chap 19 Flashcards
Cause: Streptococcus pyogenes (Group A Strep)
Transmission: Enters through wounds, spreads rapidly in fascia
Symptoms: Severe pain, swelling, skin discoloration, necrosis, fever
Treatment: IV antibiotics (Penicillin, Clindamycin), surgical debridement
Epidemiology: Rare but deadly, high
mortality if untreated
Diagnosis: Clinical signs, blood tests, imaging, tissue biopsy
Necrotizing Fasciitis
Cause: Propionibacterium
Transmission: Overproduction of sebum, clogged pores, bacterial overgrowth
Symptoms: Pimples, blackheads, cysts, inflammation
Treatment: Topical retinoids, benzoyl peroxide, oral
antibiotics (Doxycycline), isotretinoin for severe cases
Epidemiology: Common in teens, hormonal influence
Diagnosis: Clinical presentation
Acne
Cause: Bartonella henselae
Transmission: Cat scratches or bites
Symptoms: Swollen lymph nodes, fever, fatigue, red papule at scratch site
Treatment: Self-limiting; Azithromycin for severe cases
Epidemiology: More common in children, worldwide
Diagnosis: Serology, PCR,
Cat Scratch Disease
Cause: Pseudomonas aeruginosa
Transmission: Contaminated water, wounds, hospital settings
Symptoms: Greenish-blue pus, fever, sepsis, pneumonia in immunocompromised
Treatment: Antibiotics (Piperacillin-tazobactam, Ceftazidime), resistant strains require combination therapy
Epidemiology: Nosocomial infection, common in burns & cystic fibrosis
Diagnosis: Culture, Gram stain
Pseudomonas Infection
Cause: Rickettsia rickettsii
Transmission: Tick bites (Dermacentor spp.)
Symptoms: Fever, headache, rash (starts on wrists/ankles, spreads centrally)
Treatment: Doxycycline
Epidemiology: Southeastern & South-Central U.S., high fatality if untreated
Diagnosis: Serology, PCR, clinical suspicion
Rocky Mountain Spotted Fever
Cause: Bacillus anthracis (spore-forming bacterium)
Transmission: Contact with contaminated animal products
Symptoms: Painless black eschar, fever, lymphadenopathy
Treatment: Ciprofloxacin or Doxycycline
Epidemiology: More common in agricultural workers
Diagnosis: Culture, PCR, serology
Cutaneous Anthrax
Cause: Clostridium perfringens
Transmission: Deep wounds contaminated with spores
Symptoms: Severe pain, crepitus, foul-smelling discharge, necrosis
Treatment: IV Penicillin, Clindamycin, hyperbaric oxygen therapy, debridement
Epidemiology: More common in trauma and war injuries
Diagnosis: Gram stain, imaging (gas in tissues)
Gas Gangrene
Cause: Herpes Simplex Virus (HSV-1, HSV-2)
Transmission: Direct contact, sexual, vertical (mother to child)
Symptoms: Painful vesicles, fever, recurrence common
Treatment: Acyclovir, Valacyclovir
Epidemiology: Worldwide, lifelong infection
Diagnosis: PCR, Tzanck smear
Cause: Herpes Simplex Virus (HSV-1, HSV-2)
Transmission: Direct contact, sexual, vertical (mother to child)
Symptoms: Painful vesicles, fever, recurrence common
Treatment: Acyclovir, Valacyclovir
Epidemiology: Worldwide, lifelong infection
Diagnosis: PCR, Tzanck smear
Herpes Infection
Cause: Human Papillomavirus (HPV)
Transmission: Direct contact, fomites
Symptoms: Skin growths, common on hands & feet
Treatment: Cryotherapy, salicylic acid, laser therapy
Epidemiology: Common in children, sexually transmitted types (HPV 6,11) cause genital warts
Diagnosis: Clinical appearance, biopsy if uncertain
Warts
Cause: Variola virus (Smallpox), Monkeypox, Molluscum contagiosum
Transmission: Respiratory droplets, direct contact
Symptoms: Fever, pustular rash, scarring
Treatment: Supportive, smallpox vaccine available
Epidemiology: Smallpox eradicated, Monkeypox emerging
Diagnosis: PCR, serology
Diseases of Pox Viruses
Transmission: Respiratory droplets, transplacental
Symptoms: Mild rash, fever, lymphadenopathy; congenital
rubella causes birth defects
Treatment: Supportive, MMR vaccine prevents
Epidemiology: Rare in vaccinated populations
Diagnosis: Serology (IgM, IgG)
Rubella (German Measles)
Transmission: Airborne droplets
Symptoms: High fever, cough, conjunctivitis, Koplik spots, maculopapular rash
Treatment: Supportive, Vitamin A for severe cases, MMR vaccine prevents
Epidemiology: Highly contagious, outbreaks in unvaccinated groups
Diagnosis: Serology, PCR
Measles (Rubeola)
Cause: Varicella-Zoster Virus (VZV)
Transmission: Respiratory droplets, direct contact
Symptoms: Itchy vesicular rash, Painful, dermatomal vesicles
Treatment: Acyclovir for severe cases, VZV vaccine prevents
Diagnosis: PCR, Tzanck smear
Chickenpox & Shingles
Transmission: Respiratory droplets
Symptoms: “Slapped-cheek” rash, fever, arthralgia
Treatment: Supportive
Epidemiology: More common in children, can cause fetal anemia in pregnant women
Diagnosis: Serology, PCR
Erythema Infectiosum (Fifth Disease)
Cause: Human Herpesvirus 6 (HHV-6)
Transmission: Saliva
Symptoms: High fever (3-5 days), rash appears after fever resolves
Treatment: Supportive
Epidemiology: Common in infants
Diagnosis: Clinical presentation
Roseola (Exanthem Subitum)
A diabetic patient presents with rapidly spreading skin discoloration, extreme pain, and fever. What is the likely diagnosis?
Necrotizing fasciitis
A patient with a deep laceration from an accident develops severe pain disproportionate to the wound size. What is the next best step?
Immediate surgical debridement and IV antibiotics
A 16-year-old with persistent cystic acne not responding to topical treatment asks for stronger medication. What is a possible option?
Isotretinoin (if severe and unresponsive to other treatments)
female patient develops acne flare-ups before her menstrual cycle. What is the likely cause?
Hormonal fluctuations
A child presents with a fever and swollen lymph nodes after a recent cat scratch. What is the most likely diagnosis?
Cat scratch disease
A patient has persistent swollen lymph nodes and fatigue after a cat bite. What test can confirm the diagnosis?
Serology or PCR for Bartonella henselae
A burn patient develops a wound with green pus and a sweet odor. What is the likely causative organism?
Pseudomonas aeruginosa
A hospitalized patient on a ventilator develops pneumonia. What bacteria should be suspected?
Answer: Pseudomonas aeruginosa
A hiker develops a fever and rash starting on the wrists and ankles after a tick bite. What is the likely diagnosis?
Rocky Mountain Spotted Fever
