Upper respiratory tract infections

Question 1

COMMON COLD

Answer 1

• Rhinitis/rhinorrhoea, fever, cough
• Dx by clinical appearance
• Rhino virus causes majority of cases
• Diagnosis important when LRT involved e.g. flu, RSV in children

Question 2

STOMATITIS

Answer 2

• Vesicular or ulcerative eruptions on tongue or palate usually by infection of enterovirus or herpes simplex

Question 3

PHARYNGITIS/ TONSILLITIS

Answer 3

• 70% acute sore throat caused by virus (commonly adenovirus)
• Bacterial causes include Strep. pyogenes, Neisseria Gonorrhoeae, Corynebacterium diphtheria, Haemophilis influenza
• Strep. pyogenes infection can also causes complications such as scarlet fever, rheumatic fever, acute glomerulonephritis
• Rx- phenoxymethylpenicillin(oral), benzathine penicillin (IM), roxithromycin (sensitive to penicillin)

Question 4

DIPHTHERIA

Answer 4

• Toxin-producing strain of corynebacterium diphtheria which can colonise in pharynx, larynx, nose
• Can cause life threatening respiratory obstruction
• Disease requires production of exotoxin
• Signs include ulcer, necrotising exudate, ‘false membrane’, extensive inflammation
• Rx- antibiotics and antitoxin, immunisation(preventative)
• Rare in developed countries, common in undeveloped

Question 5

CYTOMEGALOVIRUS (CMV)

Answer 5

• Largest human herpes virus – species specific
• Transmitted by saliva, urine, semen, blood, cervical secretion
• Clinically silent URTI- generally asymptomatic glandular fever like illness
• Not cleared by antibody or CMI response – shed in saliva and urine
• Can reactivate in macrophage and important in Tx

Question 6

EPSTEIN-BARR VIRUS (EBV)

Answer 6

• Transmitted via exchange of saliva
• Replicates mostly in B lymphocytes, remains latent despite antibiotics and CMI response
• Disease mostly attributed to immune response (release of cytokines)- infectious mononucleosis in adolescents
• Characterised by atypical lymphocytes in blood smear
• Treatment with amoxicillin causes macular rash
• Cancers associated: Burkitt’s lymphoma (Africa, PNG), B-cell lymphoma (immunodeficient), nasopharyngeal carcinoma (Asia)

Question 7

LARYNGITIS

Answer 7

• Croup-acute laryngotracheobronchitis- commonly in children 1 to 3 years and generally self limiting
• Hoarseness, barking cough – no treatment/corticosteroid for severe
• Commonly due to Parainfluenza virus

Question 8

ACUTE EPIGLOTTITIS (SUPRAGLOTTITIS)

Answer 8

• Organism- Haemophilis influenza
• Rx- maintenance of airway and control of infection so urgent transport to hospital required
• Large epiglottis can be seen in x-ray

Question 9

OTITIS EXTERNA

Answer 9

• Bacteria include Pseudomonas aeruginosa, Staph. aureus but most commonly Strep. pneumonia, Haemophillis influenza and viruses
• Rx- amoxicillin for children orally
• Can become necrotising causing osteomyelitis in elderly, immunocompromised or diabetic almost always due to Pseudomonas aeruginosa

Question 10

OTITIS MEDIA

Answer 10

• Commonly in infants and small children; 50% due to viruses – self limiting
• Bulging ear drum, fluid in middle ear – many children with URI have mild inflammation in middle ear
• Symptomatic treatment with Ab. If not treated- chronic discharge, perforated ear drum, impaired hearing