Comprehensive HEENT Infectious Diseases: Bacteria, Viruses, Fungi & Treatments

What are the main types of bacteria associated with HEENT infections?

Gram-positive cocci

Gram-negative diplococci

Gram-positive rods

Gram-negative rods

obligate intracellular bacteria

What are the risk factors for Staphylococcus aureus ear infections?

frequent swimming

retained water after bathing

minor ear trauma

ear piercing or scratching

What are the risk factors for Staphylococcus aureus eye infections?

infrequent cleaning of eyelids and lashes

improper contact hygeine

dry eyes

What are the clinical features of otitis externa caused by Staphylococcus aureus?

Severe ear pain

purulent ear discharge

temporary hearing loss

erythema of the ear canal

What is the common cause of conjunctivitis in adults?

Staphylococcus aureus, often due to direct contact with contaminated hands or improper contact lens use.

What is the common cause of blepharitis in adults?

Staphylococcus aureus

What are the virulence factors of Staph aureus?

protein A

MecA

biofilm formation

What are the key features of Streptococcus pneumoniae?

It is a Gram-positive cocci in pairs (Lancet diplococci), catalase negative, optochin sensitive, and alpha hemolytic.

What infections can Streptococcus pneumoniae cause?

Otitis media, sinusitis, pneumonia, and meningitis.

What are the risk factors for pneumococcal infections?

Age (≤2 or ≥65)

splenic dysfunction

alcohol use disorder

cigarette smoking

recent upper respiratory infections

What are the virulence factors of Strep pneumoniae?

polysaccharide capsule

IgA protease

What is the primary treatment for acute otitis media caused by Streptococcus pneumoniae?

Amoxicillin, which prevents peptidoglycan synthesis.

What is the treatment for acute otitis media caused by Streptococcus pneumoniae in daycare or recurrent AOM?

Augmentin

What are the characteristics of Streptococcus pyogenes?

Gram-positive cocci in long chains, catalase negative, bacitracin sensitive, and beta hemolytic.

What is the common presentation of Group A Streptococcus pharyngitis?

Sudden onset sore throat, red inflamed throat, swollen tonsils with exudate, and fever.

What are some virulence factors of Streptococcus pyogenes?

M protein, hyaluronic acid capsule, and streptolysin O.

What diagnostic tests are used for Streptococcus pyogenes infections?

Rapid strep test and anti-streptolysin O (ASO) antibodies.

What are the common symptoms of sinusitis caused by Streptococcus pneumoniae?

Facial pain/pressure, nasal congestion, purulent nasal discharge, and headache.

How is streptococcal pharyngitis treated?

Penicillin

Amoxicillin

What are the common treatments for otitis externa?

Ciprofloxacin and dexamethasone ear drops for MSSA; topical mupirocin for MRSA.

What is the typical treatment for purulent conjunctivitis?

Amoxicillin-Clavulanate (Augmentin) for coverage against Haemophilus influenzae and Moraxella catarrhalis.

What are the characteristics of Bacillus cereus?

Gram-positive rods, spore-former, facultative anaerobe, motile, and beta-hemolytic.

How is Bacillus cereus transmitted to the eye?

Through traumatic entry of spores, often from soil-contaminated objects or during eye surgery.

What are the clinical features of Bacillus cereus endophthalmitis?

Rapidly progressive eye pain, redness, vision loss, hypopyon, corneal edema, inflammation

What is the treatment of Bacillus cereus endophthalmitis?

Intravitreal Vanco and Floxacin

Vitrectomy

What are the clinical features of Bacillus cereus keratitis?

corneal ulcer, pain, photophobia

mucopurulent discharge

hypopyon

What is the treatment of Bacillus cereus keratitis?

topical floxacin

corneal debridement

What are the characteristics of Corynebacterium diphtheriae?

Gram-positive rods with clubbed ends, metachromatic granules, non-spore-former, and non-motile.

How is diphtheria transmitted?

Person-to-person via aerosols and respiratory droplets.

What are the key clinical features of diphtheria?

