{"id":5017,"date":"2024-12-11T15:31:00","date_gmt":"2024-12-11T23:31:00","guid":{"rendered":"https:\/\/www.osmosis.org\/blog\/?p=5017"},"modified":"2025-10-01T11:38:24","modified_gmt":"2025-10-01T19:38:24","slug":"usmle-step-2-question-of-the-day-serum-potassium","status":"publish","type":"post","link":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium","title":{"rendered":"USMLE\u00ae Step 2 Question of the Day: Serum potassium"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_80 ez-toc-wrap-center counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">In This Article<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\/#The_correct_answer_to_todays_USMLE%C2%AE_Step_2_CK_Question_is%E2%80%A6\" >The correct answer to today&#8217;s USMLE\u00ae Step 2 CK Question is&#8230;<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\/#Incorrect_Answer_Explanations\" >Incorrect Answer Explanations<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\/#Main_Explanation\" >Main Explanation<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\/#Major_Takeaway\" >Major Takeaway<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\/#References\" >References<\/a><\/li><\/ul><\/nav><\/div>\n\n<p class=\"wp-block-paragraph\"><strong><em>Prepare for your USMLE Step 2 CK with a question focusing on hypokalemia in adults. Can you formulate and prioritize a differential diagnosis for a patient presenting with hypokalemia, and identify the additional tests needed to confirm your diagnoses? Enhance your clinical reasoning skills with this important assessment.&nbsp;<\/em><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A 26-year-old man presents to the emergency department for evaluation of sudden-onset weakness that started two hours ago. The patient has experienced two similar episodes that each resolved within one hour. However, today, the patient was unable to get out of bed and continued to be weak for 2 1\/2 hours, prompting the patient to call an ambulance. The patient has experienced about six months of heat intolerance, palpitations, anxiety, and weight loss. On physical examination, the patient is noted to be thin and diaphoretic. The patient is alert and oriented and appears anxious. The patient\u2019s skin is warm to the touch, and the patient has thinning hair. There is flaccid paralysis of the lower extremities as well as decreased strength in the proximal arms. Distal arm strength is normal without fatigability. Reflexes are diminished throughout. Laboratory studies are notable for a serum potassium of 2.1 mEq\/L. Which of the following laboratory results would be consistent with the underlying diagnosis?&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>A. Low TSH and high T4<br><br>B. Low magnesium<br><br>C. Elevated urine potassium-to-creatinine ratio<br><br>D. Positive acetylcholine receptor antibodies<br><br>E. Elevated creatine kinase<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Scroll down for the correct answer!<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"The_correct_answer_to_todays_USMLE%C2%AE_Step_2_CK_Question_is%E2%80%A6\"><\/span>The correct answer to today&#8217;s USMLE\u00ae Step 2 CK Question is&#8230;<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>A. Low TSH and high T4<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Before we get to the&nbsp;<strong>Main Explanation<\/strong>, let&#8217;s see why the answer wasn&#8217;t B, C, D, or E. Skip to the bottom if you want to see the correct answer right away!<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Incorrect_Answer_Explanations\"><\/span>Incorrect Answer Explanations<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>B. Low magnesium<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Incorrect:<\/strong>&nbsp;Hypomagnesemia can cause hypokalemia. However, severe hypomagnesemia is typically associated with seizures, tetany, and hyperreflexia. This patient is not exhibiting these but has evidence of thyrotoxicosis.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>C. Elevated urine potassium-to-creatinine ratio&nbsp;<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Incorrect:<\/strong>&nbsp;An elevated urine potassium-to-creatinine ratio would be seen in renal potassium wasting syndromes. This patient\u2019s signs and symptoms are more concerning for thyrotoxic periodic paralysis.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;<strong>D. Positive acetylcholine receptor antibodies&nbsp;<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Incorrect:<\/strong>&nbsp;Anti-acetylcholine receptor antibodies are seen with myasthenia gravis, which can also cause proximal limb weakness. However, this patient did not demonstrate typical muscle fatigability during the examination.