Neurology 1998 Aug;51(2 Suppl 2):S25-s29.
Classification of fluctuations in patients with Parkinson's disease.
Quinn NP
University Department of Clinical Neurology, Institute of Neurology;
London; England.
Patients with Parkinson’s disease are subject to a wide range of
fluctuations in their clinical state, most of them treatment-related but
some more disease-related. Short-duration motor fluctuations include
freezing and paradoxic kinesi, lasting seconds to minutes. It is
important to distinguish between “off” period freezing, which may be
helped by measures to increase time “on,” and freezing that is present
in both “on” and “off” periods, which is difficult if not impossible to
treat. Medium-duration fluctuations associated with chronic L-dopa
treatment include wearing-off and “on-off” responses, which can involve
(a) return of parkinsonism, (b) dyskinesias, and (c) non-motor
fluctuations. A poorly understood long-duration pharmacodynamic response
to L-dopa lasting up to 2 weeks may also be seen. This may manifest as
late deterioration after L-dopa is withdrawn. More importantly, and more
commonly, it is important to recognize that the ultimate effect of an
alteration in L-dopa treatment may take 2 weeks to equilibrate in the
brain. “Optimization” of L-dopa therapy is therefore not a realistic
expectation during an inpatient admission and is instead primarily a
long-term outpatient procedure. The “off” state is not the same as
untreated PD, and may represent rebound worsening after the beneficial
effect of L-dopa has worn off. Sometimes there is also transient
worsening at the onset of effect of a dose. “Off” period dyskinesias
tend to be relatively fixed, and painful, and dystonic. Biphasic
(beginning and/or end of dose) dyskinesias are often severe; ballistic;
and stereotypic. Peak dose or “square wave” dyskinesias comprise a mix
of mobile dystonia or chorea that is usually painless. Many patients
experience any combination of panic; anxiety; and depression in their
“off” periods, and many also experience pain; with instant relief as
they turn “on”. Other parameters that may vary between the “on” and
“off” states include urinary and bowel dysfunction, blood pressure,
respiratory function, and sweating attacks Most but not all of
these phenomena can be related to a simplistic but nevertheless usually
practically useful model of differing levels of central dopaminergic
stimulation. In difficult cases, an acute apomorphine challenge
analogous to the effects of a “Tensilon test’ in myasthenia gravis
may help to determine whether a given clinical feature represents over-
or understimulation of central dopamine receptors.
PMID: 9711977, UI: 98375795
--
Judith Richards, London, Ontario, Canada
<[log in to unmask]>
^^^
\ /
\ | / Today’s Research
\\ | // ...Tomorrow’s Cure
\ | /
\|/
```````
