Review of Skin, Respiratory, Gastrointestinal, STI, Urinary Tract, Eye, Nervous System, and Systemic Infections

Flashcards about Infections of the Skin, Respiratory System, Gastrointestinal Tract, Sexually Transmitted Infections, Urinary Tract, Eye, Nervous System and Other Systemic Infections

What type of skin lesion is flat and discolored?

Macule

What is a raised, solid skin lesion that is less than 5mm in diameter?

Papule

What elevated skin lesion has a flat top and is larger than 5mm?

Plaque

What raised skin lesion is rounded and greater than 5mm in diameter?

Nodule

What are pinkish, ring-like papules or plaques known as?

Urticaria (Wheals or Hives)

What type of skin lesion is filled with fluid and less than 5mm in diameter?

Vesicle

What fluid-filled skin lesion is larger than 5mm?

Bulla

What type of lesion is filled with exudate or pus?

Pustule

What term describes bleeding into the skin?

Purpura

What size are petechiae?

Less than 3mm

What size is an ecchymosis?

Greater than 3mm

What is a crater-like skin lesion involving the epidermis and dermis?

Ulcer

What is a necrotic ulcer covered with a blackened scab or crust?

Eschar

What are the Gram stain characteristics of Staphylococcus aureus?

Gram-positive cocci in grape-like clusters

What test differentiates Staphylococcus aureus from other Staphylococci?

Coagulase-positive

What test differentiates Staphylococcus from Streptococcus?

Catalase-positive

How is Staphylococcus aureus typically transmitted?

Direct contact with purulent lesions, healthcare worker hands, fomites

What is a pyogenic infection of hair follicles called?

Folliculitis

What is a larger, painful nodule with necrotic tissue extending from folliculitis?

Furuncle (Boil)

What is the term for the coalescence of furuncles into subcutaneous tissue with multiple sinus tracts?

Carbuncle

What is folliculitis at the base of the eyelid called?

Stye (Hordeolum)

What skin infection is common in young children and presents with honey-colored crusts?

Impetigo

What is the cause of Staphylococcal Scalded Skin Syndrome (Ritter’s disease)?

Exfoliative toxin

What lab findings can confirm S. aureus?

Gram-positive cocci, catalase-positive, coagulase-positive

What antibiotic is effective against many strains of Staphylococcus aureus?

Oxacillin

Staphylococcus epidermidis is part of the normal skin flora, but what infections is it associated with?

Stitch abscess, UTI, endocarditis, and infections with prosthetic devices.

Streptococcus pyogenes belongs to what Lancefield group?

Group A Streptococci (GAS)

What type of hemolysis does Streptococcus pyogenes exhibit on blood agar?

Beta-hemolytic (complete hemolysis)

What virulence factor is a major component of Streptococcus pyogenes and is antiphagocytic?

M protein

How is Streptococcus pyogenes typically transmitted?

Direct contact with infected persons or fomites

What is a localized purulent skin infection caused by Streptococcus pyogenes?

Pyoderma (Impetigo)

What skin infection presents as raised, painful, erythematous, warm areas distinctly differentiated from normal skin?

Erysipelas (St. Anthony’s Fire)

In what Streptococcus pyogenes infection is the demarcation between normal and infected skin poorly defined?

Cellulitis

In what Streptococcus pyogenes infection does localized cellulitis become bullous and gangrenous, and spread rapidly to fascia, muscle and fat?

Necrotizing Fasciitis

What are the nonsuppurative, immune-mediated complications of Streptococcus pyogenes infections?

Acute Glomerulonephritis and Rheumatic Fever

What test is positive for Streptococcus pyogenes?

Bacitracin test

What is the drug of choice for Streptococcus pyogenes infections?

Penicillin

What are the Gram stain and morphology of Pseudomonas aeruginosa?

Gram-negative bacilli, encapsulated pairs

What color pigment does Pseudomonas aeruginosa produce?

Blue pyocyanin

What is a clinical finding of Pseudomonas aeruginosa infections in burn wounds?

Blue-green pustules with a sweet grape-like odor

What is the most common cause of osteochondritis after penetrating injury?

Pseudomonas aeruginosa

What test is positive for Pseudomonas aeruginosa?

Oxidase test

What is the Gram stain of Clostridium perfringens?

Gram-positive, anaerobic bacilli

What toxin is produced by Clostridium perfringens that causes lysis of erythrocytes, platelets, and leukocytes?

Alpha toxin

What is a life-threatening Clostridium perfringens infection characterized by massive tissue necrosis with gas formation?

Gas gangrene

What is the treatment for Clostridium perfringens infections?

Surgical wound debridement and high-dose penicillin

What are the Gram stain and arrangement of Bacillus anthracis?

Gram-positive bacilli, individually, in pairs, or long serpentine chains

What is the appearance of Bacillus anthracis on Gram stain?

"Bamboo fishing rod" or "Medusa head" appearance

What are the three forms of Bacillus anthracis infection?

Cutaneous, gastrointestinal, pulmonary

What is the most common form of Bacillus anthracis infection?

Cutaneous anthrax

What is the treatment and prevention for Bacillus anthracis infections?

