Systemic infections Flashcards
37 year old with fever, and leukocytosis. Had non-itching pink rash on arms/ torso, particularly when had fever.
Given co-amoxiclav with no improvement, then given tazocin.
CXR - bilateral pulmonary infiltrates
CRP 268
Ferritin >40 000
Raised ALT
CT CAP - nil obvious found
What criteria does patient meet to be diagnosed with PUO?
- Temp >38.3 on 3x occasions, over 3 weeks
- Includes a week of routine hospital based investigation, without diagnosis being reached
Can also be classified by patient group -
- HIV patient
- transplant patient
- returning traveller
- nosocomial onset
37 year old with fever, and leukocytosis. Had non-itching pink rash on arms/ torso, particularly when had fever. Arthralgia
Given co-amoxiclav with no improvement, then given tazocin.
CXR - bilateral pulmonary infiltrates
CRP 268
Ferritin >40 000
Raised ALT
CT CAP - nil obvious found
What is possible diagnosis?
What is significance or extremely high ferritin?
Adult onset Stills disease (AOSD)
fever, arthralgia, leukocytosis, hepatitis may indicate this
high ferritin suggestive of haemophagocytosis, which can occur in Still disease, and HLH (haemophagocytic lymphohistiocytosis)
treatment is NSAIDs/ steroids
What are causes of PUO?
Infection - 1/3 of cases. This is more likely if from poorer country. Developed country patients are less likely to have chronic bacterial infections
auto-immune
malignancy
vasculitis
42 year old with tunneled dual lumen vascular haemodialysis catheter has fever while on dialysis.
4x blood culture bottles grow staph epidermidis, susceptible to vancomycin
Should line be removed?
No
coagulase negative staph are unlikely to form biofilms, so catheter salvage can be attempted
if pseudomonas/ candida - line needs removed
If no evidence of infection of skin, then infection is likely intraluminal. And therefore more likely to point to biofilm producing organism
42 year old with tunneled dual lumen vascular haemodialysis catheter has fever while on dialysis.
4x blood culture bottles grow staph epidermidis, susceptible to vancomycin
How should they be managed?
Give vancomycin, as can be given on dialysis
2 weeks antibiotics for CoNS
consider using line lock e.g vancomycin, ethanol for 2 weeks.
42 year old with tunneled dual lumen vascular haemodialysis catheter has fever while on dialysis.
4x blood culture bottles grow staph epidermidis, susceptible to vancomycin.
Treated with vancomycin.
1 month later has fever, erythema and tenderness around line site.
Blood culture grow MRSA
What is further management?
Start treatment for MRSA - vancomycin for 14 days
blood cultures 48 hours on treatment - to ensure no persisting bacteraemia. As this may suggest complicated/ metastatic infection
examine for back/ joint pain, IE
may need ECHO if not a simple infection - e.g not responding to antibiotics
Patient has hemicolectomy, and goes on ventilator after this.
Jugular vein used for TPN.
Develops fever
Paired peripheral and central blood cultures flag positive at 12 hours.
Identified as candida albicans in central/ peripheral cultures. staph epidermidis only peripheral cultures
What is significance of these isolates?
candida is unlikely to be contaminant - forms biofilms
S epidermidis likely contaminant as just peripheral cultures
What us management of catheter related candidaemia?
What is duration of treatment?
- C. albicans is normally susceptible to azoles, echinocandins, and amphotericin B
- fluconazole favoured due to good tolerability
800mg loading dose, followed by 400mg daily - C glabrata, C krusei are increasing in prevalence, and show reduced susceptibility to azoles.
- Follow up blood cultures required to assess if clearing candidaemia
- Normally 14 days treatment
- refer for ECHO/ ophthalmology to ensure not seeded infection
What is criteria of culture negative endocarditis?
3 blood cultures negative after 5 days
when suspecting IE, what questions in history help point towards possible aetiological agent?
unpasteurised cheese/ milk, undercooked meat, or travel to Middle East/ Mediterranean - Brucella
Occupational exposure e.g farms/ abattoir - coxiella
Contact with human louse/ homeless/ alcoholism - Bartonella quintana
Cat scratch - Bartonella henselae
Also useful - cardiac device intravascular lines HIV history of previous antimicrobials
Can endocarditis be non-infective in origin?
Non-bacterial thrombotic endocarditis (NBTE) is form of endocarditis where small sterile vegetations deposited on valve leaflets
associated with connective tissue disease e.g rheumatic fever, SLE
NBTE associated with SLE is also known as Libman-Sacks endocarditis
How to optimize blood cultures growth?
