Environment and Toxicology Emergencies, and Communicable Diseases Study Guide for the CEN

General Information

One of the moderately assessed areas on the Certified Emergency Nurse (CEN) exam is the realm of assessing and treating emergencies caused by the environment. It occupies about 9% of the exam. The concepts tested vary from general environmental toxins to communicable disease emergencies.

Environment

Environment is the patient’s surroundings, whether at home, at work, or during leisure activities. Accidents or injuries can happen in various ways that vary depending on the environment where the patient is located. Examples include exposure to toxic or caustic chemicals, heavy equipment, extreme heat or cold, animal stings or bites, slips or falls, and more.

Burns

Burns are injuries to the skin, underlying tissue, eyes, mouth, or respiratory system caused by heat, friction, or corrosive chemicals. Burns can cause severe damage that takes weeks, months, or even years to heal fully. Depending on the severity and location of the burn, it can even be life-threatening.

Assessment

The first priority is to assess the patient’s airway, breathing, and circulation (remember: ABC). Be aware that even if their breathing initially appears stable, pulmonary edema can set in rapidly if any airway burns have occurred, thereby causing severe respiratory distress, even requiring intubation. Symptoms of pulmonary edema include orthopnea (shortness of breath, especially while lying flat); tachycardia; bloody or frothy sputum; and the sensation of drowning or being unable to breathe. The presence of pulmonary edema can be confirmed with a chest computed tomography (CT) scan.

Assess the area of the burn and the level of damage that the patient has sustained. Skin burns are graded on the following scale:

• first degree—superficial
• second degree—partial thickness
• third degree—full thickness
• fourth degree—burns to tissues beneath the skin

Evaluate the patient’s motor function, sensation, and blood flow to the injured area as well as you can. Laser Doppler imaging helps to assess blood flow to the burned area; in general, the more severe the burn, the less blood flow there will be. Thermography measures temperature variations across the burned area.

Treatment

The top priority is to maintain the patient’s airway. Pulmonary edema is treated by providing oxygen therapy, diuretics and vasodilatory medications, and intubation and ventilation in severe cases.

The immediate treatment for burns is to remove the source of the burn. If it is a thermal burn, removing the patient from the heat source will stop the progression of the burn. If it is a chemical burn, the patient’s burn will continue to worsen until the chemical has been completely rinsed away from their skin.

A patient will often require multiple surgical repairs, skin grafts, and ongoing specialized wound care to heal their burns and allow for the best possible appearance and function going forward. Preventing infection is key, especially if a large area of the patient’s skin is affected. Strong intravenous (IV) antibiotics and multiple surgical debridements are sometimes necessary to control the infection.

Chemical Exposure

Chemical exposure happens when a patient is inadvertently exposed to a noxious chemical. This usually occurs at the workplace, but it can also happen at home. Examples of toxic chemicals include organophosphates, which are commonly used in pesticides and cleaning chemicals, the primary culprit of which is sodium hypochlorite. Remember that mixing ammonia and bleach creates chlorine gas, which can cause severe respiratory distress.

Assessment

The specific symptoms depend on the chemical to which the patient was exposed. Assess the patient’s airway, breathing, and circulation. Monitor the patient closely for oxygen desaturation or any signs of respiratory distress such as tachypnea or increased work of breathing.

• Symptoms of organophosphate toxicity include diarrhea, emesis, urinary incontinence, excessive tearing, and, in later stages, unresponsiveness, pinpoint pupils, muscle fasciculations, and diaphoresis.

• Symptoms of sodium hypochlorite poisoning depend on the amount consumed or exposed to. Small amounts cause only mild stomach or skin irritation and nausea/vomiting or coughing. Larger quantities can cause burning or tearing eyes, drooling, burns or blistering, esophageal or oral burns, delirium, chest pain, difficulty breathing, and even organ damage, shock, hypotension, and eventual coma and/or death.

Comprehensive questions and an environmental survey are the best way to determine which chemicals the patient was exposed to, which will also guide their course of treatment.

Treatment

The first step is removing the patient from the source of the chemical to prevent further exposure.

• Organophosphate toxicity is treated by administering atropine to block the effects of excess acetylcholine like bronchospasm. Pralidoxime is administered after atropine to treat the effects of excess acetylcholinesterase and address neuromuscular symptoms. The patient will also need supportive care, IV fluids, and close monitoring.

