Infection - Level 1 Flashcards
Preventative measures of surgical site infections in theatre?
o Staff preparation
o No hand jewellery, artificial nails, nail polish
o Hand decontamination
o Staff theatre wear and sterile gowns
Patients preparation before surgery to prevent surgical site infections?
o Advise patient to have shower using soap, either day before or on day of surgery
o If hair removal needed, use single use electric clippers on day of surgery (shaving increases risk of infection)
o Antibiotic prophylaxis
Give to clean surgery involving placement of prothesis or implant, clean-contaminated surgery and contaminated surgery
Give single dose IV antibiotics before surgery
Wound management in prevention of surgical site infections?
o Aseptic dressing changes
o Use sterile saline for wound cleansing up to 48 hours after surgery
o May shower safely 48 hours after surgery
o Tap water for wound cleansing after 48 hours if the surgical wound has separated or has been surgically opened to drain pus
Definition of wound dehiscence?
- Wound fails to heal and re-opens a few days after surgery
Types of wound dehiscence?
o Superficial dehiscence – skin wound alone fails
o Full thickness dehiscence – rectus sheath fails to heal and bursts with protrusion of small bowel and omentum
Risk factors of wound dehiscence?
o Patient
Age, male, DM, steroids, smoking, obesity
o Intra-operative
Emergency surgery, abdominal surgery, long surgery, wound infection (most common), poor technique
o Post-operative
Prolonged ventilation, blood transfusion, patient coughing, radiotherapy
Clinical features of wound dehiscence?
o Visible opening of wound, healing poorly following operation
o Typically, 5-7 days post-operatively
o Full thickness dehiscence – bulging of wound and seepage of pink serous or blood-stained fluid
Investigations of wound dehiscence?
o Clinical diagnosis
o If infection – wound swabs for culture
o Bloods – FBC, CRP, blood cultures (if signs of sepsis)
Management of superficial wound dehiscence?
Washing out wound with saline and then wound care (pack with gauze)
Wound heals by secondary intention which may take several weeks
Larger wounds – Vacuum-assisted closure full thickness
Management of full wound dehiscence?
Analgesia IV fluids Broad spectrum IV antibiotics Cover wound in saline-soaked gauze Urgent return to theatre for re-closure of wound – large uninterrupted sutures
Definition of surgical site infections?
- Infection that occurs in the incision created by surgical procedure
- Doubles mortality rates and increasing overall length of stay
Risk factors of surgical site infections?
Patient Factors Age, poor nutritional states DM CKD Immunosuppression Smoker
Operation Factors Preoperative shaving Long operation Insertion of surgical drain Poor wound closure
Symptoms of surgical site infections?
o Appear 5-7 days post-procedure – can be weeks after o Spreading erythema o Localised pain o Pus/Discharge from wound o Wound dishiscence o Persistent pyrexia
Investigations of surgical site infections?
o Wound swab – cultures
o Bloods – FBC, CRP, cultures (if systemic features)
Management of surgical site infections?
o Remove sutures or clips, allow drainage of pus
o Empirical antibiotics (follow local guidelines depending on wound)
Tailor according to culture
Definition of stoma?
Stoma = created opening into hollow organ, covered by removable pouch that collects output for disposal
o E.g. – colostomy (opening into large bowel), ileostomy (ileum), urostomy (urinary system)
Inspecting stoma - site?
LIF (colostomy), RIF (ileostomy)
Inspecting stoma - spout?
spouted = ileostomy as small bowel contents irritant, flush to skin = colostomy
Inspecting stoma - consistency?
colostomy output is thick and sludgy, whereas ileostomy is waterier and greener
Inspecting stoma - complications?
Stenosis
Hernia
Prolapse
Retraction
Dehiscence of stoma
o If healthy looking & no bowel herniating – clean and encourage secondary healing
o If red, infected, bowel herniating – emergency surgery
Infarction (jet black)
o Caused by:
Tight opening – need surgery to excise & replace
Bowel necrosis – emergency surgery
Palpation of stoma?
Ask to cough to feel parastomal hernia
Digitate stoma to assess stenosis and patency
Definition of anastomotic leak?
- Leak of luminal contents from surgical join, usually following GI surgery
Risk factors of anastomotic leak?
o Steroids o DM o Obesity o Emergency surgery o Long operation o Oesophageal-gastric or rectal anastomosis
Symptoms and signs of anastomotic leak?
o Usually 5-7 days post-operative
o Abdominal pain and fever
o Prolonged ileus
o Delirium
Investigations of anastomotic leak?
