Pharyngeal infection Flashcards
What is infectious mononucleosis?
Clinical syndrome caused by primary EBV (HHV-4) infection aka glandular fever.
What is the aetiology of infectious mononucleosis?
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.
What is the pathophysiology of infectious mononucleosis?
- 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.
What is the epidemiology of infectious mononucleosis: Age? Prevalence?
Bimodal age distribution: 1-6 years (asymptomatic) and 14-20 years. Over 90% of the adult population are EBV-IgG +ve worldwide.
What is the incubation period of infectious mononucleosis?
4-8 weeks; means transmission low.
What are the signs and symptoms of infectious mononucleosis? (x3 +3)
- 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
What are the investigations of infectious mononucleosis? (x5 (x2))
- 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
How is infectious mononucleosis managed? (x3)
- 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
What if infectious mononucleosis is treated with amoxicillin or ampicillin?
This occurs if patient mistakenly diagnosed with bacterial tonsilitis: Patients develop widespread maculopapular rash.
What are the complications of infectious mononucleosis? (x6)
- 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
What is tonsilitis?
Acute infection of the parenchyma of the palatine tonsils.
What is the difference between parenchyma and mesenchyma?
Parenchyma is the functional tissue of an organ; mesenchyma is the connective tissue of an organ.
What is the aetiology of tonsillitis? (x4 and x3)
- 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)
What is the pathophysiology of tonsillitis?
Local inflammatory pathways lead to oropharyngeal swelling, oedema, erythema and pain. May progress to soft palate and uvula.
What is the epidemiology of tonsillitis: Type? Age? When?
Most commonly viral (70%-90%). Most common in children. Most common in winter and early spring.