A Case of Non-cirrhotic Hyperammonemic Encephalopathy in a Patient With Metastatic Gastrointestinal Stromal Tumor.

Acute toxic encephalopathy (ATE) is a widely recognized medical emergency with an expansive differential. One particular known etiology for ATE is elevated ammonia, a powerful neurotoxin that often presents with clinical findings of confusion, disorientation, tremors, and in severe cases, coma and death. Hyperammonemia is most commonly associated with liver disease and presents as hepatic encephalopathy in the setting of decompensated cirrhosis; however, in rare cases, a patient may suffer from non-cirrhotic hyperammonemic encephalopathy. We describe the case of a 61-year-old male with metastatic gastrointestinal stromal tumor who was diagnosed with non-cirrhotic hyperammonemic encephalopathy, and briefly explore the literature describing its mechanisms.

Postmortem CT in decedents with SARS-CoV-2 infection. A single institution experience.

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 produced a global pandemic with significant mortality. As autopsies are not routinely performed on all decedents with SARS-CoV-2 infection, postmortem CT (PMCT) may be valuable to provide additional information on the cause of death and risk factors known to be associated with an increased mortality in COVID-19. The purpose of this manuscript is to review the PMCT findings in a series of 42 decedents with SARS-CoV-2 infection from our institution. Retrospective analysis of 42 decedents who had a positive postmortem nasopharyngeal swab for SARS-CoV-2 and had a PMCT were included in this study. Images were reviewed for pulmonary findings seen in COVID-19 and other organ involvement. Of the 42 decedents, although the majority had imaging findings in the lungs that would be consistent with COVID-19 and acute respiratory distress syndrome, in 14% of the decedents the SARS-CoV-2 infection was likely coincidental and the PMCT findings suggested that they died from other pathology. Over half of the decedents that died from COVID-19 had PMCT findings of vascular disease. PMCT is useful to identify pulmonary and extra pulmonary findings in decedents with SARS-CoV-2 infection that can provide additional information, which may be useful for the forensic pathologist to help determine the underlying cause of death. Supplemental data for this article are available online at.

Case Report: A Case of Severe Cryptococcal Immune Reconstitution Inflammatory Syndrome Presenting with Brain and Intradural Abscesses in an HIV Patient.

Clinical worsening or new manifestation of cryptococcal disease following initiation of anti-retroviral therapy (ART) in an HIV patient is a hallmark of cryptococcal immune reconstitution inflammatory syndrome (C-IRIS). However, it can be difficult to distinguish IRIS from worsening or new infection. Here, we present a case of severe C-IRIS involving multiple cerebellar, spinal, and intradural abscesses and spinal arachnoiditis 7 months after ART initiation in an AIDS patient with uncertain prior ART compliance. He had multiple prior episodes of cryptococcal meningitis with complications necessitating ventriculoperitoneal shunt placement and was on suppressive fluconazole when he developed worsening brain manifestations. He received empiric anti-cryptococcal re-induction without improvement. All cerebrospinal fluid cultures remained sterile, with negative Cryptococcus PCR testing, and his condition continued to worsen prior to corticosteroid initiation. Ultimately, C-IRIS was diagnosed by brain biopsy. This case demonstrates an extreme in severity of C-IRIS and in the timeline of presentation after ART initiation.

MELAS: Monitoring treatment with magnetic resonance spectroscopy.

BACKGROUND: To assess the utility of Magnetic Resonance Spectroscopy (MRS) as a biomarker of response to L-arginine in mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). AIMS: To describe a case of MELAS treated with L-arginine that showed improvement clinically and on serial MRS METHODS: MRS was performed on a 1.5-Tesla scanner to evaluate a MELAS patient before, during, and after intravenous (IV) L-arginine therapy for the treatment of stroke-like episodes. L-arginine was infused at a dose of 500 mg/kg daily for 7 days followed by oral arginine therapy. RESULTS: The patient had clinical improvement after treatment with IV L-arginine. MRS performed before, during, and after treatment with IV L-arginine showed significant improvement in brain lactate and increase in the N-acetylaspartate/Choline (NAA/Cho) ratio compared to pre-treatment baseline. CONCLUSION: Serial MRS imaging showed significant improvement in lactate peaks and NAA/Cho ratios that corresponded with clinical improvement after L-arginine therapy. Given this correlation between radiologic and clinical improvement, MRS may be a useful biomarker assessing response to treatment in MELAS.

Headache in an Obese Adolescent Male: A Nonclassical Presentation of an Uncommon Disease.

Background. Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a diagnosis of exclusion in the clinical scenario of increased intracranial pressure without an identifiable cause. This case report provides a brief review of current literature on IIH, important differential considerations to rule out prior to diagnosis, and relevant imaging findings of IIH. Case Presentation. An 18-year-old male presenting with headache and blurry vision was found to have signs of increased intracranial pressure on imaging without other abnormalities to explain the cause, suggesting IIH as a diagnosis. Conclusion. IIH is classically seen in overweight females of childbearing age but should be considered in all obese patients, including the pediatric population given the increasing rate of childhood obesity.

