Passmedicine - Infection Flashcards
What kind of bacteria is staph aureus?
Facultative anaerobe
Gram positive cocci
Catalase +ve
How do most staph aureus strains have resistance to penicillin?
Beta-lactamase production
How is resistance to methiillin usually mediated by?
Mec operon (penicillin binding protein is altered to be resistant to methicillin)
What kind of bacteria is strep pyogenes?
Gram positive
Chain forming
Lancefield group A (produces beta-haemolysis on blood agar)
Catalase negative
What superantigens can strep pyogenes release? What can this superantigen result in?
Pyogenic exotoxin A which –> scarlet fever
What kind of antibiotic is used for strep pyogenes infections?
Penicillin/macrolides
What kind of bacteria is E. coli?
Gram negative rod
Facultative anaerobe, non-sporing
What is the mechanism of action of enterotoxigenic E. coli?
Produces enterotoxin that results in a large volume fluid secretion into the gut (via cAMP activation)
What is the mechanism of action of enteropathogenic E. coli?
Binds to intestinal cells + causes structural damage –> large volume diarrhoea and fever
What kind of bacteria is c. jejuni?
Gram negative, non-sporulating
What kind of symptoms does c. jejuni infection cause?
Diffuse diarrhoea
RIF pain
What antibiotic should be given for c. jejuni infection?
Usually self-limiting so does not require antibiotics
Quinolones often rapidly effective
What kind of bacteria is H. pylori?
Gram negative, helix shaped rod, microaerophilic
Flagellated
What enzyme do h. pylori produce?
Hydrogenase which derives energy from hydrogen released by intestinal bacteria
How can h. pylori cause ulcers?
Secretes urase which breaks down gastric urea –> CO2 and ammonia –> bicarbonate which neuralises gastric acid (so stomach produces more acid)
Where does h. pylori most commonly colonate?
Gastric antrum
What patients get gastric ulcers + which patients get duodenal ulcers with h. pylori infections?
If colonises antrum - irritation leads to increased gastrin release + higher levels of gastric acid –> duodenal ulcers
More diffuse infection –> gastric acid levels lower and ulcers develop by local tissue damage from h. pylori –> gastric ulcers
How is h. pylori infection diagnosed?
Serology
What is the standard active TB therapy?
First 2 months:
rifampicin, isoniazid, pyrazinamide, ethambutol
Next 4 months:
rifampicin, isoniazid
What is the treatment of latent TB?
3 months isoniazid (with pyridoxine) + rifampicin OR 6 months of isoniazid (with pyridoxine)
What is the treatment of meningeal TB?
Treat for 12 months with steroids
Who may have to undergo directly observed therapy (with 3x weekly dosing regimen) for TB?
Homeless with active TB
Patients who are likely to have poor concordance
All prisoners with active/latent TB
Visual acuity should be checked before starting what TB drug?
Ethambutol
What are features of genital herpes?
Painful genital ulceration
Urinary retention may occur
How is genital herpes managed?
Oral aciclovir
What is the management of primary attack of herpes during pregnant?
Elective c-section >28 weeks
Supressive oral aciclovir until delivery
How is transmission of herpes to a baby in a women with recurrent herpes minimised?
Treatment with suppressive therapy until delivery
NB risk of transmission to baby is low
What is EBV aka?
Herpesvirus 4
What is the most common cause of infectious mononucleosis?
EBV
Less common causes include CMV, HHV-6
What classic triad of symptoms is seen in 98% of IM patients?
Sore throat
Pyrexia
Lympadenopathy
What other features can be seen in IM?
Malaise, anorexia, headache
Palatal petechiae
Splenomegaly (may predipose to splenic rupture)
Hepatitis
Lymphocytosis
Haemolytic anaemia secondary to cold agglutins
Maculopapular, pruritic rash develops in 99% of IM patients who take ampicillin/amoxicillin
How long do symptoms of IM typically take to resolve?
2-4 weeks
How is IM diagnosed?
Heterophil antibody test (monospot)
NICE recommend this + FBC in 2nd week of illness to confirm diagnosis
How is IM managed?
Supportive - rests, avoid alcohol, simple analgesia, hydration
What must those with IM avoid?
Contact sports for 8 weeks after having glandular fever to reduce risk of splenic rupture
List the live attenuated vaccines
BCG measles, mumps, rubella (MMR) influenza (intranasal) oral rotavirus oral polio yellow fever oral typhoid
List the inactivated vaccines
rabies
hepatitis A
influenza (intramuscular)
List the toxoid vaccines (inactivated toxins)
tetanus
diphtheria
pertussis
What is a subunit vaccine?
Only part of the pathogen is used to generate an immunogenic response
What is a conjugate vaccine?
A vaccine that links the immunogenic bacterial polysaccharide outer coats to the proteins to make them more immunogenic
List some conjugate vaccines
Pneumococcus
Haemophilus
Meningococcus
List some subunit vaccines
Hep B
HPV
What does the Hep B vaccine contain?
HbsAg adsorbed onto aluminium hydroxide adjuvant
What groups are at risk from HIV?
IVDAs
Those who received a blood transfusion prior to 1991
What kind of virus is hep C?
RNA flavivirus
What is the risk of transmission of hep C during a needlestick injury?
2%
What is the risk of vertical transmission of hep C?
6%
Is breastfeeding CI in hep C positive mothers?
No
What are the features of hep C infection?
Usually asymptomatic
May experience: rise in aminotransferases/jaundice, fatigue, arthalgia
What is the investigation of choice to diagnose acute hep C infection?
HCV RNA
What is the outcome of a hep C infection?
15-45% clear it after an acute infection
55-85% go on to develop a chronic infection
Define chronic hepatitis C
Persistence of HCV RNA in the blood for 6 months
What are potential complications of chronic hep C?
Arthalgia, arthritis Sjogren's Cirrhosis Heptocellular cancer Cryoglobulinaemia (usually type II) Porphyria cutanae tarda Membranoproliferative GN
How is chronic hep C infection treated?
Depends on viral genotype (test prior)
Combination of protease inhibitors (e.g. daclatasvir + sofosbuvir or sofosbuvir + simeprevir) with or without ribavirin
What are SEs of ribavirin?
Haemolytic anaemia
Cough
Teratogenic (do not become pregnant <6m after use)
What is the best way to assess response to treatment of hep C infection?
