COMMON VIRAL INFECTIONS

1. COMMON VIRAL INFECTIONS Dr.H.N.Sarker MBBS. FCPS.MACP(USA) Assistant professor Medicine

2. Topics • Introduction • Clinical syndromes caused by viruses • SYSTEMIC VIRAL INFECTIONS

3. Introduction • Viruses are simple infectious agents consisting of a portion of genetic material, RNA or DNA, enclosed in a protein coat. • They are essentially intracellular and cannot exist in a free-living state, needing to infect host cells to survive.

4. Clinical syndromes caused by viruses • Classification/viruses involved Clinical syndromes • DNA VIRUSES(PHAPH) • Poxviruses(Variola) Smallpox • Herpes viruses • Herpes simplex types 1 and 2 Acute/recurrent vesicular rash(Herpes labialis) • Varicella zoster Chickenpox/shingles

5. Clinical syndromes caused by viruses • Cytomegalovirus Acute/recurrent hepatorenal infection • Epstein-Barr virus Infectious mononucleosis Burkitt'slymphoma Nasopharyngeal carcinom

6. Clinical syndromes caused by viruses • Human erythrovirus 19 Erythema infectiosum • Adenoviruses Upper respiratory tract infection/pharyngitis Acute diarrhoea

7. Papovaviruses • Human papillomavirus Common wart • Polyoma (human BK and JC) Progressive multifocal leucoencephalopathy Hepadnavirus Hepatitis B

8. Clinical syndromes caused by viruses • RNA VIRUSES(MRTCRP) • Myxovirus- OrthomyxovirusesInfluenzaA,B ParamyxovirusesMeasles Mumps Respiratory syncytial virus

9. Clinical syndromes caused by viruses • RetrovirusesHIV-1 and 2HIV infection syndrome/AIDS • TogavirusesRubella German measles   Dengue fever  

10. Clinical syndromes caused by viruses Calicivirus Hepatitis-E Rhabdoviruses Rabies Picornaviruses Poliovirus polio Coxsackie viruses pericarditis

11. SYSTEMIC VIRAL INFECTIONS • INFLUENZA • INFECTIOUS MONONUCLEOSIS (IM) • ACQUIRED CYTOMEGALOVIRUS INFECTION • DENGUE • YELLOW FEVER

12. INFLUENZA • A specific acute illness caused by a group of myxoviruses • Aetiology: Influenza A and B virus

13. INFLUENZA • Clinical feature: Sudden onset of pyrexia Generalized ache and pains , headache. Anorexia , nausea and vomiting

14. INFLUENZA Harsh nonproductive cough Acute symptoms subside within 3-5 days but may be followed by post influenza asthenia which may persist for several weeks.

15. INFLUENZA • Complication: Most patients donot develop complication. Trachitis, bronchitis, bronchiolitis , Bronchopneumonia Secondary bacterial invasion by Streptococcus pneumoniae, H. influenzae, Staph. aureus.

16. INFLUENZA • Complication: Rare Toxic cardiomyopathy may cause sudden death Encephalitis Demyelinating encephalopathy Peripheral neuropathy

17. INFLUENZA • Management: Bed rest till fever subsides Parectamol .5-1 gm(1-2 tab) 4-6 hrly Pholcodine 5-10 mg 6-8 hrly Antibiotic if secondary bacterial infection.

18. INFECTIOUS MONONUCLEOSIS (IM) • INFECTIOUS MONONUCLEOSIS (IM) is caused by the Epstein-Barr virus (EBV), a gamma herpes virus.

19. Virology and epidemiology • Epstein-Barr virus (EBV) is a B lymphotropic human herpes virus which is worldwide in distribution. • Primary infection with EBV which occurs during childhood is usually subclinical. • Between 25-70 % of adolescents are usually subclinical.

20. Virology and epidemiology • Between 25-70 % of adolescents and adults who undergo a primary EBV infection develop the clinical syndrome of infectious mononucleosis. • Saliva is the main means of spread, either by droplet infection or environmental contamination in childhood, or by kissing among adolescents and adults.

21. Clinical features • Infectious mononucleosis is defined by the clinical triad of fever, lymphadenopathy, and pharyngitis • combined with the transient appearance of heterophil antibodies and an atypical lymphocytosis.

22. Clinical features • Other features- splenomegaly, palatal petechiae, periorbital oedema, clinical or biochemical evidence of hepatitis, and a non-specific rash.

23. Diagnosis • Diagnosed by the clinical triad of fever, lymphadenopathy, and pharyngitis in typical age group(10-30 yrs). • combined with an atypical lymphocytosis.(20% or more of peripheral lymphocytes must have an atypical morphology). and

24. Diagnosis • the transient appearance of heterophil antibodies by 1.the classical Paul-Bunnell titration Or 2. a more convenient slide test such as the 'Monospot'.

25. Diagnosis • Specific EBV serology (immunofluorescence) can be used to confirm the diagnosis if necessary. • antiviral capsid (VCA) antibodies in the IgM class • antibodies to EBV early antigen (EA) • absent antibodies to EBV nuclear antigen (anti-EBNA).

26. COMPLICATIONS • Common • Severe pharyngeal oedema • Antibiotic-induced rash • Chronic fatigue syndrome (10%)

27. COMPLICATIONS Uncommon Neurological Cranial nerve palsies Polyneuritis Transverse myelitis Meningoencephalitis Haematological Haemolytic anaemia Thrombocytopenia

28. COMPLICATIONS • Renal Glomerulonephritis Interstitial nephritis • Cardiac Myocarditis Pericarditis • Pulmonary Interstitial pneumonitis

29. COMPLICATIONS • Rare Ruptured spleen Respiratory obstruction Arthritis Agranulocytosis Agammaglobulinaemia

30. Management • Treatment is largely symptomatic: aspirin gargles to relieve a sore throat. If a throat culture yields a β-haemolytic streptococcus, a course of erythromycin should be prescribed.

31. Management Amoxicillin and similar semi-synthetic penicillins should be avoided because they commonly induce a maculo-papular rash in patients with IM.

32. Management • When pharyngeal oedema is severe a short course of corticosteroids, e.g. prednisolone 30 mg daily for 5 days, may help to relieve the swelling.

33. Thank you