Medical Emergencies Study Guide for the CEN

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General Information

It is not one of the four most tested areas on the CEN, but questions about medical emergencies do occupy about 9% of the exam. Since this field covers virtually all body systems, there is a lot to study.

Allergic Reactions and Anaphylaxis

Allergic reactions occur when the patient’s immune system overreacts to a foreign substance, usually after repeated exposure, but sometimes after the first contact with the substance. The severity of allergies can range from a mild rash or nasal congestion to anaphylaxis, a severe, life-threatening reaction. The patient becomes hypotensive; develops tachycardia; has swelling in their mouth, tongue, lips, airway, face, or extremities; becomes confused; develops shortness of breath or wheezing; and sometimes has nausea or vomiting. Some of the most common allergens include food, medications, stinging insects, and environmental allergies.

Assessment

Immediately assess the patient’s airway, breathing, and circulation. Carefully note any signs of shortness of breath, wheezing, or difficulty in speaking. Watch for generalized rashes, hives, or complaints of lip or tongue tingling. Swelling in the face, neck, eyelids, lips, or tongue can indicate an impending airway obstruction. Their oxygen saturation and heart rate should be monitored continuously and their blood pressure should be taken regularly. Mild chronic allergies in response to allergens such as pollen can present with clear nasal drainage or congestion, post-nasal drip, sneezes, a chronic cough, itchy eyes, and sinus pressure.

Treatment

The first intervention is to remove the allergen from the patient’s location if possible. An anaphylactic reaction should be treated immediately with epinephrine administered intramuscularly or intravenously if the patient has IV access established. Remember the phrase “blue to the sky, orange to the thigh” when administering an EpiPen. Assist the patient’s oxygenation if necessary with an appropriate respiratory device like a nasal cannula or face mask. An albuterol or DuoNeb (ipratropium/albuterol combination) breathing treatment can help to relieve shortness of breath and airway stenosis. A patient with severe anaphylaxis may require emergent intubation if their airway is going to close. Fluid boluses will be administered to treat hypotension. Methylprednisolone (solumedrol) is a corticosteroid considered a second-line treatment to manage delayed or biphasic anaphylactic reactions (those that recur less than 72 hours later without reexposure to the initial trigger).

In the long term,avoidance and antihistamines can help to control most allergy symptoms. Various nasal sprays are also available to treat nasal congestion. Immunotherapy (allergy injections) can be used to desensitize the patient to a number of different allergens over time. A patient with a history of anaphylaxis should always carry an EpiPen with them.

Hematologic Disorders

Hematologic disorders are bleeding or clotting disorders that are acquired (due to circumstances such as immobilization or surgery) or hereditary. They must be treated immediately to prevent severe injury to the patient or even death. A deep vein thrombosis (DVT) can lead to a pulmonary embolism or have a clot break off that can travel to the heart or brain. Bleeding disorders can lead to severe hemorrhages during surgery or after even a relatively minor trauma.

Clotting disorders that you may encounter include Factor V Leiden deficiency, a prothrombin gene mutation, antithrombin deficiency, and antiphospholipid syndrome. Bleeding disorders include hemophilia, von Willebrand disease, disseminated intravascular coagulation (DIC), and platelet disorders like heparin-induced thrombocytopenia (HIT). In sickle cell anemia, abnormally shaped hemoglobin molecules cause red blood cells to become stiff and crescent shaped, limiting their ability to carry oxygen and obstructing blood flow.

Assessment

Symptoms of bleeding disorders include prolonged bleeding from cuts and surgical sites, bruising easily, heavy menstrual cycles, nosebleeds, and unexplained blood in the urine or stool.

Symptoms of clotting disorders vary depending on the location of the clot. A DVT causes leg swelling, pain, warmth, redness, and tenderness. A pulmonary embolism presents with shortness of breath, chest pain, hemoptysis, and dizziness. A clot that travels to the heart or brain will present with symptoms of a myocardial infarction or stroke, respectively. Petechiae (bleeding under the skin) can be seen in both HIT and DIC. Symptoms of sickle cell anemia include anemia, joint pain, frequent infections, and pain crises.

There are a number of lab tests that can be used to diagnose clotting disorders:

  • A complete blood count will provide valuable information about the patient’s red and white blood cell counts and platelet levels.

  • A PT (Prothrombin time) and PTT (Partial thromboplastin time) measure clotting times.

