Electroencephalogram with chromophobe adenomata and rathké pouch cysts: Modification by associated metabolic disorder

Abstract

1. 1. One hundred and two electroencephalograms from 59 patients with a pituitary chromophobe adenoma and 32 EEG's from 17 patients with a Rathké pouch cyst have been reviewed. 2. 2. The records of those with a pituitary chromophobe adenoma could be divided as follows: the bulk of the records showed a clear theta rhythm (4–7 c/sec.) which was often asymmetrical. Of the remainder, 10 were normal or borderline normal; 9 were of low voltage; and 3 showed generalized delta waves. 3. 3. Although similar features occurred among some of the patients with a Rathké pouch cyst, recordings in the presence of a Rathké pouch cyst frequently showed bilaterally synchronous rhythmic delta bursts (1.5–2.5 c/sec.) such as were only once observed with a pituitary chromophobe adenoma. 4. 4. Serial EEG's have been obtained in many of these patients, and it has usually been possible to demonstrate recession of the abnormal activity with hormone replacement therapy (cortisone, thyroid and sometimes testosterone). It is known that symmetrical theta activity may occur as a manifestation of suprarenal failure and that it can be dispersed by treatment with cortisone. 5. 5. It is our belief that many of the EEG abnormalities commonly ascribed to pituitary tumour are in fact caused by associated endocrine deficiencies. However, it seems possible that the asymmetries of the record in these patients are associated with asymmetrical pressure upon structures at the base of the brain. 6. 6. The possible value of the EEG in the diagnosis and management of these patients is discussed.