Antibiotics like penicillin or doxycycline. Ciprofloxacin for resistant cases. Vaccination for animals and at-risk individuals.

What is the etiologic agent of Tinea versicolor?

Malassezia furfur

What clinical findings are associated with Tinea versicolor?

Irregular, discrete hypo- or hyperpigmented macules on face, neck, trunk, arms.

What microscopic appearance is associated with Tinea versicolor?

"Spaghetti and meatballs" appearance (hyphae and yeast cells)

What is the etiologic agent of Tinea nigra?

Hortaea werneckii

What are the clinical findings of Tinea nigra?

Lesions on palms and soles, gray to black, well-demarcated macules.

What are cutaneous mycoses also known as?

Dermatophytosis

What structures do cutaneous mycoses infect?

Keratinized structures (skin, hair, nails)

Name the 3 genera of Dermatophytes.

Microsporum, Trichophyton, Epidermophyton

What classification of Dermatophytes describes fungi transmitted from animals to humans?

Zoophilic

Name the anatomical sites of cutaneous mycoses.

Feet (Tinea pedis), Scalp (Tinea capitis), Body (Tinea corporis), Groin (Tinea cruris), Hands (Tinea manus), Beard (Tinea barbae), Nails (Tinea unguium)

What is the pattern of skin lesions associated with dermatophytosis?

"Ringworm" pattern: reddish border with central clearing, inflammatory scaling.

How are subcutaneous mycoses transmitted to humans?

Traumatic inoculation

How does Sporotrichosis present clinically?

Small nodule, may ulcerate/pustulate. Develops painless, subcutaneous nodules along lymphatic drainage.

What is the etiologic agent of Sporotrichosis?

Sporothrix schenckii

What is a common name for Sporotrichosis?

Rose Gardener’s Disease

What are the clinical findings associated with Chromoblastomycosis?

Verrucous nodules or plaques with insidious onset and a chronic course

What is the clinical triad associated with Mycetoma (Madura Foot)?

Tumefaction (swelling), granules, and draining sinus tracts

How are skin warts transmitted?

Direct contact (mucosal/skin breaks), sexual contact, passage through infected birth canal.

What is the etiologic agent of skin warts?

Human Papillomavirus (HPV)

What HPV types are associated with skin warts?

HPV types 1–4

What is the treatment and prevention for warts?

Removal. Interferon for genital warts. Avoiding contact.

What is the etiologic agent of Herpes Simplex Infections?

Herpes simplex virus types 1 (HSV1) and 2 (HSV2)

Which type of herpes simplex virus (HSV) is more frequently associated with primary oral infections?

HSV1

What are the clinical findings of Gingivostomatitis?

Vesicles rupture and ulcerate. Lesions on buccal mucosa, palate, gingivae, pharynx, tongue. Striking gingivitis.

What are the clinical findings of Herpes labialis (Fever Blister or Cold Sore)?

Lesions on vermillion borders of lips; vesicular, rupture, ulcerate, crust.

What is HSV infection of the fingers called?

Herpetic whitlow

What antiviral is recommended for the treatment of herpes simplex virus?

Acyclovir

Name the etiologic agents that cause the common cold.

Rhinoviruses, Coronaviruses, Adenoviruses.

How does transmission of viruses that cause the common cold occur?

Airborne droplets, direct contact with secretions/fomites.

Sore throat, difficulty swallowing, fever, and swollen tonsils are all clinical findings of what?

Pharyngitis

While Pharyngitis is typically viral, what bacterial agent can cause it?

Streptococcus pyogenes

Facial pain, pressure, nasal discharge, congestion, and headache are all clinical findings of what?

Sinusitis

What is another term for Otitis Externa?

Swimmer's Ear

Ear pain, fever, irritability, fluid drainage, and hearing loss are all clinical findings of what?

Otitis Media

Name the Influenza viruses.

A, B, C, D

Abrupt onset of fever, body aches, headache, fatigue, cough, sore throat, and runny nose are all clinical findings of what?

Influenza (Flu)

Cough, wheezing, rapid breathing, and difficulty feeding in infants are all clinical findings of what?

Bronchiolitis

What is the most common etiologic agent of Bronchiolitis?

RSV (Respiratory Syncytial Virus)

Severe coughing fits followed by a characteristic "whooping" sound, especially in children is a clinical finding of what respiratory infection?

Pertussis (Whooping Cough)

What etiologic agent causes Whooping Cough?

Bordetella pertussis

Inflammation of the stomach lining is known as what?

Gastritis

Inflammation of the small intestine is known as what?

Enteritis

Inflammation of the large intestine is known as what?

Colitis

Inflammation of both the stomach and intestines is known as what?

Gastroenteritis

Inflammation of the liver is known as what?

Hepatitis

What term defines severe diarrhea with blood, mucus, and abdominal pain?

Dysentery

What is a major cause of gastritis and peptic ulcers?

Helicobacter pylori

Which form of hepatitis has no chronic state?

Hepatitis A (HAV)

Blood-borne hepatitis can lead to what diseases?

Cirrhosis, liver failure, liver cancer