Spontaneous resolution of frontotemporal brain sagging syndrome

Editor – Like Dr Kent and colleagues,¹ I have recently seen a patient with apparently spontaneous resolution of neuroradiological features of frontotemporal brain sagging syndrome (FTBSS), but with different clinical outcome.

A previously healthy 70-year-old man was referred from primary care with memory symptoms and headaches, the latter worse in the mornings. Family members reported forgetfulness over about 12 months, mixing up people’s names and sometimes repeating himself. He had developed low mood, not helped with antidepressant medications.

On neurological examination, there was psychomotor retardation, and the head turning and applause signs were evident,² but no other features. On the Mini-Addenbrooke’s Cognitive Examination he scored 10/30 (attention 2/4, memory 4/7, letter fluency 2/7, clock drawing 0/5, memory recall 2/7), and on Free-Cog 12/30 (cognitive function 8/25, executive function 4/5).

Magnetic resonance (MR) brain imaging, performed prior to neurology referral, showed normal brain parenchyma aside from minor small vessel ischaemic changes, but bilateral shallow subdural collections, slight inferior displacement of the brainstem, and uniform meningeal enhancement on contrast imaging, suggestive of low cerebrospinal fluid (CSF) pressure. A presumptive diagnosis of FTBSS was made. Subsequent MR spinal imaging revealed no CSF leak.

Blind blood patching was planned, but deferred when at 3-month follow-up both the patient and his family reported improvement in cognitive function. However, at 6-month follow-up the patient’s clinical state had deteriorated, with reduced speech output and personality change with uncharacteristic outbursts of anger. Repeat MR imaging, 10 months after the initial study, showed complete resolution of both subdural collections and meningeal enhancement. There was evidence for right temporal lobe atrophy. A presumptive diagnosis of frontotemporal dementia was made.

The exact relationship of the neuroradiological signs of low pressure and the clinical features was uncertain in this patient. Resolution of the former with progression of the latter suggests that in this case they were incidental. Clinicians should keep an open mind on the cause of cognitive symptoms in the presence of neuroradiological signs of low CSF pressure. Based on experience of this case, I suggest continued follow-up of patients with spontaneous resolution of FTBSS is indicated.

• © 2019 Royal College of Physicians