Viral load
What types of HPV generally cause genital warts?
6 and 11
How are genital warts treated?
First line
Topical podophyllum - multiple/non-keratinised
Cryotherapy - solitary/keratinised
Second line
Imiquimod (topical cream)
What is the most common cause of oesophagitis in HIV patients?
Oesophageal candidiasis
What CD4 count is oesophagal candidiasis typically seen in?
<100
What are typical symptoms of oesophageal candidiasis?
Dysphagia
Odynophagia
How is oesophageal candidiasis treated?
Fluconazole, itraconazole
What kinds of infections can E. coli cause?
Diarrhoea
UTI
Neonatal meningitis
What are the different E. coli antigens
A - O
B - K
C - H?
A - O = lipopolysaccharide layer
B - K = capsule (usually what causes neonatal meningitis)
C - H = flagellin
What does mycoplasma pneumoniae tend to cause?
An atypical pneumonia in younger patients
What are characteristic complications associated with mycoplasma pneumonia?
Erythema multiforme Cold autoimmune haemolytic anaemia Meningoencephalitis, GBS Bullous myringitis Pericarditis/myocarditis GI - hepatitis/pancreatitis Acute GN
What are features typical of a mycoplasma pneumonia?
Prolonged + gradual onset
Flu like symptoms preceding a dry cough
What do you see on CXR in mycoplasma pneumonia?
Bilateral consolidation
What is bullous myringitis?
Painful vesicles on the tympanic membrane
How is mycoplasma pneumonia generally diagnosed?
Mycoplasma serology
also have a positive cold agglutination test
How is mycoplasma pneumonia managed?
Doxycycline or macrolide
What kind of bacteria are salmonella spp?
Aerobic, gram negative robs
Remember - these are not normally gut commensals
What bacteria causes typhoid?
Salmonella typhi
What bacteria causes paratyphoid?
Salmonella paratyphi
How is typhoid transmitted?
Faecal-oral
What are the clinical features of typhoid/paratyphoid?
Systemic upset (headache, fever, arthalgia)
Relative bradycardia
Ab pain, distension
Constipation (more common in typhoid) or diarrhoea
Rose spots on the trunk (more common in paratyphoid)
What are complications of typhoid/paratyphoid?
Osteomyelitis (esp. in sickle cell disease) GI bleed/perforation Meningitis Cholecystitis Chronic carriage
What antibiotic can be used to treat typhoid/paratyphoid?
Ciprofloxacin
What is the first line treatment of syphillis?
IM benzylpen
Alt: doxycycline
What reaction is sometimes seen after treatment of syphillis?
Jarisch-Herxheimer
(fever, tachycardia, rash after first dose)
Thought to be due to release of endotoxins following bacterial death (occurs few hours after treatment)
How is Jarisch-Herxheimer treated?
Antipyretics
Following splenectomy, what infections are patients particularly at risk of?
Pneumococcus
Haemophilus
Meningococcus
When should patients due to undergo splenectomy receive their vaccinations?
2 weeks prior to the operation
What vaccinations should those undergoing splenectomy receive?
Hib, meningitis A and C
Annual flu jab
Pneumococcal every 5 years
What antibiotic prophylaxis should those who have undergone splenectomy receive?
Penicillin V
What are indications for splenectomy?
Trauma
Spontaneous rupture, e.g. EBV
Hypersplenism - hereditary spherocytosis, elliptocytosis etc..
Malignancy - lymphoma/leukaemia
Splenic cysts, hydatid cysts, splenic abscesses
What are complications of splenectomy?
Haemorrhage
Pancreatic fistula (due to damage to pancreatic tail)
Thrombocytosis
Encapsulated bacteria infection (e.g. strep pneumoniae, Hib, Neisseria meningitidis)
What changes will occur in the body post-splenectomy?
Platelets rise
Howell-jolly bodies appear
Target cells, Pappenheimer bodies
Post-splenectomy sepsis typically occurs with what organisms?
Encapsulated organisms
What pathogen causes bronchiolitis?
RSV
What pathogen causes croup?
Parainfluenza virus
What pathogen causes the common cold?
Rhinovirus
What pathogen causes flu?
Influenza
What pathogen most commonly causes community acquired pneumonia?
Strep pneumoniae
What pathogen most commonly causes bronchiectasis exacerbations?
Hib
What pathogen causes acute epiglottitis?
Hib
What pathogen causes pneumonia, especially following flu?
Staph aureus
What organisms most commonly cause an atypical pneumonia?
Mycoplasma pneumoniae - flu symptoms –> dry cough
Legionella pneumoniae - causes dry cough, lymphopenia, deranged LFTs, hyponatraemia
What classically spreads legionella?
Air conditioning systems
What is a common cause of pneumonia in HIV patients?
PJP
What are typical features of a PJP pneumonia?
Few chest signs, exertional SoB
What are typical features of pulmonary TB?
Cough
Night sweats
Weight loss
What is meant by a ‘notifiable disease’?
Disease that the proper officer at the local health protection team needs to be notified about
What are notable exceptions to notifiable diseases?
HIV
List 5 notifiable diseases
Acute encephalitis Acute infectious hepatitis Acute meningitis Acute poliomyelitis Anthrax Botulism Brucellosis Cholera Diphtheria Enteric fever (typhoid or paratyphoid fever) Food poisoning Haemolytic uraemic syndrome (HUS) Infectious bloody diarrhoea Invasive group A streptococcal disease Legionnaires Disease Leprosy Malaria Measles Meningococcal septicaemia Mumps Plague Rabies Rubella SARS Scarlet fever Smallpox Tetanus Tuberculosis Typhus Viral haemorrhagic fever (VHF) Whooping cough Yellow fever
What kind of virus is CMV?
Herpes virus
It is thought that ___% of people have been exposed to CMV virus, but it only causes disease in those who are…
50%
Immunocompromised, e.g. HIV/following organ transplant
What do cells infected with CMV look like?
Owl’s eye appearance due to intranuclear inclusion bodies
What are features of congenital CMV infection?
Growth retardation Pinpoint petechial blueberry muffin skin lesions Microencephaly Sensorineural deafness Encephalitis (seizures) Hepatosplenomegaly
Who does CMV retinitis tend to develop in?
