Study Guide For Infectious Disease

Antibiotics

Bacteria are broadly classified into gram-positive (staphylococci, streptococci, and enterococci) and gram-negative (the rest)
Antibiotics can also be specific for gram-negative, gram-positive, or broad spectrum
The broad spectrum covers both gram-negative and gram-positive classes of bacteria (Savaris et al., 2020)

Antibiotic classes and their indications

Class/example	Class of bacteria	Common Indications
Penicillins (e.g., amoxicillin)	Broad	Urinary tract infections (UTIs), sexually transmitted infections (STIs), skin infections
Aminoglycosides (e.g., Gentamicin)	Gram-negative	Gastroenteritis, bacterial colitis, bacteremia
Sulfonamides (e.g., sulfasalazine)	Broad spectrum	Inflammatory bowel disease, burns, UTIs, keratitis, endophthalmitis, and conjunctivitis
Tetracyclines (e.g., tetracycline and doxycycline)	Broad spectrum	Pelvic inflammatory disease (PID), Other Sexually Transmitted Infections, and Lyme disease
Vancomycin (Glycopeptide)	Garam positive	Methicillin-resistant staph aureus infections (MRSA), endocarditis, dermatitis
Clindamycin (lincosamide)	Gram-positive	Pneumonia, osteomyelitis, dermatitis, pelvic abscess, endometritis, PID, bacterial vaginosis (Savaris et al., 2020)
Carbapenems (meropenems)	Broad spectrum	UTIs, abdominal infections, acute pancreatitis, cystic fibrosis, pneumonia, bacterial meningitis
Cephalosporins	Broad spectrum	Pneumonia, UTI, skin infections
Macrolides (e.g., erythromycins and azithromycin)	Gram-positive	Sinusitis, pharyngitis, pneumonia, STIs, peptic ulcer disease (PUD), urinary tract infections
Fluoroquinolones	Broad spectrum	Pneumonia and UTI

Vaccines

A substance used to prove an active acquired immunity against infectious agents and diseases
Can be classified by method of production live attenuated, killed whole organism, recombinant, toxoid, polysaccharide, and glycoconjugate

Live attenuated

Also weakened vaccine
From an alive organism whose virulence has been reduced
Examples include measles, smallpox, BCG for TB, rubella, influenza, oral polio, rotavirus, rabies, typhoid, and yellow fever (Pollard & Bijker, 2021)
Risk of reverting to virulence
Sometimes, multiple doses may be given to induce a strong immune response
Measle, Mumps, and rubella (MMR) vaccine is commonly used type internationally
MMR is given to the pediatric population older than 12 months
Rash and fever are common adverse effects that disappear with time
Need to reassure the patient about these adverse events
Used cautiously among immunocompromised individuals

Killed Orgasm Vaccine

Also inactivated vaccines (Shocking Journals, 2019)
Inactivated by health or chemicals
Require an adjuvant to enhance their immunogenicity (Centers for Disease Control and Prevention (U S), 2021)
The main examples are inactivated polio vaccine (IPV), whole cell pertussis vaccine, hepatitis A, Rabies, cholera, influenzas, tick-borne encephalitis, and rabies (Woo, 2022).

Subunit vaccine

Made from an antigenic portion of a bacteria or virus
These units can be polysaccharides or proteins in compositions
Examples are conjugate vaccines such as pneumococcal conjugate vaccines, Hemophilus influenza type B, meningococcus C, and typhoid (Vi)
Polysaccharide subunit vaccines are not effective in children under age 2

Toxoid Vaccines

Made from inactivated toxins from bacteria
Examples include tetanus toxoid, diphtheria, acellular pertussis, anthrax, influenza subunit
The Novavax COVID-19 vaccine is one novel example under this class (Mayo Clinic, 2022)
Tetanus and diphtheria toxoid vaccines are purified from the pathogen itself