  • A platelet aggregation test measures how well platelets clump together at the site of an injury.

  • A D-dimer test measures a protein fragment released when blood clots break down.

  • Genetic testing for disorders such as Factor V Leiden deficiency or von Willebrand disease may be indicated.

  • A blood smear to evaluate the shapes of red blood cells under the microscope to check for disease like sickle cell anemia might be necessary.

Treatment

A bleeding disorder is treated with antifibrinolytic agents such as tranexamic acid, desmopressin (DDAVP), specific monoclonal antibodies to replace missing factors in forming blood clots, administering fresh frozen plasma or platelets during invasive procedures (depending on the cause of the bleeding), and vitamin K (in the case of a deficiency or to reverse warfarin). Lifestyle changes such as avoiding high-impact sports and taking precautions to avoid falling are also helpful.

A clotting disorder is managed acutely or in the surgical setting through anticoagulation medications that include heparin (administered intravenously or subcutaneously), enoxaparin sodium (administered subcutaneously), or argatroban (rarely used, usually if the patient has a heparin allergy or history of HIT). Long term, a patient with a clotting disorder will usually receive an oral anticoagulant such as warfarin, Eliquis (apixaban), Xarelto (rivaroxaban), Pradaxa (dabigatran), Plavix (clopidogrel), and Brillinta (ticagrelor), which is usually used to treat ischemic stroke, coronary artery disease, and acute coronary syndrome. The specific anticoagulant depends in large part on the patient’s insurance and how often the patient is able to have lab work done.

If a patient has been diagnosed with heparin-induced thrombocytopenia, the heparin should be immediately stopped; the patient will likely need to be started on another anticoagulant, usually argatroban, to prevent further thromboses.

Physical interventions such as TED hose, sequential compression devices, and early and frequent ambulation also help to reduce the incidence of blood clots. Sickle cell anemia is treated with hydroxyurea, pain relievers, and antibiotics. In some cases, newer gene therapies like xagamglogene autotemcel (Casgevy) and lovotibeglogene automecel (Lyfgenia) are available, which treat the genetic defect that causes sickle cell anemia.

Electrolyte and Fluid Imbalance

Fluid and electrolyte imbalances occur when a patient’s fluid and electrolyte levels like potassium, magnesium, sodium, and calcium are too high or too low. These imbalances can cause life-threatening cardiac arrhythmias, pulmonary and peripheral edema, seizures and acute organ injury. This can happen due to medication side effects, organ dysfunction like renal failure and congestive heart failure or hyperparathyroidism, and uncontrolled output like vomiting, diarrhea or a bowel preparation for a colonoscopy or other bowel procedure.

Assessment

Here is a rundown of symptoms listed by the type of imbalance:

  • fluid overload—swelling, shortness of breath, rapid weight gain, elevated blood pressure, nausea, vomiting, and headache

  • dehydration—hypotension, concentrated urine, dry mucous membranes, and acute kidney injury

  • hyponatremia (low sodium)—headache, seizures, fatigue, weakness, muscle cramping, confusion, drowsiness, and irritability

  • hypernatremia (elevated sodium)—extreme thirst, lethargy, seizures, muscle twitching, nausea/vomiting, hypertension, and eventually lapsing into a coma

  • hypokalemia (low potassium)—muscle cramping, weakness, cardiac arrhythmias, confusion, frequent urination, and nausea/vomiting. ECG changes include a peaked P-wave, prolonged PR interval, ST depression, shallow T-wave, and prominent U-wave.

  • hyperkalemia—muscle weakness, numbness and tingling, chest pain, cardiac arrhythmias, nausea, bradycardia, and cardiac arrest in severe cases. ECG changes include a peaked T-wave, flattened P-wave, prolonged PR interval, ST depression, and prolonged QRS interval.

