Vaccine-Induced Thrombotic Thrombocytopenia

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In this episode, we discuss thrombotic thrombocytopenia associated with the viral vector COVID-19 vaccines (VITT: Vaccine-Induced Thrombotic Thrombocytopenia) – a very very rare, but real entity. Information is still emerging so numbers will likely change in the coming days. For more on cerebral vein thrombosis in general, check out this podcast.

Greinacher et al NEJM 2021
Schultz et al. NEJM 2021
ACIP Presentation by Jannsen 4/14/21, Muir et al NEJM 2021

International Society of Thrombosis and Hemostasis Statement

United Kingdom Guidance On Thrombosis Following Vaccinations

Thromboelastography (TEG) Guided Resuscitation

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Thromboelastography (TEG) or its related counterpart rotational thromboelastometry (ROTEM) have gained in popularity over the past several years. These tests assess viscoelastic clot strength in whole blood. These tests may offer more granular and potentially reliable information on the patient’s clot formation and fibrinolytic state than traditional measures of coagulation such as International Normalized Ratio (INR), partial thromobplastin time (PTT), and prothrombin time (PT).

One of the primary advantages to TEG/ROTEM is the ability to target transfusion related therapies to the patient’s overall coagulation profile. Below are some common patterns that emerge and the recommended therapies.

Evidence for TEG in Cirrhosis

Additional FOAM resources: PulmCrit

References:

  1. Wikkelsø A, Wetterslev J, Møller AM, Afshari A. Thromboelastography (TEG) or thromboelastometry (ROTEM) to monitor haemostatic treatment versus usual care in adults or children with bleeding. Cochrane Database Syst Rev. 2016;(8):CD007871.
  2. Kumar M, Ahmad J, Maiwall R, et al. Thromboelastography-Guided Blood Component Use in Patients With Cirrhosis With Nonvariceal Bleeding: A Randomized Controlled Trial. Hepatology. 2019; In Press
  3. Rout G, Shalimar, Gunjan D, et al. Thromboelastography-guided Blood Product Transfusion in Cirrhosis Patients With Variceal Bleeding: A Randomized Controlled Trial. J Clin Gastroenterol. 2019; In Press.
  4. Goodman MD, Makley AT, Hanseman DJ, Pritts TA, Robinson BR. All the bang without the bucks: Defining essential point-of-care testing for traumatic coagulopathy. J Trauma Acute Care Surg. 2015;79(1):117-24.

You are called to the bedside for a postoperative patient who is hypotensive, febrile, and has acute onset of respiratory distress following the initiation of a blood transfusion. Which of the following is the most appropriate initial action in the management of this patient?

A. Apply oxygen

B. Call the blood bank

C. Order steroids

D. Stop the transfusion

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Transfusion-related acute lung injury is a blood transfusion complication characterized by a rapid onset of non-cardiogenic pulmonary edema. The pathogenesis is thought to be a two-part mechanism involving neutrophil sequestration with priming in the lung microvasculature followed by neutrophil activation by a factor in the blood product. Pre-transfusion risk factors include current smoking, chronic alcohol use, liver transplantation surgery, positive fluid balance, shock, and higher ventilated peak airway pressures. Though there is an association of transfusion-related acute lung injury with all blood products, high-plasma-volume products (plasma, apheresis platelet concentrations, and whole blood) have the greatest risk. Clinical presentation may occur immediately after the initiation of the blood transfusion although it can be delayed up to six hours. The patient may rapidly develop acute respiratory distress syndrome, with symptoms that may include hypoxemia, fever, hypotension, cyanosis, pulmonary infiltrates on chest imaging, and if intubated, pink frothy secretions when suctioned. Treatment involves immediate discontinuation of the transfusion followed by supportive care of the acute respiratory distress syndrome. This includes oxygen supplementation and hemodynamic support. Apply oxygen (A), call the blood bank (B), and order steroids (C) are treatments for transfusion-related acute lung injury but are not the most appropriate in the initial management. Discontinuing the transfusion, which is the cause of the acute lung injury, is the immediate need upon identifying the condition.

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Emergent Issues in Sickle Cell Disease

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Sickle cell disease (SCD) is a terminal disease resulting from sickled blood cells caused by an abnormally folded beta-globin chain. The sickled cells cause occlusion and hyperviscosity leading to a myriad of complications. Unfortunately, some stigma associated with SCD persists in the healthcare field leading to undertreatment of pain or marginalization of patients. The American Society of Hematology (ASH) currently has draft recommendations that are open for public comment until May 13, 2019.

Which of the following is the most common cause of an aplastic crisis in a child with sickle cell disease?