Recombinant vaccines

Also called genetic vaccines
Made through recombinant technology
Are produced from recombinant DNA technology
Examples include the hepatitis B vaccine (HBV), human papillomavirus (HPV), cholera toxin B, hepatitis E vaccine, and meningococcus B
Most Covid-19 vaccines are made from recombinant RNA technology (British Society for Immunology, 2021)
The recombinant RNA leads to translational production of antigenic SARS Cov2 to invoke an immune response, thus, immune memory

Vaccine considerations

All children in the US should receive MMR – at least 2 doses
First MMR dose after 12 months of age
A second MMR dose must come at least 28 days after the previous dose – recommended after 4 years of age
Flu vaccine can start at 6 months of age
Children younger than 12 months do not receive live vaccines
Allergies to eggs are an important consideration before vaccination
Injection site swelling, redness, and pain are common adverse events.
Severe immunosuppression is an absolute contraindication of vaccines
Encephalopathy within a week after pertussis vaccination warrants stoppage of subsequent doses (Centers for Disease Control and Prevention (U S), 2021)

Vaccine Precautions

Guillain Barre Syndrome in less than 6 weeks after the previous dose
Guillain Barre Syndrome in less than 6 weeks after the previous dose – of influenza vaccines
Thrombocytopenia or purpura – MMR
Chronic gastrointestinal disease – rotavirus
History of Arthus type reaction – tetanus toxoid, diphtheria
Progressive neurologic disorder – diphtheria

Vaccines in Pregnancy and Breastfeeding

A pregnant mother should receive inactivated influenza and Tdap vaccines
No live attenuated vaccines are recommended during pregnancy
Only if indicated, HBV vaccine, hepatitis A vaccine, and meningococcal can be given
Yellow fever vaccine can be given with caution to lactating mothers
Breastfeeding is not a contraindication to any vaccination
A hygienic strategus is recommended for the mother and close family members

Kawasaki disease

Was initially referred to as mucocutaneous lymph node syndrome
Vasculitis of the medium vessels
Rarer before 5 but common after 2 years
In most cases in the east, especially in Japan
More males were affected than females
Common in winter and spring

What is presentation? What do you find in physical exam?

Acute and self-limiting disease in most cases
Persistent hotness of body that can last more than 5 days
Rash and conjunctivitis
Strawberry tongue
The convalescent phase is marked by sole and palm desquamations
Arthritis can also ensue

What are the diagnostic criteria?

The patient must meet at least five of the following six criteria
Fever lasting more than 5 days
Nonexudative bilateral conjunctivitis
Oral changes – strawberry tongue, pharyngitis, fissured lips, or oral erythema
In the extremities – edema, desquamation, erythema, or peeling around the nails
Polymorphous rash
At least more than 1.5 cm cervical lymphadenopathy

Are any diagnostics needed?

Echocardiogram to rule out cardiac complications
Complete blood count for leukocytosis and thrombocytosis
Liver function tests – marked liver enzymes elevations
Erythrocyte sedimentation rates

How are these patients managed?

Acute phase – aspirin and intravenous immunoglobulin
In the long term – aspirin can prevent coronary artery aneurysms
Coronary artery bypass grafting (CABG) may be required in cases of coronary artery aneurysm

Do they need a referral? What type?

Cardiologist for suspected carditis
Cardiothoracic surgeon for suspected coronary artery aneurysms

Flu

Caused by influenza viruses types A and B
Airborne transmission

What is the presentation of the illness? What is found on physical examination

Fever, anorexia, fatigue, rigors, headache, nausea, vomiting,
Photophobia, conjunctivitis
Cough, coryza

Who should receive immunization?

Pregnant mothers (Centers for Disease Control and Prevention (U S), 2021)
Adults aged 65 years
Toddlers above 12 months of age
Chronic obstructive pulmonary disease and asthma
Chronic kidney, liver, or heart failure
Immunosuppressed (mild and moderate)

Who should not receive immunization?

Those receiving live injected vaccines
Those who developed GBS within 6 weeks after the previous Flu Mist dose
Patients allergic to egg or egg-containing products who showed symptoms other than hives

What are the complications?