&nbsp;&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>E. Elevated creatine kinase&nbsp;<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Incorrect:<\/strong>&nbsp;Rhabdomyolysis can result in muscle weakness but more commonly results in muscle pain. Additionally, it is more often associated with hyperkalemia rather than hypokalemia.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Main_Explanation\"><\/span>Main Explanation<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This patient is experiencing&nbsp;leg paralysis and proximal arm weakness&nbsp;in association with&nbsp;severe hypokalemia.&nbsp;Additionally, the patient has had several months of symptoms consistent with&nbsp;hyperthyroidism&nbsp;(e.g. heat intolerance, palpitations, weight loss). The patient has evidence of muscle weakness and thyrotoxicosis on examination. Thus,&nbsp;thyrotoxic periodic paralysis&nbsp;is the most likely diagnosis. This would be associated with a&nbsp;low TSH and elevated T4.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">There are many potential causes of hypokalemia. Often, this can be elicited from the history and presentation (e.g., decreased potassium intake, recent GI illness, diuretic use). If the cause is not obvious, additional workup can be obtained. This should start with obtaining a&nbsp;serum magnesium&nbsp;level to rule out hypomagnesemia. From there, patients should be evaluated for potential causes of&nbsp;transcellular potassium shifts.&nbsp;This should include reviewing medications (e.g., theophylline, beta-agonists, insulin) and evaluating for conditions like hyperthyroidism, which may be accompanied by symptoms (e.g., heat intolerance, palpitations) and a low TSH.&nbsp;&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Periodic paralysis (PP) is a muscle disease where patients experience episodes of muscle weakness that can last from hours to days. When patients are also hypokalemic during these episodes of muscle weakness and are found to have symptoms and evidence of thyrotoxicosis, then&nbsp;thyrotoxic periodic paralysis&nbsp;can be diagnosed.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If these causes are ruled out, the next step is to obtain urine studies in order to calculate a&nbsp;urine potassium-to-creatinine ratio.&nbsp;If this ratio is&nbsp;\u2264 1.5, extrarenal potassium wasting&nbsp;is most etiology, which can be caused by laxative overuse, other causes of severe diarrhea, or excessive sweating.&nbsp;If the ratio is&nbsp;&gt; 1.5, then a condition causing renal potassium wasting&nbsp;is likely. In patients with hypertension or evidence of hypervolemia, consider diseases affecting mineralocorticoid activity, such as Cushing syndrome, hyperaldosteronism, and congenital adrenal hyperplasia. If no cause is found, the next step is to check the patient\u2019s acid-base status. Metabolic acidosis is associated with renal tubular acidosis and acetazolamide use. Metabolic alkalosis is associated with Bartter and Gitelman syndrome as well as diuretics.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/osmose-it.s3.amazonaws.com\/S8vyHi5pQrGaW94Fd3mVAnO6TsK2ZqJr\/_.png\" alt=\"Hypokalemia due to Potassium Transcellular Shift\n- Can occur in several other conditions\n- Exercise, low carb meals, stress\n- Temporary muscle weakness or paralysis\n- Familial hypokalemic periodic paralysis (FHPP)\n- Life-threatening paralysis\n- Thyrotoxic periodic paralysis\"\/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Major_Takeaway\"><\/span>Major Takeaway<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">When evaluating a patient with hypokalemia, consider additional workup based on the history and physical examination. Thyroid studies should be performed in patients where no cause can be identified and in patients with symptoms suggestive of hyperthyroidism (e.g. heat intolerance, palpitations, weight loss).&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"References\"><\/span>References<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Lulsegged, A., Wlodek, C., and Rossi, M. (2011). Thyrotoxic periodic paralysis: Case reports and an up-to-date review of the literature. Case Reports in Endocrinology.&nbsp;<a href=\"https:\/\/www.hindawi.com\/journals\/crie\/2011\/867475\/\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/www.hindawi.com\/journals\/crie\/2011\/867475\/<\/a>&nbsp;<\/li>\n\n\n\n<li>Idham, M., and Prajitno, J.H. (2022). Management of hypokalemia in patients with thyrotoxicosis periodic paralysis in Soetomo general hospital: A case report. Annals of Medicine and Surgery, 84.