Patients not progressing as expected or deteriorating after surgery should be suspected to have an anastomotic leak until proven otherwise
o Urgent CT scan with contrast of abdomen and pelvis
o Urgent Bloods (FBC, CRP, U&E, LFTs, clotting, VBG)
Management of anastomotic leak - initial management?
NBM (may need TPN if long-term NBM)
Broad spectrum IV antibiotics
IV fluids
Urinary catheter
Management of anastomotic leak - definitive management?
o Urgent Senior review
Minor leaks – conservative – IV antibiotics
Large leaks – Percutaneous drainage
Large leaks with sepsis – exploratory laparotomy with wash outs and drain insertions
Definition of atelectasis?
o Partial collapse of small airways resulting in abnormal lung function
o Important as precursor to post-op pulmonary complications
Pathology of atelectasis?
o Airway collapse due to combination of airway compression, alveolar gas resorption intra-operatively and impaired surfactant production
o Reduced airway expansion predispose to pulmonary complications (hypoxia, reduced lung compliance, infection, ARDS)
Risk factors of atelectasis?
o Age o Smoking o General Anaesthesia o Long surgery o Prolonged bed rest o Poor post-operative pain control
Symptoms of atelectasis?
o Develops within 24h of surgery
o Increased RR
o Reduced O2 sats
o Low grade fever
Investigations of atelectasis?
o CXR – small areas of airway collapse
o Ct more sensitive if unclear
Management of atelectasis?
o Oxygen (if low sats)
o Deep breathing exercises
o Chest physio
Definition of infectious mononucleosis (EBV)?
- Glandular fever is an infectious, usually self-limiting disease
- Virus has tropism for B lymphocytes and epithelial cells of pharynx
- EBV infection leads to a lifelong latent carrier state
Epidemiology of infectious mononucleosis (EBV)?
- 50% of children will have detectable EBV antibodies by 5 years of age
- 90% of people will have antibodies by 25 years of age
Cause of infectious mononucleosis (EBV)?
- Caused by the Epstein-Barr virus (EBV), a member of the human herpes virus family (hHV4)
Incubation period of infectious mononucleosis (EBV)?
33-49 days
Spread of infectious mononucleosis (EBV)?
contact with saliva through kissing or sharing food and drink
Symptoms of infectious mononucleosis (EBV)?
- Most people are asymptomatic
- In most people, the disease is self-limiting and lasts 2–3 weeks
- Symptoms:
o Fever
o Malaise, myalgia, rigors, anorexia
o Lymphadenopathy
o Tonsillopharyngitis – sore throat
Enlargement, whitewash exudate of tonsils and palatal petechiae
o Hepatosplenomegaly
o Maculopapular rash
o Jaundice
Diagnostic confirmation of infectious mononucleosis (EBV) - in >12 year olds?
o FBC with differential WCC and Monospot heterophile test in 2nd week of illness
Lymphocytosis with >20% atypical or reactive lymphocytes or >10% atypical lymphocytes and >50% of total WCC
If Monospot negative and still symptoms – repeat after 1 week
If rapid diagnosis needed – blood for EBV IgM serology
Diagnostic confirmation of infectious mononucleosis (EBV) - in <12 year olds or immunocompromised?
o Bloods for EBV IgM serology after person ill for >7 days
o If two monospots negative – test for CMV and toxoplasmosis
Other investigations to consider in infectious mononucleosis (EBV)?
LFTs – Raised AST/ALT
Management of infectious mononucleosis (EBV)?
- Supportive
o Ibuprofen and paracetamol - Avoid kissing, sharing eating or drinking utensils and clean all items thoroughly
- Avoid contact sports or heavy lifting for 1 month of illness (risk of splenic rupture)
- If airway compromised, then corticosteroids could be used
- AVOID AMPICILLIN/AMOXICILLIN AS CAUSES MACULOPAPULAR RASH IN CHILDREN AFFECTED WITH EBV
When to admit patient with infectious mononucleosis (EBV)?
- Glandular fever confirmed/suspected & stridor/dehydration/suspected splenic rupture/complications
Prognosis of infectious mononucleosis (EBV)?
