National Registry Paramedic Exam: Infectious Diseases

This guide talks about a variety of infectious diseases that the paramedic should be concerned about when encountering patients. It also will discuss ways to prevent the transmission of these diseases from patient to provider and from patient to patient.

Protections for Providers and the Public
Agencies at all levels of government—federal, state, and local—exist for the protection of the public. The Occupational Safety and Health Administration (OSHA) is a national agency responsible for establishing rules to ensure the safety of employees. One of the more important rules for EMS agencies is the Blood Borne Pathogen Standard, which establishes an exposure control plan and preexposure education requirements for all healthcare facilities and agencies. The Ryan White Act, among other things, requires that hospitals notify emergency response personnel whenever they have been exposed to any of a wide array of diseases, particularly those that are airborne or droplet borne. The Centers for Disease Control and Prevention (CDC) keeps tabs on disease statistics and works with state and local health departments to ensure that prevention and follow-up activities are implemented and working. They often will intervene if there is an increase beyond the endemic number of cases in an area. A rise in the number of cases above the endemic, or expected, number of cases may signal an epidemic. If the disease spreads worldwide with a great number of new cases all over, it is called a pandemic.
Paramedics need to be a part of the protection of their patients, through community education whenever possible; they also have an obligation to prevent or minimize the chances of nosocomial infections—infections spread in the healthcare environment. To achieve this, after every call ensure that the ambulance is cleaned to OSHA standards, which includes sterilizing any reusable equipment that comes in contact with patient fluids, such as laryngoscope blades with chemical sterilants. Clean other equipment that comes in contact with skin, such as stethoscopes, the stretcher, and blood pressure cuffs, with a bleach and water mixture whenever the equipment is used.

Modes of Transmission
Patient-to-provider transmission is rare, but understanding modes of disease transmission and taking steps for protection against those modes of transmission is crucial to being able to protect yourself from getting sick. Pathogens are spread in 1 of 4 ways from person to person, as follows:

- Airborne Transmission. Pathogens are capable of surviving in air for an extended period of time without being supported in a medium such as a droplet. They have the ability to carry long distances on air currents.
- Direct Contact. This is where transmission of the disease comes from intimate contact with the carrying individual. Direct contact includes casual contact with the person, accidental needle stick transmission, or transfusion of contaminated blood.
- Droplet Transmission. Infection occurs when a person inhales droplets contaminated with the pathogen. These droplets tend to be microscopic and are released when a person coughs or sneezes. They tend to fall after 3–6 feet.
- Indirect Contact. Touching something that the infected person also handled is called indirect contact. The objects that are contaminated with pathogens that are still capable of causing disease are called fomites. The fact that some microorganisms can survive for long periods on fomites is a good reason to conduct thorough cleanings after every patient.

Paramedics need to protect themselves from potential transmission of diseases from the patient. The agency for which the paramedic works is responsible for providing personal protective equipment (PPE), based on OSHA and CDC recommendations. PPE protects the provider from getting any potentially contaminated material on his or her hands.
Gloves should be the bare minimum of PPE worn for every patient contact. Gloves are the first-line defense against blood-borne pathogens of the patient and surfaces. Other PPE that the provider will need to use on a much less frequent basis includes gowns, face and eye shields, and surgical masks or respirators. These PPE should be employed anytime there is risk of splashing or squirting bodily fluids, including blood, amniotic fluid, or vomit.
After the call and throughout the day, providers should ensure proper hand washing with soap and water. The CDC identifies hand washing as the ideal way to clean hands when they are visibly soiled. When hands are not visibly soiled or if soap and water are not immediately available, the CDC recommends using a waterless alcohol cleaner rubbed over all areas of the hands until dry. One of these 2 methods should be employed after every patient contact. Hand washing with regular soap and water or the regular use of a waterless alcohol based cleaner can break the infection cycle immediately.

Exposures
Not every patient you encounter with an infectious disease constitutes an exposure; simply being on scene with a patient or having a patient in the ambulance who has pneumonia does not necessarily mean an exposure has occurred. An exposure to a blood-borne pathogen has occurred when a potentially infectious material—such as blood, vomit, saliva, semen, vaginal fluids, amniotic fluid, feces, or urine from a person who is known to have or has later been proven to have a communicable disease—comes in contact with a mucous membrane; splashes into the eyes, nose, or mouth; or comes in contact with an open wound on the provider. Under this set of circumstances, the employer is responsible for having the potential source of the transmission tested. Under the Ryan White Comprehensive AIDS Resources Emergency Act, the medical facility must release these test results back to the infection control officer for the requesting agency, who will then share the information with the employee. At this point, the affected provider can receive proper care and counseling as needed.
For airborne or droplet borne diseases, the agency’s designated infection control officer will consider the circumstances surrounding the possible exposure. The circumstances include the amount of time with the patient and the proximity of the provider to the patient. The infection control officer also will consider the possible organism involved and the task(s) the provider performed on the patient. For example, if the provider needed to intubate the patient and the patient with bacterial pneumonia coughed, this may constitute an exposure. Alternatively, if a patient with TB was wearing a mask during a routine transport and never took off the mask, and the provider was never in close contact with the patient, an exposure likely did not happen.

