MRI and CT appearances in metabolic encephalopathies due to systemic diseases in adults

Pathogenesis of acute encephalopathy in acute hepatic porphyria

Acute encephalopathy (AE) can be a manifestation of an acute porphyric attack. Clinical data were studied in 32 patients during AE with or without polyneuropathy (PNP) together with 12 subjects with PNP but no AE, and 17 with dysautonomia solely. Brain neuroimaging was done in 20 attacks during AE, and PEPT2 polymorphisms were studied in 56 subjects, 24 with AE. AE manifested as a triad of seizures, confusion and/or blurred vision. Symptoms lasting 1-5 days manifested 3-19 days from the onset of an attack. 55% of these patients had acute PNP independent of AE. Posterior reversible encephalopathy syndrome (PRES) was detected in 42% of the attacks. These patients were severely affected and hyponatremic (88%). Reversible segmental vasoconstriction was rare. There was no statistical difference in hypertension or urinary excretion of porphyrin precursors among the patients with or without AE. In 94% of the attacks with AE, liver transaminases were elevated significantly (1.5 to fivefold, P = 0.034) compared to a normal level in 87% of the attacks with dysautonomia, or in 25% of patients with PNP solely. PEPT2*2/2 haplotype was less common among patients with AE than without (8.3% vs. 25.8%, P = 0.159) and in patients with PNP than without (9.5% vs. 22.9%, P = 0.207), suggesting a minor role, if any, in acute neurotoxicity. In contrast, PEPT2*2/2 haplotype was commoner among patients with chronic kidney disease (P = 0.192). Acute endothelial dysfunction in porphyric encephalopathy could be explained by a combination of abrupt hypertension, SIADH, and acute metabolic and inflammatory factors of hepatic origin.

Neuroimaging for differential diagnosis of transient neurological attacks

BACKGROUND

Rapid yet comprehensive neuroimaging protocols are required for patients with suspected acute stroke. However, stroke mimics can account for approximately one in five clinically diagnosed acute ischemic strokes and the rate of thrombolyzed mimics can be as high as 17%. Therefore, to accurately determine the diagnosis and differentiate mimics from true transient ischemic attacks, acute ischemic stroke is a challenge to every clinician.

DISCUSSION

Medical history and neurological examination, noncontract head computed tomography, and routine magnetic resonance imaging play important roles in the assessment and management of patients with transient neurological attacks in the emergency department. This review attempts to summarize how neuroimaging can be utilized to help differentiate the most common mimics from transient ischemic attack and acute ischemic stroke.

CONCLUSION

Although imaging can help direct critical triage decisions for intravenous thrombolysis or endovascular therapy, more detailed medical history and neurological examination are crucial for making a prompt and accurate diagnosis for transient neurological attack patients.

Newly Diagnosed Hepatic Encephalopathy Presenting as Non-convulsive Status Epilepticus: A Case Report and Literature Review

BACKGROUND

Hepatic encephalopathy is characterized by psychiatric and neurological abnormalities, including epileptic seizure and non-convulsive and convulsive status epilepticus. Conventional brain magnetic resonance imaging is useful in supporting diagnosis since it can reveal specific radiological findings. In the literature, there is no description of hepatic encephalopathy onset as non-convulsive status epilepticus; we provide the first report.

CASE SUMMARY

We report a case of a 67-year-old woman, without history of cirrhosis, presenting altered mental state, normal brain computed tomography imaging, and electroencephalography suggestive of epileptic activity. We suspected non-convulsive status epilepticus, and we administered diazepam and levetiracetam with clinical improvement. Thus, we made a diagnosis of non-convulsive status epilepticus. A radiological study with brain magnetic resonance imaging showed bilateral hyperintensity on T1-weighted sequences of globus pallidus and hyperintensity of both corticospinal tracts on T2-weighted fluid-attenuated inversion recovery sequences. Blood tests revealed hyperammonemia, mild abnormality of liver function indices, and chronic Hepatitis B and D virus coinfection. Hepatic elastosonography suggested liver cirrhosis. The patient started antiviral therapy with entecavir and prevention of hepatic encephalopathy with rifaximin and lactulose; she was discharged with a normal mental state.

CONCLUSIONS

Hepatic encephalopathy can present as an initial manifestation with non-convulsive status epilepticus. Electroencephalography is useful for differentiating non-convulsive status epilepticus from an episode of hepatic encephalopathy, and neuroimaging aids the diagnostic process.

