Free COMLEX Level 3 Questions
We understand that it’s all about the content. That’s why we have high-yield COMLEX Level 3 practice questions written and screened by OMM physicians that are updated on a regular basis to ensure our SmartBanks stay up-to-date with exam blueprint changes.
Our SmartBank is not a typical qbank. Our questions contain thorough answers and explanations to help improve your understanding of the material. We explain the correct answer, as well as why the others options were incorrect. They are designed to help prepare you for the COMLEX Level 3 exam and for your career.
Take a look at our free practice questions to see for yourself.
Your First Free COMLEX Level 3 Question
A 27-year-old female with a history of sickle cell anemia and chronic pain syndrome presents to the emergency department with worsening nausea, vomiting, and fatigue over the past few days associated with worsening joint aches, chest pain, and shortness of breath. She admits to thinking that she may have contracted influenza from her coworker, but she cannot confirm this. She says that a few days ago she felt otherwise well. She does not smoke, drink alcohol, or use illicit drugs. She is on morphine at home for chronic joint pain. She also takes hydroxyurea for her sickle cell disease. Vital signs reveal:
- Temperature: 39.3°C (102.7°F)
- Blood pressure: 142/84 mmHg
- Pulse rate: 118/min
- Respiratory rate: 24/min
- Initial oxygen saturation: 80% on room air
On examination, she appears distressed with increased work of breathing. You note rales at the left lung base. Her abdomen is soft. Her heart exam is unremarkable. A CT angiogram is performed and shows a left lower lobe consolidation without signs of pulmonary emboli. In the time necessary to obtain her workup, she has rapid deterioration of her clinical status and requires intubation. An influenza swab returns positive. You are able to get some basic laboratories back just as you are intubating her:
|Test||Patient’s Value||Reference Range|
|MCV||69 μm3||81-99 μm3|
|MCHC||22 g/dL||33-37 g/dL|
|Platelet count||135 × 103/μL||130-400 × 103/μL|
|Hemoglobin||7.2 g/dL||12.0-16.0 g/dL|
What is the most important treatment for this patient’s underlying condition?
- A) ceftriaxone and azithromycin
- B) exchange transfusion
- C) heparin infusion
- D) oseltamivir
- E) rapid fluid resuscitation
The Answer and Explanation
Did you get it right? The correct answer is ‘B’.
This patient with known sickle cell disease is presenting with fever, chest pain, shortness of breath, and a new radiographic infiltrate on her CT scan. In any patient with sickle cell disease, these findings together meet the criteria for acute chest syndrome (ACS). There are limited randomized trials for the treatment of acute chest syndrome. However, there is a general consensus that in severe cases (such as this one requiring intubation for rapidly progressive respiratory failure), patients should proceed to exchange transfusion with the goal of reducing the percentage of sickle hemoglobin to below 30%.
This is critical to improving blood flow, decreasing viscosity, and optimizing oxygen delivery to the tissues. This patient has a hemoglobin count of 7.2 g/dL, and simple transfusions would not suffice to radically change the percent of HgbS within any meaningful timeframe without markedly increasing her hemoglobin (likely near 14 g/dL before you were even close to reducing her HgbS < 30%). High hemoglobin is undesirable in the setting of sickle cell disease as the risk for increased blood viscosity and decreased organ perfusion increases with increasing hemoglobin concentrations.
The etiology of acute chest syndrome is not always clear but is felt to be secondary to vaso-occlusion within the pulmonary vasculature. Common causes include asthma, infection, hyperviscosity, hypoventilation (due to pain from rib infarcts or oversedation), pulmonary thrombi of sickle erythrocytes (usually in situ rather than emboli) or bone marrow, and fat emboli, which can be present in the circulation, due to sickle cell vaso-occlusive crisis and damage to bones, and leads to a vicious cycle.
Acute chest syndrome as a complication of sickle cell disease
Diagnostic criteria (note that pneumonia and ACS cannot be distinguished on the basis of these guidelines):
- Radiographic evidence of consolidation (at least 1 segment) and one of the following:
- Respiratory signs or symptoms (tachypnea, rales, wheezing, cough, chest pain, accessory muscle use, nasal flaring, or retractions)
- Hypoxemia or greater than 2% decrease in oxygen saturation from steady-state on room air
- Temperature ≥ 38.5°C (101.3°F)
- CBC with differential
- Reticulocyte count
- AP and lateral CXR
- Blood and sputum cultures
- CT angiogram and troponin can be considered depending on severity
- Fluids (usually D5/.45 to avoid hypernatremia)
- Transfusion strategy
- For mild ACS: simple transfusion and hydration
- For moderate ACS: consider simple or exchange transfusion depending on course (improving/worsening) and clinical judgment
- For severe ACS (patients requiring ICU, step-down management, or intubation): exchange transfusion*
*In patients with low hemoglobin < 5.0, simple transfusion can often be used with hydration, instead of exchange transfusion, as this will dilute the HgbS sufficiently to be nearly equal to an exchange transfusion.
Wrong Answer Explanations
Answer A: Ceftriaxone and azithromycin could be possible adjuncts to therapy while she was undergoing exchange transfusion if it was believed that this infiltrate was due to community-acquired pneumonia. Given that she has influenza, MRSA coverage with vancomycin should be started in addition to some kind of Gram-negative coverage. Pure community-acquired pneumonia coverage, in this case, would be inadequate. Either way, recognizing that exchange transfusion is urgently needed is more important in this patient and cannot be missed or delayed.
Answer C: There is no evidence of pulmonary embolus on her CT scan so a heparin drip is not necessary at this time. Additionally, many of the thrombi that form in sickle cell disease are in situ thrombi, and not actually emboli. These are not treated well by anticoagulation and may eventually organize.
Answer D: While this patient does have influenza and oseltamivir would be appropriate therapy, it will not treat the more urgent issue of acute chest syndrome. Additionally, this medication will only shorten her course of symptoms and does not have a significant impact on mortality, although it is generally used in all hospitalized patients.
Answer E: This is an important step to help decrease blood viscosity but would not treat her underlying acute chest syndrome. She is neither hypotensive nor in shock so it cannot be argued that fluid is urgently necessary or the “most important” treatment for her infection. She needs an urgent exchange transfusion. Fluid administration is an important step in the treatment of a general sickle cell crisis, but not the life-saving as exchange transfusion may be.
Bottom Line: Acute chest syndrome is a life-threatening complication of sickle cell anemia that is diagnosed when a patient presents with a new radiographic density on chest imaging with associated new fever and/or respiratory symptoms. This requires urgent evaluation for consideration of simple or exchange transfusion, depending on severity.
All patients with acute chest syndrome will get antibiotic therapy, and many people may assume that this is a correct answer. However, the Comprehensive Osteopathic Medical Licensing Examination (COMLEX) will often have multiple “nearly” correct answers to a question. Your job is to pick the best answer. In this case, recognizing that an exchange transfusion is urgently needed is the most important part of this question rather than just assuming that this patient has pneumonia and starting antibiotics.
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