• Sodium hypochlorite toxicity is treated with primarily supportive care since there is not a specific antidote. Vomiting should not be induced if ingested orally. Instead, the patient should be encouraged to drink plenty of water. Examples of supportive care include methylene blue administration for methemoglobinemia, blood transfusions for severe hemolytic anemia, and renal replacement therapy for kidney issues.

Poison Control is a valuable resource when caring for patients with chemical exposure.

Electrical Injuries

Electrical injuries occur when a patient comes into contact with an electrical source such as wiring, a lightning strike, a battery, or an electric fence. Injuries range from mild numbness and tingling to severe tissue injuries, cardiac arrest, and even death. Anyone can experience an electrical injury, but workers such as electricians and line workers are at a particularly high risk.

Assessment

The first step is to ensure that the source of the electrical injury is turned off or moved away from the injury site to prevent further electrocution for either the patient or the first responder. If the situation is particularly dangerous, your first action should be to call 911 to ensure someone with the proper training and equipment can remove the source of electricity.

The next step is to assess the patient’s airway, breathing, or circulation. Depending on how much electricity the patient was hit with and where it traveled, the patient may be in respiratory or cardiac arrest. If they are, CPR should be initiated immediately.

The patient will need to have a thorough head-to-toe physical assessment to look for any injuries such as burns, neurological deficits, or fractures, especially if the patient fell from a height after their electrical injury. Diagnostic testing includes an electrocardiogram (ECG), complete blood count (CBC), electrolyte levels, and a urinalysis. Diagnostic imaging such as X-rays, CT scans, or even magnetic resonance imaging (MRI) may be necessary depending on the mechanism of injury.

Treatment

CPR needs to be initiated following advanced cardiac life support (ACLS) protocols if the patient is in cardiac or respiratory arrest. Patients who experienced a shock of less than 1,000 volts are often able to go home the same day as long as they did not lose consciousness and had a normal ECG. If the patient experienced a high-voltage injury, the patient should remain on a constant cardiac monitor for at least 24 hours to rule out any arrhythmias. Any electrolyte or other lab abnormalities should be addressed.

Other injuries, such as severe burns or fractures, will require ongoing wound care and surgical repair or skin grafts. The patient may be hospitalized for a more extended period of time. Physical therapy and occupational therapy will also help the patient to regain their strength after severe injuries.

Envenomation Emergencies

Envenomation is the process of having a venom or toxin injected through a bite or a sting. These can range from a yellowjacket sting to snake or spider bites. The seriousness of the envenomation depends on what the source is and whether the patient has an anaphylactic allergy. Some venoms are mild, while others can be life-threatening.

Assessment

Evaluate the area of the bite. Look for any bleeding, redness, darkening of the surrounding tissue, or swelling, especially if it is traveling up the patient’s limb.

It is extremely important to identify the source of the venom because different venoms have different effects. Certain snake venoms are neurotoxic and affect the nervous system, while others are hemotoxic and affect clotting, others are ototoxic and damage the hearing, and still others are cytotoxic and damage tissue.

Monitor the patient’s vital signs and airway closely in case widespread swelling occurs that can compromise the patient’s airway. Perform frequent neurological checks to assess their neurological status, and watch for excessive salivation and abnormal eye movements. Diagnostic testing includes a CBC, comprehensive metabolic panel (CMP), clotting panel (INR, aPTT, fibrinogen), creatinine kinase, urinalysis, and, for patients with neurotoxic symptoms, end-tidal carbon dioxide (EtCO2) monitoring.

Treatment

The primary treatment is antivenom. There are two different kinds of antivenom:

• monovalent—treats venom from a specific species of snake
• polyvalent—treats venom from multiple snake species

Supportive care, such as IV hydration and pain medication, helps to keep the patient stable and comfortable until the antivenom can take effect. Until antivenom can be administered, the patient should remain still and keep their injury site below the level of their heart to slow the spread of the venom. The injury site can be washed gently with soap and water, if available, and any snug clothing or jewelry should be removed before swelling sets in. The patient often needs to be observed for 24 hours.

Submersion Injury

A submersion injury occurs when a patient becomes submerged in water or another liquid and experiences respiratory impairment due to the liquid entering their lungs. The term encompasses both fatal drownings and near-drownings. The liquid can cause aspiration pneumonia and hypoxia severe enough that it can lead to eventual respiratory and then cardiac arrest. Dry drownings occur when a patient develops respiratory distress minutes or hours after leaving the water.

