Common infections Flashcards
Definition of pharyngitis
Infection or irritation of the pharynx and/or tonsils
Most cases are of viral origin, benign + self-limiting
Which specialty encounters the majority of pharyngitis patients?
Paediatrics
Causative organisms in pharyngitis?
Viral
- rhinovirus
- corona virus
- adenovirus
- parainfluenza
- influenza
- Epstein-Barr
- cytomegalovirus
Bacterial
- GABHS (15-30% paediatric cases; 5-10% adult cases)
- mycoplasma pneumoniae
Clinical presentation in pharyngitis
Sore throat Odynophagia Fever Anterior cervical lymphadenopathy Pharyngotonsillar exudate NO cough
Treatment of pharyngitis
- Oral penicillin is 1st line (94% clinical response and 84% strep eradication rate)
- Cephalosporins 1st line in pt w/ history of recent AB use, recurrent pharyngitis infection, high community penicillin failure rate
- Macrolides if penicillin or cephalosporins C/I
Definition of tonsillitis
Inflammation of the tonsils
Causative organisms in tonsillitis
Viral
- Epstein-Barr virus
- cytomegalovirus
- herpes simplex virus
- adenovirus
Bacterial
- GABHS
Clinical presentation of tonsillities
Sore throat Fever Halitosis Dysphagia Odynophagia Tender cervical lymph nodes Tonsillar exudate
What is dysphagia?
Difficulty swallowing
What is odynophagia?
Painful swallowing
Complications of tonsillitis
Peritonsillar abscess (Quinsy)
Peritonsillar cellulitis
GABHS complications
Complications of GABHS
Scarlet fever
Acute poststreptococcal glomerulonephritis
Rheumatic fever
Treatment of tonsillitis
- Oral penicillin
- Penicillin allergy
- cephalosporin
- macrolide
- clindamycin - Recurrent tonsillitis
- amoxicillin/clavulanate
Definition of rhinosinusitis
Inflammation of the lining of the nasal cavity and paranasal sinuses
Causative organisms of rhinosinusitis
Viral
- common cold
Bacterial
- strep pneumonia
- strep pyogenes
- morazella catarrhalis
- staph aureus
Clinical presentation of sinusitis
Pain + pressure over cheek radiating to frontal region/teeth (often maxillary sinuses affected) Postnasal discharge Blocked nose Cough Discoloured nasal discharge Poor response to decongestants
Complications of sinusitis
Orbital cellulitis
Osteomyelitis
Intracranial extension
Cavernous sinus thrombosis
What ocular sign is present in caverneous sinus thrombosis?
Ophthalmoplegia
Acute viral rhinosinusitis treatment
Symptomatic
Analgesic
Antipyretic
Saline irrigation
Intranasal glucocorticosteroids in underling allergic rhinitis
Oral decongestants in Eustachian tube dysfunction
Intranasal decongestants e.g oxymetazoline (no evidence)
Antihistamine
Mucolytics
Bacterial sinusitis treatment
1st line - Amoxicillin w/wo clavulanate - Doxycycline 2nd line - fluoroquinolones (levofloxacin, moxifloxacin) - clindamycin
When prescribing intranasal glucocorticosteroids, which patients must you take caution with?
Hypertensive
Cardiovascular disease
Angle closure glaucoma
Bladder neck obstruction
Causative organisms of community acquire pneumonia (CAP)
Bacterial - strep pneumo - haemophilus influenza - moraxella catarrhalis Above account for 85% of cases
Which organism is a likely cause of CAP in a chronic alcoholic?
Klebsiella pneumoniae
Which organism is a likely cause of CAP in post-influenza patient?
Staph aureus
Which organism is a likely cause of CAP in bronchiectasis patient?
Pseudomonas aeruginosa
Which organism is a likely cause of CAP in cystic fibrosis patient?
Pseudomonas aeruginosa
Atypical causes of CAP?
Chlamydia pneumoniae
Mycoplasma pneumoniae
Legionella spp
Clinical presentation of CAP?
Fever
Productive cough
Pleuritic chest pain
How does one diagnose CAP?
Clinically
CXR
Outpatient treatment of CAP?
Patient <65yo w/o comorbidities or AB exposure in past 90 days
- oral high dose amoxicillin
- oral macrolide/azalide in presence of severe betalactam allergy
Patient >65 yo, w/ comorbidities or AB within past 90 days
- oral amoxicillin-clavulanate
- oral 2nd generation cephalosporin
Hospital treatment of CAP?
Patient <65yo w/o comorbidities or AB exposure in past 90 days
- IV amipicillin
- IV penicillin if above unavailable
Patient >65 yo, w/ comorbidities or AB within past 90 days
- IV amoxicillin-clavulanate
- cefuroxime
- 3rd gen cephalosporin (ceftriaxone; cefotaxime)
Severe CAP
- same options as above + macrolide
Definitive therapy based on drug susceptibility testing
Role of respiratory fluoroquinolones in treatment of CAP
Moxifloxacin, levofloxacin
Reserved for patients with
- severe beta lactam allergy
- no alternative to beta-lactam/macrolide treatment
Pathophysiology of urinary tract infections
Ascending colonization of the urinary tract
a) vaginal flora
b) perineal flora
c) fecal flora
Causative organisms of acute cystitis
Escherichia coli Staphylococcus sacrophyticus Klebsiella Proteus Enterobacter Pseudomonas
Clinical presentation of acute cystitis
Dysuria Frequency Urgency Haematuria Suprapubic discomfort
Diagnosis of acute cystitis
Urine dipstix
Midstream clean catch urine specimen
- urine microscopy
- urinalysis
Treatment of acute cystitis
1st line
- nitrofurantoin 100mg BD x5days
- trimpethoprim/sulfamethoxazole 960mg BD
- fosfomycin tromeatamol
2nd line
- fluoroquinolones (ofloxacin, ciprofloxacin, levofloxacin)
- beta lactams (amoxyclav, cefaclor, cefpodoxime)
Why are beta lactams not recommended for 1st line acute cystitis treatment?
