Infectious diseases Flashcards
1
Q
HIV
- Associated diseases
- Primary infection signs/symptoms
- Seroconversion symptoms
- Commonest/most accurate test
- Other diagnostic tests
- May not detect antibodies for how long
- When to start ARVT
- AVRT - important monitoring
- Common pneumonia and management
- Other AIDS-defining illnesses
- AIDS CD4 count vs normal
- Post-exposure prophylaxis - regime
A
- Oral candidiasis, TB, PCP, streptococcus pneumoniae, salmonella, non-hodgkin’s lymphoma, CMV retinitis
- Rash, fever, lymphadenopathy, weight loss, night sweats, fatigue, meningitis
- Glandular fever symptoms for 6-8 weeks (can take up to 3 months)
- HIV antibody (ELISA and western blot assay)
- HIV PCR and p24 antigen tests can confirm diagnosis
- 3 months (most created by 4-6 weeks)
- Immediately from diagnosis
- Viral load, lipids, glucose, renal function, LFT
- Pneumocystic jirovecii (PCP), co-trimoxazole (give prophylactically if CD4 <200)
- Kaposi’s sarcoma, CMV, candidiasis, lymphoma, TB
- Under 200 cells/mm3, 500-1200 is normal
- Truvada (emtricitabine/tenofovir) + raltegravir for 28 days
2
Q
Hospital acquired pneumonia
- Definition
- Commonest cause
Treatment before culture result
- No risk factor for multi-resistance
- Multi resistance risk factors
A
- Infection acquired >48 hours post-admission
- Gram negative bacteria e.g. E. Coli, Pseudomonas etc
- Tazobactam, but speak to microbiology
- Tazobactam, gentamicin, vancomycin
3
Q
Post-operative fever - common causes
- Day 1-2
- Day 3-5
- Day 5-7
- Day D+
- Any time
A
- ‘Wind’ - Pneumonia, aspiration, pulmonary embolism
- ‘Water’ - Urinary tract infection (especially if the patient was catheterised)
- ‘Wound’ - Surgical site infection / abscess formation
- ‘Walking’ - DVT or pulmonary embolism
- Drugs, transfusion reactions, sepsis, line contamination
4
Q
Candidiasis
- Oral - risk factors
- Topical antifungal
- Skin - prescription if inflamed
- Vaginal - risk factors
- Systemic management (if severe)
A
- HIV infection, advanced malignancy, chemotherapy/radiotherapy, immunosuppressants, antibiotics, inhaled corticosteroids, diabetes
- Clotrimazole oropharyngeal / nystatin
- Corticosteroid cream
- Pregnancy, DM, hormonal contraceptives, immunosuppressed, recent ABX
- Fluconazole / echinocandins (caspofungin)
5
Q
Malaria
- Causative mosquitos
- Presentation
- Diagnostic test
- Management
- Complications from Falciparum
A
- Plasmodium (falciparum likely if neuro involvement)
- Fever, malaise, myalgia, headache, N+V, anaemia (pallor), jaundice, hepatosplenomegaly
- Blood film (3 samples, 3 consecutive days to exclude)
- Chloroquinine, doxycycline
- Cerebral malaria (seizures, reduced GCS), AKI, pulmonary oedema, DIC
6
Q
Lyme disease
- Causative organism
- First sign
- General symptoms
- Management
A
- Borrelia burgdorferi
- Erythema migrans
- Fever, malaise, headache, myalgia, arthralgia, lymphadenopathy
- Doxycycline - 14 to 21 days
7
Q
Tuberculosis
- Gram stain
- Primary presentation
- Progressive presentation
- Bedside investigation
- Immune response to TB - tests
- CXR - primary TB
- Reactivated TB - lobe usually affected
- Term used when spread to blood (+ CXR finding)
- First area of granular inflammation
- Potential urinary finding
- Medical management - drugs + SEs (4 - ‘RIPE’)
- Medical management - regime
A
- Acid-fast bacilli, need Zeihl-Neelsen stain - turns bright red against blue background
- Normally asymptomatic, maybe mild fever
- Cough, haemoptysis, fever, night sweats, weight loss, sputum, malaise, cervical lymphadenopathy (‘cold abscess’ - firm, painless, in neck), erythema nodosum
- Rapid sputum identification test, culture sputum
- Mantoux (previous vaccination, latent, or active)
