Infections 2 Flashcards
What causes encephalitis?
Direct invasion of the cerebrum by a neurotoxic virus (such as herpes simplex virus, HSV)
• Delayed brain swelling following a disordered neuroimmunological response to an antigen, usually a virus (postinfectious encephalopathy), e.g. following chickenpox
• A slow virus infection, such as HIV infection or subacute sclerosing panencephalitis (SSPE) following measles.
What are the clinical features of encephalitis?
Fever
Altered conciousness
Seizures
What is the management for encephalitis?
treat with acyclovir in case it’s HSV
PCR and CSF
EEG and CT/MRI show focal changes
What is toxic shock syndrome?
Caused by Staphylococcus aureus and group A streptococci
Fever >39°C
• Hypotension
• Diffuse erythematous, macular rash.
What are the organ dysfunction features in toxic shock syndrome?
Mucositis- conjunctivae, oral mucosa, genital mucosa
Gastrointestinal: vomiting/diarrhoea
• Renal impairment
• Liver impairment
• Clotting abnormalities and thrombocytopenia • Central nervous system: altered consciousness.
What is the management for toxic shock syndrome?
Intensive care support
Areas of infections surgically debrided
Antibiotics often include a thirdgeneration cephalosporin (such as ceftriaxone) together with clindamycin,
What is cytomegalovirus?
Transmitted via saliva, genital secretions or breast milk and more rarely via blood products, organ transplants and transplacentally.
Most children have been infected by 2yrs
Can be treated with ganciclovir or foscarnet
What are the clinical features of CMV?
Pharyngitis and lymphadenopathy are not usually as prominent as in EBV infections
Atypical lymphocytes on blood film
Maternal CMV can result in congenital infection
In immunocompromised- retinitis, pneumonitis, bone marrow failure, encephalitis, hepatitis, colitis, oesophagitis
How do HHV6 and HHV7 present?
Usually infected by 2 yrs by oral secretions of a family member
Exanthem subitum (roseola infantum)
High fever and malaise
Febrile convulsions
How does coxsackie A16 disease present?
Hand, foot and mouth Painful vesicular lesions Often on buttocks too Systemic features are mild Disease subsides in a few days with fluids and analgesia
What are the infective causes of a prolonged fever?
Localised infection
• Bacterial infections: e.g. typhoid, Bartonella
henselae (cat scratch disease), Brucella
• Deep abscesses: e.g. intraabdominal, retro
peritoneal, pelvic
• Infective endocarditis
• Tuberculosis
• Nontuberculous mycobacterial infections:
e.g. Mycobacterium avium complex
• Viral infections: e.g. EBV, CMV, HIV
• Parasitic infections: e.g. malaria, toxocariasis
What are the non-infective causes of a prolonged fever?
Systemic juvenile idiopathic arthritis (SJIA)
• Systemic lupus erythematosus (SLE)
• Vasculitis (including Kawasaki disease)
• Inflammatory bowel disease
• Sarcoidosis
• Malignancy: e.g. leukaemia, lymphoma,
neuroblastoma
• Macrophage activation syndromes: e.g. HLH
(haemophagocytic lymphohistiocytosis)
• Drug fever
• Fabricated or induced illness.
What causes scarlet fever?
Reaction to erythrogenic toxins produced by Group A haemolytic streptococci (usually Streptococcus pyogenes). It is more common in children aged 2 - 6 years with the peak incidence being at 4 years
Spread via respiratory route
How does scarlet fever present?
Incubation period 2-4 days fever: typically lasts 24 to 48 hours malaise, headache, nausea/vomiting sore throat 'strawberry' tongue rash Desquamation in fingers and toes Flushed appearance, rash more obvious in flexures Rough sandpaper texture rash
What is the management for scarlet fever?
Oral penicillin V for 10 days
patients who have a penicillin allergy should be given azithromycin
children can return to school 24 hours after commencing antibiotics
scarlet fever is a notifiable disease
