View PDF Edition - U.S. Pharmacist

ProgressiveSupranuclear PalsyPARKINSON’S-LIKE SYMPTOMSDifficulty looking upwithout extendingthe neck ordifficulty climbingup and down stairsmay signal thiscondition.Progressive supranuclearpalsy (PSP) is an uncommonneurodegenerative disorderoften misdiagnosed, mostfrequently as Parkinson’s disease(PD). 1,2 Although PSP is lesscommon than PD, both are characterizedby progressive loss ofselected neurons in certain areasof the brain, which causes disease.3,4 Approximately 4% ofpatients experiencing parkinsoniansymptoms have PSP. 2 Few cliniciansare proficient at recognizingthe nonclassic presentationsof PSP and also at treating it. 5Pharmacists should be aware ofthis distinct condition with anunknown cause, also known asSteele-Richardson-Olszewski syndrome.Although PSP usuallystrikes individuals after age 50years, some patients can developsigns in their fourth decade. 1,2Mary Ann E. Zagaria, PharmD, MS, CGPSenior Care Consultant Pharmacist andPresident of MZ Associates, Inc.Norwich, New Yorkwww.mzassociatesinc.comRecipient of the Excellence in Geriatric PharmacyPractice Award from the Commission forCertification in Geriatric PharmacyDisability develops in PSPpatients within 3 to 5 years ofdiagnosis; death usually occurswithin 10 years of symptomonset, often secondary to infection(e.g., pneumonia) or othercomplications of immobility. 2,6,7Advance directives, such as a livingwill or durable power of attorney(see Reference 8), should beprepared by patients diagnosedwith PSP so that they have theopportunity to indicate the typeof medical treatment they wish toreceive as part of their end-of-lifecare plan. 6,8Pathophysiologyand DiagnosisWhile PD is slowly progressiveand primarily involves the substantianigra, patients with PSPshow a degeneration of neuronsthat occurs in the basal ganglia—the part of the brain that helpscoordinate and ensure smoothbody movements—and in thebrain stem, the part of the brainthat controls vital body functions(e.g., breathing, heart rate, swallowing)and eye movements. 1,6 Inaddition, neurofibrillary tanglesare detected (containing abnormaltau protein), and strokes (lacunar)may occur in the basal gangliaand deep white matter. 1According to Schneider andMandelkow, neurofibrillary tanglesare a hallmark of Alzheimer’sand other neurodegenerative diseases(e.g., PSP, Pick’s disease,frontotemporal dementia, andparkinsonism linked to chromosome17) referred to astauopathies, since neurofibrillarytangles are composed of intracellularaggregates of the microtubule-associatedprotein tau. 9While the mechanisms underlyingtau-mediated neurotoxicity arenot well understood, neurodegenerationand neuronal dysfunctionare associated with pathologichyperphosphorylation and aggregationof tau. 9 A shared characteristicof PD and PSP is the presenceof Lewy bodies (abnormalintracytoplasmic inclusiondeposits), although Lewy bodiesare found in a minority of PSPcases. 3Diagnosis of PSP is clinical, byhistory and physical examination. 2Neuroimaging is not required fordiagnosis since findings are notspecific. 2Signs and SymptomsA core feature of PSP is known asvertical supranuclear gaze palsy,where the voluntary vertical gazeis impaired; this causes difficultylooking up or down withoutextending or flexing the neck, ordifficulty climbing up and downstairs, and may be the first noticeablesymptom of the disease. 1,2Shortly after onset of the disorder,patients present with posturalinstability, causing gait unsteadinessand falls (typically backward).2,3 A staring, astonishedappearance may be caused byretraction of the upper eyelids. 2Other findings (TABLE 1) mayinclude dysphagia and dysarthriawith emotional lability(pseudobulbar palsy). Emotional20U.S. Pharmacist • November 2009 • www.uspharmacist.com