ID Flashcards
What are the positive acute phase reactants
CRP, ferritin, fibrinogen, hepcinin, amyloid A
What are the negative acute phase reactants
Albumin, transferrin, antithrombin
What is iron with holding - when would you see it
Acute infection
Drop in transferrin (prevent bacteria getting iron - they can scavenge from transferrin and macrophages)
Rise in ferritin because of fall in transferrin
Rise in hepcidin - causes reduced uptake of iron from gut and release of iron from cells (hepcidin regulates ferroportin)
Over long time this mechanism causes anaemia bc iron isnt absorbed, moved out of cells or transported
What needs to be checked when starting a pt on a macrolide
LFTs and stop statin
macrolides are P450 inhibitors
What is CURB 65
Confusion Urea >7 Respiratory rate >30 BP <90 / 60 >65
What is the management of CAP based on curb65 score
0-1 consider home management
2 consider admission / closer home monitoring
3 admit
What is the antibiotic management based on curb 65
0-2 PO amox plus/ or clarithyromycin ; 2nd line PO doxcy or levofloxacin
3-5 IV amox plus/ or IV clarithyromycin
If legionella pneumophila
1st line: PO/IV Levofloxacin or Clarithromycin
Complications of pneumonia
ARDS Pneumothorax Emphyema Pleural effusion PE Lung abscess Sepsis
Common and atypical pathogens for CAP
Strep pneumoniae
atypical - mycoplasma pneumoniae, legionella, chlamydia pneumoniae
Criteria for hospital acquired pneumonia
> 48 hours after hospital admission
pseduomonas more likely organism
klebsiella
bacteroides
Investigations for pneumonia
Sputum culture and PCR
Urinalysis for legionella antigens
What is the criteria for ARDS
CXR - bilateral infiltrates (normal heart size)
Acute onset (1 week)
Refractory hypoxaemia
Pulmonary wedge pressure <19 mmHg
What are red flags for ARDS
Diffuse fine crackles, non cardiogenic pulmonary oedema (on XR)
What is the main differential for ARDS
Cardiogenic pulmonary oedema (HF)
Features of HF on an XRay
A - alveolar odema B - Kerley B lines C - cardiomegaly D - dilated prominent upper lobe veins E - pleural effusions
What is an important consideration when considering whether NIV is appropriate for a pts
Secretions
Consciousness
Severe hypoxaemia
What are absolute contraindications to NIV
Facial burns/ trauma
Vomiting
Fixed obstruction upper airway
Recent facial upper airway surgery
what are the different levels of oxygen therapy and indications
Nasal cannula - 24-50% o2
Simple mask - 24-60% o2
Venturi mask - 24 - 60% o2 - COPD when need to know specificially what FiO2 being delivered
Non-rebreather + bag - 60-80% O2
What considerations should you think of before starting oxygen therapy
Acutely unwell - non rebreather + bag to get highest oxygen delivered
Risk of type 2 respiratory failure (COPD) - venturi lowest 28% - 4 L O2 until ABG results
What are the indications for noninvasive ventilation
Type 1 or 2 RF
If a patient has a NEWS of >3 what should you do
Sepsis screening tool ASAP
What size is petechiae
<3mm
What is the first step of management in suspected meningitis
IV ceftriaxone
Other investigations shouldnt delay giving antibiotics
What is the management of suspected meningitis
IV Ceftriaxone 2-4g daily, dose at the higher end of the recommended range used in severe cases.
Abx should be given within 1 hour
Symptoms of meningitis
Headache
Photophobia
Neck stiffness
N/ V
What type of antibiotics if ceftriaxone
Cephalosporin
What is the overlap of penicillin and cephalosporin allergies
Both beta lactams
0.5-6.5% of patients with penicillin allergy will also be allergic to other Beta-Lactams such as cephalosporins.
For this reason, patients with only a mild penicillin allergy (not anaphylaxis) should be given cephalosporins and be monitored closely for any drug reactions.
For patients with anaphylaxis to penicillin suspected of having acute bacterial meningitis, empirical guidelines state they should be given chloramphenicol 25mg/kg 6 hourly.
