Medical Image of the Week: Central Pontine Myelinolysis

Figure 1. MRI axial T2 Image showing central pontine lesion consistent with osmotic demyelination. 

Figure 2. MRI axial (Panel A) and sagittal (Panel B) flair Images showing a hyperintensity located centrally within the pons with some sparing of the periphery measuring 1.6 by 1.3 cm.

A 38-year-old woman with history of alcohol abuse was admitted with generalized weakness, dehydration, alcoholic hepatitis, hyponatremia (serum sodium 116 mM/L), and cachexia (BMI 19 kg/m2).  She developed hypoxemic respiratory failure after intravenous fluid resuscitation and required intubation and mechanical ventilation.  Neurological exam revealed motor weakness, hyporeflexia, ataxia, and unsustained clonus.  Neurology consultation was obtained and MRI revealed hyperintensity in the pons consistent with osmotic demyelination syndrome (1).  Review of her records revealed her sodium level increased by 8 mM/L in first 6 hours of presentation, and then a slow increase of 4-6 mM/L daily to the normal range. She received nutritional support and aggressive physical therapy, and was discharged to skilled nursing facility after six weeks of hospitalization.

Tauseef Afaq Siddiqi, MD; Yeeck Sim, MD; Thi Nguyen, MD; Afshin Sam, MD

Division of Pulmonary, Allergy, Critical Care and Sleep Medicine,

Department of Medicine

University of Arizona

Tucson, AZ

Reference

Kumar S, Fowler M, Gonzalez-Toledo E, Jaffe SL. Central pontine myelinolysis, an update. Neurol Res. 2006;28(3):360-6. [CrossRef] [PubMed] 

Reference as: Siddiqi TA, Sim Y, Nguyen T, Sam A. Medical image of the week: central pontine myelinolysis. Southwest J Pulm Crit Care. 2013;8(1):18-9. doi: http://dx.doi.org/10.13175/swjpcc159-13 PDF

Medical Image of the Week: Azygous Lobe

Figure 1. Chest X-Ray (A) and thoracic CT scan (B) shows the azygos fissure and the ‘tadpole’ appearance (arrow).  Chest CT (C) shows the lateral course of the azygos vein (arrow) and the accessory lobe.

A 59 year old man underwent chest radiography for evaluation of fever and cough. Imaging showed an accessory azygous lobe.  An azygos lobe is found in 1% of anatomic specimens and forms when the right posterior cardinal vein, one of the precursors of the azygos vein, fails to migrate over the apex of the lung (1). Instead, the vein penetrates the lung carrying along pleural layers that entrap a portion of the right upper lobe. The vein appears to run within the lung, but is actually surrounded by both parietal and visceral pleura. The azygos fissure therefore consists of four layers of pleura, two parietal layers and two visceral layers, which wrap around the vein giving the appearance of a tadpole. Apart from an interesting incidental radiological finding, it is of limited clinical importance except that its presence should be recognized during thoracoscopic procedures. This patient was found to have a cavitary lung lesion which was the cause of his symptoms.

Bhupinder Natt MD, Abdulmagid Eddib MD, Dena H’Leureux MD

Department of Pulmonary, Allergy, Critical Care and Sleep Medicine

University of Arizona and the Southern Arizona VA Health Care System

Tucson, AZ 

Reference

Mata J, Cáceres J, Alegret X, Coscojuela P, De Marcos JA. Imaging of the azygos lobe: normal anatomy and variations. AJR Am J Roentgenol. 1991;156(5):931-7. [CrossRef] [PubMed]

Reference as: Natt B, Eddib A, H'Leureux D. Medical image of the week: azygous lobe. Southwest J Pulm Crit Care. 2013;7(6):353-4. doi: http://dx.doi.org/10.13175/swjpcc158-13 PDF