Assessment

Assess the patient’s airway, breathing, and circulation. Symptoms include coughing, chest pain, and difficulty breathing. Depending on the severity of the submersion injury, some patients may be completely unresponsive and have experienced a cardiac or respiratory arrest. Diagnostic testing includes continuous pulse oximetry, chest CT scan, chest X-ray, ECG monitoring, and arterial blood gases.

Treatment

If the patient is unresponsive, CPR should be initiated immediately. Oxygen support should be provided as necessary to maintain adequate oxygen saturation; this may range from a nasal cannula to intubation and mechanical ventilation. If the patient has aspiration pneumonia, they will also receive intravenous antibiotics. The patient may be hospitalized for at least several days. Preventing submersion injuries is key. Children should be taught basic water safety and swimming skills as early as possible and should always be supervised around water. Furthermore, pools and other water sources should be fenced off.

Temperature-Related Emergencies

Temperature-related emergencies are conditions triggered by extreme heat or cold, including hypothermia, heat exhaustion, and heat stroke. Hypothermia occurs when the core temperature drops below 95 degrees Fahrenheit or 35 degrees Celsius. Heat stroke occurs when the core temperature reaches 104 degrees Fahrenheit or 40 degrees Celsius and is not triggered by an immune response to an infection. Heat exhaustion is essentially a milder version of heat stroke.

Assessment

Symptoms of hypothermia include shivering, confusion, drowsiness, and slurred speech. Symptoms of heat exhaustion include heavy sweating, pallor, muscle cramps, weakness, dizziness, headache, nausea, and vomiting. Symptoms of heat stroke include a core temperature over 40 degrees Celsius, hot and dry skin, anhidrosis, loss of consciousness, and seizures. Diagnostic testing includes a rectal temperature, close monitoring of vital signs and arterial blood gases (ABG), and a CMP.

Treatment

The primary treatment is temperature regulation.

• For hypothermia, this is gentle rewarming using warming blankets, warmed IV fluids, heated humidified oxygen, and, in extreme cases, extracorporeal membrane oxygenation (ECMO) and body cavity lavage.

• Heat exhaustion is treated by moving the patient to a cooler place, encouraging them to rest, applying cool compresses, and having them sip on a cool beverage to rehydrate.

• Heat stroke is treated by rapidly lowering the patient’s body temperature to prevent organ damage using cooled IV fluids, ice packs applied to vascular regions, fans, and cooling sheets. The patient may require supplemental oxygen, electrolyte monitoring, and ABG monitoring for several days.

Animal Bites

Any animal can bite, whether it is a domestic cat or dog or a wild animal like a raccoon or squirrel. The primary risk of animal bites is viral infections, such as rabies, and bacterial infections, such as tetanus. The severity of a bite can range from a minor puncture to life-threatening wounds.

Assessment

Assess the area of the bite carefully. Check for bleeding, blood flow, motor function, and sensation to the injured area. If the patient’s face is injured, monitor their airway carefully to ensure that it remains patent. Reassure the patient and help them to remain calm. If possible, obtain vaccination information if a domestic animal caused the bite, or keep the wild animal in sight if it caused the bite.

Diagnostic testing depends on the severity of the bite. If it’s simply a minor puncture, nothing needs to be done. A more severe bite will require diagnostic imaging such as an X-ray or CT scan to reveal underlying tissue damage. Lab tests include a CBC, type and screen, and wound and blood cultures to reveal any bacteria growing in the wound.

Treatment

Irrigate the injured area thoroughly with saline for at least five to 10 minutes to wash away pathogens. Depending on the severity of the bite wound, only a stitch or two may be necessary, or extensive surgical repair and skin grafts may be needed. Provide pain medication as needed to the patient. The patient will need at minimum a prophylactic course of oral antibiotics and stronger IV antibiotics if an infection presents.

Educate the patient about signs and symptoms of infection, such as redness, swelling, fever, purulent drainage from the wound, and red streaks around the wound. The patient will need to receive a Tdap injection if they are not up to date. If a domestic animal is unvaccinated for rabies or the patient is bit by a wild animal, they may need to receive a series of rabies vaccinations to prevent the possible contraction of rabies.

Toxicology

Toxicology describes the harmful effects that chemicals, substances, or environmental agents have on living systems. Examples include carbon monoxide, cyanide, and noxious chemicals as discussed above.