Acute Acquired Metabolic Encephalopathy Based on Diffusion MRI

Metabolic encephalopathy is a critical condition that can be challenging to diagnose. Imaging provides early clues to confirm clinical suspicions and plays an important role in the diagnosis, assessment of the response to therapy, and prognosis prediction. Diffusion-weighted imaging is a sensitive technique used to evaluate metabolic encephalopathy at an early stage. Metabolic encephalopathies often involve the deep regions of the gray matter because they have high energy requirements and are susceptible to metabolic disturbances. Understanding the imaging patterns of various metabolic encephalopathies can help narrow the differential diagnosis and improve the prognosis of patients by initiating proper treatment regimen early.

Intracranial Abnormalities with Diffusion Restriction

Multiple pathologic conditions can cause changes in the random movement of water, which can be detected with diffusion-weighted imaging (DWI). DWI plays a powerful clinical role in detecting restricted diffusion associated with acute brain infarction. Other disorders can also result in restricted diffusion. This article focuses on showing examples of common and uncommon disorders that have restricted diffusion secondary to cytotoxic and/or intramyelinic edema. These disorders include ischemia, infection, noninfectious demyelinating diseases, genetic mutations affecting metabolism, acquired metabolic disorders, toxic or drug exposures, neoplasms and tumorlike lesions, radiation treatment, trauma, and denervation.

Current perspectives on neuroimaging techniques used to identify stroke mimics in clinical practice

INTRODUCTION

Urgent clinical assessment and brain imaging are essential for differentiating stroke mimics from stroke and to avoid unnecessary initiation of reperfusion and other therapies in stroke mimic patients.

AREAS COVERED

In this article, the authors will review acute stroke imaging and then the imaging patterns of the most common stroke mimics. The authors have focused our review on brain CT scan, and more specifically CT perfusion, as this is the most commonly available and emerging tool in emergency settings. The authors also provide information on acute brain MRI and MR perfusion.

EXPERT OPINION

Imaging can contribute to the detection and diagnosis of acute stroke mimics. Knowledge of imaging findings in different stroke mimics can help distinguish these from patients with stroke who require timely reperfusion therapy. CT and MRI perfusion and diffusion-weighted imaging (DWI) MRI are useful imaging modalities for the assessment of acute stroke patients as they provide more accurate information than plain CT scan. Some of these modalities should be available in the emergency setting. The authors recommended CT perfusion as a useful tool for stroke management and differentiation with stroke mimics.

Gastrointestinal Disorders and the Nervous System

PURPOSE OF REVIEW

This article describes the neurologic sequelae of various nutritional micronutrient deficiencies, celiac disease, inflammatory bowel disease, and liver disease. Where relevant, appropriate treatments for these conditions are also discussed. The developing field of the microbiome and nervous system interaction is also outlined.

RECENT FINDINGS

Pathology in the gastrointestinal system can affect the nervous system when it causes micronutrient deficiency, when immune responses created by the gastrointestinal system affect the nervous system, when toxins caused by gastrointestinal organ failure harm the nervous system, and when treatments aimed at a gastrointestinal medical condition cause damage to the nervous system as a side effect.

SUMMARY

This article addresses familiar concepts and new developments in the treatment and understanding of diseases that affect the gut and nervous system simultaneously.

Will MRI replace the EEG for the diagnosis of nonconvulsive status epilepticus, especially focal?

Magnetic resonance imaging (MRI) can now be used to diagnose or to provide confirmation of focal nonconvulsive status epilepticus (NCSE). Approximately half of patients with status epilepticus (SE) have signal changes. MRI can also aid in the differential diagnosis with generalized NCSE when there is a clinical or EEG doubt, e.g. with metabolic/toxic encephalopathies or Creutzfeldt-Jakob disease. With the development of stroke centers, MRI is available 24h/24 in most hospitals. MRI has a higher spatial resolution than electroencephalography (EEG). MRI with hyperintense lesions on FLAIR and DWI provides information related to brain activity over a longer period of time than a standard EEG where only controversial patterns like lateralized periodic discharges (LPDs) may be recorded. MRI may help identify the ictal nature of LPDs. The interpretation of EEG tracings is not easy, with numerous pitfalls and artifacts. Continuous video-EEGs require a specialized neurophysiology unit. The learning curve for MRI is better than for EEG. It is now easy to transfer MRI to a platform with expertise. MRI is more accessible than single photon emission computed tomography (SPECT) or positron emission tomography (PET). For the future, it is more interesting to develop a strategy with MRI than SPECT or PET for the diagnosis of NCSE. With the development of artificial intelligence, MRI has the potential to transform the diagnosis of SE. Additional MRI criteria beyond the classical clinical/EEG criteria of NCSE (rhythmic versus periodic, spatiotemporal evolution of the pattern…) should now be systematically added. However, it is more complicated to move patients to MRI than to perform an EEG in the intensive care unit, and at this time, we do not know how long the signal changes persist after the end of the SE. Studies with MRI at fixed intervals and after SE cessation are necessary.