Sore throat, malaise, low-grade fever, dysphagia, thick grey pseudomembrane, and 'Bull neck' swelling.

How does the diphtheria toxin work?

AB toxin binds to EF2

prevents protein synthesis

host cell dies

What is the gold standard for diagnosing diphtheria?

Throat/nose swab or pseudomembrane tissue culture

What is the treatment for diphtheria?

Diphtheria antitoxin, along with penicillin or erythromycin.

What are the characteristics of Moraxella catarrhalis?

Gram-negative diplococci, oxidase positive, and does not ferment sugars.

What are the common diseases caused by Moraxella catarrhalis?

Otitis media, bacterial rhinosinusitis, and community-acquired pneumonia.

What are the risk factors for Moraxella catarrhalis infections?

Young children, daycare attendees, and individuals with allergic rhinitis.

What are the virulence factors of Moraxella catrrhalis?

adhesins

biofilm formation

possess beta lactamase

What is the treatment for Moraxella catarrhalis infections?

Amoxicillin-clavulanate (Augmentin).

What are the characteristics of Neisseria gonorrhoeae?

Gram-negative diplococci, often found inside neutrophils, oxidase positive, glucose fermentation positive.

What are the clinical features of gonococcal infections?

Pharyngitis, purulent conjunctivitis, and potential blindness in infants.

What are the virulence factors of Neisseria gonorrhoeae?

Pili for adherence and antigenic variation.

What are the complications of untreated gonococcal conjunctivitis?

Corneal perforation and blindness within 24-48 hours.

What are the common symptoms of otitis media in children?

Painful tugging at the ear, bulging red tympanic membrane, and fever.

What is the first-line treatment for neonatal gonorrhea?

Erythromycin drops at birth

Immediate ceftriaxone IV or IM

What is the first-line treatment for gonococcal pharyngitis?

single dose ceftriaxone IM

What is the culture grown on if concern for Neisseria?

thayer martin agar

What are the virulence factors of Pseudomonas aeruginosa?

Exotoxin A, biofilm formation, and antibiotic resistance mechanisms.

How is Pseudomonas antibiotic resistant?

limited membrane permeability

efflux pumps

AmpC beta lactamase

extended spectrum B lactamase

What infections are commonly caused by Pseudomonas aeruginosa?

External otitis, malignant otitis externa, and keratitis.

What is the characteristic appearance of Pseudomonas aeruginosa in culture?

Green pigment production on cetrimide agar

What are the characteristics of Pseudomonas keratitis?

eye pain, redness, purulent discharge, and blurred vision

What are the treatment options for Pseudomonas infections?

Ear: Piperacillin-tazobactam, meropenem, cefepime

Eye: topical ciprofloxacin, steroids

What are the key characteristics of Haemophilus influenzae?

Gram-negative coccobacillus, oxidase positive, requires factors V and X for growth.

What type of infections does Haemophilus influenzae commonly cause?

Otitis media, sinusitis, and conjunctivitis.

What is the significance of the polysaccharide capsule in Haemophilus influenzae?

It contributes to the virulence of invasive infections because the PRP is unique

What is the recommended treatment for Haemophilus influenzae otitis media?

Amoxicillin or Augmentin if recurrent or resistant.

What is the recommended treatment for Haemophilus influenzae sinusitis?

Augmentin

What is the recommended treatment for Haemophilus influenzae conjunctivitis?

topical erythromycin

What are the characteristics of Chlamydia trachomatis?

Obligate intracellular pathogen that cannot make ATP and lacks peptidoglycan in its cell wall.

How is Chlamydia trachomatis transmitted?

Through direct contact during birth or via flies in trachoma.

What are the symptoms of neonatal conjunctivitis caused by Chlamydia trachomatis?

Eyelid swelling, watery/mucopurulent discharge, and red thickened conjunctiva.

How is trachoma primarily spread?

Through flies that come into contact with the eyes.

What can repeated infections of trachoma lead to?

Cicatricial disease, causing eyelid scarring and potential blindness.

What is the causative agent of trachoma?

Chlamydia trachomatis.

What diagnostic test is used for trachoma?