  • hypocalcemia—numbness and tingling in the hands/feet and around the mouth, Chovstek’s sign (cheek twitches when facial nerve is tapped), irritability, anxiety, confusion, seizures, muscle weakness and twitching, cardiac arrhythmia, and hypotension

  • hypercalcemia—increased thirst, frequent urination, muscle cramping and weakness, bone pain, fatigue, confusion, hypertension, and cardiac arrhythmias

Serum electrolyte levels will be used to identify any abnormalities in the patient’s electrolytes. Diagnostic imaging such as a chest X-ray will be used to diagnose pulmonary edema. A chest CT offers more detailed imaging. An echocardiogram offers valuable information about the patient’s cardiac functionality, cardiac output, and any underlying abnormalities in the cardiac structure or valves that might lead to pulmonary edema. Normal lab values are as follows:

  • sodium (Na)—135 to 145 mEq/L
  • potassium (K)—3.5 to 5.2 mEq/L
  • magnesium (Mg)—1.3 to 2.1 mg/dL
  • calcium (Ca)—8.5 mg to 10.2 mg/dL

Treatment

The treatment depends on the cause of the electrolyte or fluid imbalance. Fluid overload will be treated with **diuretics (intravenous or oral), fluid restriction, very judicious use of intravenous fluids if the overload is due to an acute kidney injury (to help the kidneys recover), and dialysis if the patient is in end stage renal failure. Dehydration will be treated with fluid replacement, both intravenous and oral. Low electrolytes will be replaced, either in an intravenous or oral form, depending on the patient’s other underlying conditions and the severity of their deficit. The treatment for elevated electrolyte levels is as follows:

  • hypernatremia—fluid replacement, diuretics, desmopressin or mannitol, dietary modifications

  • hypermagnesemia—intravenous calcium gluconate, diuretics, stopping supplements containing magnesium dialysis in severe cases

  • hyperkalemia—intravenous calcium gluconate, intravenous insulin with glucose, albuterol nebulizer, Kayexalate, dialysis in severe cases

  • hypercalcemia—intravenous fluids, calcitonin, bisphosphonates, treatment of underlying cause (e.g., removing parathyroid glands or treating cancer), dialysis in severe cases

Endocrine Disorders

The endocrine system encompasses many organs that produce hormones integral to metabolism, growth, and sexual development. In endocrine disorders, these important organs malfunction, producing too little or too much of their respective hormones. Types of endocrine disorders include hypo- and hyperthyroidism (Graves’ disease), diabetes (both type 1 and type 2), Cushing syndrome, Addison’s disease (chronic adrenal insufficiency), acute adrenal crisis, hypo- and hyperparathyroidism, diabetes insipidus, pheochromocytoma (adrenal gland tumor), and syndrome of inappropriate secretion of antidiuretic hormone. Emergency situations caused by these conditions include hypoglycemia, myxedema coma (from extreme hypothyroidism), diabetic ketoacidosis, an adrenal crisis, thyroid storm (from extreme hyperthyroidism), and **hypertensive crises.

Assessment

The symptoms can vary depending on the specific hormone or organ that has been affected. Here’s a quick rundown of symptoms of endocrine emergency situations:

  • hypoglycemia—shakiness, sweating, hunger, irritability, anxiety, confusion, and eventual seizure, coma or death if the sugar becomes low enough

  • myxedema coma—hypothermia, lethargy, weakness, altered mental status, and coma

  • diabetic ketoacidosis—fruity smelling breath, Kussmaul’s respirations, frequent urination, excessive thirst, nausea and vomiting, confusion, and elevated ketones (in both blood and urine) and blood glucose.

  • adrenal crisis—extreme fatigue, nausea, weakness, vomiting, hypotension, dehydration, tachycardia, confusion, and seizures

  • thyroid storm—fever greater than 39.4 degrees, heart rate over 140 bpm, agitation, nausea, vomiting, diarrhea, blurred or double vision, weakness, confusion, bulging eyes, confusion, and agitation

  • hypertensive crisis—usually due to Cushing syndrome or pheochromocytoma if endocrine-related. BP 180/120, chest pain, shortness of breath, severe headache, vision changes, confusion, and stroke-like symptoms.

Many of the disorders share common symptoms that include severe fatigue that interferes with ADLs, weight fluctuations, insomnia, heat or cold intolerance, mood changes, cognitive difficulties, and decreased libido. Physical characteristics include a goiter, edema, round face also known as a “moon” face, unusual hump on the upper back, heavy trunk and thin extremities, hair loss, slow wound healing, bulging eyes, and female facial hair. Vital signs should be evaluated for bradycardia or tachycardia and hypo- or hypertension. Conditions such as Cushing syndrome also result in hyperglycemia.

