Thiamine deficiency disorders: a clinical perspective.

Thiamine is an essential water-soluble vitamin that plays an important role in energy metabolism. Thiamine deficiency presents many challenges to clinicians, in part due to the broad clinical spectrum, referred to as thiamine deficiency disorders (TDDs), affecting the metabolic, neurologic, cardiovascular, respiratory, gastrointestinal, and musculoskeletal systems. Concurrent illnesses and overlapping signs and symptoms with other disorders can further complicate this. As such, TDDs are frequently misdiagnosed and treatment opportunities missed, with fatal consequences or permanent neurologic sequelae. In the absence of specific diagnostic tests, a low threshold of clinical suspicion and early therapeutic thiamine is currently the best approach. Even in severe cases, rapid clinical improvement can occur within hours or days, with neurological involvement possibly requiring higher doses and a longer recovery time. Active research aims to help better identify patients with thiamine-responsive disorders and future research is needed to determine effective dosing regimens for the various clinical presentations of TDDs. Understanding the clinical diagnosis and global burden of thiamine deficiency will help to implement national surveillance and population-level prevention programs, with education to sensitize clinicians to TDDs. With concerted effort, the morbidity and mortality related to thiamine deficiency can be reduced.

Infantile encephalitic beriberi: magnetic resonance imaging findings.

BACKGROUND: Thiamine deficiency in infants is still encountered in developing countries. It may present with acute neurological manifestations of infantile encephalitic beriberi. OBJECTIVE: To review brain MRI findings in infantile encephalitic beriberi from a single institution. MATERIALS AND METHODS: A retrospective review of MRI scans in 22 infants with acute-onset beriberi encephalopathy was carried out. RESULTS: Hyperintense lesions on T2-weighted images were seen symmetrically in the putamen in all patients, in the caudate nuclei in 16/22 (73%), the thalami in 7/22 (32%) and the globi pallidi in 3/22 (14%) of the infants. Altered signal intensity lesions in the cerebral cortex were seen in 7/22 (32%). The mammillary bodies were seen in one infant and the periaqueductal gray matter in two. There was restricted diffusion in 14/22 (64%), and 6/8 children with no evidence of restriction had been imaged ≥10 days after presentation. MR spectroscopy showed increased lactate peak in 6/8 infants (75%). CONCLUSION: Recognition of symmetrical T2-W hyperintense lesions in the basal ganglia with restricted diffusion and prominent lactate peak may allow early diagnosis of encephalitic beriberi in at-risk infants.

Subcutaneous emphysema due to bronchial foreign body demonstrated by multidetector-row computed tomography.

Foreign body aspiration is an important cause of emergency hospital admissions in young children less than 3 years of age. It may manifest with acute respiratory difficulty, choking and wheeze acutely or may be asymptomatic. Surgical emphysema is an unusual presentation of bronchial foreign body aspiration in young children. We describe an infant with bronchial foreign body aspiration that manifested with subcutaneous emphysema and pneumomediastinum. Multidetector-row CT with virtual bronchoscopy helped in the diagnosis by detecting and localizing the intraluminal foreign body in the right main bronchus that was removed with rigid bronchoscopy.

Perinephric fluid collections due to renal lymphangiectasia.

Fluid collections around the kidneys on cross-sectional imaging may be caused by urine, blood, pus, lymph, or plasma. Ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) can not only show and characterize the fluid, but also may help determine the underlying cause of the perinephric fluid collection, such as ureteric obstruction, kidney injury, infection, or renal lymphangiectasia. Renal lymphangiectasia is characterized by abnormal and ectatic lymphatic vessels within and around the kidneys. Dilated lymphatics may result in peripelvic cysts (intrarenal lymphangiectasia) and perinephric fluid collections (extrarenal lymphangiectasia), which can be visualized using US, CT, and MRI. Proper diagnosis on imaging helps in planning a conservative management approach to this benign condition, which requires intervention for only significant symptoms or complications. We describe a 60-year-old man with normal kidney function and bilateral perinephric fluid collections in whom renal lymphangiectasia was diagnosed noninvasively on the basis of characteristic findings on US, CT, and MRI.

Sagittal sinus thrombosis due to L-asparaginase.

Cerebral Sinovenous Thrombosis (CSVT) is a serious complication of L-asparaginase chemotherapy for leukemia in children. Clinical features of headache, altered consciousness, focal neurological deficit, and seizures developing during or immediately after treatment with L-asparaginase should alert the treating physician to the possibility of CSVT. Immediate imaging of the brain should be done using CT and MRI and the veins should be visualized noninvasively by CT and MR venography. We report two children on induction therapy for acute leukemia who presented with seizures, headache, and altered consciousness. Venous infarcts with and without hemorrhage were seen on CT in one patient and the empty delta sign was seen after contrast injection; however, the early changes were missed by CT. MRI detected dural sinus thrombosis relatively earlier in another patient, while the CT findings were equivocal; in this patient, contrast-enhanced MRI showed the empty delta sign and MR venography confirmed absent flow in the superior sagittal sinus, which was diagnostic of sinus thrombosis. Rapid anticoagulation was started with heparin and maintained with warfarin. The child with a unilateral small nonhemorrhagic infarct made a complete recovery while the other, with bilateral hemorrhagic infarcts, did not survive. We stress the importance of early diagnosis of CSVT using CT and MRI in children with leukemia being treated with L-asparaginase; this will permit timely treatment.