Carbon Monoxide

Carbon monoxide poisoning occurs when the patient breathes in a large amount of carbon dioxide, which causes hypoxia. Left untreated, it can lead to loss of consciousness, coma, and eventually death. Common causes of elevated carbon monoxide levels include gas appliances, vehicle engines, portable generators, charcoal grills, and kerosene heaters. Using them in an unvented space increases the buildup of carbon monoxide gas. It is important to note that carbon monoxide is colorless, odorless, and tasteless.

Assessment

Patients with carbon monoxide poisoning frequently complain of a headache, irritability, weakness, nausea, drowsiness, shortness of breath, and loss of muscle control, and can eventually experience loss of consciousness. If hypoxia is left untreated, coma, brain damage, and death can occur. Infants, young children, and the elderly are at the greatest risk of severe complications.

Carbon monoxide poisoning is diagnosed using a carboxyhemoglobin blood test. A normal level is about three to four percent; anything over 20 percent is considered significant poisoning. An ECG, CBC, arterial blood gases, and chest X-ray should also be obtained. A carbon monoxide detector can be used to locate the source of the carbon dioxide.

Treatment

The first step is to immediately remove the patient from the area of the carbon monoxide poisoning and get them into fresh air. The patient should receive 100% oxygen/high-flow oxygen (15 L/minute) via nonrebreather mask until carboxyhemoglobin levels drop below five percent and/or symptoms resolve. If the patient has an insufficient respiratory drive, they should be intubated and receive mechanical ventilation with a fraction of inspired oxygen (FiO2) of 100%. In severe cases, a hyperbaric oxygen chamber can help to treat the poisoning. The patient may need to be transferred to a facility where one is available.

Cyanide

Cyanide is found naturally in many different substances and food but is most toxic in four different forms:

• sodium cyanide
• potassium cyanide
• hydrogen cyanide
• cyanogen chloride

Cyanide can appear as a solid, a liquid, or a gas. The most common source of cyanide exposure is building fires due to smoke inhalation. Cyanide poisoning can be both acute, with immediately life-threaning effects, or chronic, building up slowly over time before symptoms appear.

Assessment

Early symptoms include tachycardia, dizziness, headache, shortness of breath, bright red flushing, and vomiting. Later symptoms include seizures, bradycardia, dilated pupils, clammy skin, hypotension, loss of consciousness, and eventual cardiac arrest. The primary concerns are hemodynamic instability and pulmonary edema. Symptoms usually appear anywhere from a few seconds to a few minutes after acute exposure, but they can build up over a longer period of time in chronic exposures.

Cyanide poisoning is diagnosed using an elevated lactate level (6.0 mmol/L or higher; 10.0 mmol/L if combined with smoke exposure) combined with cardiovascular collapse. Arterial blood gases monitor the patient’s oxygenation status. A red blood cell cyanide concentration is used to confirm the diagnosis but cannot produce results in time to guide treatment.

Treatment

Treatment should be initiated immediately if cyanide poisoning is suspected, even before it is confirmed with lab results. There are two treatments available on the market: hydroxocobalamin (Cyanokit®) and sodium thiosulfate/sodium nitrate (Nithiodote®), both of which are administered intravenously. Cyanokit should be administered first, and Nithiodote should be used if Cyanokit is unavailable. If the patient’s symptoms resolve spontaneously without treatment, they should be admitted to the hospital for observation for at least 24 hours following exposure. Patients should also receive high-flow oxygen of 100% FiO2, and the patient may require intubation and mechanical ventilation.

Communicable Diseases

Communicable diseases are those that spread from person to person via viruses, bacteria, or fungi. They range from the common cold to COVID-19 to the measles. Everyone will contract multiple communicable diseases throughout their lifetime. Infants, young children, the elderly, and immunocompromised patients are at the greatest risk of complications from communicable diseases.

Clostridioides difficile (C. difficile)

C. difficile (or C. diff) is an inflammatory gastrointestinal bacterial infection that causes severe diarrhea and inflammation of the colon. It is most common in hospitalized patients, immunocompromised patients, patients over 65, people who have been receiving antibiotics (due to their effect on gut flora), and healthcare workers. Left untreated, it can cause life-threatening damage to the colon.

Assessment

The primary symptom is watery, foul-smelling diarrhea. Other symptoms include abdominal pain and cramping, fatigue, loss of appetite, nausea, and fever. C. difficile is diagnosed through a stool sample to confirm the presence of the bacteria in correlation with the patient’s symptoms. A basic metabolic panel (BMP) may be ordered to check the patient’s electrolyte levels and kidney function, especially if they are dehydrated.