When should you do a lumbar puncture in suspected meningitis
Patient not in shock
In patients with suspected meningitis (with no signs of shock or severe sepsis) LP should ideally be performed within 1hr of admission to hospital. Treatment should be commenced immediatly after the LP. If delays to LP are anticipated this should not delay treatment which should be given straight after blood cultures and within the hour.
In patients who are unstable with rapidly evolving sepsis &/or rash, LP should not be performed at this time. Treatment should be given immediatly.
What bloods would you request for an unstable patient with suspected meningitis
full blood count, C-reactive protein, coagulation screen, blood cultures, meningococcal PCR and blood glucose
How do you determine if it is safe to do an LP
CT head if: - Focal neurological signs - Presence of papilloedema - Continuous or uncontrolled seizures - GCS <12 Lumbar puncture should not be performed in those with an uncorrected coagulopathy or those with evidence of skin infection near the site of the lumbar puncture.
What are the commonest causes of meningitis in adults
Streptococcus pneumoniae
Neisseria meningitidis
What should you consider in patients over 65 with suspected meningitis
Listeria
Include amoxicillin in treatment
What is the treatment for viral meningitis
Viral meningitis does not require antibiotics however antibiotic treatment may be commenced initially in an unwell patient until bacterial causes have been fully excluded. Treatment of viral meningitis is often supportive requiring analgesia, fluids & rest. If herpes simplex virus is isolated the patient may require a course of aciclovir.
Usually self resolving in 10-14 days
What is the most common cause of meningitis
Viral
Causative organisms include enteroviruses, herpes simplex virus, varicella zoster virus and mumps.
What should be given to close contacts of those with bacterial meningitis
500 mg ciprofloxacin oral single dose
How would you determine if someone should get prophylaxis treatment for bacterial meningitis
- People who have had prolonged close contact with the case in a household-type setting during the 7 days before onset of illness (for example, people who are living or sleeping in the same household, pupils in the same dormitory, boy/girlfriends, or university students sharing a kitchen in a hall of residence).
- People who have had transient close contact with a case only if they have been directly exposed to large particle droplets/secretions from the respiratory tract of a case around the time of admission to hospital.
Is bacterial meningitis a notifiable disease
Yes - tell PHE
Difference between pneumonitis and pneumonia
Pneumonia localised area of lung inflammation
Pneumonitis entire lung inflammed
Common causes for deterioration in covid
Pneumonitis progressing to ARDS
PE/ VTE
Secondary bacterial pneumonia
Myocarditis
What blood borne infection/s test should you do for any patient with CAP
HIV, Hep B, Hep C
What blood results would make you suspicious of HIV
Raised protein
Low WBC
List some AIDs defining diseases that you would do a HIV test for
Non hodgkins lymphoma (T cells) Pneumocystis (fungal infection) Glandular fever TB Cervical cancer Toxoplasmosis Primary CNS lymphoma Kaposi sarcoma
List some clinical sceanarios where you should consider a HIV test
Any recurrent and unexplained disease Unexplained enlarged lymph node Weight loss Recurrent skin infections/ rashes Oral candida Unexplained B symptoms - fatigue etc Recurrent pneumonia Recurrent diarrhoea Dementia
What CD4 count represents AIDS
<200
What is the management of HIV - how do the drugs work and what problems are associated
Highly active antiretroviral therapy (HAART)
Work by inhibiting reverse transcription of the virus
Problems: viral resistance
Should push virus to undetectable level
What is the vertical transmission rate of HIV in pregnant women
20-40 %
In utero, labour, breastmilk
Main transmission risks are labour (blood to blood and mucous membrane contact, high viral load in breast milk)
What is the transmission rate of HIV sexually
Receptive anal sex 0.1-3%
Receptive vaginal 0.1
*receptive risk greater than insertive
Insertive 0.03-0.01
What prevention methods are there for HIV
PrEP - pre-exposure prophylaxis (contraceptive pill)
PEP - post exposure prophylaxis (morning after pill - must take within 72 hrs for 1 month - 28 days)
condoms
How is HIV transmitted
Blood contact
Sexual contact through mucous membranes
Vertical - blood, genital tract, breast milk
What are the clinical features of HIV