A. Epstein-Barr virus

B. Parvovirus B19

C. Salmonella

D. Streptococcus pneumoniae

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[toggle title=”Answer” state=”closed”] B. Predominantly affecting individuals of African ancestry, sickle cell anemia is a genetic disease that results in the formation of sickled red blood cells. Affected patients are homozygous for sickle hemoglobin (HbSS) which results in deoxygenated red blood cells developing a sickle or crescent shape. This leads to inflexible red blood cells, increased blood viscosity, and decreased blood flow within organs or extremities. A complication of sickle cell anemia is a transient aplastic crisis. This is caused by a short-lived stoppage of erythropoiesis, resulting in acute reductions in red cell precursors in the bone marrow, severely reduced reticulocytes in the peripheral blood, and an abrupt drop in hemoglobin level. Return to normal erythropoiesis usually occurs within two to 14 days. This transient aplastic crisis is typically caused by infection, with Parvovirus B19 being the most common etiologic agent in children. Individuals with a transient aplastic crisis are managed with transfusion. [/toggle]
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References:

  1. Glassberg J, Tanabe P, Richardson L, Debaun M. Among emergency physicians, use of the term “Sickler” is associated with negative attitudes toward people with sickle cell disease. Am J Hematol. 2013;88(6):532-3.
  2. Aisiku IP, Smith WR, Mcclish DK, et al. Comparisons of high versus low emergency department utilizers in sickle cell disease. Ann Emerg Med. 2009;53(5):587-93.
  3. Lovett PB, Sule HP, Lopez BL. Sickle Cell Disease in the Emergency Department. Hematol Oncol Clin North Am. 2017;31(6):1061-1079.
  4. Glassberg JA, Tanabe P, Chow A, et al. Emergency provider analgesic practices and attitudes toward patients with sickle cell disease. Ann Emerg Med. 2013;62(4):293-302.e10.

Episode 17 – The Spleen!

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The Free Open Access Medical Education (FOAM)

We review Dr. Scott Weingart’s episode 133 on pre-hospital REBOA (resuscitative endovascular balloon occlusion of the aorta). Weingart interviews Dr. Gareth Davies about the encounter, underscoring the increasing use of REBOA.

For a quick REBOA refresher, check out Episode 121.

REBOA (Review of REBOA) – First described in 1954 in the Korean War, this is a form of hemorrhage control below the level of the chest without having to do a thoracotomy with aortic cross clamping, which has sparse mortality benefit and can be dangerous to providers.  Most of the REBOA literature is from swine models and case-series, although there are currently larger trials underway.

  • Outline of procedure – Obtain arterial access through the common femoral artery, pass a vascular sheath, float a balloon catheter to the appropriate section of the aorta, and inflate the balloon to occlude blood flow. The aorta is divided into three zones so that balloon occlusion is performed in Zone 1 for abdominal injuries or Zone 3 for pelvic injuries, while Zone 2 is a proposed no-occlusion zone.

The Bread and Butter

Rosen’s Chapter 46, 134 and Tintinalli Chapter 260.

What DOES the spleen do?

Answer: More than most appreciate. The spleen filters the blood, removing abnormal or old red blood cells (RBCs), debris, and antibody coated bacteria from the bloodstream.  It also serves as a reservoir for RBCs and platelets and synthesizes antibodies, opsonins, etc.

Splenic Trauma – EAST Guidelines (their podcast)

Diagnosis – suspect spleen trauma clinically, with hypotension, left upper quadrant abdominal pain, or even minimal trauma, especially after infectious mononucleosis.

  • CT with IV contrast (hemodynamically stable patients).  While FAST and DPL can detect peritoneal free fluid, they can’t detect subcapsular bleeds.
  • Unstable patients – operating room versus interventional radiology

Grading – 1 is 1 (<1 cm laceration depth), 3 is 3 (>3 cm laceration depth). Everything else is somewhere in between.   Higher grades typically result in more aggressive interventions. Historically these get operative intervention

  • Grade 1: < 1 cm laceration depth or<10% subcapsular hematoma
  • Grade 2: 1-3 cm laceration or 10-50% subcapsular
  • Grade 3: > 3 cm laceration depth or >50% subcapsular hematoma
    • Grade 3 or higher should be considered for angiography with embolization (Level II, III – EAST)
  • Grade 4: partially devascularized spleen or contrast blush
  • Grade 5:  a very battered, devascularized spleen

There’s slightly more to spleen grading, check out this post from Dr. McGonigal

Trivia:  The punctate extravasation sometimes seen on angiogram after blunt trauma?