Patients with extremely severe cases may require a colonoscopy to evaluate the colon in greater detail and/or a CT scan to check for a bowel perforation, colon wall thickening, or an enlarged bowel. It is important to distinguish between colonization (the presence of bacteria without any active symptoms) and an active, symptomatic infection, because only an active infection requires treatment.

Treatment

The primary treatment for mild to moderate cases of C. diff is metronidazole, which can be administered orally or intravenously if the patient is unable to tolerate PO medications. Severe cases of C. diff are most commonly treated with intravenous vancomycin or fidaxomicin. If the patient is hospitalized or in a long-term care facility, they should be placed in contact precautions to limit the spread of the disease. Patients in their own home should be educated about the importance of adequate hand washing to limit the spread of the infection.

Patients with recurrent C. diff infections that are resistant to antibiotics may qualify for an antibody-based therapy called bezlotoxumab or a fecal transplant to introduce healthy gut flora into the patient’s intestines. Patients with severe C. diff that has caused a bowel perforation will require surgical repair and even a possible ostomy.

Vaccine-Preventable Diseases

Vaccine-preventable diseases are those that can be prevented and/or mediated through the use of vaccines. Common examples include measles, mumps, tetanus, varicella, polio, and diphtheria. Administering vaccines following the standard vaccination schedule helps to keep the patient from contracting these diseases and lessens the severity of the diseases if they do contract them.

Assessment

The symptoms vary depending on the specific illness. In general, the early onset will include a fever, sore throat, malaise, sometimes watery eyes and nasal drainage, and a cough. Some diseases, such as measles, mumps, and varicella, include a specific rash. Paralytic polio will cause muscle weakness, loss of reflexes, respiratory difficulties, and difficulty swallowing.

Diphtheria, in addition to causing respiratory difficulties, cough, fever, and stridor, presents with a distinctive gray and white membrane covering the tonsils, throat, and nasal passages. Tetanus causes painful muscle spasms, a high fever, lockjaw, and seizures. The diseases are usually diagnosed through a throat or nasal swab. Some, such as measles, are also diagnosed through a blood antibody test.

Treatment

For most of these diseases, the primary treatment is supportive care with rest and fluids. Severe cases may require hospitalization for closer monitoring, supplemental oxygen, and intravenous fluids to treat dehydration. Diphtheria and tetanus are both bacterial infections that can be treated with specific antibiotics. Muscle relaxers can help to relieve some of the discomfort caused by tetanus-induced muscle spasms. Steroids may help in severe cases of inflammation. Vaccination helps to minimize the spread of the diseases and lessen the severity if the patient does contract the disease.

Influenza

Influenza is a group of contagious respiratory viruses that spreads via respiratory droplets emitted when an infected person coughs or sneezes. The flu season generally occurs during the winter. In the United States, there are two primary strains of the flu: A and B. The specific genetic makeup of the flu changes slightly every year, which is why a patient can catch the flu repeatedly instead of building immunity after a single occurrence.

Assessment

Flu symptoms can range from mild to severe and can even require hospitalization and be life-threatening, especially in the very young, very old, and immunocompromised patients, as well as patients with underlying respiratory diseases such as chronic obstructive pulmonary disease (COPD) and asthma. Symptoms of the flu include fever, chills, nausea and vomiting (especially in children), nasal congestion, sore throat, cough, body aches, and headache. If the flu progresses to sepsis, the patient will develop hypotension, tachycardia, and eventual life-threatening organ dysfunction.

The flu can be diagnosed using a rapid antigen test, polymerase chain reaction/nucleic acid amplification tests (PCR/NAAT), and multiplex test that are part of a broader respiratory panel. If sepsis is suspected, a CBC, CMP, and lactic acid level will also be ordered.

Treatment

For mild to moderate cases, the primary treatment is rest, fluids, and using over-the-counter (OTC) medications such as ibuprofen and acetaminophen to manage high fevers. Patients with underlying conditions may be prescribed Tamiflu® (oseltamivir), an antiviral medication that helps to prevent and treat the flu. More severe cases may require the patient to be admitted to the hospital for close monitoring, respiratory support, including oxygen, breathing treatments, and even intubation and mechanical ventilation, intravenous fluids, and pressors to support blood pressure and cardiac output in patients with sepsis.

A flu vaccine is recommended for everyone over the age of six months to reduce the chance of catching the flu, as well as to lessen the severity of the flu if the patient does catch it.