Unexplained enlarged lymph nodes Flu like symptoms - malaise Oral thrush Recurrent unexplained fever Unexplained weight loss Recurrent opportunistic infections (viral, particularly VZV and CMV), bacterial - pneumonia Immuno compromised tumours - cervical, NHLymphoma, kaposi's sarcoma, CNS lymphoma (primary), recurrent diarrhoea Recurrent flu like symptoms
List some AIDS defining illnesses
Oral thrush Any fungal infection in an organ NHL Kaposis sarcoma TB Toxoplasmosis Cervical canver Primary CNS lymphoma
What is an important differential for HIV
Secondary syphilis
When can you test for HIV
early test from 2 weeks post contact but risk of false negative - if so, repeat in 4 weeks
Ideally anytime from 6 weeks
Seroconvert around 2 months - this is when you would get primary illness
What is HIV primary illness, what causes it
Seroconversion - when immune system kicks it to target HIV - flu like/ glandular fever
Explain the pathophys of HIV
Virus - enters through mucous membranes or blood to blood
Has gp 120 protein on it which is same as CD4/ Antigen presenting cells so taken in bc body recognises it
Predominantly enters CD4 cells, but also some antigen presenting cells
It then reverse transcribes RNA to DNA and puts this in cells DNA - the cells then makes more virus protein which is released into blood
First couple of month - immune system responds and kills infected cells (CD8 response) - virus count depletes
Then move into latent stage where virus and immuno system co-exist, but pt grdually becomes more immune compromised as viral load is slowly increasing
Eventually load becomes so high that cd4 count is too low for any sufficient immune response (<200) - AIDS
What is the role of CD4 cells
Support CD8 cytotoxic effects (T1)
Activate macrophages
Activate B cells - humoural response (antibody production)
Eventually HIV depletes functional cd4 count to the point where the body has no humoral response (no antibodies can be make in response to infection) and any cd8 response is too weak without cd4 support, the innate immune system is also compromised without cd4 support as part of innate inflammatory response
Also modulate NKC - so get less immune surveillance
What blood tests can be helpful for considering HIV
FBC - low white cell count
LFT - raised total protein (IgM chucked out by immune system as can detect virus but struggling to develop effective IgG as virus keeps mutating)
Explain the different hep b tests you can do and what they mean
Hep B core antibody (always positive in anybody infected with hep b)
Hep b surface antibody - present in those who mounted an adequate immune response
Hep b surface antigen - present in those who have active viral replication
What organ does hep b target, what is the difference in response between adults and children
Liver
Children - 90% cant clear and develop chronicity
Adults - 90% clear and dont develop chronicity
Explain what conditions are associated with what falling cd4 levels
> 500 : more of common bacterial and viral infections, eg pharyngitis, sinusitis, TB
200-500 : recurrent bacterial infections when wouldn’t expect this, eg pneumonia, atypical viral infections VZV pneumonia
<200 : fungal infections, PJP, disseminated TB
<100 : fungal infections, aspergillus pneumonia, CMV pneumonia
what blood results would you see in DIC
Clotting: Low platelets High fibrinogen High d-dimer Bleeding: Raised (long) prothrombin time Raised (long) aptt time
what are cytokines
peptides that immune cells communicate with
eg alpha-TNF, interferons, interleukins
what is the pathophys of sepsis
innate immune system - massive vasodilation in response to pathogen
endothelium activation - leaky as part of immune response
coagulation cascade activation - part of endothelium activation
= reduced perfusion = increase in tissue co2 and reduced oxygen
Initially warn shock with vasodilation stage then get surge in catecholamines to shunt blood to vital organs - cold shock
differentials for sepsis
thyroid storm
neuroleptic malignant syndrome
sertionergic syndrome
massive pulmonary embolus
outline the management of a patient news-ing >3
sepsis screening tool
how would you manage a patient with suspected sepsis
news score >3 - sepsis screen
what clinical features do you need for diagnosis of SIRS
two of:
Temperature >38°C or <36°C
Tachycardia: >90 beats per minute
Tachypnoea: >20 breaths per minute) or PCO2 <4.3kPa
WCC >12 or <4 (or >10% immature (band) forms)
what is septic shock
lactate >2 despite adequate fluid resus
pt requires vasopressors to maintain MAP >65 mmHg
sepsis symptoms
Drowsiness Confusion Dizziness Malaise Localising symptoms of infection (e.g. productive cough, vomiting, diarrhoea, dysuria etc.)