Role of Melatonin on Virus-Induced Neuropathogenesis-A Concomitant Therapeutic Strategy to Understand SARS-CoV-2 Infection

Viral infections may cause neurological disorders by directly inducing oxidative stress and interrupting immune system function, both of which contribute to neuronal death. Several reports have described the neurological manifestations in Covid-19 patients where, in severe cases of the infection, brain inflammation and encephalitis are common. Recently, extensive research-based studies have revealed and acknowledged the clinical and preventive roles of melatonin in some viral diseases. Melatonin has been shown to have antiviral properties against several viral infections which are accompanied by neurological symptoms. The beneficial properties of melatonin relate to its properties as a potent antioxidant, anti-inflammatory, and immunoregulatory molecule and its neuroprotective effects. In this review, what is known about the therapeutic role of melatonin in virus-induced neuropathogenesis is summarized and discussed.

A Review on the Neurological Manifestations of COVID-19 Infection: a Mechanistic View

There is increasing evidence of neurological manifestations and complications in patients with coronavirus disease 19 (COVID-19). More than one-quarter of patients with COVID-19 developed various neurological symptoms, ranging from headache and dizziness to more serious medical conditions, such as seizures and stroke. The recent investigations introduced hyposmia as a potential early criterion of infection with COVID-19. Despite the high mortality and morbidity rate of COVID-19, its exact mechanism of action and pathogenesis is not well characterized. The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could interact with angiotensin-converting enzyme 2 (ACE2) in the endothelial, neural, and glial cells. In the present study, we reviewed the most common neurological manifestations and complications that emerged after infection with the SARS-CoV-2 and discussed their possible relation to the expression and function of ACE2. Comprehensive and detailed studies are required to uncover how this virus invades the neural system as well as other critical organs.

Fishing in muddy waters- co-existing dual intracranial pathology in PRES: A case series and review of literature

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state often characterized by altered mental state and is seen in various clinical settings. Although it is often reversible, it may result in long term sequelae. The typical and atypical neuroimaging findings seen in PRES have been previously well-described in the literature. However, the presence of other co-existing intracranial lesions along with PRES can occasionally confound the imaging findings and poses a diagnostic challenge. Herein, the authors report four cases of PRES with etiologically different co-existing intracranial lesions confounding the clinical and imaging manifestations. When presented with atypical imaging findings in PRES, the possibility of a co-existing intracranial pathology with superimposed imaging findings should be considered.

Chorea Hyperglycemia Basal Ganglia Syndrome in a Young Patient with Type 1 Diabetes Mellitus: a Case Report

Chorea hyperglycemia basal ganglia (CHBG) syndrome is an uncommon manifestation of diabetes seen in patients with poor glycemic control. It is characterized by sudden onset of chorea with characteristic hyperintensities of the basal ganglia on brain magnetic resonance imaging. We report a case of a 31-year-old female patient with a history of type 1 diabetes mellitus, renal failure, and hypertension, who presented with acute symptoms of chorea involving both the upper and lower limbs with facial and cervical dystonia. Magnetic resonance imaging revealed bilateral hyperintensities of the globus pallidus and putamen. Control of blood glucose levels led to resolution of the choreic movements. In addition, follow-up magnetic resonance imaging studies revealed improvement in the hyperintensities of the basal ganglia bilaterally.

Neuroimaging of Patients in the Intensive Care Unit: Pearls and Pitfalls

A brief introduction is provided of the different imaging modalities encountered in the intensive care unit (ICU). The spectrum of intracranial pathology as well as potential postsurgical complications is reviewed, with a focus on pearls and pitfalls. A brief overview also is provided of imaging of the spine in an ICU patient.

