Pharyngeal infection

Question 1

What is infectious mononucleosis?

Answer 1

Clinical syndrome caused by primary EBV (HHV-4) infection aka glandular fever.

Question 2

What is the aetiology of infectious mononucleosis?

Answer 2

EBV is a gamma-herpes virus (ds-DNA) present in pharyngeal secretions of infected individuals and transmitted by close contact e.g., kissing, sharing eating utensils and less commonly sexual intercourse. There may be reactivation following primary infection from stress or immunosuppression.

Question 3

What is the pathophysiology of infectious mononucleosis?

Answer 3

• LYTIC PHASE: EBV infection develops in oropharyngeal B cells (incorporation of viral DNA into host DNA) which circulate and spread infection to the liver, spleen and peripheral lymph nodes (reticulonodular system)
• Subsequent humoral (heterophile antibodies) and cell-mediated (T cells) immune response and production of IL-2 and IFN-gamma.
• There are also atypical activated CD8+ T cells
• LATENT PHASE: Despite these immune responses, EBV remains latent in lymphocytes (B cells and T cells) and can reactivate.

Question 4

What is the epidemiology of infectious mononucleosis: Age? Prevalence?

Answer 4

Bimodal age distribution: 1-6 years (asymptomatic) and 14-20 years. Over 90% of the adult population are EBV-IgG +ve worldwide.

Question 5

What is the incubation period of infectious mononucleosis?

Answer 5

4-8 weeks; means transmission low.

Question 6

What are the signs and symptoms of infectious mononucleosis? (x3 +3)

Answer 6

• Abrupt onset pharyngitis: oedema and erythema of pharynx, faucial pillars and soft palate with white/creamy exudate on tonsils which becomes confluent (merges into one) within 1-2 days, palatal petechiae
• Fever (less than 39 degrees)
• Lymphadenopathy (this and the two above symptoms form the classic triad)
• Signs of hepatitis: splenomegaly (50%), hepatomegaly (10%), jaundice (5%)
• Headache
• Anorexia
• Sweating

Question 7

What are the investigations of infectious mononucleosis? (x5 (x2))

Answer 7

• BLOODS: LEUKOCYTOSIS, transient raised aminotransferases (ALT, AST) from associated hepatitis (LFTs) • BLOOD FILM: at least 20% atypical lymphocytes
• PAUL-BUNNEL/MONOSPOT TEST: detects presence of IgM heterophile antibodies that are produced in response to EBV infection but are not actually against EBV antigens (as such, 10% of patients don’t have these antibodies)
• THROAT SWABS: exclude streptococcal tonsilitis
• EBV-SPECIFIC ANTIBODIES (x2): IgM or IgG to EBV viral capsid antigen (VCA) tested only in patients with negative monospot test; IgG against Epstein-Barr nuclear antigen (EBNA) appears 6-12 weeks after onset of symptoms and is a resolution antibody. EBNA antibodies exclude acute primary EBV and should prompt consideration of CMV/HIV/toxoplasmosis

Question 8

How is infectious mononucleosis managed? (x3)

Answer 8

• Treat symptoms: analgesics for throat discomfort, NSAIDs for fever
• Corticosteroids (prednisolone) for upper airway obstruction or complications
• ADVICE: advise against contact sports for 2 weeks as increased risk of splenic rupture from splenomegaly

Question 9

What if infectious mononucleosis is treated with amoxicillin or ampicillin?

Answer 9

This occurs if patient mistakenly diagnosed with bacterial tonsilitis: Patients develop widespread maculopapular rash.

Question 10

What are the complications of infectious mononucleosis? (x6)

Answer 10

• Lethargy for months following acute infection
• RESPIRATORY: airway obstruction by oedematous pharynx, secondary bacterial infection, pneumonitis (general term for lung inflammation)
• HAEMATOLOGICAL: haemolytic/aplastic anaemia, thrombocytopenia
• GI/RENAL: splenic rupture, fulminant hepatitis, pancreatitis, renal failure
• CNS: Guillain-Barre syndrome, encephalitis, viral meningitis
• EBV-ASSOCIATED MALIGNANCY: Burkitt’s lymphoma, nasopharyngeal carcinoma, Hodgkin’s lymphoma

Question 11

What is tonsilitis?

Answer 11

Acute infection of the parenchyma of the palatine tonsils.

Question 12

What is the difference between parenchyma and mesenchyma?

Answer 12

Parenchyma is the functional tissue of an organ; mesenchyma is the connective tissue of an organ.

Question 13

What is the aetiology of tonsillitis? (x4 and x3)

Answer 13

• VIRAL: rhinovirus, coronavirus and adenovirus (pharyngitis, gastroenteritis) infections, EBV (in infectious mononucleosis-related tonsillitis)
• BACTERIAL: Group A beta-haemolytic streptococci (aka Strep pyogenes) and other streptococci, Mycoplasma pneumoniae, Neisseria gonorrhoeae (cause in sexually active adolescents; oral-genital sex)

Question 14

What is the pathophysiology of tonsillitis?

Answer 14

Local inflammatory pathways lead to oropharyngeal swelling, oedema, erythema and pain. May progress to soft palate and uvula.

Question 15

What is the epidemiology of tonsillitis: Type? Age? When?

Answer 15

Most commonly viral (70%-90%). Most common in children. Most common in winter and early spring.

Question 16

What are the signs and symptoms of tonsillitis?

Answer 16

• Erythematous and oedematous tonsils
• Dysphagia
• Fever (over 38 degrees)
• Cervical lymphadenopathy
• BACTERIAL: uvulitis, spotting, grey/furry tongue

Question 17

What are the Centor criteria in tonsillitis?

Answer 17

Need three of four to make bacterial infection more likely: C: absence of Cough (common aetiology); E: tonsillar Exudates; N: tender anterior cervical lymph Nodes; T: Temperature (fever); OR: Add 1 point is under 15, OR subtract a point if over 44.

Question 18

What are the investigations for tonsillitis? (x2)

Answer 18

• THROAT CULTURE: test for bacteria; definitive test for bacterial
• STREPTOCOCCAL ANTIGEN TEST: rapid result for bacterial, but less sensitive