&nbsp;<a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S2049080122016855\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/www.sciencedirect.com\/science\/article\/pii\/S2049080122016855<\/a>&nbsp;<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\"><em><strong>Want more &nbsp;USMLE\u00ae Step 2 CK practice questions?&nbsp;<\/strong><\/em><em><strong>Try Osmosis by Elsevier today! Access your&nbsp;<a href=\"https:\/\/www.osmosis.org\/login?type=create\" target=\"_blank\" rel=\"noreferrer noopener\">free trial<\/a>&nbsp;and find out why millions of current and future clinicians and caregivers love learning with us.<\/strong><\/em><\/p>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"https:\/\/osmosis.org\/create\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" src=\"https:\/\/osmose-it.s3.amazonaws.com\/QAjRxrSTSrWqy8myI-vHEEFMS9uGh5l7\/_.png\" alt=\"\"\/><\/a><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Prepare for your USMLE Step 2 CK with a question focusing on hypokalemia in adults. Can you formulate and prioritize a differential diagnosis for a patient presenting with hypokalemia, and identify the additional tests needed to confirm your diagnoses? Enhance your clinical reasoning skills with this important assessment.&nbsp; A 26-year-old man presents to the emergency [&hellip;]<\/p>\n","protected":false},"author":202,"featured_media":5018,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[27,5,10,16,1370,45],"tags":[],"class_list":["post-5017","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-medicine","category-clerkships","category-clinical-skills","category-do","category-step-2-questions","category-step-2"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v23.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>USMLE\u00ae Step 2 Question of the Day: Serum potassium - Osmosis Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"USMLE\u00ae Step 2 Question of the Day: Serum potassium - Osmosis Blog\" \/>\n<meta property=\"og:description\" content=\"Prepare for your USMLE Step 2 CK with a question focusing on hypokalemia in adults. Can you formulate and prioritize a differential diagnosis for a patient presenting with hypokalemia, and identify the additional tests needed to confirm your diagnoses? Enhance your clinical reasoning skills with this important assessment.&nbsp; A 26-year-old man presents to the emergency [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\" \/>\n<meta property=\"og:site_name\" content=\"Osmosis Blog\" \/>\n<meta property=\"article:published_time\" content=\"2024-12-11T23:31:00+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-01T19:38:24+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1080\" \/>\n\t<meta property=\"og:image:height\" content=\"1080\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Marina Horiates Kerekes, MD &amp; Team\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":[\"Article\",\"BlogPosting\"],\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\"},\"author\":{\"name\":\"Marina Horiates Kerekes, MD &amp; Team\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/#\/schema\/person\/c7e60a94ecf3ec6e6cfe4855957afafc\"},\"headline\":\"USMLE\u00ae Step 2 Question of the Day: Serum potassium\",\"datePublished\":\"2024-12-11T23:31:00+00:00\",\"dateModified\":\"2025-10-01T19:38:24+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\"},\"wordCount\":948,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/#organization\"},\"image\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg\",\"articleSection\":[\"Allopathic Medicine (MD)\",\"Clerkships\",\"Clinical Skills\",\"Osteopathic Medicine (DO)\",\"USMLE Step 2\",\"USMLE\u00ae Step 2\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\",\"url\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\",\"name\":\"USMLE\u00ae Step 2 Question of the Day: Serum potassium - Osmosis Blog\",\"isPartOf\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg\",\"datePublished\":\"2024-12-11T23:31:00+00:00\",\"dateModified\":\"2025-10-01T19:38:24+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage\",\"url\":\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg\",\"contentUrl\":\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg\",\"width\":1080,\"height\":1080},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.osmosis.org\/blog\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"USMLE\u00ae Step 2 Question of the Day: Serum potassium\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/#website\",\"url\":\"https:\/\/www.osmosis.org\/blog\/\",\"name\":\"Osmosis Blog\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.osmosis.org\/blog\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/#organization\",\"name\":\"Osmosis