HIV patients with a low CD4 (<50)
How does CMV retinitis present?
Visual impairment, e.g. b blurred vision
What do you see on fundoscopy in CMV retinitis?
Multiple retinal haemorrhages and necrosis - pizza retina
What is the treatment of choice for CMV retinitis?
IV ganciclovir
What organism causes chancroid?
Haemophilus ducreyi
What are features of chancroid?
Painful genital ulcers (with sharply defined, ragged, undetermined border)
Unilateral, painful inguinal LN enlargement
What causes lymphogranuloma venereum?
Chlamydia trachomatis
What are the three stages of lymphogranuloma venereum?
1 - small painless pustule which later forms an ulcer
2 - painful inguinal lympadenopathy
3 - proctocolitis
How is LVG treated?
Doxycycline
What organisms typically cause cellulitis?
Strep pyogenes
Staph aureus
What are features of cellulitis?
Erythema, pain, swelling
Systemic upset, e.g. fever
Commonly occurs on shins
What classification is used to guide how we manage patients with cellulitis?
Eron
Eron I
No signs of systemic toxicity
No uncontrolled co-morbs
Eron II
Systemically unwell
Systemically well with co-morb
Eron III
Significant systemic upset, e.g. acute confusion, tachycardia, tachynoea, hypotension or unstable co-morbs
Eron IV
Sepsis or severe life-threatening infection, e.g. necrotizing fasciitis
What patients with cellulitis should be admitted for IV antibiotics?
Eron III or IV
Severe/rapidly deteriorating cellulitis, e.g. large areas of skin
Very young (<1y) or frail
Immunocompromised
Has significant lymphoedema
Has facial cellulitis/periorbital cellulitis
How are Eron II patients managed?
Can be treated with IV antibiotics in the community
How are all other patients (Eron I) with cellulitis managed?
Oral antibiotics
Flucloxacillin 1st line (clarithromycin, erythromycin (in pregnancy), doxcycline if penicillin allergic)
What antibiotic should be given to those with severe cellulitis?
Co-amoxiclav, cefuroxime, clindamycin, ceftriaxone
When is trimethoprim a risk for teratogenicity?
First trimester
What patients should be screened for MRSA?
All patients awaiting elective admissions
Emergency admission
How should a patient be screened for MRSA?
Nasal swab and skin lesions/wounds
Wipe inside rim of nose for 5 seconds
How is MRSA supressed from a carrier once identified?
Nose - mupirocin 2% in white soft paraffin tds for 5 days
Skin - chlorhexidine gluconate od 5 days (apply all over)
What antibiotics can be used to treat MRSA infections?
Vancomycin
Teicoplanin
Linezolid (reserve for resistant cases)
What organisms can cause community acquired pneumonia?
Strep pneumoniae
H. influenzae
Staph aureus
Viruses
What organism classically causes pneumonia in alcoholics?
Klebsiella pneumoniae
What are the characteristic features of a pneumococcal pneumoniae?
Rapid onset
High fever
Pleuritic chest pain
Herpes labialis
What causes kaposi’s sarcoma?
HHV-8
How does kaposi sarcoma present?
Purple papules/plaques on skin or mucosa which may ulcerate
Respiratory involvement may –> massive haemoptysis + pleural effusion
How is kaposi sarcoma treated?
Radiotherapy + resection
What causes amoebiasis?
Entamoeba histolytica
What kinds of syndromes can amoebiasis lead to?
Amoebic dysentry
Amoebic liver abscess
How is amoebic dysentry treated?
Metronidazole
What is an amoebic liver abscess classically like?
Single mass in right lobe filled with ‘anchovy sauce’
What are clinical features of an amoebic liver abscess?
Fever
RUQ pain
Give examples of tetracyclines
Doxycyline
Tetracycline
What is the mechanism of action of tetracyclines?
Protein synthesis inhibitors
What is the commonest mechanisms of resistance against tetracyclines?
Increased efflux of the bacteria by plasmid-encoded transport pumps, ribosomal protection
What are indications for tetracycline use?
Acne vulgaris
Lyme disease
Chlamydia
Mycoplasma pneumoniae
What are notable AEs associated with tetracyclines?
Discolouration of teeth - do not use before age 12
Photosensitivity
Anigioedema
Black hairy tongue
What are important CIs to the use of tetracyclines?
Pregnancy + breastfeeding due to discolouration of the neonates teeth
What malignancies are associated with EBV?
Burkitt’s lymphoma
Hodgkin’s lymphoma
Nasopharyngeal carcinoma
HIV-associated central nervous system lymphomas
What non-malignant condition is EBV associted with?
Hairy leukoplakia
What is leprosy?
Granulomatous disease primarily affecting the peripheral nerves and skin
What causes leprosy?
Mycobacterium leprae
What are the clinical features of leprosy?
Patches of hypopigmented skin typically affecting the buttocks, face, extensor surfaces of limbs
Sensory loss
What determines the type of leprosy a patient gets?
Low degree of cell mediated immunity –> lepromatous leprosy = extensive skin involvement, symmetrical nerve involvement
High degree of cell mediated immunity –> tuberculoid leprosy = limited skin disease, asymmetric nerve involvement
How is leprosy managed?
Triple therapy - rifampicin, dapsone, clofazimine
Gram positive cocci =
Staph, strep
Gram negative cocci =
Neisseria meningitis/gonorrhoeae
Moraxella catarrhalis
Gram positive bacilli =
ABCD L Actinomyces Bacillus anthracis Clostridium Diphtheria Listeria monocytogenes
Gram negative rods =
E. coli H. influenzae Pseudomonas aeruginosa Salmonella spp. Shigella spp. C. jejuni
What diseases does parovirus B19 cause?
Erythema infectiosum (slapped cheek syndrome)
How does slapped cheek syndrome present?
Mild feverish illness +/- bright, red rash over the cheeks
Child feels better as rash appears
How long does the rash in slapped cheek syndrome tend to take to go away?
Usually peaks after a week and then fades
BUT for some months after, a warm bath, sunlight, heat/fever may trigger its recurrence
How is slapped cheek managed?
Usually self-limiting
Is school exclusion with slapped cheeky req?
No as once the rash appears the child is no longer infectious
In adults what can parovirus B19 cause?