sepsis signs
Tachycardia Hypotension Tachypnoea Cyanosis Fever/hypothermia Reduced urine output Rash Mottled/ashen appearance
what is part of the sepsis 6 care bundle
Give high flow oxygen (monitor oxygen saturations – aim for SaO2 over 94%) Take blood cultures Measure lactate levels Give IV antibiotics Give IV fluids Monitor urine output
pair as take 3, give 3 Take cultures, give IV abx Take lactate, give oxygen Take urine, give fluids CUL (cultures, urine, lactate)
Outline an approach for managing a patient with sepsis
ABCDE History - infection source focused Lungs (most common) - cough, SOB, pain, GI - diarrhoea, vomitting, abdo pain Pancreas - back pain GU - flank pain, UTI, dyuria Neuro - headache, photophobia, GCS Skin - lesions, ulcers? MSK - joint pain, trauma Travel? Contact with anyone sick? Animals/ pets? PMHx - diabetes?, immuno suppressed? Meds - any that would immuno supress? Cancer? weight loss? past/ recent surgery? Exam: Respiratory - crackles? Fluid? Heart - murmurs? GI/ GU - peritonitis, flank pain, supra pubic pain, jaundice, hepatomegaly Skin - ulcerations/ breaks?, rash Investigations: All bloods, cultures, CRP, lactate, glucose, ABG, clotting ECG CXR ?echo, invex organ focused
Outline ABCDE approach for septic patient
Airway - can patient talk, any signs of airway compromise, can you see chest movement, obstruction in airway - consider calling anaesthetist if sign of airway compromise, Basic airway manoevers - head tilt, chin lift, jaw thrust, nasopharyngeal airway, or guedel airway
Breathing - see-saw, kaussmaul, tachynpnea, oxygen sats, percussion (dull, hyperrosonate?), expansion, auscultate (reduced air entry, absent sounds)
Intervention - high flow oxygen - non-rebreather
Request ?CXR, ABG
Circulation - BP, CRP, pulse (bounding/ irregular), temp, fluid output (oligouria hypoperfusion of kidneys)
Feel peripheries, JVP
Auscultate - murmur, muffled / pericardial rub (pericarditis)
IV access and fluids
ECG
Full bloods
Disability - GCS (eyes, motor, verbal), drug chart (opioids, sedatives, anxiolytics, antihypertensives), blood glucose
Exposure - rashes, wound, surgical site incisions, source of infection
what investigations should you consider in addition to sepsis 6
All bloods - plus CRP, lactate , clotting, blood sugar, ABG
CXR
ECG
Invex focused at particular source of infection, MRI, echo etc
what antibiotics should you give straight away for meningitis in an adults
IV ceftriaxone 2-4 g
what should you give instead of ceftriaxone if patient has an allergy
chloramphenicol 25mg/kg 6 hourly.
list some non infective causes of gastroenteritis
Inflammatory causes (Inflammatory bowel disease, diverticular disease)
Loss of absorptive area (coeliac, small bowel resection, tropical sprue)
Pancreatic disease
Drugs (e.g. antibiotics, magnesium, digoxin)
Colon cancer
Systemic disease (thyrotoxicosis, uraemia, carcinoid)
Others: IBS, gastrectomy, HIV (diarrhoea for >2 weeks in the absence of a clear cause should prompt HIV testing!)
what is the main treatment of gastroenteritis
supportive - IV fluids, manage electrolytes
risk factors for cellulitis
Immunodeficiency Underlying skin conditions (e.g. eczema & athletes foot) Lymphoedema Chronic venous insufficiency Wounds and injuries Obesity diabetes
what are the most common causes of cellulitis (pathogens)
Staphylococcus aureus and Beta-haemolytic streptococcus
what is the main differential for cellulitis
necrotising fascitis