Bacterial pneumonia
Viral pneumonia
Sepsis, sinusitis, otitis media, bronchitis
Severe acute respiratory syndrome (SARS) (McCance & Huether, 2018)

What diagnostic tests are used for diagnosis?

Compete, blood count,
C-reactive protein levels
Chest x-ray to rule out pneumonia
Sputum culture and examination

How is the disease managed pharmacologically?

Neuraminidase inhibitors such as oseltamivir and zanamivir
Acetaminophen for headaches and pyrexia
Vaccination for the population at risk
Antibiotics within four hours at presentation to prevent pneumonia

How is the disease managed non-pharmacologically?

Rest
Hydration
Oral and endotracheal tube hygiene to reduce the risk of ventilator-associated pneumonia (VAP)
Prevention aspiration to prevent pneumonia
Isolation of immunopurified individuals

Fifth Disease

Also called erythema infectiosum
What is the causative pathogen and mode of transmission?
Caused by parvovirus B19, also called retrovirus
The mode of transmission is through the air in aerosol droplets, saliva, sneezing, and nasal mucous
Blood and blood products can also transmit this virus from an infected person.
What is the NP’s role if a pregnant patient is exposed?
Establish contact and exposure
Educate patient on hygiene such as handwashing
Educate patient about possible outcomes through rare such as miscarriage and fetal anemia
Closely monitor the mother through obstetric ultrasounds
Referral to an obstetrician
Rash with a prodrome. Know the type of rash (lacelike appearance). How long does the rash last?
Signature rash “slapped cheek” – malar rash, laced network appearance, common in limbs and trunk, disappears within two weeks (CDC, 2022b)
Prodromal headache, malaise, fever, and myalgia

What typical age of patients that are infected? This can help confirm the diagnosis.

Common among children between 2 and 5 years (2-10%)
Prevalence increases in adults older than 20 years – 40-60%
Commoner in adults above 70 years more than 80% (Macri & Crane, 2022)

What are complications in adults and their management

Polyarthritis – symmetrical, small joints affected (CDC, 2022b)
Anemia – rare
Management usually symptomatic in regular patients
Polyarthritis among managed by NSAIDs
Transfusion might be required in immunocompromised patients with anemia
Papular Purpuric Gloves and Socks Syndrome can occur among young adults

Rocky Mountain spotted fever and lyme disease

Rocky Mountain spotted fever is caused by the strict intracellular parasite Rickettsia rickettsii from a tick bite (McCance & Huether, 2018)
Lyme disease caused by Borrelia burgdorferi from

What is presenting S&S of each? How do they differ?

RMSF – fever, rash (2-4 days later), headache, nausea, vomiting, myalgia, poor appetite, abdominal pain
Lyme disease – fever, headache, erythema migrans, and fatigue (CDC, 2022a)
The splotchy or spotty rash is specific to RMSF
Bull’s eye rash specific to Lyme disease
In some cases, Lyme disease can cause neck stiffness, arthralgia, dizziness, and facial palsy

What diagnostic tests are used to confirm if any?

ELISA test or western blot for Lyme disease
For RMSF, serology becomes positive after convalescence – immunofluorescent antibody, latex agglutination, and ELISA
Basic tests such as CBC and liver function are also important but nonspecific

What are differential diagnoses?

Ehrlichiosis
Typhus
Tularemia
Bacterial meningitis
Q-fever
Typhoid fever

What are the non-pharmacological and pharm management for adults and children?

Doxycycline for all ages for RMSF
Doxycycline is also available for Lyme disease treatment but only from 8 years of age and above
Patients younger than 8 years can use amoxicillin or cefuroxime
Avoiding tick contacts
Showering immediately after coming from tick-infested areas
Tick removal involves the use of tweezers to steadily and evenly pull out the tick and cleaning the area thoroughly using alcohol or soap and water (CDC, 2022a)

When do you refer?