Incubate within 4 hours of taking
Take 3 sets - yield increases from 61% from 1 set, to 93% yield in 3 sets
Patient with ruptured appendix, then deteriorates.
Fever, hypotension.
Not responding to cefotaxime/ metro
Gram neg bacilli seen on culture
Why might patient not be responding to antibiotics?
Gram negative bacilli likely E. coli/ klebsiella
cefotaxime can be inactivated by ESBL
source of infection not controlled - collection
What are the most common ESBL enzymes?
TEM - 50% of ESBL
SHV
CTX-M
Patient with ruptured appendix, then deteriorates.
Fever, hypotension.
Not responding to cefotaxime/ metro
Gram neg bacilli seen on culture
Thought to be CPE
How to reduce spread of CPE in hospital?
Early recognition
patient isolation - for duration of hospital admission
contact precautions/ hygiene
weekly rectal swabs
no methods of decolonisation available
What drugs are available to treat CPE infections?
Colistin
aminoglycosides
tigecycline
fosfomycin - can be used IV
newer agents showing promise - ceftazidime-avibactam, aztreonam-avibactam, eravacycline
What are CPEs?
Bacteria which produce enzymes which hydrolyse all beta-lactam molecules, including carbapenems
How to identify CPE in laboratory?
Disk diffusion may show resistance to ertapenem
MALDI-TOF may show genotypic likely to be resistance
How long can incubation period of Plasmodium falciparum be?
Can be up to 12 months since exposure
What are features of severe malaria?
Biochemical
Biochemical - AKI pH <7.3 Glucose <2.2 Hb <8 Parasitaemia >10%
Thrombocytopenia is always seen in malaria, but does not necessarily indicate severe disease
What are features of severe malaria?
Clinical
Clinical - neurological - reduced GCS, seizures, confusion hypotension/ shock pulmonary oedema spontaneous bleeding/ DIC
What is treatment for severe malaria?
IV artesunate
Once improved, switch to oral option -
artemether-lumefantrine
atovaquone-proguanil
quinine + doxycycline
usually 7 days total treatment, but can be extended
Severe malaria, artesunate not available.
What is treatment option?
IV quinine
then switch to -
oral quinine plus doxycycline
oral quinine plus clindamicin
7 days treatment total
What is evidence for exchange transfuion in severe malaria?
No evidence of any benefit, so not recommended
Plasmodium vivax and falciparum dual-infection
how does treatment differ?
initial treatment the same - artesunate then oral option for 7 days
but will then require primaquine to remove hypnozoite from liver
Patients with recurrent shingles.
What further investigations should be considered?
HIV causing immunosuppression, can lead to reactivation
What benefits does co-trimoxazole have in HIV patient prophylaxis?
reduces risk of -
PCP
toxoplasma reactivation
GI protozoa - cyclospora/ cycloisospora/ microsporidia
23 year old solider presents with non-tender ulcerate lesion on distal right forearm. Nodules extend proximally up arm and a palpable lymph node in right axilla.
Had period of jungle training 8 weeks ago in Belize
What are differential diagnoses?
Leishmaniasis
non-tuberculous mycobacteria
Sporotrichosis
Blastomycosis
Non-infective -
pyoderma gangrenosum
cutaneous sarcoidosis
23 year old solider presents with non-tender ulcerate lesion on distal right forearm. Nodules extend proximally up arm and a palpable lymph node in right axilla.
Had period of jungle training 8 weeks ago in Belize
Thought to be cutaneous leishmaniasis
How to diagnose?
Punch biopsy
Giemsa stain - look for intracellular amastigotes within macrophages
Patients with cutaneous leishmaniasis e.g skin ulcer
What other areas should be examined?
Some species e.g L braziliensis can cause mucosal leishmaniasis
More common in New World species. Old World species more often resolve spontaenously
examine oropharynx/ vocal cords, and biopsy any abnormal material
What are treatment options for leishmaniasis?
antimony compounds e.g sodium stibogluconate
IV treatment initially to help stop progressional to mucosal leishmaniasis
miltefosine is oral opton
What are risks associated with sodium stibogluconate use in treating leishmaniasis?
anaemia
hepatitis
pancreatitis
non-specific ST changes
requires weekly routine bloods, and weekly ECG
Renal transplant patient presents with hepatitis, fever, sore throat.
What are possible diagnoses?
CMV
EBV
HIV
Toxoplasma
Toxoplasma primary infection can cause mononucleosis type illness with sore throat. But reactivation tends to be focal e.g brain
Renal transplant patient presents with hepatitis, fever, sore throat.
Thought to be EBV post-transplant lymphoproliferative disorder
What other investigations are required?