An acute arthritis
What is the most important thing to remember about parovirus B19?
Can affect unborn baby in first 20 weeks
If women exposed before 20 weeks must have IgM and IgG checked
When is someone with parovirus B19 infectious?
3-5 days before the rash appears
How might parovirus B19 infection present in immunocompromised patients?
Pancytopenia
How might parovirus B19 infection present in sickle cell patients?
Aplastic crises (parovirus B19 supresses erythropoiesis for about a week)
What are the two types of necrotizing fasciitis?
1 - caused by mixed anaerobes + aerobes (often occurs post-surgery in DM) - most common
2 - strep pyogenes most common cause
What are the clinical features of necrotizing fasciitis?
Acute onset
Painful, erythematous lesion develops
Often presents as rapidly worsening cellulitis with pain out of keeping with physical features
Extremely tender over underlying tissue
How is necrotizing fasciitis managed?
Urgent surgical referral for debridement
IV antibiotics
What is a spinal epidural abscess (SEA)?
Collection of pus superficial to the dura mater of the spinal cord
Why is SEA an emergency?
Requires urgent treatment to avoid progressive spinal cord damage
Define abscess
Collection of pus encapsulated by a pyogenic membrane
How can bacteria enter the epidural space to cause SEA?
Contiguous spread from adjacent structures, e.g. discitis
Haematological spread, e.g. from bacteraemia from IVDU
Direct infection, e.g. post-spinal surgery
What is a major risk factor for SEA?
Immunosupression, e.g. HIV, DM, alcoholism, chemotherapy, steroids etc.
What organism most commonly is responsible for SEA?
Staph aureus
How do patients with SEA typically present?
Fever
Back pain
Focal neurological deficits according to the segment of cord affected
What investigations should be done in suspected SEA?
Bloods - inflammatory markers, HIV, Hep B, Hep C, coagulation, group and save
Blood cultures
Infection screen (incl. CXR and urine culture)
MRI whole spine
Why do you need to MRI the whole spine in SEA?
Skip lesions may be present
If the primary source of infection in SEA is not clear what further investigations may be required?
Dental x-rays, ECG etc.
What is the management of SEA?
Long term broad spectrum antibiotics, later refined based on cultured results
Large/compressive abscess or significant neurological deficits/not responding to antibiotics alone –> surgery
What are potential complications of chlamydia?
Epididymitis PID Endometritis Increased risk of ectopic Infertility Reactive arthritis Perihepatitis (Fitz-Hugh-Curtis syndrome)
When should chlamydia testing be carried out?
2 weeks after a possible exposure
How is chlamydia managed?
7d doxycycline or azithromycin (single dose) 1g
What is the main technique used to test for latent TB?
Mantoux test
In which people would you use interferon gamma blood test to test for latent TB?
Then the mantoux test is positive/equivocal
In those where the tuberculin test may be falsely negative
What does the mantoux test involve?
0.1ml of 1:1, 000 purified protein dervative injected intradermally
Result read 2-3d later
How do you interpret a mantoux test?
Diam <6mm - negative (no significant hypersensitivity to tuberculin protein - never been exposed to TB/BCG)
Diam 6-15mm - positive (hypersensitive to tuberculin protein - do not need BCG as have had it before/had TB before)
Diam >15mm - strongly positive (strongly hypersensitive to tuberculin - suggests TB infection)
What things may cause a false negative mantoux test?
Miliary TB Sarcoidosis HIV Lymphoma Very young age (<6m)
What test for TB is no longer used in the UK?
Heaf test
When should someone receive their tetanus vaccinations?
2 months 3 months 4 months 3-5 years 13-18 years
This gives long term protection against tetanus
What wounds are considered to be at high risk of leading to tetanus?
Compound fractures Delayed surgical intervention (>6h) Significant degree of devitalised tissue Wounds contaminated with soil Wounds containing FBs Wounds/burns in people with sepsis
How should wounds at high risk of tetanus be managed?
IM human tetanus Ig regardless of whether they have been vaccinated
If vaccination history incomplete/unknown give dose of tetanus vaccine as well
What are the following CSF characteristics: A. appearance B. glucose C. protein D. white cells In bacterial meningitis?
A. appearance: cloudy
B. glucose: low (<1/2 plasma)
C. protein: high
D. white cells: 10-5, 000 polymorphs
What are the following CSF characteristics: A. appearance B. glucose C. protein D. white cells In viral meningitis?
A. appearance: clear/cloudy
B. glucose: 60-80% plasma
C. protein: normal/raised
D. white cells: 15-1, 000 lymphocytes
Exceptions - mumps and herpes encephalitis –> low glucose
What are the following CSF characteristics: A. appearance B. glucose C. protein D. white cells In tuberculous meningitis?
A. appearance: slight cloudy, fibrin web
B. glucose: low (<1/2 plasma)
C. protein (high)
D. white cells: 10-1, 000 lymphocytes
What else can you do to the CSF if you suspect tuberculous meningitis?
ZN stain (but only sensitive in 20%) so PCR sometimes used
What causes cholera?
Gram negative vibro cholerae
What are features of cholera?
Rice water diarrhoea (profuse)
Dehydration
Hypoglycaemia
How is cholera managed?
Oral dehydration therapy
Doxycyline, ciprofloxacin
Where is chancroid usually acquired?
In the tropics
In post-splenectomy patients what organism does penicillin V prophylaxis not protect against?
H. influenzae (due to production of beta-lactamases)
What vaccines should not be given to immunocompromised patients?
Live attenuated ones - e.g. BCG
What causes tetanus?
Tetanospasmin exotoxin released from clostridium tetani
Where are tetanus spores found?
Soil
How does tetanospasmin cause tetanus?
Prevents release of GABA
What are features of tetanus?
Prodrome fever, lethargy, headache Trismus Risus sardonicus Opishtotonus (arched back, hyperextended neck) Spasms, e.g. dysphagia
How is tetanus manaed?
Supportive, e.g. muscle relaxants, ventilatory support
IM human tetanus Ig for high risk wounds
Metronidazole is first line antibiotic
What is the pathophysiology of mycobacterium tuberculosis?