Nucleic acid amplification tests (NAATs).

What is a key preventive measure for trachoma?

Facial cleanliness and access to clean drinking water.

What is the treatment for neonatal infections caused by chlamydia?

Oral erythromycin.

What is the treatment for trachoma?

Azithromycin and possibly surgical intervention for trichiasis.

What type of viruses are herpes simplex and Epstein-Barr?

DNA viruses.

What is a characteristic feature of herpesviridae?

They are enveloped, double-stranded DNA viruses that replicate in the nucleus.

What are characteristics of herpes labialis?

painful multiple vesicular lesions on erythematous base

fever

lymphadenopathy

fatigue

What are characteristics of HSV1 keratoconjunctivitis?

blurred vision and photophobia

ocular pain, redness, tearing

corneal scarring and blindness

dendritic ulcer under fluorescein

What is the treatment for HSV?

acyclovir

valacyclovir

Where does EBV establish latency?

B cells by binding to CD21

What is the classic triad of symptoms for infectious mononucleosis caused by EBV?

Fever, pharyngitis, and bilateral posterior cervical lymphadenopathy.

What can happen if a patient with EBV is treated with amoxicillin?

They may develop a widespread, non-itchy maculopapular rash.

What is oral hairy leukoplakia, and what does it indicate?

A benign white patch on the tongue indicating profound immunosuppression, often seen in HIV patients.

What is the characteristic of adenoviruses?

Non-enveloped, double-stranded DNA (linear) viruses that replicate in the nucleus

long fiber capsid protein

How is adenovirus transmitted?

Fecal-oral route, contaminated fomites, aerosols, and respiratory droplets

What are common symptoms of adenovirus infections?

Pharyngitis, conjunctivitis, runny nose, cough

What are characteristics of rhinovirus?

non-enveloped, positive single-stranded RNA, does not replicate at body temo

What are common symptoms of the common cold caused by rhinovirus?

Sneezing, sore throat, runny nose, post-nasal drip, dry cough, mild fatigue, itchy red eyes, headache

What are the characteristics of the mumps virus?

Enveloped, single-stranded RNA virus, HN and fusion surface proteins

What are the clinical signs of mumps parotitis?

Painful swelling of the parotid glands, usually unilateral, with pain when consuming acidic foods

What is the treatment for mumps?

Symptomatic relief, including pain relief and hydration

What are the clinical features of oral candidiasis (thrush)?

White patches in the mouth and throat that can be scraped off, with erythema underneath

What is the treatment for oral candidiasis?

Oral or topical fluconazole

What are the characteristics of Mucor/Rhizopus?

Molds with non-septate hyphae that branch at 90 degrees, opportunistic pathogens

What are the risk factors for mucormycosis?

Diabetes mellitus, immunosuppression, trauma, and iron overload

What is the pathogenesis of mucormycosis?

Hyphae disrupt normal tissue function and can cause thrombosis and necrosis

angioinvasive

What are symptoms of rhinocerebral mucormycoses?

necrotic lesions in paranasal sinuses

rapid progression

What is the critical treatment for Mucormycosis?

Early and aggressive debridement is critical.

Which antifungal is less nephrotoxic and used for Mucormycosis?

Liposomal Amphotericin B.

What antifungals are ineffective against Mucor and Rhizopus?

Voriconazole, fluconazole, and echinocandins.

What are the characteristics of Aspergillus fumigatus?

It has fuzzy growth on agar, septate hyphae that branch at acute angles (45 degrees).

What are common reservoirs for Aspergillus species?

Soil and compost.

What are the risk factors for Aspergillus infections?

Neutropenia, hematologic malignancies, HIV, COPD, CF, and long-term steroid use.

What is the pathogenesis of Aspergillus infections?

Hyphae disrupt normal tissue function, are angioinvasive, and can cause infarction and tissue necrosis.

What is the presentation of sinus aspergillosis?

facial pain, nasal congestion, possible mass effect

What is the diagnostic process and treatment for sinus aspergillosis?

Sinus CT and MRI, then biopsy to confirm aspergillus

treat with surgical debridement and voriconazole