Infections Flashcards
(18 cards)
Viral hepatitis
All viral hepatitis are notifiable disease to UK health Security Agency
5 - 15% develop chronic hepatitis B
Treated, 10% develop chronic hepatitis C
Presentating features in viral hepatitis
- Abdo pain
- Fatigue
- Flu-like illness
- Pruritus
- Muscle and joint aches
- N + V
- Jaundice
Liver function tests in viral hepatitis
“Hepatitic picutre” = high transminases (AST and ALT), high bilirubin, less increase of ALP
Key viral markers in hepatitis B
- Surface antigen (HBsAg) – active infection
- E antigen (HBeAg) – a marker of viral replication and implies high infectivity
- Core antibodies (HBcAb) – past (IgG) or current (IgM) infection
- Surface antibody (HBsAb) – implies vaccination or past or current infection
- Hepatitis B virus DNA (HBV DNA) – a direct count of the viral load
Gangrene
Tissue death due to lack of blood supply or infection or both.
Commonly extremities e.g. toes, fingers
Medical emergency
Causes:
- Arterial occlusion: atherosclerosis, thrombosis
- Infection: bacteria
- Trauma
- Chronic conditions: diabetes
Types of gangrene
- Dry gangrene: chronic ischaemia e.g. PAD
- Wet gangrene: sudden lack of blood supply + bacterial infection = rapid spread and systemic symtoms > sepsis
- Gas gangrene = Clostridium bacteria gas + toxins > septic shock (tachy, hypotension)
- Necrotising fascitis
Types of gangrene
- Dry gangrene: chronic ischaemia e.g. PAD
- Wet gangrene: sudden lack of blood supply + bacterial infection = rapid spread and systemic symtoms > sepsis
- Gas gangrene = Clostridium bacteria gas + toxins > septic shock (tachy, hypotension)
- Necrotising fascitis
Management of gangrene
- Control infection, restore blood supply and remove necrotic tissue
- Surgical: debridement, amputation, revascularsation e.g. angioplasty
- Abx: empirical broad-spectrum, then targeted based on culture
- Supportive: fluid resus, analgesia and nutritional support, tx of comorbid
- Hyperbaric O2 therapy in gas gangrene
Haemochromatosis
Autosomal recessive iron storage disorder = iron overload, excess total body iron + iron deposition in tissue
Presentation of haemochromatosis
Usually > 40 when symptomatic
Females = elimination via menstruation
Features: chronic tiredness, joint pain, pigmentation (Bronze skin), testicular atrophy, ED, amenorrhoea, mood/memory disturbance, hepatomegaly
Diagnosis of haemochromatosis
- Initial: serum ferritin
- Transferrin sats to differentiate iron overload (high) vs other causes (normal)
- Genetic testing if serum ferritin + transferrin sats both high
- MRI for iron conc (to avoid biopsy)
Management and complications of haemochromatosis
- Venesection (regularly removing blood to remove excess iron – initially weekly)
- Monitoring serum ferritin
- Monitoring and treating complications
Infective endocarditis
Infection of the endothelium of the heart, most commonly affects valves. Acute, subacute or chronic
Staphylococcus aureus, streptococcus viridans group
Risk factors: IVDU, structual heart pathology (e.g.valvular/congenital), prosthetic heart valves, pacemakers, CKD, immunocompromised, previous hx of IE
Presentation of infective endocarditis
Fever, fatigue, night sweats, muscle aches, anorexia
On exam:
- New heart murmur
- Splinter haemorrhages
- Petechiae on trunk, limbs, oral mucosa or conjunctiva
- Janeway lesions (painless red flat macules on palms and soles)
- Osler’s (OW) nodes (painful red/purple nodules on fingers and toes)
- Roth spots (retinal haemorrhages)
- Splenomegaly and finger clubbing if chronic
Investigations for infective endocarditis
- Blood cultures before abx, 3x sepeerated by 6 hours, different sites
- Echo = initial imaging, transoesophageal echo (TOE) peferred
Modified Duke Criteria for diagnosis:
- Major + 3 minor
- 5 minor
Major:
- Persistently positive blood cultures (typical causative microorganism
- Vegetation on echo
Minor:
- Predisposition
- Fever > 38
- Vascular phenomena
- Immunological phenomena
- Microbiological phenomena (culture not qualifying as major criterion)
Management of infective endocarditis
- Admission and management by specialist teams (e.g. infectious diseases
- IV broad spectrum abx: typically amoxicillin +/- gentamicin, 4 weeks if native heart valves, 6 weeks if prosthetic
- Surgery if HF, large vegtations or abscesses, IV abx ineffective
Complications of infective endocarditis
- Heart valve damage, causing regurgitation
- Heart failure
- Infective and non-infective emboli (causing abscesses, strokes and splenic infarction)
- Glomerulonephritis, causing renal impairment
Prophylaxis not routinrly given for dental/non-dental procedures, considered if high-risk, good oral care as prevention