Macrophages migrate to regional LNs (lung lesion + affected LNs = Ghon complex)
Leads to formation of granuloma (collection of epitheloid histiocytes)
Caseous necrosis in centre
Inflammatory response mediated by T4HS
In healthy people, disease may be contained, in immunocomp patients disseminated (miliary TB) may occur
Why can’t you use normal stains to view mycobacterium tuberculosis?
It membrane is waxy and prevents binding with normal stains
What stain is typically used to see TB?
Ziehl Neelsen stain
What is the recommended antibiotic therapy for exacerbations of COPD?
Amoxicillin
Tetracycline or clarithromycin
What is the recommended antibiotic therapy for uncomplicated CAP?
Amoxicillin
(doxycyline/clarithromycin if penicillin allergic)
Add in fluclox if staph suspected e.g. flu
What is the recommended antibiotic therapy for pneumonia caused by atypical pathogens?
Clarithromycin
What is the recommended antibiotic therapy for hospital acquired pneumonia?
Within 5d of admission - co-amoxiclav or cefuroxime
>5d after admission - piperacillin with tazobactam or broad spectrum cephalosporin (e.g. ceftazidime) or a quinolone (e.g. ciprofloxacin)
What is the recommended antibiotic therapy for a lower UTI?
Trimethoprim or nitrofuratoin
Alt: amoxicillin
What is the recommended antibiotic therapy for acute pyelonephritis?
Broad spectrum cephalosporin or quinolone
What is the recommended antibiotic therapy for acute prostatitis?
Quinolone or trimethoprim
What is the recommended antibiotic therapy for impetigo?
Topical fusidic acid
Oral fluclox or erythromycin if widespread
What is the recommended antibiotic therapy for celullitis?
Flucloxacillin (clarithromycin, erythromycin or doxy if penicillin allergic)
What is the recommended antibiotic therapy for cellulitis near nose or eyes?
Co-amoxiclav (clarithromycin, + metronidazole if penicillin-allergic)
What is the recommended antibiotic therapy for erysipelas?
Flucloxacillin (clarithromycin, erythromycin or doxycycline if penicillin-allergic)
What is the recommended antibiotic therapy for animal/human bite?
Co-amoxiclav (doxycycline + metronidazole if penicillin-allergic)
What is the recommended antibiotic therapy for mastitis whilst breast feeding?
Flucloxacillin
What is the recommended antibiotic therapy for throat infections?
Phenoxymethylpenicillin (erythromycin alone if penicillin-allergic)
What is the recommended antibiotic therapy for sinusitis?
Amoxicillin or doxycycline or erythromycin
What is the recommended antibiotic therapy for otitis media?
Amoxicillin (erythromycin if penicillin-allergic)
What is the recommended antibiotic therapy for otitis externa?
Flucloxacillin (erythromycin if penicillin-allergic)
What is the recommended antibiotic therapy for periapical/periodontal absces?
Amoxicillin
What is the recommended antibiotic therapy for gingivitis (acute necrotizing ulcerative)?
Metronidazole
What is the recommended antibiotic therapy for gonorrhoea?
Intramuscular ceftriaxone
What is the recommended antibiotic therapy for chlamydia?
Doxycycline or azithromycin
What is the recommended antibiotic therapy for PID?
Oral ofloxacin + oral metronidazole or intramuscular ceftriaxone + oral doxycycline + oral metronidazole
What is the recommended antibiotic therapy for syphillis?
Benzathine benzylpenicillin or doxycycline or erythromycin
What is the recommended antibiotic therapy for BV?
Oral or topical metronidazole or topical clindamycin
What is the recommended antibiotic therapy for c. diff infections?
First episode: metronidazole
Second or subsequent episode of infection: vancomycin
What is the recommended antibiotic therapy for campylobacter enteritis?
Clarithromycin
What is the recommended antibiotic therapy for salmonella?
Ciprofloxacin
What is the recommended antibiotic therapy for shigellosis?
Ciprofloxacin
What baseline tests are required before someone starts anti-TB therapy?
LFTs as all drugs are hepatotoxic
UE
Baseline visual assessment (ethambutol)
FBC for platelet count
What are the features of primary syphillis?
Chancre - painless ulcer at site of sexual contact
Local non-tender lymphadenopathy
What are features of secondary syphillis?
6-10w post primary infection
Systemic symptoms -fever, lymphadenopathy
Rash on trunk, palsm and soles
Buccal snail track ulcers
Condylomata lata (painless, warty lesions on genitalia)
What are features of tertiary syphillis?
Gumma (granulomatous lesions of skin and bones) Ascending aorta aneurysm General paralysis of the insane Tabes dorsalis Argyll-Robertson pupil
What are features of congenital syphillis?
Blunted upper incisor teeth (Hutchison’s teeth), mulberry molars
Rhagades (linear scars at angle of mouth)
Keratitis
Saber shins
Saddle nose
Deafness
What causes legionnaire’s disease?
Intracellular bacterium Legionella pneumophilia
Why does legionella typically spread?
Colonizes water tanks or can spread through AC systems
What are features of legionnaire’s disease?
Flu like symptoms + fever Dry cough Relative bradycardia Confusion Lymphopaenia Hyponatraemia Derranged LFTs Pleural effusion 30%
How is legionnaire’s disease diagnosed?
Urinary antigen
How is legionnaire’s disease treated?
Erythromycin/clarithromycin
What is the most common cause of viral encephalitis in the adult population?
HSV
What features are suggestive of a viral encephalitis?
Sudden change in behaviour
Fever
Seizures
What kind of bacteria is pseudomonas aeruginosa?
Aerobic gram negative rod
What kind of infections does pseudomonas cause?
Chest infections (esp. in CF)
Skin - burns, chronic wound infections
Otitis externa (esp in DM)
UTIs
What is the most common organism found in central line infections?
Staph epidermidis
What are the main differences between staph aureus and staph epidermidis?
Aureus - coagulase +ve, skin infections, asbcesses, OM, toxic shock syndrome
Epidermidis - coagulase -ve, central line infections, IE
How is BV treated in pregnancy?
Oral metronidazole still
What PEP is used for hep A?
Human normal immunoglobulin or hep A vaccine
What PEP is used for Hep B?
Vaccinated (HBsAg positive) - booster dose of HBV vaccine
Non-vaccinated/non-responder - hepatitis B Ig and vaccine
In process of being vaccinated - accelerated course of HBV
What PEP is used for hep C?