Imaging appearances of toxic and acquired metabolic encephalopathic disorders

Most imaging findings relating to toxic and acquired metabolic disorders follow a certain pattern with affinity to a specific topographic area, which can help narrow the differential diagnosis. This is especially useful when the clinical presentation can be variable and there is diagnostic uncertainty. Usually, there is bilateral symmetrical abnormality within the deep grey matter structures and the cerebral cortex because of the high metabolic activity and raised oxygen requirements in these areas. Magnetic resonance imaging, particularly diffusion weighted imaging and fluid-attenuated inversion recovery sequences, is very important in differentiating between various aetiologies in this group. Magnetic resonance imaging can be useful in demonstrating both acute and chronic damage, in evaluating treatment response and in disease prognostication. This pictorial review discusses the computed tomography and magnetic resonance imaging appearances of a spectrum of toxic and metabolic disorders observed in a district general hospital with reference to clinical presentation and imaging features that may allow diagnosis. This includes carbon monoxide poisoning, hypoglycaemia, non-ketotic hyperglycaemia, osmotic demyelination syndrome, posterior reversible encephalopathy syndrome, hypoxic ischaemic encephalopathy, the syndrome of delayed post-hypoxic leukoencephalopathy, hepatic encephalopathy and cocaine toxicity.

Posterior reversible encephalopathy syndrome and Wernicke encephalopathy in patient with acute graft-versus-host disease

Graft-versus-host disease (GVHD) is an immune triggered process leading to severe immune dysregulation and organ dysfunction until death and it is one of the worst medical complications after a transplant. Patients with GVHD may have several neurological alterations: during this acute severe phase there is coexistence of various and nonspecific neurological symptoms. We are reporting a case of a 53 year old woman with severe GVHD after bone marrow transplant with acute neurological signs and symptoms. MRI study showed findings consistent with Posterior reversible encephalopathy syndrome and Wernicke encephalopathy.

Beyond stroke-uncommon causes of diffusion restriction in the basal ganglia

In the emergency setting, a regional area of restricted diffusion involving the basal ganglia typically represents an acute infarct due to small vessel occlusion. However, it is important to consider additional differentials, specifically systemic causes. This article will review anatomy of the basal ganglia and pertinent associated vasculature, followed by other entities that can be a cause of restricted diffusion. These include hemolytic uremic syndrome, hypereosinophilic syndrome, fat embolism, meningitis, and hypoxic-ischemic injury. It is important to recognize presenting findings in these conditions, as the radiologist may be the first to give an accurate diagnosis or prompt additional testing.

Case of steroid-responsive encephalopathy from hypoglycaemia

Hypoglycaemic encephalopathy is a feared complication in the management of patients with diabetes mellitus. We report on a 73-year-old woman with type 1 diabetes managed with an insulin pump who presented unresponsive after an inappropriate insulin bolus. The patient had minimal improvement in her neurological status over 8 days. After administration of 1 g intravenous methylprednisolone, she had dramatic neurological improvement including successful extubation and discharge from the intensive care unit. Steroid responsive encephalopathy is increasingly recognised in practice and literature. However, to the best of our knowledge, this is the first case of hypoglycaemic encephalopathy that responded to high-dose steroids.

Magnetic resonance imaging features of leukoaraiosis in elderly dogs

Leukoaraiosis is a descriptive term used to designate bilateral, symmetrical, white matter lesions identified in brains of elderly human patients. These lesions are isointense to normal in magnetic resonance imaging (MRI) T1-weighted pulse sequences, non-contrast enhancing, and hyperintense in T2-weighted and FLAIR pulse sequences. Pathophysiologic mechanisms for leukoaraiosis remain incompletely understood; however, an ischemic origin is currently being favored. Age-related changes, such as brain atrophy, ventricular enlargement, and well-demarcated sulci, have also been previously described in dogs over 9 years of age. Objectives of this retrospective case series study were to describe MRI features of leukoaraiosis and brain atrophy in a group of elderly dogs. The Dick White Referrals MRI database between October 2009 and April 2016 was reviewed. Dogs with bilaterally symmetrical periventricular areas of T2 and FLAIR hyperintensity compatible with leukoaraiosis, and older than 9 years, were included. Fourteen dogs met the inclusion criteria, with a total of 18 MRI studies available for review. Median age for sampled dogs was 13 years. Ten dogs had MRI signs of concurrent brain atrophy; one of them had signs of brain atrophy before leukoaraiotic changes could be identified. In those cases where serial MRIs were available, progressive reduction of interthalamic adhesion thickness was observed. The current study introduces leukoaraiosis as a descriptive term for the MRI sign of bilaterally symmetrical, periventricular T2, and FLAIR hyperintensities in brains of elderly dogs. Future studies are needed to determine pathophysiologic mechanisms for this MRI sign.