Answer: The Seurat Spleen (pubmed), named after the pointillist painter.

Treatment –

  • Unstable patients: Operating room or Angiographic Intervention (IR) (Level II – EAST)
    • Note: Board exam? Send the patient to the OR.  In reality, there is some practice variation. Many would still argue the patient belongs in the OR, some places have combined OR/IR suites, and some opt for IR.
    • Post splenectomy patients will need immunizations for the encapsulated bacteria
  • Stable patients: Nonoperative management, which often comprises in-hospital monitoring, serial abdominal exams and hematocrits, etc is becoming increasingly common as first line for higher grade splenic injuries.  The key here is that the team must be able to take the patient to the OR or IR should the situation change.  Angioembolization has also gained momentum as management

Post-Splenectomy Sepsis (Review)– Most common in the first years after splenectomy and in children.

Presentation – Patients may present with a vague flu-like illness or gastroenteritis but may go on to develop septic shock, DIC, and multiorgan dysfunction. In addition, meningitis without overwhelming infection or shock is a common presentation of pneumococcal infection in asplenic patients.

Etiology – encapsulated bacteria (Streptococcus pneumoniae, Haemophilus influenza, and Neisseria meningitidis), capnocytophaga canimorsus (dog bites), and parasites such as babesiosis (endemic in New England), malaria, and ehrlichiosis.

Management – Labs, blood cultures, antibiotics (typically ceftriaxone)

Splenic Sequestration – Second most common cause of death in kids with Sickle Cell Disease <5 years of age.

Classic presentation – LLL: LUQ, lethargy, lightness (pallor).

Labs: 3 point drop in hemoglobin, increased reticulocyte count, and thrombocytopenia.

Generously Donated Rosh Review Questions (Scroll for Answers)

Question 1.  [polldaddy poll=8376275]

Question 2.  A 23-year-old man presents with a stab wound to the abdomen. His vital signs are HR 132, BP 88/45. He has a positive FAST.[polldaddy poll=8376283]

 

References:

Chapter 46, 134. Rosen’s Emergency Medicine, 8e.

Chapter 260. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011

 

Answers.

1.  C.  Splenic artery aneurysms are the most common type of visceral arterial aneurysms, accounting for up to 60% of cases. Etiologies include arterial fibrodysplasia, portal hypertension, and increased splenic AV shunting in pregnancy. Clinical presentation is vague with left upper quadrant pain with radiation to the left shoulder or subscapular area. Most of the aneurysms are <2 cm in diameter; only 2% result in life-threatening rupture. Treatment is surgical resection if the patient is symptomatic. Otherwise, asymptomatic patients can undergo transcatheter embolization. Of those aneurysms that rupture, up to 95% occur in young pregnant women.

Hepatic artery aneurysms (A) represents 20% of visceral artery aneurysms and are caused by atherosclerosis, infection, and abdominal trauma. Clinical presentation can mimic cholecystitis. Inferior mesenteric artery aneurysms(B) are uncommon. Superior mesenteric artery aneurysms (D) are the 3rd-most common visceral aneurysms. IV drug abusers are at increased risk.

2. D. This patient presents with hemorrhagic shock from a penetrating abdominal trauma and should be immediately transferred to the operating room for an exploratory laparotomy. Stab wounds are the most common form of penetrating trauma. About 70% of anterior stab wounds penetrate the peritoneum. It is difficult to predict the specific organ injured based on the external location of the wound. Initial management should focus on securing the airway, assessing and supporting the patients breathing and circulation. IV access and supplemental oxygen should be provided. In hypotensive trauma patients, early blood transfusion should be initiated and consideration should be made for massive transfusion protocol. Concomitant with the primary and secondary survey, a Focused Assessment with Sonography for Trauma (FAST) exam should be performed. The speed and accuracy of the FAST has almost completely replaced the need for diagnostic peritoneal lavage. In a FAST exam, images are obtained of the splenorenal space, hepatorenal space (Morrison’s pouch), heart and bladder (pouch of Douglas). A FAST exam has high sensitivity in detecting as little as 100 ml of fluid. A FAST examination showing free fluid in any of the abdominal views in the presence of hypotension should lead to the patient being transported to the operating room for exploratory laparotomy according to the Advanced Trauma Life Support (ATLS) algorithm. Angiographic embolization (A) is useful in patients with pelvic fractures and bleeding from pelvic vessels. CT scan of the abdomen and pelvis (B) can be performed in trauma patients who are stable to further assess for injuries.Diagnostic peritoneal lavage (C) does not play a role in management of penetrating trauma patients with hypotension and positive FAST examination.