Monthly PCR - if seroconversion then inferferon +/i ribavirin
What PEP is used for HIV?
Low risk incidents, e.g. human bites don’t req. PEP
Combination of ARTs ASAP (within 72h) for 4 weeks
Serological testing 12 weeks after completion of PEP
What PEP is used for VZV?
VZIg for Ig negative pregnant women/immunosupressed
What is the risk of transmission of Hep B from a needlestick injury?
20-30%
What is the risk of transmission of Hep C from a needlestick injury?
0.5-2%
What is the risk of transmission of HIV from a needlestick injury?
0.3%
What herpes virus mostly causes oral lesions?
HSV1
What herpes virus mostly causes genital herpes?
HSV2
How is herpes gingivostomatitis managed?
Oral aciclovir
Chlorhexidine mouthwash
How are cold sores managed?
Topical aciclovir
How is genital herpes managed?
Oral aciclovir (if frequent exacervations may require long term aciclovir)
What is classical of the fever in malaria?
It comes on alternating days
Nb other symptoms of malaria include headache, myalgia, hepatomegaly
What investigations are recommended by NICE in suspected meningitis?
FBC CRP Coagulation screen Blood culture Whole blood PCR Blood glucose Blood gas LP if no signs of raised ICP
How is suspected meningitis managed?
Admit to hospital
If in GP + meningococcal disease suspected –> IM benzylpenicillin + transfer to hospital
What initial empirical therapy is given for meningitis in those aged <3 months?
IV cefotaxime + amoxicillin
What initial empirical therapy is given for meningitis in those aged 3 months - 50 years?
IV cefotaxime
What initial empirical therapy is given for meningitis in those aged >50 years?
IV cefotaxime + amoxicillin
What therapy is given for meningococcal meningitis?
IV benzylpenicillin or cefotaxime
What therapy is given for meningitis for those with pneumococcal meningitis?
IV cefotaxime
What therapy is given for meningitis due to H. influenzae?
IV cefotaxime
What therapy is given for meningitis due to listeria?
IV amoxicillin + gentamicin
What drug (aside from antimicrobials) should be given in meningitis management and why?
IV dexamethasone to reduce risk of neurological sequelae
What drug should be used to treat meningitis if the patient is allergic to penicillin or cephalosporins?
Chloramphenicol
For what kind of meningitis must you offer household/close contacts prophylaxis? What is this prophylaxis?
Meningococcal
(If been in contact within 7 days of onset)
Oral ciprofloxacin (1st line) or rifampicin
Offer meningococcal vaccine to close contacts when serotype results are available
What are the most common causes of meningitis in those aged 0-3 months?
Group B Streptococcus (most common cause in neonates)
E. coli
Listeria monocytogenes
What are the most common causes of meningitis in those aged 3 months - 6 years?
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
What are the most common causes of meningitis in those aged 6 years - 60 years?
Neisseria meningitidis
Streptococcus pneumoniae
What are the most common causes of meningitis in those aged >60 years?
Streptococcus pneumoniae
Neisseria meningitidis
Listeria monocytogenes
What is a common cause of bacterial meningitis in those who are immunosupressed?
Listeria monocytogenes
Which STI is a ‘strawberry cervix’ associated with?
Trichomonas vaginalis
How is uncomplicated falciparum malaria treated?
1st line - Artemisinin based combination therapies
How is complicated falciparum malaria treated?
IV artesunate (parasite >10% - consider exchange transfusion)
What is rabies?
Viral disease that causes an acute encephalitis
What kind of virus causes rabies?
Lyssavirus
What kinds of bites can spread rabies?
Usually dog
Others - bat, racoon, skunk
Following a bite how does the rabies virus spread in the body?
Up nerve axons towards the central nervous system
What are the clinical features of rabies?
Prodrome - headache, fever, agitation
Hydrophobia - water provoking muscle spasms
Hypersalivation
What kind of bodies are seen in neurons infected with rabies?
Negri bodies (cytoplasmic inclusion bodies)
How should animal bites in at risk countries (of rabies) be managed?
Wash wound
Vaccinated - give further 2 doses of vaccine
Not vaccinated - human rabies Ig + full vaccination course (administer locally around wound)
What is the prognosis of rabies?
Untreated disease is nearly always fatal
What is the first line treatment of animal bites?
Co-amoxiclav
What individuals are offered a BCG?
All infants (0-12m) living in areas where annual incidence of TB 40/100, 000+ or with a grandparent/parent who was born in a country where the incidence of TB is that
Previously unvaccinated tuberculin -ve contacts of cases of respiratory TB
Previously unvaccinated tuberculin negative new entrants under 16 who were born/lived (>3m) in a country with annual TB incidence 40/100, 000+
Healthcare workers
Prison staff
Staff of care home for the elderly
Those working with the homeless
What does the BCG vaccine contain?
Live attenuated mycobacterium bovis
What must you have prior to having a BCG?
Tuberculin skin tests (unless younger than 6 and no contact with TB)
What can BCG not be given at the same time as?
Other live vaccines (leave 4 week interval)
What are contraindications to getting a BCG?
Prev. BCG Hx of TB HIV Pregnancy >35 years (no evidence of efficiacy) Positive tuberculin test
What are the two tuberculin tests?
Heaf and mantoux
When is it appropriate to perform stool microbiological investigations for a child with diarrhoea?
- Suspected septicaemia
- Blood/mucous in stool
- Child is immunocompromised
Define PUO
Fever >3 weeks with resists diagnosis after 1 week in hospital
What are causes of PUO
Neoplasia - lymphoma, hypernephroma, preleukaemia, atrial myxoma
Infections - TB, abscess
Connective tissue disorders
What is the quickest way to determine lactate levels?
ABG or VBG
What is co-trimaxazole a mix of?
Trimethoprim and sulfamethoxazole
Drugs that end in -navir are from what class of drugs?
Protease inhibitors
Drugs that end in -gravir are from what class of drugs?
Integrase inhibitors
How is legionella pneumophilia best diagnosed?
Urinary antigen test
What is the single most effective single measure to reduce the incidence of MRSA?
Hand hygiene
What organism is responsible for causing toxoplasmosis?
Toxoplasma gondii
How does toxoplasmosis spread?
