Anesthetic Considerations for Chiari I Malformation in a BMI 62 Patient

Patients with Chiari I malformations present with tonsillar herniation below the foramen magnum causing abnormal spinal anatomy. Anesthesia challenges in this population include difficult airway management, monitoring intraoperative autonomic dysfunction, avoiding increased intracranial pressure, and accommodating sensitivity to neuromuscular blockade. We present a case with an additional airway management challenge due to morbid obesity with a BMI of 62. A 23 year old female with a history of Covid pneumonia and morbid obesity who presented with syringomyelia and Chiari I malformation. She initially presented with bilateral numbness, tingling, weakness, and pain in her hands. Imaging with MRI at the time showed downward displacement of the cerebellar tonsils with the tips reaching the lower portion of C1 and overall 10-12 mm displacement below the level of the foramen magnum. Syrinx was also visualized from the level of C1-C2 extending down to the level of T5-T6. Repeat MRI a year later showed no significant changes. However, she has worsening symptoms of pain in her right arm preventing her from working. She is agreeable to surgical decompression of the posterior fossa through a suboccipital craniotomy with resection of the posterior arch of C1 with duraplasty. Significant findings on the physical exam include Mallampati III, shorter thyromental distance, and limited range of motion of her cervical spine due to pain in her arms. We chose awake fiberoptic intubation due to difficult airway from morbid obesity and limited cervical spine range of motion and the consideration of hypercapnia induced from brief apnea the patient may not tolerate. She was premedicated with versed, glycopyrrolate, and dexmedetomidine, and given a 5% lidocaine paste lollipop to topicalize oropharynx. She was also started on a low dose remifentanil infusion for sedation during the awake fiberoptic approach. Blood pressure, heart rate, respiratory rate with continuous end-tidal capnography, and pulse oximetry were monitored during the awake fiberoptic intubation. A 7.0 endotracheal tube was lubricated with viscous lidocaine and placed over a fiberoptic scope. Once there was visualization of the vocal cords, additional 2% lidocaine was administered directly at the vocal cords. She was intubated smoothly on the first attempt. She was then immediately induced to general anesthesia with propofol and non-depolarizing muscle relaxant to avoid using succinylcholine due to the possible hypersensitivity caused by denervation. Intraoperatively, a conventional air warmer was used to prevent hypothermia. Invasive arterial blood pressure monitoring was applied. Normotensive blood pressure and normocapnia were maintained throughout the surgery. Muscular blockade was reversed with sugammadex at the end of surgery to ensure adequate ventilation especially with the patient's body habitus. Upon extubation, the patient had acute hypertension which was managed by nicardipine infusion and hydralazine boluses. Patient was taken to a neurosurgical intensive unit and monitored for two days. She was discharged home without any complication. In conclusion, anesthetic considerations for patients with Chiari I malformation include airway management, monitoring for autonomic dysfunction, avoiding increase in ICP, and optimizing postoperative neurological status with balanced anesthetic management.

Seizure, abdominal pain, and urine pink in an adolescent female-what's the link?

Case Report A 17 year-old female with history of depression was transferred to the pediatric intensive care unit (PICU) from an emergency department (ED) for first time seizure and subsequent encephalopathy after five days of severe, diffuse abdominal pain and vomiting. The night prior to admission, she complained of lightheadedness and then had a witnessed generalized tonic-clonic seizure lasting 45 seconds. She initially returned to her baseline but then had three additional seizures requiring ED evaluation. She received intravenous doses of lorazepam and levetiracetam that aborted the clinical seizures. She remained encephalopathic and was orotracheally intubated for airway protection. Family denied known ingestions but reported she did vape nicotine. Urine drug screen was positive for benzodiazepines, consistent with seizure management. Cerebrospinal fluid analysis was unrevealing. Urinalysis showed moderate ketones and trace blood. Urine pregnancy test and nasopharyngeal SARS-CoV-2 polymerase chain reaction were negative. Head computerized tomography scan showed no intracranial pathology. On arrival to the PICU, the patient was afebrile, tachycardic, and hypertensive to 171/118 mmHg. She was somnolent on arrival but aroused to sternal rub without focal neurologic deficit. She presented with a Foley catheter that drained pinkorange urine. A nicardipine infusion was started given concern for the development of posterior reversible encephalopathy syndrome (PRES). Thyroid function tests were consistent with euthyroid sick syndrome. BioFire meningitis panel, plasma SARS-CoV-2 IgG, and toxicologic evaluation were all negative. Electrocardiogram showed sinus tachycardia. Magnetic resonance imaging of the brain revealed cortical and subcortical areas of diffusion restriction consistent with PRES. Ultimately, a random urine porphobilinogen and a 24-hour measurement of urine porphyrins collected on hospital day 1 were both markedly elevated. A diagnosis of Acute Intermittent Porphyria (AIP) was made. A gastrointestinal porphyria specialist was consulted and recommended monthly outpatient injections of givosiran upon hospital discharge. Discussion This case illustrates the importance of considering AIP in the differential diagnosis of new onset seizure or encephalopathy associated with hypertension, tachycardia, and abdominal pain in an adolescent. This case also adds to a small number of cases associating AIP with PRES. AIP is often viewed as an adult disease because it typically presents in the third or fourth decade of life. Timely recognition of AIP in the pediatric setting is critical to preventing delays in diagnosis, treatment, and patient education on triggers of acute attacks. AIP attacks are treated with dextrose and hemin infusions to reduce production of porphyrin precursors. Prophylactic treatment of AIP now includes givosiran, an interfering mRNA that reduces levels of intermediates in heme synthesis that are neurotoxic when elevated.