Methemoglobinemia in the Morning

At Hillcrest this morning Janna Raphelson, one of our stellar residents, presented a case of a 75-year-old man with history of steroid-dependent interstitial lung disease, chronic kidney disease, and serious TMP-SMX allergy who presented to the VA with increased dyspnea, fatigue, and headache one month after starting dapsone for Pneumocystis jiroveci pneumonia prophylaxis. He was found to have an acute anemia that was stabilized by transfusion of pRBCs and subsequently characterized as hemolytic. On exam, the patient was cyanotic with an oxygen saturation in the mid-80% that was unresponsive to up titration of supplemental oxygen.

We were joined by Dr. Mark Hepokoski from our PCCM division as we unpacked the causes of hypoxemia and why we need to calculate an alveolar-arterial (A-a) gradient. While the patient’s A-a gradient was increased (from baseline IPF and mild interstitial edema), there was a clear discrepancy between his SpO2 (pulse oximeter) and PaO2 (blood gas). This reminded us that impaired oxygen delivery to tissues (hypoxia) has multiple potential etiologies: hypoxemic, anemic, circulatory, histotoxic. The next step in the evaluation of our patient involved obtaining co-oximetry which revealed increased levels of methemoglobin!

The pulse oximeter is only able to distinguish between saturated and unsaturated hemoglobin. If significant levels to methemoglobin build up, the machine interprets this as a saturation of approximately 85%. In addition to causing a functional anemia, methemoglobinemia shifts the hemoglobin-oxygen dissociation curve to the left. This effect causes increased affinity of hemoglobin for oxygen and decreases oxygen unloading in tissues. We compared our patient’s case to the other acquired dyshemoglobinemia that we sometimes encounter, carbon monoxide poisoning. 

Despite the patient’s normal G6PD screen prior to starting dapsone, he still developed known complications of this medication’s oxidative effect: hemolytic anemia and methemoglobinemia. Our patient’s methemoglobinemia was partially treated by blood transfusions and given concern for toxicity in renal failure, he did not receive the standard treatment of methylene blue and vitamin C. The patient slowly recovered following discontinuation of dapsone (switched for inhaled pentamidine for ongoing PJP ppx) and is now back to his baseline. 

Thank you to Dr. Hepokoski for sharing his wisdom and clinical expertise and thank you to all of our applicants for joining us for another great morning report!

Thursday Maputo-VA Conference

This Thursday, we restarted our join teaching conferences with our partners in Maputo, Mozambique! We discussed a case of an 83-year-old man who presented with several months of progressive shortness of breath, dry cough, and weight loss. On exam, he had absence of breath sounds over the right hemithorax with dullness to percussion and absent tactile fremitus. His chest radiograph demonstrated unilateral white out, and we considered two possibilities for this finding: a large pleural effusion or a mainstem bronchial obstruction causing lung collapse. 

Our expert discussant, the legendary VA pulmonologist Dr. Judd Landsberg, guided us through the CXR interpretation and why it was consistent with an effusion: large spacing between ribs and tracheal deviation away from the affected hemithorax.  

A thoracentesis was performed and was consistent with an exudate by Light’s criteria. We formed a differential for exudative effusion and discussed why two possibilities were most likely for this particular patient: malignancy and Tuberculosis. Unfortunately, the patient’s thoracentesis was followed by the discovery of a pneumothorax. We considered the mechanism and management of this complication and how to proceed in case where the pneumothorax is increasing: placement of a chest tube. 

Thank you to Dr. Landsberg for all of his clinical pearls and the Maputo residents for their participation!

ECMO in COVID-19

Join the COVID-19 Critical Care Training Forum for another high-yield session this Tuesday, 12/8 at 5pm. This week’s topic is “The Management of Patients with Severe ARDS Due to COVID-19 with Extracorporeal Membrane Oxygenation (ECMO).” 