A Proposed Physiopathological Pathway to Hyperammonemic Encephalopathy in a Non-Cirrhotic Patient with Fibrolamellar Hepatocellular Carcinoma without Ornithine Transcarbamylase (OTC) Mutation

Patient: Male, 31

Final Diagnosis: Fibrolamellar hepatocellular carcinoma

Symptoms: Encephalopathy

Medication:—

Clinical Procedure: —

Specialty: Gastroenterology and Hepatology

MRI in the Evaluation of Acute Visual Syndromes

Acute visual symptom emergencies occur commonly and present a challenge to both clinical and radiologic facets. Although most patients with visual complaints routinely require clinical evaluation with direct ophthalmologic evaluation, imaging is rarely necessary. However, there are highly morbid conditions where the prompt recognition and management of an acute visual syndrome (AVS) requires an astute physician to probe further. Suspicious symptomatology including abrupt visual loss, diplopia, ophthalmoplegia, and proptosis/exophthalmos require further investigation with advanced imaging modalities such as magnetic resonance imaging and magnetic resonance angiography. This review will discuss a variety of AVSs including orbital apex syndrome, cavernous sinus thrombosis, cavernous carotid fistula, acute hypertensive encephalopathy (posterior reversible encephalopathy syndrome), optic neuritis, pituitary apoplexy including hemorrhage into an existing adenoma, and idiopathic intracranial hypertension. A discussion of each entity will focus on the clinical presentation, management and prognosis when necessary and finally, neuroimaging with emphasis on magnetic resonance imaging. The primary purpose of this review is to provide an organized approach to the differential diagnosis and typical imaging patterns for AVSs. We have provided a template for radiologists and specialists to assist in early intervention in order to decrease morbidity and provide value-based patient care through imaging.

What to see when you are looking at confusion: a review of the neuroimaging of acute encephalopathy

Acute encephalopathy is a clinical conundrum in neurocritical care facing physicians with diagnostic and therapeutic challenges. Encephalopathy arises from several concurrent causes, and delayed diagnosis adds to its grim prognosis. Diagnosis is reached by melding clinical, neurophysiological and biochemical features with various neuroimaging studies. We aimed to compile the pathophysiology of acute encephalopathies in adults, and the contribution of cerebral CT, MRI, MR spectroscopy (MRS), positron emission tomography (PET) and single-photon emission CT (SPECT) to early diagnosis, treatment and prognostication. Reports from 1990 to 2013 were identified. Therefore, reference lists were searched to identify additional publications. Encephalopathy syndromes best studied by neuroimaging emerge from hypoxic-ischaemic injury, sepsis, metabolic derangements, autoimmune diseases, infections and rapidly evolving dementias. Typical and pathognomonic neuroimaging patterns are presented. Cerebral imaging constitutes an important component of diagnosis, management and prognosis of acute encephalopathy. Its respective contribution is dominated by rapid exclusion of acute cerebral lesions and further varies greatly depending on the underlying aetiology and the range of possible differential diagnoses. CT has been well studied, but is largely insensitive, while MRI appears to be the most helpful in the evaluation of encephalopathies. MRS may provide supplementary biochemical information and determines spectral changes in the affected brain tissue. The less frequently used PET and SPECT may delineate areas of high or low metabolic activity or cerebral blood flow. However, publications of MRS, PET and SPECT are limited only providing anecdotal evidence of their usefulness and sensitivity.