IGRA (no symptoms, positive Mantoux, confirms latent) - Patchy consolidation, effusions, hilar lymph nodes
- Upper; patchy/nodular consolidation + cavities
- Miliary (many tiny spots distributed across lung fields)
- Ghon focus
- Sterile pyuria
- Rifampicin (orange urine, hepatitis), Isoniazid (peripheral neuropathy, psychosis, hepatitis), Pyrazinamide (gout), Ethambutol (optic neuritis)
- RIPE - 2 months, then RI - 4 months
8
Q
Infectious mononucleosis (glandular fever)
- Cause in 90%
- Classic triad
- Investigation
A
- EBV
- Sore throat, pyrexia, anterior and posterior triangle lymphadenopathy
- Monospot (EBV serology)
9
Q
Syphilis
- Primary features
- Secondary features
- Management
A
- Chancre (painless ulcer at sexual contact site), local non tender lymphadenopathy
- Fever, lymphadenopathy, buccal ulcers, rash (trunk, palms, soles)
- IM benzathine penicillin (10d) / doxycycline (14d)
10
Q
HSV
- Causes for recurrence
- Expectant mothers with active genital HSV
- Management
A
- Stress, fever, tissue damage, immunocompromise
- Offer C-section
- Aciclovir
11
Q
Gonorrhoea
- Type of bacteria
- Presentation
- Urethritis - management
- Can cause what in newborns (+ management)
A
- Gram negative
- Purulent discharge, perianal/anal discharge, urethritis, dysuria, pruritis ani, pain
- Single dose cefixime/ceftriaxone +/- azithromycin PO
- Neonatal conjunctivitis; give erythromycin
12
Q
Chlamydia
- Type of bacteria
- Presentation
- Management
A
- Gram negative
- Sometimes asymptomatic, discharge (non-purulent), urethritis, post-coital/intermenstrual bleeding
- Single dose azithromycin, or doxycycline PO 7 days
13
Q
Live vaccines
- Examples
A
- Live attenuated vaccines, BCG, MMR, oral polio, oral typhoid, yellow fever
14
Q
Cellulitis
- Points of entry for bacteria (4)
- Features
- Feature suggestive of staph. aureus
- Other causative organisms (3)
- Classification to assess severity
- Management - 1st line
- Other options
- When to admit
A
- Skin trauma, eczema, fungal nail infections, ulcers
- Erythematous, hot, tender, tense, thick, oedema, bullae
- Golden-yellow crust
- Group A Streptococcus (mainly strep. pyogenes)
Group C Streptococcus (mainly strep. dysgalactiae)
MRSA - Eron
Class 1 – no systemic toxicity or comorbidity
Class 2 – systemic toxicity or comorbidity
Class 3 – significant systemic toxicity/comorbidity
Class 4 – sepsis or life threatening - Flucloxacillin PO/IV (good against gram positive cocci)
- Clarithromycin, clindamycin, co-amoxiclav
- Eron Class 3/4 - admit for IV ABX
15
Q
Bacteria - definitions
- Aerobic
- Anaerobic
- Gram-positive
- Gram-positive
- Bacilli
- Cocci
A
- Require oxygen
- Do not require oxygen
- Thick peptidoglycan cell wall, stains with crystal violet
- Thinner, not P cell wall, safranin counter-stains red/pink
- Rod-shaped
- Circular- shaped
16
Q
Bacteria - examples
- Gram-positive cocci (3)
- Management
- Management if MRSA (4 options)
- Gram-positive rods - important to remember (3)
- Gram-positive anaerobes - important to remember (1)
- Gram-negative
- Extended Spectrum Beta Lactamase - examples
- EBSL - management
- Atypical (3)
A
- Staphylococcus, streptococcus, enterococcus
- Flucloxacillin
- Doxycycline, clindomycin, vancomycin, teicoplanin
- Mycobacteria, listeria, bacillus
- Clostridium
- Neisseria (meningitis, gonorrhoea), haemophilus,
E. coli, klebsiella, pseudomonas aeruginosa moraxella catarrhalis - Some E.coli, klebsiella
- Carbapenems, e.g. meropenem / imipenem
- Legionella, chlamydia psittaci, mycoplasma pneumoniae
17
Q
Antibiotic choice - stepwise approach
- Start with amoxicillin to cover
- Switch to co-amoxiclav to additionally cover
- Switch to tazocin to additionally cover
- Switch to meropenem to additionally cover