In cases of complications such as carditis, reactive arthritis, or Post-Treatment Lyme Disease Syndrome
Meningitis symptoms, fever, petechial rash
Recurrence of acute symptoms after treatment after 2-4 weeks
Know that no child under 8 should get doxycycline unless it is for RMSF.

Mononucleosis

Also known as the kissing disease
EBV is the main causative agent
CMV has also been implicated in some cases

What is the disease presentation? What is found in a physical exam?

Symptoms – Fever, Arthralgia, malaise
Signs – lymphadenopathy, fever, pharyngitis; sometimes splenomegaly and hepatomegaly

How do you differentiate between mono and group A strep?

IM has a triad of lymphadenopathy, fever, and pharyngitis
Streptococcal pharyngitis is caused by bacterial infection and may present with exudative tonsillitis and pharyngitis
Additionally, IM has fatigue and myalgia that I rare in streptococcal pharyngitis
Lack of response to antibiotics highly suggests IM than streptococcal pharyngitis owing to the difference in etiology

What diagnostic testing is done?

Monospot testing – can cause false positives due to other infections – toxoplasmosis
Heterophile antibody test – quantitative antibody test – the test may not yield positive results for up to 2 weeks due to a lack of antibody
Peripheral blood film – atypical lymphocytes + leukocytosis
Antistreptolysin O (ASO) titer is an antigen test that quantifies group A anti-streptococcal antibodies
IgG against the EBV nuclear antigen [EBNA]) used where Monospot is inappropriate or unreliable (McCance & Huether, 2018)

How is the disease managed pharmacologically?

Usually, self-limiting
Medical interventions are required in a few cases
Amoxicillin or erythromycin can be used empirically or in isolated streptococcal pharyngitis cases
Ampicillin is contraindicated due to the risk of rash in most patients with IM
Analgesics and antipyretics remain the mainstay of treatment
Aspirin is not used among children due to the risk of Reyes syndrome
Ibuprofen is indicated instead
Steroids can be used when there is a risk or impending airway occlusion due to edema from inflammation

How is the disease managed non-pharmacologically?

Bedrest and retreat from strenuous activities are advised due to the risk of splenic rupture
When does a patient need to refrain from sports? When can they resume?
Splenic removal in cases of high risk of splenic rupture
Splenectomy must be followed by vaccinations against encapsulated bacteria Streptococcus, Meningococcus, and Hemophilus influenzae

What are POTENTIALLY fatal complications

Carditis
Thrombocytopenic purpura
Splenic rupture and overwhelming post-splenectomy infection (OPSI)
Airway obstruction
CNS involvement

Measles (Rubeola)

Also called the red measles
Caused by the morbillivirus virus, an RNA virus that is airborne
Different from the German measles/rubella

How is this disease transmitted?

Sneezing
Coughing
Aerosol droplets
Highly infectious four days before and four days after the onset of the rash

What are the 3c’s?

Coryza
Conjunctivitis
Cough
Koplik spots

What is the presentation?

The incubation period is up to 3 weeks (McCance & Huether, 2018)
Start with a fever of up to 40.5°C followed by the three C’s above
The cough is a barking type
Marked by a maculopapular rash that starts from behind the ears and spreads to the whole body
The rash extends to palms and soles
Additionally, there is malaise, runny nose, and lymphadenopathy

What are Koplik’s spots?

White spots on the buccal mucosa
Are pinpointed and surrounded by an erythematous ring
Appear one to two days before the rash

What diagnostic tests are needed?

A throat swab for polymerase chain reaction (PCR)
Serum IgM against rubeola virus

What are differential diagnoses?

Kawasaki disease
Systemic lupus erythematosus
Rubella
Serum sickness
Infectious mononucleosis
Roseola

What is the best prevention?

Vaccination is the best prevention (McCance & Huether, 2018)
What is given to susceptible contacts?
Postexposure prophylaxis with antivirals is given to susceptible individuals

Other treatments

Antibiotic therapy is in cases of secondary bacterial infection
Rest
Hydration
Vaporization of the airway

Roseola

Also called the Exanthema Subitum or 6th Disease

What is a causative agent?