Blog\",\"url\":\"https:\/\/www.osmosis.org\/blog\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/07\/OsmosisElsevierStacked.png\",\"contentUrl\":\"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/07\/OsmosisElsevierStacked.png\",\"width\":1276,\"height\":596,\"caption\":\"Osmosis Blog\"},\"image\":{\"@id\":\"https:\/\/www.osmosis.org\/blog\/#\/schema\/logo\/image\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/#\/schema\/person\/c7e60a94ecf3ec6e6cfe4855957afafc\",\"name\":\"Marina Horiates Kerekes, MD &amp; Team\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.osmosis.org\/blog\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/c4eaddbf095676223204097f8973e0eed2b2b435a8c32f8f6b8c06da77819aa6?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/c4eaddbf095676223204097f8973e0eed2b2b435a8c32f8f6b8c06da77819aa6?s=96&d=mm&r=g\",\"caption\":\"Marina Horiates Kerekes, MD &amp; Team\"},\"description\":\"Authors: Marina Horiates Kerekes, MD &amp; Osmosis Question Writing Team\",\"url\":\"https:\/\/www.osmosis.org\/blog\/author\/marinahoriateskerekesandteam\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"USMLE\u00ae Step 2 Question of the Day: Serum potassium - Osmosis Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium","og_locale":"en_US","og_type":"article","og_title":"USMLE\u00ae Step 2 Question of the Day: Serum potassium - Osmosis Blog","og_description":"Prepare for your USMLE Step 2 CK with a question focusing on hypokalemia in adults. Can you formulate and prioritize a differential diagnosis for a patient presenting with hypokalemia, and identify the additional tests needed to confirm your diagnoses? Enhance your clinical reasoning skills with this important assessment.&nbsp; A 26-year-old man presents to the emergency [&hellip;]","og_url":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium","og_site_name":"Osmosis Blog","article_published_time":"2024-12-11T23:31:00+00:00","article_modified_time":"2025-10-01T19:38:24+00:00","og_image":[{"width":1080,"height":1080,"url":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg","type":"image\/jpeg"}],"author":"Marina Horiates Kerekes, MD &amp; Team","twitter_card":"summary_large_image","schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":["Article","BlogPosting"],"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#article","isPartOf":{"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium"},"author":{"name":"Marina Horiates Kerekes, MD &amp; Team","@id":"https:\/\/www.osmosis.org\/blog\/#\/schema\/person\/c7e60a94ecf3ec6e6cfe4855957afafc"},"headline":"USMLE\u00ae Step 2 Question of the Day: Serum potassium","datePublished":"2024-12-11T23:31:00+00:00","dateModified":"2025-10-01T19:38:24+00:00","mainEntityOfPage":{"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium"},"wordCount":948,"commentCount":0,"publisher":{"@id":"https:\/\/www.osmosis.org\/blog\/#organization"},"image":{"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage"},"thumbnailUrl":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg","articleSection":["Allopathic Medicine (MD)","Clerkships","Clinical Skills","Osteopathic Medicine (DO)","USMLE Step 2","USMLE\u00ae Step 2"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium","url":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium","name":"USMLE\u00ae Step 2 Question of the Day: Serum potassium - Osmosis Blog","isPartOf":{"@id":"https:\/\/www.osmosis.org\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage"},"image":{"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage"},"thumbnailUrl":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg","datePublished":"2024-12-11T23:31:00+00:00","dateModified":"2025-10-01T19:38:24+00:00","breadcrumb":{"@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#primaryimage","url":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg","contentUrl":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg","width":1080,"height":1080},{"@type":"BreadcrumbList","@id":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-question-of-the-day-serum-potassium#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.osmosis.org\/blog"},{"@type":"ListItem","position":2,"name":"USMLE\u00ae Step 2 Question of the Day: Serum potassium"}]},{"@type":"WebSite","@id":"https:\/\/www.osmosis.org\/blog\/#website","url":"https:\/\/www.osmosis.org\/blog\/","name":"Osmosis Blog","description":"","publisher":{"@id":"https:\/\/www.osmosis.org\/blog\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.osmosis.org\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/www.osmosis.org\/blog\/#organization","name":"Osmosis