- Add what to cover MRSA
- Add what to cover atypical bacteria
A
- Streptococcus, listeria and enterococcus
- Staphylococcus, haemophilus and e. coli
- Pseudomonas
- ESBLs
- Teicoplanin / vancomycin
- Clarithromycin / doxycycline
18
Q
Sepsis
- Definition
- Consequence of inflammation
- Septic shock - definition
- Severe sepsis - definition
- NEWS - check what
- Other examination signs
- Management - ‘Sepsis 6’
- Other bloods
- Other investigations
A
- Immune response to infection, causes systemic inflammation
- Vasodilation, capillary leak (oedema, low intravascular volume), tissue hypoperfusion (so high lactate), coagulation system activation (so low platelets / clotting factors, DIC)
- Systolic BP <90 despite fluids, lactate >4
- Sepsis results in organ dysfunction (e.g. hypoxia, AKI, oliguria, coagulation dysfunction)
- T, HR, RR, SpO2, BP, consciousness level
- Potential source, rash, reduced UO, mottling, cyanosis, arrhythmias
- Within 1 hour
Out: blood cultures, lactate (blood gas), urine output
In: ABX, fluids, oxygen to maintain 94-98% - FBC, U+E, LFT, CRP, clotting
- Urine dipstick/culture, CXR, LP, CT abdomen
19
Q
Neutropaenic sepsis
- Neutrophil count
- Difference in presentation
- Causative drugs, so consider NS in what diseases
- Empiral ABX - example
A
- Less than 1 x 109/L
- May have normal obs + temperature
- Cancer (chemotherapy)
Schizophrenia (clozapine)
RA (hydroxychloroquine, sulfasalazine, methotrexate)
Hyperthyroidism (carbimazole)
Malaria (quinine)
Other immunosuppression (monoclonal antibodies) - Piperacillin with tazobactam (tazocin)
20
Q
UTI
- Commonest causative organism + description
- Pregnancy - avoid what in 1st trimester + why
- Avoid what in 3rd trimester + why
- ABX - 3 days treatment if
- 5-10 days if
- 7 days if
- Alternatives to T / N (3)
- Pyelonephritis - ABX and length of treatment (4)
A
- E.coli - gram negative, anaerobic, bacilli
- Trimethoprim, ciprofloxacin - anti-folate
- Nitrofurantoin - haemolytic disease of newborn
- Simple lower UTI in women
- Immunosuppression, abnormal anatomy/renal function
- Men, pregnant women, catheter-related
- Pivmecillinam, amoxicillin, cefalexin
- 7-10 days, cefalexin / co-amoxiclav / trimethoprim / ciprofloxacin
21
Q
ENT
- Bacterial tonsillitis - commonest cause
- Otitis media + sinusitis - commonest cause
- Tonsillitis - 1st line ABX
- Systemically unwell OM - 1st + 2nd line ABX
- Sinusitis - 10 days no improvement - 1st line ABX
A
- Group A Streptococcus (strep. pyogenes)
- Strep. pneumoniae (+ tonsillitis not from GAS)
- Penicillin V 10 days
- Co-amoxiclav if no response in 2 days
- Penicillin V 5 days
22
Q
Intra-abdominal infections
- Differentials
- Common causative organisms
- Co-amoxiclav - covers
Doesn’t cover - Quinolones - covers
Doesn’t cover, therefore paired with - Gentamicin - covers what particularly well
Pair with what to cover MRSA
Pair with what to cover anaerobes in penicillin allergy - ABX most likely to cause C. difficile
A
- Acute diverticulitis, cholecystitis (with secondary infection), ascending cholangitis, appendicitis, spontaneous bacterial peritonitis, abscess
- Anaerobes (bacteroides, clostridium), E. coli, klebsiella, enterococcus, streptococcus
- Gram positive, gram negative, anaerobes
Pseudomonas / atypical bacteria - Gram positive, gram negative, atypical
Anaerobes, so paired with metronidazole - Gram negative, + staphylococcus (gram positive)
Vancomycin
Metronidazole - Cephalosporins
23
Q
Spontaneous bacterial peritonitis
- Common patient cohort
- 1st line ABX
- If penicillin allergic
A
- Liver failure patients
- Tazocin
- Levofloxacin + metronidazole
24
Q
Septic arthritis
- Commonest organism - overall
- Sexually active adults