The causative agent is human herpesviruses 6 (HHV6) or human herpesviruses 7 (HHV7)

What is the mode of transmission?

Airborne transmission through droplets in the air

What age group does this typically occur in?

Usually between 6 and 24 months
Can be seen in children of up to 4 years (McCance & Huether, 2018)

How does the disease present?

Symptoms follow a 5-15 day incubation period
Fever followed by a maculopapular rash
The rash is seen in the trunk, arms, and neck and lasts up to 48 hours

What are differentials?

Rubella
Rubeola
Infectious mononucleosis
Lyme disease
Rocky Mountain spotted fever
Varicella zoster
Chickenpox

How is this disease managed?

Self-limiting and no treatments are usually indicated
Supportive care through adequate water intake

Can they return to daycare or school?

No time of school is required

German Measles (Rubella)

Also called 3-Day Measles
Caused by the rubella virus, an RNA virus

What is disease presentation?

Starts with fever, malaise, runny nose, headache, cough, lymphadenopathy
Followed by a pink-reddish maculopapular rash on the face, trunk, and extremities
What are the complications that can occur with this disease?
The rash can resolve spontaneously within three days

What are the differential diagnoses?

Rubeola
Roseola
Infectious mononucleosis
Lyme disease
Rocky Mountain spotted fever
Varicella zoster
Chickenpox
Hand, foot, and mouth disease

What diagnostic tests need to be done?

CBC to rule out thrombocytopenia
Rubella IgM test
Viral culture

Common complications

Encephalitis
Thrombocytopenia
Severe arthritis
Congenital rubella syndrome (CRS)

How is this disease managed?

Mainly supportive and no definitive treatment
Starch baths (McCance & Huether, 2018)
Antihistamines
NSAIDs for joint involvement and pain
Adequate fluid intake in those at risk of encephalitis
Ophthalmology for CRS

Chickenpox

Caused by human herpes 3/ varicella-zoster virus
How is this spread?
Spread by contact

What is the incubation period?

The average incubation period is two weeks but can go up to a month

What is the presentation?

Skin rash that starts as papules and evolves into vesicles, pustules, and crusts
Rah appears on the trunk, face, head, and back
Vesicles are sometimes itching
Short-course fever, usually 2 – 3 days

Management: both pharmacologic and nonpharmacologic

Usually, conservative
Analgesia – NSAIDs are discouraged due to the risk of skin and soft tissue reactions
Acetaminophen thus recommended
Neonates/immunosuppressed/cardiovascular disease risk patients – anti-varicella zoster immunoglobulin + acyclovir (McCance & Huether, 2018)
Antihistamines to help with itching
Antibiotics if the secondary bacterial infection
Supportive – Patient to avoid school for about 5 days from the rash onset day, bath, wet dressing

Potential complications

Encephalitis
Varicella pneumonia and laryngeal edema
Epistaxis
Congenital varicella syndrome
Transecting hematuria
Can breakthrough chickenpox occur with a vaccine?

Cellulitis and erysipelas

Both dermal infections

How do you differentiate the two?

Cellulitis involves the lower dermis
Erysipelas involves the upper dermis; Therefore, erysipelas is superficial cellulitis
Erysipelas is well-defined, but cellulitis has poorly defined margins

What are the primary causative agents of each?

Cellulitis – group B streptococci, MRSA, staph aureus
Erysipelas – group A streptococci

What is the pharmacologic treatment of each?

Cellulitis – antibiotics flucloxacillin; in cases of MRSA use vancomycin; per oral analgesia (McCance & Huether, 2018)
Erysipelas – Systematic antibiotics, analgesia

When do these need to be referred?

Signs of necrotizing fasciitis – rapidly spreading infection
Suspected DVT, lymphangitis,
Suspected osteomyelitis
Poor response to treatment
Cellulitis of the face

Meningitis

Know that petechiae and fever are always emergent.