Whether a person becomes infected  depends on a lot of factors. Exposure to a pathogen must meet or exceed the following requirements for an infection to be possible:

- The organism needs to be present.
- The organism needs to be capable of causing an infection in humans. There are literally hundreds of thousands of different strains of bacteria, viruses, and fungi that do not in any way affect humans.
- The person needs to be exposed to a quantity of pathogen that will exceed the body’s ability to eliminate it before fully exerting its effects. For example, for Vibrio cholera to cause the syndrome of symptoms associated with the disease it causes (cholera), a person would need to receive a dose in excess of 10,000 organisms. Whereas for Shigella to cause disease, a person needs to come in contact with fewer than 50 live bacteria.
- The virulence of the organism is a relative term for the ability of an organism to cause disease in a host, as measured by the degree of disease it causes.
- For the disease to occur, the pathogen must enter the host through the correct route. The pathogen must successfully navigate the environment and the body’s defenses to arrive at the spot where it can reproduce. For example, swallowing bacteria that would cause pneumonia if it got into the lungs will not result in pneumonia.
- The host’s defenses must not be so strong that they fight off the pathogen invasion before the pathogen can cause the infection.

Specific Infectious Diseases
This section will discuss a variety of diseases with which the paramedic could come in contact. Rather than focusing on treatment as in previous sections, the pathophysiology and symptoms associated with the infection will be presented. Unless otherwise noted, prehospital treatment and the management of patients with these infections is supportive and focused on relieving the associated symptoms.

Tuberculosis
TB comes in 3 forms, but only 1 is communicable: Typical TB is communicable, whereas atypical TB and nonpulmonary TB (TB of the kidney, bone, etc.) are not communicable. With this in mind, only typical TB will be discussed. TB can be active or latent. In the latent form, the patient has in his or her lungs the bacterium that causes TB; however, the patient does not express any symptoms and is not able to spread the disease; in fact, the patient may never even develop the active disease, despite testing positive for it. In active TB, the patient has active live bacteria in his or her sputum and the chest x-ray shows consolidations consistent with TB. For TB to be transmitted, the disease must be active.
TB is a droplet-borne disease, and it is killed reasonably quickly when exposed to ultraviolet (UV) light (e.g., sunlight). A paramedic can be adequately protected simply by placing a surgical mask on the patient and opening the windows of the ambulance. Only providers who are in extremely close contact to the patient for an extended period of time or those who perform mouth-to-mouth on patients with TB are at an increased risk. TB is spread more readily in places such as school dormitories, prisons, and nursing homes where people remain in close contact for extended periods of time. TB, whether active or latent, is detected with a skin test and confirmed active with a chest x-ray.
Patients with active tuberculosis will have a persistent cough generally lasting >3 weeks, night sweats, fever, unexplained weight loss, and bloody sputum (hemoptysis). Patients will likely complain of respiratory distress and nonreproducible localized chest pain.

Pneumonia
Pneumonia is an all-encompassing term for any infection that causes inflammation of the lungs. Pneumonia caused by the bacteria Staphylococcus or Streptococcus is communicable, whereas pneumonia caused by viruses or fungi is not. Communicable pneumonia is transmitted via droplets sneezed or coughed out. Patients will complain of respiratory distress and have a productive cough of a colored sputum, fever, chills, and possible chest pain. The paramedics should wear a mask or place the patient on a high-flow O2 via a mask to protect themselves from transmission.

Influenza
Annually, millions are infected with influenza (the flu), and >36,000 die each year. The flu is a droplet-borne virus that is primarily transmitted by indirect contact, such as getting it on the hand and then touching one’s mouth, nose, or eyes. Patients often complain of a runny nose, muscle pain, fever, chills, and loss of appetite. The course of the infection tends to be about 3–4 days, but the patient is infectious 1 day before and 1 day after the symptoms present. For these patients, supporting the blood pressure and pulse oximetry are the goals of prehospital treatment.

Sexually Transmitted Diseases
For our purposes here, sexually transmitted diseases are primarily diseases that are not only transmitted sexually but also directly affect the genitals. This includes genital herpes, chlamydia, syphilis, gonorrhea, and the human papilloma virus. Paramedics will rarely need to assess the genitals of any patient, including the patient who complains of genital sores. This type of infection generally poses little threat of transmission to a paramedic.

Scabies
Scabies is a parasite that is transmitted through direct or indirect skin-to-skin contact, including during sexual contact or sharing towels or clothing. Scabies causes a body-wide or localized rash of small red bumps on the skin, where the parasite has burrowed into the skin. Patients often complain of intense itching, especially at night, and can scratch so feverishly that they lacerate the skin or develop larger sores. To prevent transmission, only routine cleaning of the ambulance and changing of bed linens is necessary.

