Objective: Compression of the left renal vein by the superior mesenteric artery, known as nutcracker phenomenon (NCP), can cause retrograde flow and congestion in communicating venous systems. It has recently been speculated that NCP can result in retrograde flow and congestion of the lumbar veins and epidural venous plexus (EVP), thereby affecting the central nervous system. This study describes the novel use of time-resolved magnetic resonance angiography (trMRA) to evaluate for retrograde left second lumbar vein (L2LV) flow and early EVP enhancement in patients with chronic daily headache (CDH) with and without NCP.Methods: A retrospective analysis was performed of 31 patients with CDH (27 females and 4 males; median age, 38 years [range, 18-63 years]) who underwent trMRA centered over the L2LV to evaluate the direction of blood flow and presence of early EVP enhancement from May 2020 to March 2022. Descriptive statistics were performed, and anatomic associations were analyzed in patients with and without retrograde L2LV flow and early EVP enhancement. The accuracy of magnetic resonance imaging findings in detecting these flow patterns was also assessed.
Results:Patients with NCP who demonstrated narrowing of the left renal vein, a positive beak sign ( P = 0.052), decreased aortomesenteric distance ( P = 0.038), and decreased SMA angle demonstrated increased rates of retrograde L2LV flow and early EVP enhancement. A positive beak sign was 83% specific, and an aortomesenteric distance of ≤6.5 mm was 61% sensitive and 83% specific for identifying retrograde L2LV flow with early regional EVP enhancement in patients with CDH.Conclusions: Retrograde L2LV flow with early EVP enhancement in CDH patients can be effectively evaluated using trMRA and was seen with greater propensity in those patients with NCP.
Bilateral hyperglycemic nonketotic chorea is a rare complication of hyperglycemia. In most cases, the literature illustrates patients presenting with unilateral chorea with image findings significant for hyperintense lesions in the basal ganglia on magnetic resonance imaging (MRI) or hyperdensities on computerized tomography (CT). Here, we present a case of an 83-year-old patient who was admitted to the hospital due to acute onset of orofacial and bilateral upper extremity chorea. She had no previous history of infection, genetic mutation, neoplasms, neurodegeneration, stroke, metabolic disease, drug exposure, or autoimmune disease. Surprisingly, her MRI showed only chronic microvascular changes in periventricular white matter without basal ganglia abnormalities. However, she was noted to have marked worsening of her glycemic control over the preceding 12 months based on worsening glycated hemoglobin (HbA1c) levels and elevated serum glucose on presentation. A literature review indicates that chorea caused by hyperglycemia is at times reversible with glycemic control, but as demonstrated in our patient, this is not always necessarily the case. A similar course has only been elaborated in a few other cases in the literature. We will also review the pathogenesis, the usual disease clinical course and standard treatment from the literature.
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