We conducted a questionnaire survey to collect epidemiological information on patients with Scans Without Evidence of Dopaminergic Deficit (SWEDD). We sent questionnaires to 4,970 neurology specialists in Japan in July 2015 and received responses from 933 of them. The total number of patients reported to have Parkinson’s disease was 39,532, which included 237 cases of SWEDD in patients (111 males, 125 females, and 1 case without a gender description). The disease duration in patients with SWEDD was short; 127 cases (53.6%) had a duration less than 3 years, and 78 cases (32.9%) had a duration of 3 years or more but less than 7 years. By age, 59 cases (24.9%) occurred in individuals in their 60s, and 106 cases (44.7%) occurred in individuals in their 70s. Sixty-three neurologists stated that they performed dopamine transporter single photon emission computed tomography (DaT SPECT) on almost all patients with Parkinson’s disease. They treated a total of 3,600 patients with Parkinson’s disease which included 107 cases of SWEDD; therefore, approximately 3.0% of Parkinson’s patients were estimated have SWEDD. The causes of SWEDD were unknown (101 cases), essential tremor (22 cases), vascular Parkinsonism (14 cases), and drug-induced Parkinsonism (14 cases). The majority of neurologists had doubts about the diagnosis of Parkinson’s disease prior to confirming the diagnosis using DaT SPECT for reasons such as: normal findings on meta-iodobenzylguanidine (MIBG) myocardial scintigraphy, poor responses to anti-Parkinson drugs, lack of true akinesia, unchanged symptoms, and atypical symptoms. Two hundred and nineteen cases included reports on treatment paradigms following the SWEDD diagnosis. Of those cases, patients in 159 cases were maintained on the same treatment following diagnosis.

A 70-year-old right-handed man noticed that the right side of the screen on his television displayed a time lag compared to the other side. For five days before admission, he had characteristic polyopia, visual photopia, and complex hallucination. Upon neurological examination, he showed no abnormal findings except for right homonymous hemianopia. MRI showed acute infarction of the occipital gyri and part of the lingual gyrus in the left occipital lobe. After admission, he experienced various visual hallucinations and visual illusions, including metamorphopsia and micropia, many times. They gradually disappeared after 2 months. Various hallucination was caused by the release of visual information, and illusion was thought to be due to integration failure of visual information. The appearance of complex hallucination in the blind visual field is known due to the damage of the region on the left occipital gyrus. However, the cases with various symptoms such as visual photopia and micropsia are rare.

After a 34-year-old female developed a headache and high fever, she was diagnosed with aseptic meningitis. On admission, neurological examinations revealed cerebellar limb ataxia, horizontal gaze paretic nystagmus, and pyramidal tract signs. Laboratory tests showed hyponatremia (129 mEq/l). Five days after admission, convulsions in the upper limbs due to the severe hyponatremia (108 mEq/l) were noted. In addition, serum antidiuretic hormone levels were markedly increased to 18.5 pg/ml. Brain MRI showed multiple small inflammatory lesions in the subcortical cerebral white matter, thalamus, and around the third ventricular diencephalic regions. Pulse corticosteroid treatment promptly improved her symptoms. Although tests for serum anti-aquaporin 4, anti-myelin oligodendrocyte glycoprotein, and anti-voltage-gated potassium channel antibodies were negative, cerebrospinal fluid samples tested positive for anti-N-methyl-D-aspartate (NMDA) receptor antibodies. Oral prednisolone administration was continued, but she developed paresthesia in her upper and lower extremities and gaze-evoked nystagmus three months after the first attack. MRI showed that the previously observed high-intensity regions were decreased, but a new area of high intensity was observed in ventral regions through the lower midbrain to the pons. Because pulse corticosteroid treatment was again effective, we continued the oral prednisolone treatment. This case presented none of the characteristic symptoms of anti-NMDA receptor antibody encephalitis during the clinical course other than repeated demyelinating encephalitis and severe syndrome of inappropriate antidiuretic hormone secretion (SIADH). Additional clinical observations are needed to better understand the underlying pathology of the NMDA receptor antibodies in the cerebrospinal fluid in this case.

A 42-year-old woman with bronchial asthma was admitted to our hospital due to sensory dominant mononeuritis multiplex lasting for more than 6 months. At that time, her eosinophil count was 761/μl and her sural nerve biopsy showed no findings suggestive of vasculitis. Four months later, she experienced sudden convulsions and right hemiparesis due to left lobular parietal subcortical hemorrhage, when her eosinophil count was elevated to 3,257/μl. Numerous microbleeds and small infarctions were also detected in the intracerebral areas of different regions with MRI. Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic necrotizing vasculitis of the small vessels, commonly affecting the peripheral nerves. Subarachnoid hemorrhage in patients with EGPA is extremely rare. Steep elevation of the eosinophil count may release certain cytokines, causing cerebral hemorrhage.

A 68-year-old man, who had received Billroth II gastrojejunostomy because of duodenal ulcer at the age of 20, was diagnosed to have Parkinson’s disease at age 57 years. The drug therapy has been effective in the first 10 years, however, recently he was suffering from troublesome dyskinesia and wearing-off in spite of diligent drug adjustments. Although the indication of levodopa-carbidopa intestinal gel (LCIG) treatment was good, percutaneous endoscopic gastrostomy was difficult because of abdominal adhesion. Therefore, we introduced LCIG by surgical gastrostomy. After LCIG therapy, wearing-off and dyskinesia disappeared. This is the first case of Parkinson’s disease patient with LCIG therapy by surgical gastrostomy in Japan.

A 44-year-old female developed acute hepatitis A (HA) 5 weeks after ingesting raw oysters. She developed ascending motor weakness, bilateral peripheral facial nerve palsy, and bulbar symptoms. A diagnosis of demyelinating Guillain-Barré syndrome (GBS) was made on the basis of her clinical manifestations and the results of a nerve conduction study. The patient showed improvement following combination treatment with intravascular immunoglobulin and high dose methylprednisolone. No antibodies against specific gangliosides, sulfated glucuronyl paragloboside (SGPG), or sulfatide were detected. HA virus (HAV) RNA was isolated from her serum and its full-length genome sequence was determined. It revealed a homology of 99.9% or more with HAV genotype IA (HAV-IA) of the 2014 outbreak. No mutant virus RNA was detected.