Different lab tests are used to diagnose the different disorders. Here’s a quick rundown of the diagnostic tests organized by disorder:

  • hypo- and hyperthyroidism—thyroid imaging to determine the gland size and shape of the thyroid and radioactive uptake (increased in Graves’ disease), ultrasound imaging, thyroid stimulating hormone (0.4-6.15 mIU/L), free thyroxine (free T4, 0.7-2.0 ng/dL), thyroperoxidase antibodies (to check for the presence of Hashimoto’s disease), and serum T3 (more accurately diagnoses hyperthyroidism, 80-180 ng/dL)

  • diabetes—fasting blood glucose (70-99 mg/dL normal, 100-126 prediabetic, over 126 diabetic) and A1C to measure average blood glucose over the last three months (less than 6% normal, over 7% elevated)

  • adrenal ranges (e.g., Addison’s disease, Cushing syndrome** (cortisol levels)—catecholamine levels (a 24-hour urine test), serum levels (epinephrine less than 75 ng/L and norepinephrine less than 100-550 ng/L), serum cortisol levels, ACTH stimulation test, electrolytes and blood glucose counts

  • pituitary function—serum levels of pituitary function and hormone levels of affected organs

  • parathyroid—parathyroid hormone levels (10-65 ng/L) and serum calcium levels (8.5-10.2 mg/dL) both increase with hyperparathyroidism. With hypoparathyroidism, phosphate levels (2.5-4.5 mg/dL) increase and calcium levels decrease.

Treatment

The treatment depends on the specific endocrine disorder:

  • Hypothyroidism is treated with levothyroxine to supplement low thyroxine levels.

  • Hyperthyroidism (Graves’ disease) is treated with radioactive iodine to destroy the overactive thyroid (after which the patient will require lifelong levothyroxine) and medications propylthiouracil and methoxazole to prevent the thyroid from absorbing iodine. Surgical removal of the thyroid is sometimes necessary, especially if a goiter is present.

  • Thyroid storm is treated with propranolol to control heart rate and blood pressure, cooling blankets, glucocorticoids, IV fluid and electrolyte replacement, and other treatment methods listed under hyperthyroidism directly above.

  • Type 1 diabetes is treated with insulin and continuous glucose monitoring or several glucose checks per day, a carbohydrate-controlled diet, and exercise.

  • Type 2 diabetes is treated with oral medications, GLP-1 medications, insulin in severe cases, following a low carbohydrate diet, exercise, and weight loss.

  • Hypoglycemia is treated with glucose tablets or gels, intravenous dextrose 50%, or juice/candy. If possible, the carbohydrates should be combined with a protein snack to prevent rebound hypoglycemia.

  • Diabetic ketoacidosis is treated with fluid administration, a continuous insulin infusion titrated to blood glucose, potassium replacement as needed (serum levels fall due to the insulin and fluid administration), and magnesium replacement as needed (to help with potassium uptake). If sodium levels become higher than 150 mEQ, then fluids should be switched to 0.45 normal saline.

  • Diabetes insipidus can be treated with desmopressin, diuretics (usually hydrochlorothiazide), vasopressin-releasing drugs (chlorpropamide or carbamazepine), and indomethacin.

  • Adrenal crisis requires intravenous fluids, glucocorticoid, 50% dextrose if hypoglycemic, mineralocorticoid after IV solutions, and identifying and treating underlying cause.

  • Addison’s disease calls for treatment with glucocorticoids like hydrocortisone or prednisone to replace cortisol and fludrocortisone to replace aldosterone and replacing electrolytes as necessary. Remember stress dosing for steroids in the event of surgery, illness, or other stressor.

  • Cushing syndrome is treated by weaning the patient off prednisone or other chronic steroid use, removing pituitary or adrenal adenoma, and administering metformin to treat hyperglycemia.

  • Hyperparathyroidism requires parathyroidectomy to remove affected glands.

  • Hypoparathyroidism is treated with calcium and vitamin D supplements, IV calcium gluconate if tetany is present.

  • Hypertensive crisis calls for intravenous nitroglycerin, nitroprusside, nicardipine, or clevidipine and titrate to gradually reduce blood pressure. Identify and treat underlying causes such as Cushing syndrome or pheochromocytoma.

Lifestyle changes include following a healthy diet, ensuring sufficient rest, getting regular exercise, avoiding stressors, and avoiding weight gain or losing weight. These can help manage endocrine disorders as well.

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