Lice
Lice are parasites that are spread only by being in close physical contact with or through sharing hats or clothing of an infected person. Lice cannot live for >24 hours off a person and can be located anywhere on the body. Common symptoms include intense itching because lice bite the skin in the infested area. Eggs, called nits, and the lice can be seen clinging to hair follicles. Prevention requires usual cleaning and changing bed linens. You are probably scratching your head just reading this!

Hepatitis
All forms of hepatitis caused by a viral infection result

in inflammation and failure of the liver. Hepatitis types B, C and D are all blood borne and are transmitted by coming in direct contact with blood and fluids containing blood.

They also can be transmitted via needlestick injuries and transfusions. Hepatitis B and C are primary infections. A patient can get hepatitis D only if he or she is already infected with hepatitis B.
Hepatitis A and E are not blood borne but rather are transmitted via the fecal-oral route. At some point, the infected person ate something contaminated with feces from an infected person or animal or consumed contaminated water.
The signs and symptoms for hepatitis, regardless of type, are basically the same. They include loss of appetite, jaundiced or yellow skin color, a low grade fever, general malaise, and grey feces. There may even be a yellowing of the whites of the eyes, called icterus. Patients who previously smoked often have a sudden distaste for cigarettes. The use of gloves during routine patient contact and routine cleaning of all patient contact areas is all that is needed to prevent transmission.

Human Immunodeficiency Virus
The pathophysiology of HIV at the cellular level is highly complicated, involving changes in cellular markers. A deeper discussion here is not included; however, HIV invades and kills helper T-cells required for both cellular and humoral immunity. Patients with HIV often are asymptomatic for a long period of time when HIV is in a latent period. Patients will then seroconvert, which means that they have detectable levels of antibodies to HIV in the blood. Transmission of blood-borne HIV primarily occurs from needlestick injuries and contact with blood on an open wound or through transfusion. HIV is not transmitted through casual contact or saliva. The virus also can be found in vaginal and seminal fluids, so sexual transmission is likely as well.
AIDS (acquired immunodeficiency syndrome) is the end stage of HIV infection and is characterized by an overall failure of the immune system to fight off any infections. Patients become susceptible to opportunistic infections rarely seen in the patient with a normal immune system, including pneumocystis pneumonia, atypical TB, and Kaposi sarcoma (a purplish skin cancer). Care for the patient infected with HIV is supportive and related to other diseases the patient may have. HIV does not survive for long on hard surfaces once the fluid it was in has dried. Regular cleaning procedures are all that is required to rid the ambulance of the virus.

Lyme Disease
Lyme disease, a tick-borne disease, is contracted when a tick infected with the virus bites and burrows into a person. The tick injects the bacteria Borrelia burgdorferi into the host. Lyme disease causes flu-like symptoms, including fever, chills, and muscle pains. A headache also is common as a result of meningoencephalitis (swelling of the brain and meninges). Patients also have a characteristic bull’s eye rash somewhere on their body, not necessarily related to where the bite is; it appears as a red area surrounding a white central area. This disease is not transmitted from person to person.


Figure: Classic Bull’s Eye Rash in Lyme Disease

Rabies
Rabies is transmitted through the bite of an infected animal, most commonly raccoons, skunks, and foxes. The virus that causes it is shed in the saliva of the animal and essentially injected into the bloodstream. Symptoms are, for the most part, nonspecific and flu-like in nature; however, patients often complain of numbness in the area of the bite. As the disease progresses into the neurologic phase, the patient can display hyperactive delirium, seizures, and bizarre behavior. Also during the neurologic phase, patients will have hydrophobia (fear of water) because water causes severe spasms of the throat muscles and the muscles of mastication. Symptoms can continue to worsen if left untreated, and worsening of the altered mental status to a culmination of coma and death are possible. Treatment is driven by the presenting symptoms and includes management of the ABCs and sedation for seizures or delirium.

Medication Resistant Pathogens
The overuse and misuse of antibiotic medications for decades has resulted in the creation of bacterial infections that are resistant to currently available antibiotics on the market. These so-called super bugs are very difficult to manage and generally require hospitalization for aggressive intravenous antibiotic therapy. The following list is not exhaustive but includes the most common bacteria that paramedics may encounter. Fortunately for the provider, these infections are relatively difficult to transmit from person to person, especially in people with normal immune systems; typically, gloves and hand washing are all that is required for protection because none of these are air or droplet borne.

- Methicillin-Resistant Staphylococcus aureus (MRSA). Commonly found on the skin, once these organisms enter the skin through an abrasion or laceration, they can cause skin infections and cellulitis.
- Vancomycin-Resistant Enterococcus (VRE). Commonly found in the intestinal tract, these organisms become a problem when the other natural and more numerous species of bacteria also naturally found in the intestines are killed off during long courses of antibiotic treatment. As these other species are killed off, VRE can take over, leading to diarrhea.
- Clostridium difficile (C-Diff). Similar to VRE, it causes diarrhea and is allowed to develop when other bacteria in the gut are killed off from excessive courses of antibiotic usage. It presents with copious amounts of watery green, foul-smelling diarrhea. Gloves and good hand washing after contact are generally enough to prevent spreading of the infection.