE. a commoN cOMorBiditY of the MetABolic MyopATHy McarDlE dISEase (glycogeN sTOrage dISeaSE type v) is hYpoThyroidisM. iT is alSo a cOmorBiDitY oF late-onset pompE diseasE (GlycoGen storAgE dIsEaSe typE ii). As BOth hYper- aNd hyPothyroiDIsm Disrupts muscle GlYcogEn Metabolism, iT iS importaNT to kEep IN MinD DiffeREntiaL DiaGNoses aNd their COMOrbiDities WHen tryinG tO dEteRmIne wheTher sIgnS anD symPtoms aRe eitHEr pRimARY oR SecOndary diseaSE.