EBV viral load
Blood film - atypical lymphocytes
CT CAP - enlarged lymph nodes for biopsy. Although EBV reactivation may not always give enlarged lymph nodes
Bone marrow biopsy - if diagnosis unclear
What is treatment for PTLD due to EBV?
Reduce immunosuppression
increase levels of cytotoxic T cells, than can help control EBV-driven prolfieration of B lymphocytes
rituximab - antiCD20 has show some promising effects
aciclovir/ ganciclovir is often used, but with little evidence backing this
monitor EBV viral load - although will always have low level viraemia
What is an exposure prone procedure?
Invasive procedure where there is risk that injury to healthcare worker, may result in exposure of patient’s open tissues to healthcare worker’s blood - risk of HCW to patient transmission
e.g orthopaedic surgery
Orthopaedic trainee transfers from abroad. Awaiting EPP clearance
Under what circumstances can they undertake EPPs if -
HBsAg pos
HBsAg pos
- banned if HBeAg pos
- viral load <200 copies/ ml - require frequent monitoring e.g 12 weeks if on treatment, and 12 monthly if cleared infection
Orthopaedic trainee transfers from abroad. Awaiting EPP clearance
Under what circumstances can they undertake EPPs if -
Anti-HCV pos
HCV RNA must be negative
if RNA positive, needs to start treatment prior to EPP
Orthopaedic trainee transfers from abroad. Awaiting EPP clearance
Under what circumstances can they undertake EPPs if -
Anti-HIV pos
Must be on ART
VL <200 copies/ml
viral load checks every 3 months
32 year old volunteer nurse returns from Nigeria with 3 days of fever, diarrhoea, headache, myalgia.
Did not complete malaria prophylaxis.
What diagnoses need to be considered?
Malaria dengue - less likely Africa YF Rickettsial disease Typhoid fever VHF - Lassa, Ebola
32 year old volunteer nurse returns from Nigeria with 3 days of fever, diarrhoea, headache, myalgia.
Need to exclude VHF
What are important part of history taking?
if any outbreaks in geographical area
contact with rats/ urine
contact with dead bodies/ funerals
healthcare exposure/ needlestick
32 year old volunteer nurse returns from Nigeria with 3 days of fever, diarrhoea, headache, myalgia.
Need to exclude VHF
What steps to A&E need to take?
Isolate patient
contact precautions
inform lab of category 4 pathogen. Perform routine tests locally, but sent to specialist lab for VHF testing
What are treatment options for VHF?
Lassa - ribavirin shows definite benefit
Ebola - monoclonal antibodies - ZMapp, remdesevir
most have no specific treatment, so management is supportive
Combined kidney-pancreas transplant for diabetes.
What prophylaxis is required for CMV?
D+/ R-
D+/ R+
D-/ R+
D-/ R-
D+/ R-
transplant almost like given recipient primary CMV infection. Ganciclovir for 6 months
D+/ R+
low risk, but risk of reactivation. Ganciclovir for 3 months
D-/ R+
very low risk, but risk of reactivation. No clear guidance on this
D-/ R-
no risk of reactivation, so no prophylaxis required. Use of CMV-negative, and leucocyte deplete blood products is preventative strategy
Combined kidney-pancreas transplant for diabetes. On tacrolimus/ mycophenolate
Develops fever, diarrhoea.
CMV suspected. CMV VL 800 copies
Is this cause of disease?
Cannot exclude
Viral load is surrogate marker for active viral replication. Virus is intracellular, so can have high tissue damage, and low level viraemia
Need biopsy of bowel
Combined kidney-pancreas transplant for diabetes. On tacrolimus/ mycophenolate
Develops fever, diarrhoea.
endoscopy and biopsy shows CMV colitis.
What is duration of treatment?
Guided by patient response/ viral load monitoring
typically start IV ganciclovir, and continue until improving.
Once improved, switch to valganciclovir
complete 14-21 days total
monitor viral load more frequently after that
may need long term prophylaxis
Patient with diabetes, presents unwell with DKA.
Friend says recently had facial pain/ nasal discharge, suggestive of sinusitis
Notice periorbital cellulitis
What might be cause?
mucormycosis - angiotropic fungi
haemophilus/ staph/ strep should be considered
What are clinical manifestations of mucormycosis?
close to 50% mortality
rhinocerebral most common - black eschar of hard palate
pulmonary mucormycosis if neutropenic
GI infection can occur
What are main points to managing mucormycosis?
microscopy/ culture of tissue
Antibiotics
Antifungals
MRI - assess invasion
ENT - surgical debridement for source control
Which antifungals are used in treatment of mucormycosis?
Amphotericin B
posaconazole
treat for at least 6 months
hyperbaric oxygen is sometimes used as adjunct