- Disease is self-limiting and lasts 2-3 weeks
- Sore throat severe for 3-5 days then resolves over a week
Complications of infectious mononucleosis (EBV)?
- Upper Airway Obstruction – due to tonsil enlargement or quinsy
- Splenic rupture – usually occurs 3 weeks after acute illness
- Neurological – aseptic meningitis, encephalitis, facial nerve palsy, GBS, optic neuritis, hemiplegia
- Haemolytic anaemia
- Thrombocytopenia
- Neutropenia
- Pericarditis and myocarditis
- Abnormal AST/ALT LFTs
- Risk factor for Burkitt’s lymphoma, Hodgkin’s lymphoma, B-cell lymphoma and other cancers
Description of antibiotic associated diarrhoea (C.diff infection)?
- Antibiotics cause diarrhoea via one of following mechanisms:
o Disruption of bowel microbiota and mucosal integrity
o Direct effect of antibiotic (erythromycin increases gastric emptying)
o Overgrowth of toxin-producing strains of Clostridium difficile (Gram-positive anaerobic bacillus)
Spread of C.diff?
- Spread via faecal-oral or spores (which live on environmental surfaces)
Epidemiology of C.diff?
- 20-30% of antibiotic associated diarrhoea due to C.diff
- Asymptomatic colonisation of C.diff in up to 2% of adults, up to 50% in infants
Risk factors of C.diff?
o >65
o Antibiotics - Clindamycin, cephalosporins, fluroquinolones, broad-spectrum penicillins (ampicillin, amoxicillin, co-amoxiclav)
o Hx of C.diff
o Exposure to other cases
o PPI/H2RA use
o Abdominal surgery, CKD, IBD, immunosuppression
o Hospitalisation
Risk factors of fulminant C.diff colitis?
> 70, leucocytosis, haemodynamically unstable
Symptoms and signs of C.diff?
- Pyrexia
- Colic Pain
- Diarrhoea – watery stools, pain relieved by defaecation and urgency
Severity assessment of C.diff?
o Mild – no leucocytosis, <3 episodes of loose stools per day
o Moderate – Leucocytosis, 3-5 loose stools per day
o Severe – WCC >15x109/L, temperature >38.5, increased serum creatinine
o Life threatening – hypotension, ileus, toxic megacolon, CT evidence of severe disease
Tests to perform if suspected of C.diff?
o Stool Sample
If symptomatic and contact with person with C.diff or recent antibiotics/PPIs/hospital admission
o Bloods
FBCs, U&Es
Management of C.diff - if severe?
admit to hospital
Management of C.diff - if admission not needed?
Stop antibiotic
Manage fluid losses and symptoms as for gastroenteritis
Avoid loperamide
Hygiene advice
Management of C.diff -in hospital - if C.diff positive?
Antibiotics - Mild-moderate 1st episode:
• Oral metronidazole 400mg TDS for 10-14 days
Antibiotics - Severe 1st episode or second or subsequent episodes:
• Vancomycin 125mg QDS PO for 10-14 days (fidaxomicin can be used for subsequent episodes)
If not responding – oral vancomycin + IV metronidazole for 10-14 days
Avoid loperamide, review daily in primary care, do not return to work until free of diarrhoea for 48 hours
Complications of C.diff?
- Pseudomembranous colitis
- Toxic megacolon
- Perforation of colon
- Sepsis
- Death
Prognosis of C.diff?
- Mortality – up to 25% in frail patients
- Recurrence – 20% for 1st episode and 50% after 2nd episode
Definition of MRSA - colonisation and infection?
- Strains of S.Aureus which are resistant to common antibiotics (B-lactams – flucloxacillin)
o Colonisation = people carry MRSA on skin, gut or nose but no symptoms
o Infection = MRSA causes harm and requires treatment
Types of MRSA?
o Healthcare-associated MRSA – had contact with healthcare services, inpatient >48 hours
o Community-associated MRSA – identified in community setting or within 48 hours of hospital admission
Epidemiology of MRSA?
- S.aureus nasal carriage in up to 1/3
- MRSA in 0.5%
Cause of MRSA?
Metacillin resistant staphylococcus aureus
Transmission of MRSA?
