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
Influenza
1. Vaccinations - offered free to
2. Presentation
3. Diagnosis
4. Medical management if risk of complications
5. Post-exposure prophylaxis - when, what
1. 65+, young children, pregnant, chronic health conditions, healthcare workers, carers
2. Fever, coryzal, lethargy, anorexia, muscle ache, headache, dry cough, sore throat
3. Viral nasal/throat swabs - PCR analysis
4. PO oseltamivir 75mg bd 5 days
Inhaled zanamivir 10mg bd 5 days
5. Within 48h of exposure, as above but 10 days
26
Gastroenteritis - other
1. Viral - causes (3)
2. E.coli (traveller's diarrhoea) + presentation + spread
3. Salmonella (typhoid) - spread + presentation
4. Campylobacter - spread (3)
5. ABX choice (2) (also for)
6. Bacillus cereus - appearance
7. Spread
8. Also causes
9. Yersinia - appearance
10. Think this if
11. Giardia lamblia - presentation + management
12. Isolation - until
13. Complications
1. Rotavirus, norovirus, adenovirus (subacute diarrhoea)
2. Infected faeces, unwashed salads, water
Watery stool, stomach cramps, nausea
3. Raw eggs, raw poultry
Rose spots, constipation
4. Raw poultry, untreated water, unpasteurised milk
Flu prodrome, mimics appendicitis, cramps, bloody diarrhoea
5. Azithromycin, ciprofloxacin (also for shigella)
6. Gram positive rod
7. Leftover fried rice (sick soon after- cereulide toxin)
8. Infective endocarditis in IVDUs (staph. most common)
9. Gram negative bacillus
10. Children with lymphadenopathy and GI symptoms
11. Prolonged, non-bloody diarrhoea
Metronidazole (diagnose with stool microscopy)
12. 48 hours after symptoms completely resolved
13. Lactose intolerance, IBS, reactive arthritis, GBS
27
Meningitis
1. Commonest causative bacteria (2)
2. Commonest cause in neonates
3. Contraindications for LP (4)
1. Neisseria meningitidis (meningococcus)
Streptococcus pneumoniae (pneumococcus)
2. Group B Streptococcus
3. Signs of raised ICP, sepsis, trauma, major coagulopathy
28
Respiratory conditions
1. Exacerbations of COPD
2. Uncomplicated community-acquired pneumonia
3. Pneumonia possibly caused by atypical pathogens
4. Hospital-acquired pneumonia
1. Amoxicillin or tetracycline or clarithromycin
2. Amoxicillin (doxycycline/clarithromycin in penicillin allergic, add flucloxacillin if staphylococci suspected e.g. in influenza)
3. Clarithromycin
4. <5 days since admission: co-amoxiclav / cefuroxime
>5 days after admission: tazocin / broad-spectrum cephalosporin (e.g. ceftazidime) / quinolone (e.g. ciprofloxacin)
29
Urinary tract conditions
1. Lower urinary tract infection
2. Acute pyelonephritis
3. Acute prostatitis
1. Trimethoprim / nitro / amoxicillin / cephalosporin
2. Broad-spectrum cephalosporin / quinolone (cipro)
3. Tremethoprim / quinolone (ciprofloxacin)
30
Skin conditions
1. Impetigo
2. Cellulitis
3. Cellulitis (near the eyes or nose)
4. Animal or human bite
5. Mastitis during breast-feeding
1. Topical fusidic acid, oral flucloxacillin or erythromycin if widespread
2. Flucloxacillin (clarithromycin, erythromycin or doxycycline if penicillin-allergic)
3. Co-amoxiclav (clarithromycin, + metronidazole if penicillin-allergic)
4. Co-amoxiclav (doxycycline + metronidazole if penicillin-allergic)
5. Flucloxacillin