What are the primary causative agents for bacterial, viral, and fungal?

Bacterial – strep pneumoniae, Neisseria meningitidis, Hemophilus influenza type b, Group B Streptococcus
Viral – Human immunodeficiency virus, mumps virus, herpes simplex
Fungal – cryptococcal neoformans, Histoplasma

What are Kernig and Brudzinski signs?

Kernig sign – positive when the patient lies in a supine position and hip is flexed, and extension at the knee causes pain (McCance & Huether, 2018)
Brudzinski sign – is positive when the patient flexes both knees and hip when the neck is flexed

What are the assessment findings?

Bulging fontanels in children
Opisthotonos position in children
Purpuric in septic meningococcal etiologies

What diagnostic testing is done?

CSF analysis to suggest the etiology
CSF culture to identify the etiological agent
Blood culture to rule out the septic cause
Complete blood count

What are the best prevention strategies?

Isolation in highly contagious causes
Public awareness
Early case detection
Vaccination
Prophylactic antibiotics

How is this managed?

Fluid therapy
Oxygen administration in acute settings
Broad-spectrum antibiotics while awaiting culture results
Dexamethasone if older than 3 months (McCance & Huether, 2018)

Pertussis

Caused by Bordetella pertussis (gram-negative)

What are the stages?

Catarrhal – fever, coryza, mod cough – up to 10 days
Paroxysmal – prolonged hacking cough, whoop, more at night – can last up to 6 weeks (weeks #2 – 8)
Convalescent – gradual discovery, fewer coughs, – lasts up to 3 weeks (week 8 – week 12) (CDC, 2022c)

What is the presentation?

Cough, vomiting, inspiratory whoop, fever, and coryza.

Prevention

Mainly through vaccination
Tdap is recommended for pregnant women with every pregnancy in the third trimester.
Confers protection on the unborn infant as well

References

British Society for Immunology. (2021, April). Types of vaccines for COVID-19. Immunology.org. https://www.immunology.org/coronavirus/connect-coronavirus-public-engagement-resources/types-vaccines-for-covid-19

CDC. (2021, May 27). Prevention. Centers for Disease Control and Prevention. https://www.cdc.gov/rmsf/prevention/index.html

CDC. (2022a, January 19). Lyme Disease. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/index.html

CDC. (2022b, February 16). Fifth Disease. Cdc.gov. https://www.cdc.gov/parvovirusb19/fifth-disease.html

CDC. (2022c, February 23). Clinical Features. Cdc.gov. https://www.cdc.gov/pertussis/clinical/features.html

Centers for Disease Control and Prevention (US). (2021). Epidemiology and prevention of vaccine-preventable diseases: The pink book (14th ed.). Rittenhouse Book Distributors. https://www.cdc.gov/vaccines/pubs/pinkbook/index.html

Macri, A., & Crane, J. S. (2022). Parvoviruses. In Parvoviruses. [Updated ]. In: StatPearls [Internet]. Treasure Island (FL). StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK482245/

Mayo Clinic. (2022, August 25). Different types of COVID-19 vaccines: How they work. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/different-types-of-covid-19-vaccines/art-20506465

McCance, K. L., & Huether, S. E. (2018). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Mosby.

Pollard, A. J., & Bijker, E. M. (2021). A guide to vaccinology: from basic principles to new developments. Nature Reviews. Immunology, 21(2), 83–100. https://doi.org/10.1038/s41577-020-00479-7

Savaris, R. F., Fuhrich, D. G., Maissiat, J., Duarte, R. V., & Ross, J. (2020). Antibiotic therapy for pelvic inflammatory disease. Cochrane Database of Systematic Reviews, 8(8), CD010285. https://doi.org/10.1002/14651858.CD010285.pub3

Shocking Journals. (2019). Vaccine queen: Nurse notebook medical nursing school journal (6×9). Independently Published.

Woo, J. (2022). Vaccination. The American Journal of Nursing, 122(2), 10. https://doi.org/10.1097/01.NAJ.0000820472.48310.19