Blog","url":"https:\/\/www.osmosis.org\/blog\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.osmosis.org\/blog\/#\/schema\/logo\/image\/","url":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/07\/OsmosisElsevierStacked.png","contentUrl":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/07\/OsmosisElsevierStacked.png","width":1276,"height":596,"caption":"Osmosis Blog"},"image":{"@id":"https:\/\/www.osmosis.org\/blog\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/www.osmosis.org\/blog\/#\/schema\/person\/c7e60a94ecf3ec6e6cfe4855957afafc","name":"Marina Horiates Kerekes, MD &amp; Team","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.osmosis.org\/blog\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/c4eaddbf095676223204097f8973e0eed2b2b435a8c32f8f6b8c06da77819aa6?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/c4eaddbf095676223204097f8973e0eed2b2b435a8c32f8f6b8c06da77819aa6?s=96&d=mm&r=g","caption":"Marina Horiates Kerekes, MD &amp; Team"},"description":"Authors: Marina Horiates Kerekes, MD &amp; Osmosis Question Writing Team","url":"https:\/\/www.osmosis.org\/blog\/author\/marinahoriateskerekesandteam"}]}},"jetpack_featured_media_url":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/12\/Step_2_CK_QOTD_Q4_2024_JTD_3.jpg","jetpack-related-posts":[{"id":648,"url":"https:\/\/www.osmosis.org\/blog\/usmle-step-1-question-of-the-day-frequent-urination-diagnosis","url_meta":{"origin":5017,"position":0},"title":"USMLE\u00ae Step 1 Question of the Day: Frequent Urination Diagnosis","author":"Marina Horiates Kerekes, MD &amp; Team","date":"January 13, 2021","format":false,"excerpt":"Each week, Osmosis shares a USMLE\u00ae Step 1-style practice question to test your knowledge of medical topics. Today's case involves a young boy whose worsening issues with thirst and frequent urination are worrying his parents. Can you make the correct diagnosis and help this family out? An 8-year-old boy is\u2026","rel":"","context":"In &quot;Allopathic Medicine (MD)&quot;","block_context":{"text":"Allopathic Medicine (MD)","link":"https:\/\/www.osmosis.org\/blog\/category\/medicine"},"img":{"alt_text":"USMLE\u00ae Step 1 Question of the Day: Frequent Urination Diagnosis","src":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/25.webp","width":350,"height":200,"srcset":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/25.webp 1x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/25.webp 1.5x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/25.webp 2x"},"classes":[]},{"id":1599,"url":"https:\/\/www.osmosis.org\/blog\/usmle-step-1-question-of-the-day-severe-lower-extremity-cramping","url_meta":{"origin":5017,"position":1},"title":"USMLE\u00ae Step 1 Question of the Day: Severe Lower-Extremity Cramping","author":"Marina Horiates Kerekes, MD &amp; Team","date":"April 13, 2022","format":false,"excerpt":"This week, we are sharing another USMLE\u00ae Step 1-style practice question to test your knowledge of medical topics.\u00a0Today's case focuses on a 52-year-old man with severe lower-extremity cramping. The cramping appeared after recent thyroid surgery.\u00a0Can you figure it out? A 52-year-old man comes to the emergency room because of severe\u2026","rel":"","context":"In &quot;Allopathic Medicine (MD)&quot;","block_context":{"text":"Allopathic Medicine (MD)","link":"https:\/\/www.osmosis.org\/blog\/category\/medicine"},"img":{"alt_text":"","src":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/severe-lowerextremity-cramping.webp","width":350,"height":200,"srcset":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/severe-lowerextremity-cramping.webp 1x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/severe-lowerextremity-cramping.webp 1.5x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/severe-lowerextremity-cramping.webp 2x"},"classes":[]},{"id":3769,"url":"https:\/\/www.osmosis.org\/blog\/usmle-step-1-question-tea-colored-diarrhea","url_meta":{"origin":5017,"position":2},"title":"USMLE\u00ae Step 1 Question: Tea-Colored Diarrhea","author":"Marina Horiates Kerekes, MD &amp; Team","date":"March 17, 2021","format":false,"excerpt":"Each week, Osmosis shares a USMLE\u00ae Step 1-style practice question to test your knowledge of medical topics. Today's case involves a 34-year-old woman with tea-colored diarrhea for the last 2 months. She experiences muscle cramps and feels weak.