Sporadic Creutzfeldt-Jakob Disease: Case Report and Literature Review.

The proverbial "zebras" in neurology are often times missed due to their low prevalence and incidence in the community. The number of misdiagnoses and improper therapeutic interventions that occur are further increased when patients with these rare diseases present with signs and symptoms of more common disorders. One such disease is sporadic Creutzfeldt-Jakob disease (sCJD), a prion disease that causes neuronal derangement and classically presents as a rapidly progressing dementia with extrapyramidal signs, ataxia, behavioural problems, and myoclonus in the advanced stage. It falls into the category of neurodegenerative disease, which also includes Alzheimer's disease, Huntington's disease, Parkinson's disease, and other Parkinson-related diseases. Though these diseases have overlapping symptomologies - such as cognitive impairment and neuromuscular dysfunction - they can be differentiated from one another based on the time course of the illness and the specific constellation of signs and symptoms. Our case report describes a patient who was found to have sCJD after months of treatment for Parkinson's disease and trigeminal neuralgia. Thus, we are highlighting the importance of recognizing rare diseases so that proper management can be initiated in a timely manner. Furthermore, we review the current literature on the diagnosis and management of sCJD.

Leber Hereditary Optic Neuropathy: Case Report and Literature Review.

Leber hereditary optic neuropathy (LHON) is a genetic condition that typically presents with unilateral, painless, sub-acute central vision loss followed by contralateral vision loss after a few weeks to months. It is a rare disease that typically affects young adults - men more than women - and is a relatively common cause of blindness. It is due to a mutation in mitochondrial DNA (mtDNA). The majority (more than 95%) of patients have one of three mtDNA point mutations: m.14484T→C, m.3460G→A, or m.11778G→A. These mutations lead to disruption of the mitochondrial respiratory chain activating pro-apoptotic pathways. For reasons unknown, this insult tends to affect the retinal ganglion cells more than any other cell in the body, leading to the disease state. Due to its low prevalence in the United States (1:50,000), this diagnosis is often overlooked, misdiagnosed, and mismanaged, which may exacerbate symptoms. It is essential then for physicians to recognize the presentation of and understand the diagnostic work-up for LHON. In this case report, we present the diagnostic challenges of a patient who presented with progressive vision loss, discuss the various differential diagnoses, review the literature on LHON, and propose an explanatory model for vision loss in patients with LHON.

Neurological Disorders Associated with Glutamic Acid Decarboxylase Antibodies.

Anti-glutamic acid decarboxylase (GAD) antibodies have been discovered in a variety of neurological syndromes with unique presentations. These syndromes include limbic encephalitis (LE), stiff person syndrome (SPS), opsoclonus-myoclonus-ataxia syndrome, cerebellar ataxia, status epilepticus, and palatal myoclonus among others. We present two patients who presented with Guillain-Barré (GBS) and myasthenia gravis (MG) like syndromes, who were found to have anti-GAD antibodies. These case reports highlight the complex presentation of patients with neurological disorders associated with anti-GAD antibodies. The proper identification of anti-GAD antibody's presence has proven to be beneficial in treatment and provide enhanced quality of life.

Artery of Percheron Infarct: An Acute Diagnostic Challenge with a Spectrum of Clinical Presentations.

The artery of Percheron (AOP) is a variant of the paramedian thalamic vasculature that supplies blood to the medial aspect of the thalamus and the rostral midbrain. The presentation of an infarct in this territory varies widely and is often characterized by nonspecific neurological deficits, with altered mental status, decreased level of consciousness, and memory impairment being among the most common. AOP infarcts are often missed on initial computed tomography (CT) scan, and additional imaging is usually not done due to low suspicion for stroke in most cases. There have been an increasing number of reports of AOP infarction, illustrating the diversity of clinical presentations and the challenge this presents to clinicians in the acute setting. Lacking the classic signs of stroke, many of these patients experience a delay in recognition and treatment, with the majority of diagnoses occurring outside the tissue plasminogen activator (tPA) window. This case highlights the unusual presentation and diagnostic difficulty of a patient with an AOP infarct, and serves as a reminder to include thalamic pathology in patients presenting with vague neurological symptoms and no obvious signs of stroke.

Case Report: An Incidental Finding of Fahr's Disease in a Patient with Hypochondria.

Idiopathic basal ganglia calcification (IBGC), commonly referred to as Fahr's disease, is a rare neurological disorder characterized by the abnormal, symmetrical, and bilateral calcification of the basal ganglia and other brain regions. Patients typically present in their forties and fifties with various neurologic and/or psychiatric symptoms, including movement disorders, Parkinsonism, psychosis, and depression. The pathophysiology of this disease is not completely understood; however, several gene mutations have been identified in the pathogenesis of Fahr's disease. These mutations display an autosomal dominant inheritance pattern. Furthermore, the regional phenotypic expression of calcifications differs greatly from patient to patient, as do their clinical presentations. Here, we describe a patient who presented with psychiatric manifestations and imaging consistent with Fahr's disease.