Micro Exam #2 Ch. 9 Diseases

Measles (rubeola)

Highly contagious airborne illness from the measles virus

Causing fever, cough, runny nose, red eyes, Koplik spots, and a rash that spreads from the face down the body

Rubella

Mild droplet-spread rash illness with swollen lymph nodes behind the ears and neck

Dangerous in pregnancy because it can cause congenital rubella syndrome

Chickenpox (varicella)

Primary infection with varicella-zoster virus (VZV), causing itchy blisters at different stages across the body

The virus then stays latent in nerve ganglia

Shingles (herpes zoster)

Reactivation of latent VZV, causing a painful, unilateral cluster of blisters in one dermatome

Can lead to postherpetic neuralgia

Mpox

Illness from the monkeypox virus, spread by close physical contact; causes firm, deep, painful lesions, fever, and swollen lymph nodes

Seasonal influenza

Respiratory infection from influenza A or B viruses, causing abrupt fever, aches, fatigue, and cough; can progress to pneumonia

COVID-19

Respiratory illness from SARS-CoV-2, ranging from mild symptoms to pneumonia, hypoxemia, and clotting problems

RSV infection

Respiratory syncytial virus infection causing cold-like symptoms; in infants it can cause bronchiolitis with airway obstruction and breathing difficulty

Infectious mononucleosis

Usually caused by Epstein-Barr virus (EBV), spread by saliva; causes fever, sore throat, swollen nodes, and heavy fatigue, with a risk of spleen enlargement and rupture

Mumps

Droplet-spread infection causing painful swelling of the parotid glands (parotitis); complications include orchitis, meningitis, and hearing loss

Viral gastroenteritis

Norovirus or rotavirus infection spread fecal-oral, causing vomiting and watery diarrhea; main danger is dehydration and electrolyte loss

Viral hepatitis

Liver inflammation from hepatitis A through E viruses

A and E spread fecal-oral, B, C, and D are blood-borne

B and C can become chronic and lead to cirrhosis and liver cancer

Genital herpes

Sexually transmitted HSV-1 or HSV-2 infection causing painful genital blisters and ulcers

The virus stays latent in nerve ganglia and can reactivate

Genital HPV infection

Sexually transmitted human papillomavirus infection

Types 6 and 11 cause genital warts, while persistent types 16 and 18 can cause precancer and cancer

HIV infection

Infection with a retrovirus that targets CD4 T cells; untreated, it progressively weakens immunity and leads to AIDS, but antiretroviral therapy (ART) controls it

Dengue

Mosquito-borne viral illness (Aedes bite) causing fever, headache, pain behind the eyes, and muscle pain

Severe cases involve plasma leakage, bleeding, and shock, often as the fever falls

Rabies

Infection from the bite or saliva of an infected mammal

The virus travels along nerves to the brain and causes encephalitis

Almost always fatal once symptoms start, but prompt postexposure prophylaxis can prevent it

Viral tropism

A virus's ability to infect particular cells or tissues; viruses infect cells that have appropriate surface receptors

How viruses cause disease

Viruses multiply inside host cells; replication and release may damage or destroy infected cells; manifestations vary with the cells and tissues involved

Why body site matters

The affected tissue explains the clinical manifestations (e.g., respiratory epithelial cells vs. neural tissue)

Key principle: rash or lesion

A rash or lesion describes what is observed; it does not identify the cause

Key principle: symptoms

Different viruses can cause similar syndromes, so symptoms and lesions alone do not identify the pathogen

Chickenpox/shingles pathogen

Varicella-zoster virus (VZV)

Chickenpox vs. shingles

Same virus, two patterns: chickenpox is widespread itchy vesicles; shingles is usually a painful one-sided band of vesicles after reactivation

Why an adult gets shingles after childhood chickenpox

The original virus remained capable of later reactivation

German measles (rubella) pathogen

Rubella virus

Measles (rubeola) pathogen

Rubeola virus (measles virus)

Smallpox

Caused by variola virus; eradicated

Warts pathogen

Human papillomavirus (HPV)

Measles vs. rubella: important clue

Measles: Koplik spots may occur; rubella: milder illness, lymphadenopathy may occur

Measles vs. rubella: major concern

Measles: highly contagious and airborne; rubella: pregnancy and fetal complications

Similar names and rashes

Do not mean the diseases are caused by the same virus

Koplik spots

Clinical clue associated with measles; they increase suspicion but diagnosis still depends on the complete clinical and epidemiologic context

Nursing priority for suspected measles

Initiate Airborne Precautions while the patient is evaluated; do not wait for laboratory confirmation

Lymphadenopathy

Enlarged lymph nodes

Conjunctivitis / keratoconjunctivitis (viral)

Usually adenoviruses; HSV and VZV can also cause keratoconjunctivitis

Retinitis (viral)

CMV is an important viral cause

Conjunctivitis

Inflammation of the conjunctiva

Keratitis

Inflammation of the cornea

Retinitis

Inflammation of the retina

HSV

Herpes simplex virus

VZV

Varicella-zoster virus

CMV

Cytomegalovirus

Eye infection prevention

Hand hygiene before touching the eyes or handling contact lenses

Common cold (acute viral rhinitis)

