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COMMON VIRAL INFECTIONS Dr.H.N.Sarker MBBS. FCPS.MACP(USA) Assistant professor Medicine Topics Introduction Clinical syndromes caused by viruses SYSTEMIC VIRAL INFECTIONS 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. Clinical syndromes caused by viruses Classification/viruses involved syndromes Clinical DNA VIRUSES(PHAPH) – Poxviruses(Variola) – Herpes viruses Smallpox Herpes simplex types 1 and 2 Acute/recurrent vesicular rash(Herpes labialis) Varicella zoster Chickenpox/shingles Clinical syndromes caused by viruses Cytomegalovirus Acute/recurrent hepatorenal infection Epstein-Barr virus Infectious mononucleosis Burkitt'slymphoma Nasopharyngeal carcinom Clinical syndromes caused by viruses – Human erythrovirus 19 – Adenoviruses tract infection/pharyngitis Erythema infectiosum Upper respiratory Acute diarrhoea – Papovaviruses Human papillomavirus Common wart Polyoma (human BK and JC) Progressive multifocal leucoencephalopathy Hepadnavirus Hepatitis B Clinical syndromes caused by viruses – RNA VIRUSES(MRTCRP) – Myxovirus- Orthomyxoviruses Paramyxoviruses InfluenzaA,B Measles Mumps Respiratory syncytial virus Clinical syndromes caused by viruses – Retroviruses HIV-1 and 2HIV infection syndrome/AIDS – Togaviruses Rubella German measles Dengue fever Clinical syndromes caused by viruses Calicivirus Hepatitis-E Rhabdoviruses Rabies Picornaviruses Poliovirus Coxsackie viruses polio pericarditis SYSTEMIC VIRAL INFECTIONS INFLUENZA INFECTIOUS MONONUCLEOSIS (IM) ACQUIRED CYTOMEGALOVIRUS INFECTION DENGUE YELLOW FEVER INFLUENZA A specific acute illness caused by a group of myxoviruses Aetiology: Influenza A and B virus INFLUENZA Clinical feature: Sudden onset of pyrexia Generalized ache and pains , headache. Anorexia , nausea and vomiting 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. INFLUENZA Complication: Most patients donot develop complication. Trachitis, bronchitis, bronchiolitis , Bronchopneumonia Secondary bacterial invasion by Streptococcus pneumoniae, H. influenzae, Staph. aureus. INFLUENZA Complication: Rare Toxic cardiomyopathy may cause sudden death Encephalitis Demyelinating encephalopathy Peripheral neuropathy 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. INFECTIOUS MONONUCLEOSIS (IM) INFECTIOUS MONONUCLEOSIS (IM) is caused by the Epstein-Barr virus (EBV), a gamma herpes virus. 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. 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. 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. Clinical features Other featuressplenomegaly, palatal petechiae, periorbital oedema, clinical or biochemical evidence of hepatitis, and a non-specific rash. 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 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'. 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 (antiEBNA). COMPLICATIONS Common – Severe pharyngeal oedema – Antibiotic-induced rash – Chronic fatigue syndrome (10%) COMPLICATIONS Uncommon Neurological Cranial nerve palsies Polyneuritis Transverse myelitis Meningoencephalitis Haematological Haemolytic anaemia Thrombocytopenia COMPLICATIONS Renal Glomerulonephritis Interstitial nephritis Cardiac Myocarditis Pericarditis Pulmonary Interstitial pneumonitis COMPLICATIONS Rare Ruptured spleen Respiratory obstruction Arthritis Agranulocytosis Agammaglobulinaemia 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. Management Amoxicillin and similar semi-synthetic penicillins should be avoided because they commonly induce a maculo-papular rash in patients with IM. 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.