- Infants
- Joint aspiration - send for
- 1st line ABX management
- If penicillin allergy/MRSA/prosthetic joint
- Acutely hot swollen joint - other differentials
A
- Staph. aureus
- N. gonorrhoea
- H. influenzae
- Gram stain, crystal microscopy, culture, ABX sensitivities
- Flucloxacillin + rifampicin 3-6 weeks
- Vancomycin + rifampicin 3-6 weeks
7. Gout (negatively birefringent urate crystals) Pseudogout (positive, Ca2+ pyrophosphate crystals) Reactive arthritis (urethritis/gastroenteritis trigger, associated with conjunctivitis Haemarthrosis - bleeding into joint
25
Q
Influenza
- Vaccinations - offered free to
- Presentation
- Diagnosis
- Medical management if risk of complications
- Post-exposure prophylaxis - when, what
A
- 65+, young children, pregnant, chronic health conditions, healthcare workers, carers
- Fever, coryzal, lethargy, anorexia, muscle ache, headache, dry cough, sore throat
- Viral nasal/throat swabs - PCR analysis
- PO oseltamivir 75mg bd 5 days
Inhaled zanamivir 10mg bd 5 days - Within 48h of exposure, as above but 10 days
26
Q
Gastroenteritis - other
- Viral - causes (3)
- E.coli (traveller’s diarrhoea) + presentation + spread
- Salmonella (typhoid) - spread + presentation
- Campylobacter - spread (3)
- ABX choice (2) (also for)
- Bacillus cereus - appearance
- Spread
- Also causes
- Yersinia - appearance
- Think this if
- Giardia lamblia - presentation + management
- Isolation - until
- Complications
A
- Rotavirus, norovirus, adenovirus (subacute diarrhoea)
- Infected faeces, unwashed salads, water
Watery stool, stomach cramps, nausea - Raw eggs, raw poultry
Rose spots, constipation - Raw poultry, untreated water, unpasteurised milk
Flu prodrome, mimics appendicitis, cramps, bloody diarrhoea - Azithromycin, ciprofloxacin (also for shigella)
- Gram positive rod
- Leftover fried rice (sick soon after- cereulide toxin)
- Infective endocarditis in IVDUs (staph. most common)
- Gram negative bacillus
- Children with lymphadenopathy and GI symptoms
- Prolonged, non-bloody diarrhoea
Metronidazole (diagnose with stool microscopy) - 48 hours after symptoms completely resolved
- Lactose intolerance, IBS, reactive arthritis, GBS
27
Q
Meningitis
- Commonest causative bacteria (2)
- Commonest cause in neonates
- Contraindications for LP (4)
A
- Neisseria meningitidis (meningococcus)
Streptococcus pneumoniae (pneumococcus) - Group B Streptococcus
- Signs of raised ICP, sepsis, trauma, major coagulopathy
28
Q
Respiratory conditions
- Exacerbations of COPD
- Uncomplicated community-acquired pneumonia
- Pneumonia possibly caused by atypical pathogens
- Hospital-acquired pneumonia
A
- Amoxicillin or tetracycline or clarithromycin
- Amoxicillin (doxycycline/clarithromycin in penicillin allergic, add flucloxacillin if staphylococci suspected e.g. in influenza)
- Clarithromycin
- <5 days since admission: co-amoxiclav / cefuroxime
>5 days after admission: tazocin / broad-spectrum cephalosporin (e.g. ceftazidime) / quinolone (e.g. ciprofloxacin)
29
Q
Urinary tract conditions
- Lower urinary tract infection
- Acute pyelonephritis
- Acute prostatitis
A
- Trimethoprim / nitro / amoxicillin / cephalosporin
- Broad-spectrum cephalosporin / quinolone (cipro)
- Tremethoprim / quinolone (ciprofloxacin)
30
Q
Skin conditions
- Impetigo
- Cellulitis
- Cellulitis (near the eyes or nose)
- Animal or human bite
- Mastitis during breast-feeding
A
- Topical fusidic acid, oral flucloxacillin or erythromycin if widespread
- Flucloxacillin (clarithromycin, erythromycin or doxycycline if penicillin-allergic)
- Co-amoxiclav (clarithromycin, + metronidazole if penicillin-allergic)
- Co-amoxiclav (doxycycline + metronidazole if penicillin-allergic)
- Flucloxacillin