Clinical syndrome that many viruses can cause; rhinoviruses are a common cause

RSV

Respiratory syncytial virus; causes cough, congestion, wheezing, bronchiolitis in infants, and more severe disease at the age extremes

RSV precautions

CDC recommends Contact Precautions for RSV in infants, young children, and immunocompromised adults

Influenza viruses

Cause abrupt onset of fever, myalgia, headache, fatigue, and cough

SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2; causes COVID-19, a variable respiratory/systemic illness whose symptoms overlap with other respiratory viruses

Hantavirus pulmonary syndrome (HPS)

Caused by hantaviruses; fever and myalgia followed by rapidly progressive dyspnea; rodent exposure is an important clue

History clue for HPS

Recently cleaned a rodent-infested cabin (exposure history matters)

Respiratory viral illnesses

Often overlap; clinical pattern, host factors, exposure history, and testing help distinguish the cause

COVID-19 pandemic

Global pandemic beginning in 2020; SARS-CoV-2 continues to circulate

COVID-19 risk groups

Higher risk of severe disease in older, immunocompromised, and other high-risk patients

COVID-19 vaccination

Reduces the risk of severe disease, hospitalization, and death

Long COVID

Symptoms or conditions that can persist for months or years after COVID-19

Influenza types

Human influenza viruses include types A, B, and C; influenza A infects humans and other animal hosts

Hemagglutinin (H) and neuraminidase (N)

Influenza surface antigens recognized by the immune system

Antigenic drift

Mutations alter influenza antigens over time, which is why the vaccine is updated annually

Antigenic shift

New antigens (H or H and N) appear abruptly in influenza A viruses affecting humans

Viral gastroenteritis

Vomiting and/or diarrhea from many viruses, including norovirus and rotavirus; fecal-oral transmission is an important pattern

Diarrhea

A symptom, not an etiologic diagnosis

Norovirus

Highly contagious; spreads via infected people, contaminated food/water, or surfaces; vomiting and diarrhea can lead to dehydration; outbreaks occur in confined/group settings

Norovirus prevention

Contact plus Standard Precautions; during outbreaks use soap and water after patient care or contact

Key point for viral gastroenteritis

Think transmission prevention AND fluid loss

Hepatitis

Inflammation of the liver; causes include viral infection, alcohol, drugs/medications, and others

Viral hepatitis

Hepatitis caused by a virus

-itis

Identifies inflammation, not etiology

HAV transmission

Fecal-oral

HBV transmission

Blood/body fluids; sexual and percutaneous exposures

HCV transmission

Primarily exposure to infected blood (e.g., sharing needles)

HDV

Requires HBV infection; blood/body-fluid exposure

HEV transmission

Fecal-oral, particularly contaminated water

Hepatitis vaccines

Available for HAV and HBV; preventing HBV also prevents HDV infection

Chronic HBV and HCV

Can lead to cirrhosis and liver cancer

Herpes labialis (cold sores)

Usually associated with HSV-1

HSV oral and genital infection

Either HSV-1 or HSV-2 can infect the oral or genital region; genital herpes can be caused by either

HSV shedding

HSV can spread even when visible sores are absent

Vesicle

Fluid-filled lesion

HPV disease

Can cause common and genital warts; genital HPV spreads primarily through direct/sexual contact

HPV and cancer

Persistent infection with certain high-risk types can cause cervical, anal, penile, vulvar/vaginal, and oropharyngeal cancers

HPV types

Types that cause genital warts are generally different from the high-risk types associated with cancer

HPV vaccination

Recommended for all children at ages 11-12 (may begin at age 9); can prevent more than 90% of HPV-caused cancers

Genital herpes vs. genital warts

Genital herpes involves HSV-1 or HSV-2; genital warts are associated with HPV

Prevention: respiratory transmission

Source control, ventilation, hand hygiene, Transmission-Based Precautions (Droplet/Airborne), vaccination

Prevention: fecal-oral transmission

Hand hygiene, environmental cleaning, food/water safety

Prevention: blood/body fluid transmission

Standard Precautions, sharps safety, barrier protection

Prevention: direct/sexual contact

Barrier methods can reduce risk; vaccination

Prevention: vector-borne transmission

Prevent arthropod bites and reduce exposure

Prevention: animal exposure

Avoid exposure; seek prompt care after bites or scratches

HIV

Human immunodeficiency virus (HIV-1 and HIV-2); can lead to AIDS

AIDS

Acquired immunodeficiency syndrome; advanced stage of untreated HIV infection

HIV transmission routes

Sexual exposure, contaminated needles, infected blood, perinatal transmission, occupational sharps exposure

U=U

Undetectable = Untransmittable; ART lowers viral load and maintaining an undetectable viral load prevents sexual transmission

ART

Antiretroviral therapy; lowers viral load, suppresses HIV, and helps preserve or restore immune function

Viral load

The amount of HIV in the blood

Undetectable viral load

Does not mean cured; treatment must be continued

HIV and immunosuppression

HIV damages CD4 T helper cells, causing progressive impairment of immune defenses and greater risk of opportunistic infection

Opportunistic infection

Infection from organisms that otherwise may cause little disease; more likely when host defenses are impaired, as in advanced HIV

Viremia

Presence of viruses in the bloodstream; spread through the blood can carry viruses to other tissues