Case Report
Name: Abigail Gilchrist
Placement Date: 28th September 2017
Speciality: Geriatric medicine
I wish to be considered for the clinical essay prize: Yes
Patient:
70-year-old female who initially presented in July with a fractured left hip, following a fall. Was operated on to receive a dynamic hip screw. Become infected a month later, replaced with temporary antibiotic cement implant and is now currently receiving IV vancomycin. Past medical history of corticobasal degenerative disease, arthritis, COPD and asthma.
The Diagnosis of Atypical Parkinsonism
Abstract
Idiopathic Parkinson’s disease (IPD) is a relatively common disease, however there are rarer conditions named atypical Parkinsonism which present very similarly but have distinct pathologies and treatments. Some more common subcortical degenerative diseases that can produce comparable symptoms to IPD are multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). The patient had the latter, which had been diagnosed five years prior. This diagnosis was reached using a neurological assessment and diagnostic imaging. The symptoms which are considered hallmarks for IPD are resting tremor, akinesia, bradykinesia and postural instability, which are represented in MSA, PSP, and CBD, although usually with a degree of variability. An assessment of gait can in most cases determine between IPD and an atypical Parkinsonism. The use of MRI is not always useful early in the disease progression, because the changes to the brain might be too insignificant to be noticeable, although is still used as an important diagnostic tool. Ultimately, a strong clinical knowledge is essential to the diagnosis of an atypical parkinsonism.
Clinical Essay
Hallmark symptoms of Parkinson’s disease, which are resting tremor, akinesia, bradykinesia, and postural instability, are also common symptoms in atypical Parkinsonism, although they may all not necessarily be present (Gerstenecker, 2017). Among the subcortical degenerative diseases recognised as atypical Parkinsonism are multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) (Brooks, 2002). The patient had been diagnosed with the latter, and exhibited many classic clinical signs such as asymmetrical rigidity, intense muscle aching and early onset of apraxia of the hand (Brooks, 2002). The distinct pathologies of these diseases are important to distinguish between because of their differing prognosis’ and treatments (Yu et al., 2015).
Particularly in the early stages, it can be difficult to determine whether the patient has IPD or a form of atypical parkinsonism (Nonnekes et al., 2014). A sideways balance impairment is frequently seen in patients with atypical parkinsonism, however not in patients with IPD (Nonnekes et al., 2014). The stance in IPD is normal, or potentially narrow, whereas it is widened in atypical parkinsonism (Nonnekes et al., 2014). An easy clinical test is tandem gait, where patients take ten consecutive steps along an imaginary straight line, placing the heel of the leading foot against the toe of the trailing foot (Nonnekes et al., 2014). A study with 36 patients with IPD and 49 patients with atypical parkinsonism, it was found that while only 18% of patients with atypical parkinsonism could perform tandem gait without a side step while 92% of patients with IPD could (Abdo et al., 2006). This is helpful in determining whether a patient has IPD or an atypical Parkinsonism, however further examination is necessary to confirm a more specific diagnosis.
Common motor symptoms of MSA are asymmetrical limb rigidity and bradykinesia, however these are not useful for distinguishing from idiopathic Parkinson’s disease (IPD) (Brooks, 2002). While a resting tremor can be present, an intention tremor is a more common and distinguishing clue for MSA (Brooks, 2002). Limb ataxia, more likely to present in later stages, is another unique feature of MSA to separate it from IPD (Brooks, 2002). PSP, dissimilarly, tends to have symmetrical limb rigidity beginning in the trunk rather than the limbs (Brooks, 2002). This has a great effect on posture and gait, causing a dystonic posture in which trunk is flexed and neck extended (Brooks, 2002). Patients may also present with a supranuclear gaze problem, the inability to look up, down, left or right voluntarily (Brooks, 2002). Another ocular problem in PSP is a sustained gaze deviation to optokinetic nystagmus, which is never a clinical sign of IPD, however a supranuclear gaze can sometimes be (Brooks, 2002). CBD is similar to MSA and IPD in the sense that presentation is asymmetrical, however there is apraxia of the limb in question (Brooks, 2002). Cortical sensory loss can occur in CBD patients, which is often first recognised by the patient’s inability to recognise objects in their pocket by tactile impression (Brooks, 2002). Light touch and pin prick sensation remain however (Brooks, 2002). Bulbar problems, including dysphagia and dysarthria, are usually early occurrences in CBD (Brooks, 2002). The patient is quite evidently suffering from CBD, since she has the typical asymmetrical limb rigidity with akinesia. She was experiencing painful muscle aches, and had altered sensation over her forearm. Even so, while the patient is relatively consistent with the diagnosis of CBD, she still lacks some presenting features such as dysarthria. This is an example of the wide range of potential atypical Parkinsonism presentations. As there is no test for determining the diagnosis of an atypical Parkinsonism, it is imperative to use a great foundation of clinical knowledge with the use of diagnostic imaging and physiologic tests to establish a diagnosis.
While CT and MRI tend to be less useful in the diagnosis of IPD, they can be very useful for assessing atypical parkinsonism (Sid Gilman, 1998). MRIs especially are of great importance in the diagnosis of atypical parkinsonism. While the differences can be slight, they are often consistent with each disease; MSA, PSP, and CBD. In MSA, there can be supratentorially, a hyper-intense rim at the putaminal edge, putaminal hyper-intensity and putaminal atrophy, and infratentorially, atrophy and signal change because of degeneration of pontine nuclei and transverse pontine fibres, Purkinje cells and inferior olives (Schrag et al., 2000). This creates what is often referred to as “hot cross bun sign” in the pons (Brooks, 2002). In PSP, a dilation of the third ventricle, with midbrain atrophy and pontine tegmental atrophy, and signal increase in midbrain have all been noted (Schrag et al., 2000). In differentiating PSP from MSA, the presence of marked atrophy of the midbrain (<17mm diameter) and hyper-intensity are used (Schrag et al., 2000). In CBD, cortical atrophy and hypo-intensity of the putamen and globus pallidus, and asymmetry of the global atrophy can be seen. There is still significant overlap between some findings for each of these neurodegenerative diseases (Schrag et al., 2000). The thinning of the substantia nigra, atrophy of putamen and midbrain atrophy (>17mm diameter) are some frequently repeated radiological findings (Schrag et al., 2000). Although MRI might not always be able to pinpoint the diagnosis, it is still useful for ruling out other causes of parkinsonism, mainly structural lesions such as basal ganglia tumours and haemorrhages (Brooks, 2002).
The patient benefited from a physician with a thorough understanding of atypical Parkinsonism and received a diagnosis relatively soon after onset of symptoms. This has allowed her access to appropriate clinical treatment and information about her condition and prognosis (Nonnekes et al., 2014). This is a central aim in medicine. Medicine has evolved to rely heavily on diagnostic tests although ideally it is technology that is used to confirm clinical acumen. The diagnostic process of atypical Parkinsonism is an excellent example of the continuing need for clinical acumen.