The apt diagnosis of progressive supranuclear palsy with frontal predominance: A case report

Originally described in 1964, progressive supranuclear palsy (PSP) is a neurodegenerative tauopathy with a prevalence of approximately 45% among other parkinsonian-plus syndromes. PSP can be categorized into various phenotypes among which 6% belong to the PSP-frontal predominant (PSP- F variant [1,2]. PSP-F presents primarily with vertical supranuclear palsy and frontal-cortical symptoms including apathy, bradyphrenia, impulsivity, dysexecutive syndrome, and reduced phonemic verbal fluency [3].

Here we describe the case of a 75-year-old Caucasian female with a past medical history of Parkinson’s disorder (PD), Anxiety, and Depressive disorder who presented for altered mental status after a syncopal episode. The patient had experienced multiple unprovoked falls in the past three years with PD symptoms (tremors and gait abnormalities) that were resistant to levodopa. She reported difficulty looking upwards, resulting in falls when reaching for overhead objects. As per family, she also experienced multiple crying spells during inappropriate times. Neurological exam was significant for an asymmetric resting tremor of the right hand, a rolling tremor of the neck, and limited passive range of motion of the bilateral lower extremities with 3/5 motor strength in all four extremities. Cranial nerve (CN) testing for CN III, IV, VI showed vertical gaze palsy with intact extraocular muscles, normal convergence, and no nystagmus. Neurological examination of language revealed no deficits in either receptive or expressive aphasia and naming repetition during patient interviews; however, the patient was noted to have a waxing and waning course of expressive aphasia during the hospital course by other staff. The rest of the physical examination was normal. Computed tomography of the brain showed atrophy of the cerebellum, fronto-temporal cerebral regions, and the brainstem (with a “hummingbird sign”) without evidence of acute processes. A probable diagnosis of parkinsonism secondary to PSP was made based on the National Institute of Neurological Disorder and Stroke, and the Movement Disorder Society criteria for PSP. We believe our patient had the PSP-F variant due to a history of pseudobulbar affect, expressive aphasia, and imaging findings. A conservative approach was used to manage the patient with a focus on reducing polypharmacy and establishing fall precautions at home.

The diagnosis of PSP should be made promptly but can be challenging in early phases due to confounding factors, incomplete history, and limited accuracy of diagnostic tests. In PSP-F, magnetic resonance imaging can confirm brain atrophy (specifically of the midbrain and superior cerebellar peduncles) and demonstrates a “hummingbird or penguin body” on the brainstem. It can also help exclude other differentials [4]. Positron emission tomography or single-photon emission computerized tomography may exhibit hypometabolism of the frontal cortex, caudate head, thalami, cingulate gyri, and midbrain [5]. While imaging findings are useful in identifying disease course, they are non-specific and only autopsy can definitively confirm the diagnosis [ 3]. Recognizing the signs and symptoms early in the disease is essential to avoid misuse of antidepressants, neuroleptics, anticholinesterase inhibi tors, and dopaminergic agents which have not shown any significant benefits [6].