\u00a0Can you figure it out? A 34-year-old woman comes to the office complaining\u2026","rel":"","context":"In &quot;Allopathic Medicine (MD)&quot;","block_context":{"text":"Allopathic Medicine (MD)","link":"https:\/\/www.osmosis.org\/blog\/category\/medicine"},"img":{"alt_text":"USMLE\u00ae Step 1 Question: Tea-Colored Diarrhea","src":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/2024-09-19T130650.394.webp","width":350,"height":200,"srcset":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/2024-09-19T130650.394.webp 1x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/2024-09-19T130650.394.webp 1.5x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/2024-09-19T130650.394.webp 2x"},"classes":[]},{"id":681,"url":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-ck-question-of-the-day-second-degree-mobitz-type-ii-av-block","url_meta":{"origin":5017,"position":3},"title":"USMLE\u00ae Step 2 CK Question of the Day: Second Degree Mobitz type II AV block","author":"Marina Horiates Kerekes, MD &amp; Team","date":"May 4, 2022","format":false,"excerpt":"Enhance your USMLE\u00ae Step 2 CK exam prep with this clinical case involving a 66-year-old woman with left-sided weakness and symptoms suggestive of cardiac issues. Test your clinical knowledge and improve your diagnostic skills for effective patient care!","rel":"","context":"In &quot;Allopathic Medicine (MD)&quot;","block_context":{"text":"Allopathic Medicine (MD)","link":"https:\/\/www.osmosis.org\/blog\/category\/medicine"},"img":{"alt_text":"USMLE Step 2 CK Question of the Day Second Degree Mobitz type II AV block","src":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/31.webp","width":350,"height":200,"srcset":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/31.webp 1x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/31.webp 1.5x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2024\/09\/31.webp 2x"},"classes":[]},{"id":10157,"url":"https:\/\/www.osmosis.org\/blog\/usmle-step-2-ck-question-of-the-day-withdrawal-symptoms","url_meta":{"origin":5017,"position":4},"title":"USMLE\u00ae Step 2 CK Question of the Day:\u00a0Withdrawal symptoms","author":"Rowan Bell, MD","date":"June 8, 2026","format":false,"excerpt":"A young woman presents with anxiety and tremors after binge drinking. Can you determine the appropriate next step in managing this common but nuanced clinical scenario?","rel":"","context":"In &quot;Allopathic Medicine (MD)&quot;","block_context":{"text":"Allopathic Medicine (MD)","link":"https:\/\/www.osmosis.org\/blog\/category\/medicine"},"img":{"alt_text":"USMLE\u00ae Step 2 CK Question of the Day:\u00a0Withdrawal symptoms","src":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2026\/06\/Withdrawal_symptoms_Blog.png","width":350,"height":200,"srcset":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2026\/06\/Withdrawal_symptoms_Blog.png 1x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2026\/06\/Withdrawal_symptoms_Blog.png 1.5x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2026\/06\/Withdrawal_symptoms_Blog.png 2x"},"classes":[]},{"id":5864,"url":"https:\/\/www.osmosis.org\/blog\/usmle-step-1-question-of-the-day-left-knee-injury","url_meta":{"origin":5017,"position":5},"title":"USMLE\u00ae Step 1 Question of the Day:\u00a0Left knee injury","author":"Marina Horiates Kerekes, MD &amp; Team","date":"April 2, 2025","format":false,"excerpt":"Prep for the USMLE\u00ae Step 1 exam by exploring a clinical case involving a 21-year-old man with a left knee injury. Learn to identify the most appropriate physical examination maneuver. Strengthen your clinical assessment skills!","rel":"","context":"In &quot;Allopathic Medicine (MD)&quot;","block_context":{"text":"Allopathic Medicine (MD)","link":"https:\/\/www.osmosis.org\/blog\/category\/medicine"},"img":{"alt_text":"USMLE Step 1 Question of the Day Left knee injury","src":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2025\/04\/Left_knee_injury-2.jpg","width":350,"height":200,"srcset":"https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2025\/04\/Left_knee_injury-2.jpg 1x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2025\/04\/Left_knee_injury-2.jpg 1.5x, https:\/\/www.osmosis.org\/blog\/wp-content\/uploads\/sites\/2\/2025\/04\/Left_knee_injury-2.jpg 2x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/posts\/5017","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/users\/202"}],"replies":[{"embeddable":true,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/comments?post=5017"}],"version-history":[{"count":2,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/posts\/5017\/revisions"}],"predecessor-version":[{"id":7155,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/posts\/5017\/revisions\/7155"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/media\/5018"}],"wp:attachment":[{"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/media?parent=5017"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/categories?post=5017"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.osmosis.org\/blog\/wp-json\/wp\/v2\/tags?post=5017"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}