The yield of diagnostic work-up of patients presenting with myalgia, exercise intolerance, or fatigue: A prospective observational study.

Myalgia, fatigue, and exercise intolerance are cause for referral to a neurologist. However, the diagnostic value of history, neurological examination, and ancillary investigations in patients with these symptoms is unknown. This study provides a sound footing for deciding which ancillary investigations should be conducted. A prospective observational study of the diagnostic approach in 187 patients with myalgia, exercise intolerance, or fatigue as their predominant symptom was performed. The primary outcomes were independent contribution of referral letter, history, examination, and ancillary investigations to a myopathy diagnosis. The secondary outcome was diagnostic value of combined ancillary investigations. 27% of patients had a myopathy. Positive family history (OR 3.2), progressive symptoms (OR 2.2), atrophy (OR 9.7), weakness (OR 10.9), and hyporeflexia (OR 4.4) were associated with a myopathy. Positive predictive values for myopathy were calculated for CK (0.32), EMG (0.66), ultrasound (0.47), and muscle biopsy (0.78). All contributed significantly in predicting myopathy. Multivariate analysis yielded a diagnostic algorithm facilitating a more efficient work-up in future patients. CK levels, EMG, ultrasound, and muscle biopsy independently contribute to predicting a myopathy. The diagnostic algorithm shows which combination of ancillary investigations should be employed in different subgroups and when to omit invasive techniques. This algorithm may drastically improve diagnostic efficiency.

Severe hypomagnesaemia causing reversible cerebellopathy.

Hypomagnesaemia is common among hospitalised patients and is often under-recognised. Chronic alcohol abuse and alcohol withdrawal are known causes for severe hypomagnesaemia. Hypomagnesaemia can present with cardiac arrhythmias, seizures and other neurological symptoms, among which ataxia. We present a 57-year-old man with a history of chronic alcohol abuse who developed a subacute cerebellar syndrome with hypertension after alcohol withdrawal. A severe hypomagnesaemia of 0.19 mmol/L (normal values 0.70-1.10) was found. MRI showed diffuse, T2 hyperintense lesions in and swelling of the cerebellum. Symptoms, hypertension and MRI abnormalities significantly improved rapidly after intravenous magnesium supplementation. Hypomagnesaemia can cause a subacute, cerebellar syndrome and hypertension. Symptoms, hypertension and MRI abnormalities can be reversed with rapid magnesium supplementation. MRI abnormalities are similar to those caused by vascular endothelial dysregulation seen in posterior reversible encephalopathy syndrome (PRES). A similar case was recently described. We confirm that magnesium is likely to be involved in the pathophysiology of PRES.