Widespread e.coli resistance rates >20%
Why are fluoroquinolones not recommended for 1st line acute cystitis treatment?
Preserve effectiveness against resistance
What are options for acute cystitis treatment in pregnancy?
Penicillin
Cephalosporins
Definition of pyelonephritis
Infection of the renal pelvis + kidney
Which population group is pyelonephritis most often seen in?
Most often seen in young adult women
Clinical presentation of pyelonephritis?
Fever
Flank pain
Malaise
WBCs + bacteria in urine
Causative organisms of pyelonephritis?
E.coli
Klebsiella pneumoniae
Staphylococcus saprophyticus
Rare: Candida Enterococcus Enterobacteriaeceae Pseudomonas aeruginosa Ureaplasma spp
Outpatient treatment of acute pyelonephritis
Empiric therapy:
- ceftriaxone IV 1 g daily for 48 hours, or until fever subsides OR
- entamicin IV 6 mg/kg daily (ensure normal renal function)
- piptaz
Switch to oral therapy as soon as the patient is able to take oral fluids:
- amoxicillin/clavulanic acid, oral, 875/125 mg 12-hourly for 7 days.
Change antibiotics according to culture and
sensitivity result
Nitrofurantoin in acute pyelonephritis treatment
Mechanism of action
Bioavailability
Susceptible strains
It inactivates or alters bacterial ribosomal proteins and other macromolecules that may interfere with metabolism and cell wall synthesis.
Bioavalability increased with food
Susceptible strains e.coli , klebsiella, enterobacter, staphylococcus sacrophyticus and aureus
Quinolones in acute pyelonephritis treatment
Mechanism of action
Inhibits bacterial DNA gyrase
Responsible for cutting and supercoiling DNA
Post AB effect against gram negative and
positive organisms
Quinolones in acute pyelonephritis treatment
Pharmacokinetics
80% systemic available after oral dose
Bioavailability decreased by antacids
Large volume of distribution including eye, lungs, prostatic fluid, CSF, bone and cartilage
Entero-hepatic cycle: AB in urine 5 days after stopping Rx
t½=4 hours. Rx less often than t½ (post AB effect)
Removed by glomerular filtration and tubular secretion
Less active in acidic urine
Side effects of quinolones?
GIT CNS Hypersensitivity QT prolongation/ torsades de pointes Liver and renal damage Reversible arthralgia Tendonitis/ tendon rupture Drug interactions
Dosages of quinolones in acute pyelonephritis treatment
Ciprofloxacin: - 250-500 mg bd p.o - 200-400mg IVI 8-12 hourly Norfloxacin: - 400 mg bd for 7-10 days - (3 days Rx if uncomplicated) Ofloxacin: - 100 mg bd 3-7 days - 200 mg bd (pyelonephritis)
Co-trimoxazole in acute pyelonephritis treatment
Mechanism of action
Sulfamethoxazole + trimethoprim
Inhibits folic acid production
Complications of co-trimoxazole use?
Hypersensitivity reaction (SJS)
Aplastic anemia
Hemolytic anemia
Contraindications of co-trimoxazole use?
Newborn
Porphyria
G6PD deficiency
What score can be used for assessing a sore throat?
McIsaac score for % of GAS infection
Which antibiotics are not recommended for empiric therapy of bacterial rhinosinusitis?
2nd/3rd generation cephalosporins (cefuroxime, cefpodoxime)
Macrolides (clarithromycin)
Trimethoprim sulfamethoxazole
Discuss treatment of acute otitis media
Ibuprofen
Paracetamol
Topical benzocaine if no perforation
- Amoxicillin
- Augmentin
- Macrolides/clindamycin
- Cephalosporins
How long do we treat children 2 years, children with tympanic
membrane perforation, and children with recurrent AOM for?
10 days
How long do we treat children 2 years without a history of recurrent AOM for?
5-7 days
Which infectious conjunctivitis is more likely?
Viral > bacterial
Which population group is bacterial conjunctivitis more likely in?
Children > adults
Name the red flag signs of ophthalmology
VA reduction Ciliary flush Photophobia Severe FB sensation Corneal opacity Fixed pupil Severe headache w/ nausea
Discuss the treatment of conjunctivitis
If bacterial:
- Erythromycin ophthalmic ointment
- Polymixin-trimethoprim drops
- Fluoroquinolone ophthalmic drops
- Azithromycin drops
What is the common cause of anterior blepharitis?
Staph
Seborrhea
What is the common cause of posterior blepharitis?
Meibomian gland dysfunction
Rosacea
Seborrheic dermatitis
Discuss treatment of blepharitis
Topical/systemic antibiotics
Topical glucocorticoids
Which microorganisms most commonly cause keratitis?
Bacterial
- staph aureus
- pseudomonas aeruginosa
Viral
- herpes simplex
- adenovirus
What is a hordeolum?
An acute purulent inflammation of the eyelid
AKA a stye
Discuss treatment of hordeola
Warm compress 15min x 4/d
Incision and curettage
In which patients do you not treat cystitis with a fluoroquinolone?
Pregnancy
Children