Hemophagocytic lymphohistiocytosis associated with Epstein-Barr virus in the central nervous system.

Hemophagocytic lymphohistiocytosis (HLH) is a rare immune hyperactivation syndrome which may be primary (genetic) or secondary to various immune-related conditions including infection, immunodeficiency, and malignancies. Rapid diagnosis and treatment are essential because it can be associated with significant morbidity and mortality. Epstein-Barr virus (EBV) is a known infectious cause of acquired HLH, but EBV-associated HLH involving the central nervous system is rare and not well characterized neuropathologically. We report a case of fatal EBV-associated HLH with severe involvement of the central nervous system showing florid hemophagocytosis in the choroid plexus, with extensive neuron loss and gliosis in the cerebrum, cerebellum, and brainstem.

Primary angiitis of the central nervous system presenting as unilateral optic neuritis.

A middle-aged woman who experienced recurrent episodes of unilateral vision loss and eye pain. On presentation, magnetic resonance imaging (MRI) demonstrated left optic nerve enhancement with patchy hyperintensities in the white matter of both frontal lobes and ill-defined enhancement in a lenticulostriate distribution. Ophthalmologic examination revealed left optic disc edema with a macular scar consistent with neuroretinitis. Her subsequent clinical course was notable for 2 episodes of painful vision loss, without associated neurologic symptoms, which resolved with intravenous and oral steroids. More than 1 year after her initial presentation, the patient developed right facial weakness and slurred speech, and shortly thereafter suffered a fatal intracerebral hemorrhage. Histopathology on autopsy confirmed a diagnosis of primary angiitis of the central nervous system (PACNS). This is an unusual case of PACNS presenting with recurrent unilateral optic neuritis. The vascular enhancement pattern on MRI suggesting inflamed cerebral blood vessels is a rarely described pattern, which likely reflects intracerebral extension of the ocular pathology. The combination of neuroretinitis and perivascular MRI enhancement pattern may represent a subtype of PACNS.

Multiple sclerosis with initial stroke-like clinicoradiologic features: case report and literature review.

A 17-year-old male presented with sudden onset of persistent focal neurological symptoms. Magnetic resonance imaging (MRI) demonstrated a nonenhancing white matter lesion that appeared hyperintense on fluid-attenuated inversion recovery sequence and diffusion-weighted imaging, while hypointense on apparent diffusion coefficient mapping corresponding to the patient's clinical features. A smaller subclinical lesion was also present. The patient's history, radiographic findings, and initial hospital course including response to treatment appeared supportive of a stroke diagnosis. However, a rapid recovery from his severe neurological deficits and results of subsequent serologic testing strongly indicated a demyelinating condition. The onset of adolescent multiple sclerosis can present diagnostic and therapeutic challenges, especially when the initial demyelinating event resembles an acute stroke in clinical and radiographic presentation. Every effort should be made to distinguish these diagnoses as early as possible to ensure timely and appropriate management.

Atypical imaging appearance of toxoplasmosis in an HIV patient as a butterfly lesion.

In acquired immunodeficiency syndrome (AIDS) patients, differentiating toxoplasmosis and primary central nervous system (CNS) lymphoma remains a clinical and radiographic dilemma. The presence of butterfly lesions crossing the corpus callosum is customarily used to exclude the possibility of toxoplasmosis. We present an AIDS patient who had Epstein-Barr virus (EBV) polymerase chain reaction (PCR) -positive cerebrospinal fluid studies with a butterfly toxoplasmosis lesion confirmed by multiple methods signifying the importance of including toxoplasmosis in the differential diagnosis of butterfly lesions.

Quality initiatives: blind spots at brain imaging.

Radiologists face the daily challenge of analyzing and interpreting a high volume of images in a timely manner. Minimizing errors, whether perceptual or cognitive in nature, is paramount for high-quality diagnostics and patient care. There are certain areas within the head encountered at routine brain imaging in which the interpreting radiologist is most prone to make perceptual errors. These areas, or "blind spots," include the cerebral sulci, dural sinuses, orbits, cavernous sinuses, clivus, Meckel cave, brainstem, skull base, and parapharyngeal soft tissues. In addition, the use of an inappropriate window width and level for the evaluation of computed tomographic (CT) scans can be a virtual, rather than an anatomic, blind spot. The inclusion of a comprehensive checklist for evaluation of these blind spots as part of every brain imaging study is crucial for avoiding false-negative results. Knowledge of the anatomic features of these blind spots is also crucial, as well as familiarity with the normal CT and magnetic resonance imaging findings in these areas. In addition, the radiologist should be aware of possible interpretation pitfalls that may lead to false-positive results (eg, normal anatomic variants that may be mistaken for pathologic conditions). Finally, a well-developed differential diagnosis will help ensure correct interpretation and appropriate patient treatment.