Hepatic Encephalopathy With Corticospinal Tract Involvement Demonstrated by Diffusion Tensor Tractography

A 50-year-old man with liver cirrhosis and esophageal varix for 3 years was diagnosed with hematemesis and treated for a bleeding varix. However, bleeding recurred 11 days later, and he developed drowsiness with left hemiparesis. His left upper and lower extremity muscle strengths based on the manual muscle test at the onset were grade 2/5 and 1/5, respectively. The Babinski sign was positive. His serum ammonia level was elevated to 129.9 µg/dL (normal, 20-80 µg/dL). Magnetic resonance imaging revealed restriction on diffusion and T2-hyperintensities with decreased apparent diffusion coefficient values in the bilateral frontoparietooccipital cortex. The effect was more severe in the right hemisphere and right parietooccipital cortices, which were compatible with hepatic encephalopathy. Although the patient's mental status recovered, significant left-sided weakness and sensory deficit persisted even after 6 months. Diffusion tensor tractography (DTT) performed 3 months post-onset showed decreased volume of the right corticospinal tract. We reported a patient with hepatic encephalopathy involving the corticospinal tract by DTT.

Fatal outcome of posterior "reversible" encephalopathy syndrome in metastatic colorectal carcinoma after irinotecan and fluoropyrimidine chemotherapy regimen

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headaches, altered mental status, seizures, and visual disturbances. It can occur in many different clinical entities such as severe hypertension and pre-eclampsia, or due to cytotoxic or immunosuppressive therapies. The pathogenesis of PRES is unclear, with dysregulated cerebral auto-regulation and endothelial dysfunction as important mechanisms proposed. Endothelial dysfunction is important especially in cases associated with cytotoxic therapies. Herein, we describe a patient with PRES with fatal outcome, who presented 5 days after the infusion of cycle 1 of irinotecan hydrochloride, leucovorin calcium, and fluorouracil (FOLFIRI) regimen chemotherapy, without prior hypertension and other comorbidity, suggesting a link between PRES and FOLFIRI regimen. To our knowledge, this case report is the first describing PRES after FOLFIRI regimen, although others have described PRES after FOLFIRI with bevacizumab in colonic cancer patients.

Neuroimaging correlates of acute encephalopathy

Acute encephalopathies arise as a result of various contributions from infections or toxic, metabolic, and/or structural cerebral derangements. With the variety of clinical presentations, neurologic examination, electroencephalography (EEG), and imaging may not identify specific etiologies, but in combination, they can offer guidance regarding underlying causes. Among several different neuroimaging techniques, cerebral computed tomography and brain magnetic resonance imaging are most frequently used for diagnosis, treatment monitoring, and prognostication in acute brain dysfunction. This review compiles the most common and typical features of head computed tomography and magnetic resonance imaging and presents the clinical and EEG associations in adult patients with different types of acute encephalopathy.

Extensive cortical diffusion restriction in a 50-year-old female with hyperammonemic encephalopathy and status epilepticus

Comorbid hyperammonemic encephalopathy (HE) and status epilepticus (SE) leading to extensive cortical diffusion restriction (CDR) on MRI have not been previously reported. We describe a patient with HE who subsequently developed provoked SE. Sequential MRIs demonstrated a progressive CDR that involved the entire bilateral supratentorial cortex, thalami, and basal ganglia, resulting in death from cerebral edema and brain herniation. Diffuse CDR is most frequently seen after hypotension or hypoxia, which our patient did not experience. Such findings have also been described in both HE and SE (Milligan et al. (2009), Chatzikonstantinou et al. (2011), U-King-Im et al. (2011), and Bindu et al. (2009)), but not to the extent seen in our patient. Additionally, our patient had distinct radiologic features of both disease processes, suggesting a cumulative effect. The diagnosis of HE and SE in the setting of extensive CDR should not be missed and could lead to improved outcomes for two progressive, malignant, and treatable illnesses that can be easily overlooked.

Oxidative stress mechanisms underlying Parkinson's disease-associated neurodegeneration in C. elegans

Oxidative stress is thought to play a significant role in the development and progression of neurodegenerative diseases. Although it is currently considered a hallmark of such processes, the interweaving of a multitude of signaling cascades hinders complete understanding of the direct role of oxidative stress in neurodegeneration. In addition to its extensive use as an aging model, some researchers have turned to the invertebrate model Caenorhabditis elegans (C. elegans) in order to further investigate molecular mediators that either exacerbate or protect against reactive oxygen species (ROS)-mediated neurodegeneration. Due to their fully characterized genome and short life cycle, rapid generation of C. elegans genetic models can be useful to study upstream markers of oxidative stress within interconnected signaling pathways. This report will focus on the roles of C. elegans homologs for the oxidative stress-associated transcription factor Nrf2, as well as the autosomal recessive, early-onset Parkinson’s disease (PD)-associated proteins Parkin, DJ-1, and PINK1, in neurodegenerative processes.