- Transmitted via direct contact with infect skin/contaminated objects or environmental surfaces, enters through tissue
Risk factors of hospital-associated MRSA?
o Admission o Resident in long term care or crowded facilities o Previous exposure to antibiotics o Hx of MRSA infection/colonisation o IVDU o Immunosuppression
Risk factors of community acquired MRSA?
o IVDU
o MSM
o Athletes
o Long-term care/prisons
Investigations in primary of MRSA?
o Consider MRSA if patient with potential S.aureus infection which: Has risk factors for MRSA No response to treatment Recurrent skin infections o If patient well – sample for M, C
Investigations in secondary care of MRSA?
o Swabs from two sites (anterior nose, groin) & skin lesions/catheters/insertion sites – culture
o Repeat screen after 30 days admission
Management of MRSA - primary care?
o Urgent admission if suspected/confirmed MRSA and complicated infection (sepsis, endocarditis, pneumonia, osteomyelitis)
o If uncomplicated infection:
Discuss with microbiology and follow up in 48 hours
o Advice:
Keep all wound, cuts clean and covered until healed
Wear gloves when changing dressings
Wash hands with soap and water regularly
Avoid sharing towels, razors, toothbrushes, soaps, clothing
Management of MRSA -advice?
Isolation
Wash hands and stethoscope
Eradication therapy
• Mupirocin nasal ointment if nasal carriage
o Use Naseptin if 2 failed mupirocin courses
Use PPE
Management of MRSA -antibiotics?
Discuss with microbiologist
Vancomycin (Teicoplanin)
• If unsuitable, linezolid
Management of MRSA -specific antibiotics?
- Soft-tissue – rifampicin + fusidic acid (mild)
- Complicated skin/soft-tissue – Tigecycline + daptomycin
- Bronchiectasis + UTI – Tetracycline
- Sepsis – Vancomycin
- Endocarditis – vancomycin + gentamicin
- Osteomyelitis and septic arthritis - vancomycin
Definition of pyrexia of unknown origin?
o Temperature >38.3oC for at least 3 weeks with no obvious source despite investigations (3 days in hospital or two outpatient visits)
Infectious causes of pyrexia of unknown origin?
Abscesses (lung, liver, subphrenic, perinephric, pelvic)
Empyema
Bacteria (salmonella, brucella, borrelia, leptospira)
Rheumatic fever
Infective endocarditis
HIV
TB
Toxoplasmosis
Parasites – amoebic liver abscess, malaria, schistocomiasis, trypanosomiasis
Fungi
Typhus
Neoplastic causes of pyrexia of unknown origin?
Lymphoma
Solid tumours (GI, renal)
Connective tissue disorders of pyrexia of unknown origin?
RA PMR Still’s disease GCA SLE Kawasaki disease
Other causes of pyrexia of unknown origin?
Drugs PE Stroke IBD Sarcoid/Amyloidosis
Fever patterns in patient of pyrexia of unknown origin?
o Always think of malaria, others include: PID, IE, TB, UTI
o Daily spikes – Abscess, TB, schistosomiasis
o Twice-daily spikes – Leishmaniasis
o Saddleback fever (fever for days then normal) – Colorado tick fever, Borrelia, Leptospira, Dengue, Legionnaire’s disease
o Long periodicity – Lymphoma
o Remitting (diurnal variation, not dipping to normal) – Amoebiasis, malaria, Kawasaki disease, CMV, TB
Signs of bacteraemia of pyrexia of unknown origin?
o Confusion o Renal failure o Neutrophilia o Low plasma albumin o Raised CRP
Investigations of pyrexia of unknown origin?
o Bloods
FBC, ESR, CRP, U&E, LFT, ANA, Rh factor, TFT
Blood cultures
o Urine, stool, CSF cultures
o Imaging
CXR
Abdominal CT scan
Echocardiogram (if IE suspected)
Management of pyrexia of unknown origin?
- Refer and discuss with infectious diseases specialist
- If clinically stable – watch and wait approach appropriate if extensive investigation shows no diagnosis
- If clinically unstable or neutropenic – empirical antibiotics
Timeline of post-operative complications - intraoperative?
Bleeding
Damage to structures
Anaesthetic risks
Allergic reactions
Timeline of post-operative complications - 1-3 days post-op?
Bleeding
MI/Stroke
Atelectasis
Timeline of post-operative complications - 3-7 days post-op?
Infection (wound, chest, urine)
Anastomotic leak
DVT/PE
Timeline of post-operative complications - months after surgery?
Hernia
Chronic Pain
Recurrence
