Mohan Rudrappa

Cerebral fat embolism: Use of MR spectroscopy for accurate diagnosis

Cerebral fat embolism (CFE) is an uncommon but serious complication following orthopedic procedures. It usually presents with altered mental status, and can be a part of fat embolism syndrome (FES) if associated with cutaneous and respiratory manifestations. Because of the presence of other common factors affecting the mental status, particularly in the postoperative period, the diagnosis of CFE can be challenging. Magnetic resonance imaging (MRI) of brain typically shows multiple lesions distributed predominantly in the subcortical region, which appear as hyperintense lesions on T2 and diffusion weighted images. Although the location offers a clue, the MRI findings are not specific for CFE. Watershed infarcts, hypoxic encephalopathy, disseminated infections, demyelinating disorders, diffuse axonal injury can also show similar changes on MRI of brain. The presence of fat in these hyperintense lesions, identified by MR spectroscopy as raised lipid peaks will help in accurate diagnosis of CFE. Normal brain tissue or conditions producing similar MRI changes will not show any lipid peak on MR spectroscopy. We present a case of CFE initially misdiagnosed as brain stem stroke based on clinical presentation and cranial computed tomography (CT) scan, and later, MR spectroscopy elucidated the accurate diagnosis.

Acute airway obstruction due to spontaneous intrathyroid hemorrhage precipitated by anticoagulation therapy

Acute airway compromise due to hemorrhage in of thyroid gland is a rare life-hreating condition. The increasing use of anticoagulants for various reasons is likely increased the occurrence of this this complication. We describe an elderly patient on anticoagulation for atrial fibrillation, which developed swelling on the right side of neck causing acute airway obstruction requiring emergency intubation for airway protection. Computed tomographic scan showed massive intrathyroid hemorrhage along with substernal extension. She had supratherapeutic INR which was appropriately corrected emergently. She underwent resection of the thyroid gland which showed multinodular goiter without any evidence of malignancy. Our case illustrates the rare but lethal bleeding complication of anticoagulants in critical anatomical area and we request physicians should be wary of similar conditions.

Neurological Respiratory Failure

West Nile virus infection in humans is mostly asymptomatic. Less than 1% of neuro-invasive cases show a fatality rate of around 10%. Acute flaccid paralysis of respiratory muscles leading to respiratory failure is the most common cause of death. Although the peripheral nervous system can be involved, isolated phrenic nerve palsy leading to respiratory failure is rare and described in only two cases in the English literature. We present another case of neurological respiratory failure due to West Nile virus-induced phrenic nerve palsy. Our case reiterates the rare, but lethal, consequences of West Nile virus infection, and the increase of its awareness among physicians.

Acute Stroke due to Electrocution: Uncommon or Unrecognized?

The growing dependence on electricity in our daily lives has increased the incidence of electrocution injuries. Although several neurological injuries have been described previously, acute stroke due to electrocution is rare. Our patient, a previously healthy man, was electrocuted after he grabbed a “live” high-voltage wire. Although he was hemodynamically stable, he remained confused with language defects. MRI of the brain showed acute stroke in the bilateral anterior cerebral artery territory and watershed regions of the left middle cerebral artery territory. MR angiogram incidentally showed A1 segment aplasia of the right anterior cerebral artery. Electrocution is known to cause vasospasm leading to end-organ damage similar to that seen in stroke. In our patient, vasospasm of the left anterior circulation likely led to watershed infarcts in the left parietal lobe and bilateral frontal lobes. Due to aplasia of the A1 segment on the right side, perfusion to both frontal lobes was solely from the left anterior cerebral artery.

Primary aorto-esophageal fistula: Great masquerader of esophageal variceal bleeding

Aorto-esophageal fistula is a rare cause of upper gastrointestinal bleeding. Thoracic aneurysm, the most common cause of this condition, will slowly increase over time and can erode the wall of the aorta creating a fistula and leading to torrential bleeding. High clinical suspicion is required for timely diagnosis as common investigations routinely done for gastrointestinal (GI) bleeding, including esophagogastroduodenoscopy, fails to detect most cases. The classical triad of midthoracic pain, herald bleeding and fatal hematemesis described in this condition is seen in only one-third of cases. Physician should be wary of this condition, especially in elderly patients with uncontrolled GI bleeding and who are also at risk of thoracic aneurysm. Computed tomography angiogram detects most cases and emergent endovascular repair with stents controls the initial bleeding. Later, both the aorta and the esophagus are repaired and reconstructed in staged procedures.