Please Register here: https://thoracic.zoom.us/meeting/register/tJYlc-yqrjsiGdWHR2dvpR719Cj91Q4ycHxz%20

Moderator: Mazen F. Odish, MD, UCSD

Presenters/Discussants include: Daniel Brodie, MD, Columbia College of Physicians and Surgeons; Eddy Fan, MD, PhD, FRCPC, University of Toronto and UHN/MSH; Cameron McGuire, MD, Fellow, UCSD; and Lauren Sullivan, MD, Fellow, UCSD

For recordings of prior sessions of this ATS forum, please visit:
https://www.thoracic.org/professionals/career-development/ats-virtual-network/covid-19-critical-care-training-forum.php

Pulmonary Embolism and COVID-19

Join us on Tuesday, November 10th at 5 PM to learn about the work-up and management of pulmonary emboli during the current pandemic. Dr. Laura Crotty Alexander will moderate the session and we are lucky to have amazing expert discussants, including UCSD’s own Drs. Timothy Morris, Timothy Fernandes, and Daniel Bond. We will also hear from Drs. Richard Channick (UCLA) and Victor Tapson (Cedars-Sinai).  

Earn CME Credit in this Upcoming Forum! Register here: 

https://thoracic.zoom.us/meeting/register/tJYqdOytpzsjEtxiSbIjYO_IpT-LPiQ4urIz

This one-hour webinar will focus on the incidence, pathogenesis and management of patients with thromboses during the COVID-19 pandemic. We will present cases of pulmonary emboli, review how the recommended workup and management of these cases has evolved over the duration of the pandemic, and discuss potential mechanisms underlying the prothrombotic state seen in COVID-19. 

COVID-19 Training Forum tonight at 5PM!

Join us for another installment of the ATS COVID-19 Critical Care Training Forum tonight, Tuesday 8/25, at 5 PM. This forum focuses on teaching critical care topics followed by an open discussion for early career professionals and non-ICU trained healthcare providers. Two of your co-residents, Neal Jones and Ali Crisp, will discuss their experience providing Tele-ICU care to patients in El Centro.

You can register here:

https://thoracic.zoom.us/meeting/register/tJcpd-igrj4oGN2_3zYdOtd5uflxx5ZvGUF7

Details for tonight’s session: 

Topic: Providing Virtual Critical Care / Tele-ICU in Resource Limited and Cross-Cultural Settings: Challenges and Opportunities for Volunteerism, Education and Patient Care 

Moderator: Laura E. Crotty Alexander, MD, UCSD, PCCSM

Discussants: Erica Lin, MD, UCSD; Jess Mandel, MD, UCSD; Venktesh Ramnath, MD, UCSD; Neal Jones, MD, UCSD; Ali Crisp, MD, UCSD 

ATS COVID-19 Forum Tue 8/18 at 5 PM

Join our UCSD Pulmonary and Critical Care faculty and fellows for a lively and high-yield discussion on the care of patients with COVID-19. Since April, this virtual forum has been bringing expert guidance for providers without critical care training in an accessible format. Tomorrow’s session will include an all-star UCSD line-up:

  • “COVID-19 Case Presentation” by Erica Lin, MD  
  • “Best Practices in Caring for Critically Ill COVID-19 Patients” by Amy Bellinghausen Stewart, MD 
  • “Updates and Controversies in COVID Care: what therapies have and have not panned out” by Cameron McGuire, MD 
  • “Mechanisms Underlying Hypoxemia in COVID-19″ by Atul Malhotra, MD 

You can register and watch recordings of prior sessions of this forum at:

https://www.thoracic.org/professionals/career-development/ats-virtual-network/covid-19-critical-care-training-forum.php

Hope to see you all there! 

MTC 7/23 – Pneumocystis Jiroveci Pneumonia in patient with HIV

This morning we discussed a case of 42-year-old man who presented to UCSD Hillcrest with a history of subacute cough and shortness of breath. Review of systems was additionally notable for subacute fevers and chills, night sweats, weight loss, and progressive generalized weakness. His sexual history was suspicious for potential undiagnosed HIV infection, and we created a differential of possible pulmonary disease in HIV+ patients by CD4 count. His CXR and elevated LDH and beta-D glucan (sensitive although not specific) were suspicious for PJP. The diagnosis was ultimately diagnosed by sputum silver stain, and we discussed the frequent need for bronchoscopy with BAL to obtain adequate sample. After initiation of treatment with TMP-SMX, the patient’s respiratory condition worsened, and we discussed the role of systemic steroids in PJP treatment. Thank you to Dr. Darcy Wooten from Infectious Disease, who guided us through the differential diagnosis and provided many relevant clinical pearls.