Multi-Drug-Resistant Organism (MDRO)

An MDRO is a form of bacteria that is resistant to many different types of antibiotics. When the organism becomes resistant, it renders the antibiotic ineffective. This is one reason why preventing unnecessary antibiotic use is so important. The more times an organism is exposed to an antibiotic, the more opportunities the organism has to adapt and become resistant to the antibiotic.

MDROs are most frequently found in healthcare facilities such as hospitals and long-term care facilities. Examples of MDROs include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci, and resistant Acinetobacter.

Assessment

The specific symptoms depend on the area of the body in which the infection presents. A patient with an abscess will develop an area of warmth, redness, and swelling, along with a possible fever and purulent drainage. A patient with a urinary tract infection (UTI) will develop urinary frequency, burning during urination, cloudy or foul-smelling urine, lower abdominal pain, fever, and tachycardia, hypotension, and confusion if the patient’s infection becomes systemic. A patient with pneumonia will display a cough, fever, shortness of breath, chest pain, fatigue, and confusion, especially in elderly patients.

The primary method of diagnosis is to take a culture from the affected area to determine which bacteria are causing the infection. A CBC and CMP will also be drawn. An elevated procalcitonin level can indicate the severity level of the patient’s infection. A chest X-ray will also be ordered to assess the patient’s lungs for pneumonia.

Treatment

The treatment for MRDOs is challenging because the bacteria do not respond to so many common antibiotics. Treating these organisms often requires the use of strong intravenous antibiotics that can have adverse effects on the patient’s liver and kidneys. MDROs are a growing problem worldwide. An infection from an MRDO that has formed an abscess or caused osteomyelitis will require a surgical incision and debridement. In the case of osteomyelitis, the patient will likely need multiple surgeries up to and including possible amputation of the affected area. The patient will also require supportive care, including possible supplemental oxygen and intravenous fluids, especially if they are having trouble eating or drinking.

Tuberculosis (TB)

TB is a highly contagious disease caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs but can also settle in the spine, brain, and lymph nodes. While it is relatively rare today, especially in the United States, it is extremely serious and can have devastating consequences if not identified and treated promptly. Patients with TB can have either latent infections without symptoms or active disease, meaning that they are symptomatic. Only active infections are contagious.

Assessment

The symptoms of tuberculosis include a persistent cough, chest pain, hemoptysis, weight loss, fatigue, and night sweats. TB can be diagnosed as either latent or active. Latent infections are diagnosed through a TB blood test (IGRA) or TB skin test, which can determine whether the patient has been exposed to the TB bacteria. A sputum sample and chest X-ray are used to diagnose active disease. A lumbar puncture is used to diagnose tuberculosis meningitis.

Treatment

Any patient who is diagnosed with tuberculosis needs to be placed on airborne precautions if in a healthcare facility to prevent the spread of the disease. Treatment for TB can last four, six, or nine months. Medications that are used to treat TB include ethambutol, isoniazid, moxifloxacin, rifampin, rifapentine, and pyrazinamide. The specific combination is guided by which strain of TB the patient has developed. In countries other than the United States where TB is more common, infants are commonly vaccinated with the Bacillus Calmette–Guérin vaccine to protect against TB. The vaccine keeps it from settling in cerebrospinal fluid but does not always protect against infection in the lungs.

Hemorrhagic Fevers

Hemorrhagic fevers are a group of viruses that cause bleeding of varying degrees by damaging the capillaries and interfering with the clotting cascade. The bleeding can be life-threatening if not treated. Examples of hemorrhagic fevers include Crimean-Congo, Ebola, dengue, hantavirus, Lassa, Marburg, and yellow fever. They are spread via contact with infected animals, most commonly rodents.

Assessment

Hemorrhagic fevers begin with symptoms of typical viruses: fever, body aches, nausea and vomiting, diarrhea, and fatigue. Later symptoms as the disease progresses include petechiae, internal hemorrhage (including GI hemorrhage), organ failure, respiratory failure, delirium, and coma. Diagnostic testing includes a CBC with differential, coagulation studies, and PCR testing for specific antibodies and viral genetic material.

Treatment

The primary treatment for hemorrhagic viruses is supportive care with respiratory support and IV fluids provided as needed. Ribavirin is an antiviral medication that can shorten the duration of Lassa fever. Inmazeb® and Ebanga™ are monoclonal antibodies that have been approved to treat Ebola. If the patient experiences acute renal failure, then dialysis may also be necessary. The yellow fever vaccine is effective; there is also a vaccine for one type of Ebola. The other hemorrhagic fevers do not yet have a vaccine.