Protozoa infects via GIT, lungs or broken skin
Its oocytes release trophozoites which migrate around the body, including to the muscle, eyes and brain
What is the usual reservoir for toxoplasma gondii?
Cat
What is a common presentation of toxoplasmosis?
IM type illness (fever, malaise, lymphadenopathy)
Less common manifestations include meningioencephalitis + myocarditis
How do you test for toxoplasmosis?
Ab test
Sabin Feldman dye test
Who is treated for toxoplasmosis?
Those with severe infections/immunosupressed
What is the treatment of toxoplasmosis?
Pyrimethamine + sulphadiazine for 6 weeks (at least)
What causes congenital toxoplasmosis?
Transplacental spread from mother
What are features of congenital toxoplasmosis?
Microcephaly, hydrocephalus, cerebral calcification + choriodoretinitis
What family is the ebola virus from?
Filoviridae virus family
How does ebola spread?
Human to human transmission through broken skin or mucous membranes with blood, secretions, organs or other bodily fluids of infected people and surfaces contaminated with these fluids
What is the incubation period of ebola?
2-21 days
Only infectious once symptoms develop
What are the first symptoms of ebola?
Sudden onset fever, fatigue, muscle pain, headache, sore throat
What follows the initial symptoms of ebola?
Vomiting Diarrhoea Rash Impaired kidney and liver function Internal + external bleeding
In which patients should you consider a diagnosis of ebola?
Fever 37.5C+ or have hx of fever in past 24h AND have recently visited any of the affected areas in the last 21 days/cared for/come in contact with bodily fluids of someone strongly suspected/known to have VHF
How should ebola be managed?
Advise not to visit surgery
Contact PHE
What is this history typical of?:
Bilateral conjunctivitis, bilateral calf pains, high fever in a sewage worker
Mild leptospirosis
What fluid therapy should be given to someone as part of the sepsis 6 bundle?
If >16y IV fluid resus with crystalloids 500ml STAT (over 15 min)
What causes giardiasis?
Flagellated protozoan giardia lamblia
How is giardia lamblia spread?
Faecal oral
What are the clinical features of giardiasis?
Often asymptomatic Bloating, lethargy, ab pain Flatulence Non-bloody diarrhoea Chronic diarrhoea, malabsorption, lactose intolerance
How is giardiasis treated?
Metronidazole
What happens if you take metronidazole with alcohol?
Disulfiram like reaction (flushing, nausea, vomiting, sweatiness, headache, palpitations)
How does metronidazole work?
Forms reactive cytotoxic metabolites inside bacteria
What is an aspergilloma?
Mass like fungus ball (mycetoma) which often colonises an existing lung cavity (e.g. secondary to TB, lung cancer etc.)
What are clinical features of an aspergilloma?
Usually asymptomatic
Cough, haemoptysis
What does an aspergilloma appear like on CXR?
Rounded opacity
Crescent sign may be present
Flu like symptoms, a dry cough, relative bradycardia and confusion. Blood tests show a hyponatraemia.
What is this a typical history of?
Legionnaire’s disease
List antifungal agents
Azoles Amphotericin B Terbinafine Griseofulvin Flucytosine Caspofungin Nystatin
What is the mechanism of action of azoles?
Inhibits 14α-demethylase which produces ergosterol
What is the mechanism of action of amphotericin B?
Binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
What is the mechanism of action of terbinafine?
Inhibits squalene epoxidase
What is the mechanism of action of griseofulvin?
Interacts with microtubules to disrupt mitotic spindle
What is the mechanism of action of flucytosine?
Converted by cytosine deaminase to 5-fluorouracil, which inhibits thymidylate synthase and disrupts fungal protein synthesis
What is the mechanism of action of capsofungin?
Inhibits synthesis of beta-glucan, a major fungal cell wall component
What is the mechanism of action of nystatin?
Binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
How is nystatin normally administered?
Usually topical, e.g. for oral thrush as it is very toxic
What is a SE of caspofungin?
Flushing
What is an SE of flucytosine?
Vomiting
What AE are associated with griseofulvin?
Induces P450 system
Teratogenic
What drug is commonly used in the oral form to treat fungal nail infections?
Terbinafine
What drug is mostly used to treat systemic fungal infections?
Amphotericin B
What SEs are associated with amphotericin B?
Nephrotoxicity
Flu like symptoms
Hypokalaemia
Hypomagnesaemia
What AEs are associated with azoles?
P450 inhibition
Liver toxicity
What investigation is required before starting a patient on terbinafine?
LFTs (before treatment and 4-6 weeks into treatment)
How re streptococci divided?
Alpha haemolytic (partial haemolysis) Beta haemolytic (complete haemolysis)
What is the most important alpha haemolytic strep?
Strep pneumoniae
Other e.g. is strep viridians
How are beta haemolytic streptococci divided?
A-H
A, B and D are the most important ones
What is the most important group A beta haemolytic strep?
Strep pyogenes
What kinds of infections does strep pyogenes cause?
Erysipelas, impetigo, cellulitis, type 2 necrotizing fasciitis, pharyngitis/tonsillitis
Erythrogenic toxins –> scarlet fever
Can cause rheumatic fever, post-strep GN
What a group B beta haemolytic strep?
Strep agalactiae (can cause neonatal meningitis/septicaemia)
What are group D beta haemolytic streps?
Enterococcus
What is the most common way hepatitis E is spread?
Undercooked pork
What is the most common cause of short term hepatitis in the UK?
Hep E
What causes leishmaniasis?
Intracellular protozoa leishmania
How is leishmania spread?
Sand flies
What are the types of leishmaniasis?
Cutaneous leishmaniasis
Mucocutaneous leishmaniasis
Visceral leishmaniasis (kala-azar)
What causes cutaneous leishmaniasis?
Leishmania tropica or Leishmania mexicana
What are features of cutaneous leishmaniasis?
Crusted lesion at site of bite
May be underlying ulcer
What causes mucocutaneous leishmaniasis?
Leishmania braziliensis
What are features of mucocutaneous leishmaniasis?
Skin lesions spread to involve mucosae of nose, pharynx etc.
What most commonly causes visceral leishmaniasis?
Leishmania donovani
What are features of visceral leishmaniasis?
Fever, sweats, rigors Massive splenomegaly, hepatomegaly Poor appetite, wt loss Grey skin (kala-azar = black sickness) Pancytopenia secondary to hypersplenism
What is the gold standard for diagnosing visceral leishmaniasis?
Bone marrow/splenic aspirate
Do you require consent to test for HIV?
Yes
What is red man nsyndrome?
Vancomycin related activation of mast cells with release of histamine due to rapid IV infusion of vancomycin
What are typical symptoms of redman syndrome?
Redness
Pruritus
Burning sensation in upper body
Severe cases can cause hypotension + chest pain
How is red man syndrome managed?
Cessation of infusion
After symptoms have resolved, recommence at slower infusion rate
What AEs are associated with vancomycin?
Nephrotoxicity
Ototoxicity
Thrombophlebitis
Red man syndrome
What is vancomycin used to treat?
Gram positive infections, esp MRSA
BV is primarily due to the overgrowth of what bacteria?
Gardnerella vaginalis
which leads to a fall in lactic acid producing lactobacilli –> pH to increase
What kind of virus is mumps?
RNA paramyxovirus
How is mumps spread?
By droplet
Where does mumps tend to spread?
Respiratory tract epithelial cells –> parotids –> other tissues
What are clinical features of mumps?
Fever
Malaise, muscular pain
Parotitis (earache, pain on eating), unilateral initially and then usually becomes bilateral
How is mumps managed?
Rest
Paracetamol
Notifiable disease
What are complications of mumps?
Orchitis (4-5 days after parotitis)
Hearing loss (usually unilateral and transient)
Meningoencephalitis
Pancreatitis
What should all HIV patients with CD4 <200 be given?
Prophylaxis against PJP (co-trimoxazole)
If an asymptomatic contact of a chlamydia patient comes in should you still treat?
Yes - treat straight away without waiting for results of test
How are animal bites managed?
Cleans wound
Co-amoxiclav
(if penicillin allergic - doxycyline + metronidazole)
What organisms commonly infect human bites?
Streptococci spp. Staphylococcus aureus Eikenella Fusobacterium Prevotella
What antibiotic is recommended for human bites?
Co-amoxiclav
What cancers is HPV linked to?
Cervical Anal Vulval and vaginal Penile Mouth and throat
Apart from boys and girls aged 12-13, who else should be offered the HPV vaccination?
MSM under the age of 45 (due to risk of anal, throat and penile cancers)
What kind of bacteria is clostridium botulinum?
Gram positive anaerobic bacillus
What toxin does clostridium botulinum produce?
Botulinum toxin (neurotoxin which irreversibly blocks release of ACh)
How might someone get botulism?
From eating contaminated foods (e.g. tinned) or IVDA
What nerves does the botulinum toxin often affect?
Bulbar muscles and ANS
What are features of botulism?
No sensory disturbance Descending flaccid paralysis Diplopia Ataxia Bulbar palsy
How is botulism managed?
Botulism antitoxin (only effective if given early) + supportive care
What are the main two forms of trypanosomiasis?
African trypanosomiasis - sleeping sickness
American trypanosomiasis - Chagas disease
How is trypanosomiasis spread?
Tsetse fly
What are clinical features of African trypanosomiasis?
Trypanosoma chancre - painless s/c nodule at site of infection
Intermittent fever
Enlargement of posterior cervical LNs
Later => CNS involvement, e.g. somnolence, headaches, mood changes, meningoencephalitis
How is early African trypanosomiasis managed?
IV pentamidine or suramin
How is late African trypanosomiasis or African trypanosomiasis with CNS involvement managed ?
IV melarsoprol
How does acute Chaga’s disease present?
Chagoma (an erythematous nodule at site of infection) + periorbital oedema
What are features of chronic Chaga’s disease?
Myocarditis ==> dilated cardiomyopathy + arrhythmias
GI features - megaoesophagus + megacolon –> dysphagia and constipation
What is the management of Chaga’s disease?
Acute phase - azole/nitroderivates (benznidazole)
Chronic - treat complications
Should asymptomatic bacteruria in catheterised patients be treated?
NO
What is the most frequent and severe manifestation of chronic Chaga’s disease?
Cardiomyopathy
What is the mode of action of rifampicin?
Inhibits bacterial DNA dependent RNA polymerase preventing transcription of DNA into mRNA
What AEs are associated with rifampicin?
Potent CYP450 liver inducer
Hepatitis
Orange secretions
Flu like symptoms
What AEs are associated with isoniazid?
Hepatitis
Peripheral neuropathy
Agranulocytosis
What AEs are associated with pyrazinamide?
Myalgia
Arthalgia
Hepatitis
Hyperuricaemia
Why should nitrofuratoin not be given to pregnant women in the third trimester?
Can cause haemolytic anaemia in newborn
What AEs are associated with trimethoprim?
Myelosupression
Transient rise in cr
Hyperkalaemia
(due to tubular dysfunction by blocking the ENaC channel)
How quickly do symptoms of norovirus develop after becoming infected?
15-50 hours
What are symptoms of norovirus?
Nausea, vomiting, diarrhoea
Headaches, low grade fevers, myalgia
How is norovirus spread?
Faecal oral (when virus aerosolized by vomiting/toilet flushing) Can be transmitted by cross contamination from surfaces
Once the norovirus enters the body what does it do?
Enters cell via host receptor mediated endocytosis and replicates in small intestine
How is transmission of norovirus limited?
Isolation of infected individuals
Hand hygiene with soap and water
Hand gels not effective enough
How is norovirus diagnosed?
Hx and stool culture viral PCR
What are neurological sequalae of meningitis?
Sensorineural hearing loss (most common)
Epilepsy, paralysis
Sepsis, intracranial abscess
Brain herniation, hydrocephalus
What are CIs to LP for meningitis?
Any signs of raised ICP - Focal neurological signs Papilloedema Significant bulging of fontanelles DIC Signs of cerebral herniation
For patients with menigococcal septicaemia an LP is CI - blood cultures and PCR for meningococcus should be obtained
How should meningitis in children be managed?
- Antibiotics
- IV dexamethasone if >3 months and any of:
a. frankly purulent CSF
b. CSF WCC >1000/microlitre
c. raised CSF WCC with protein conc >1g/l
d. bacteria on gram stain - Fluid
- Cerebral monitoring
- PH notification and prophylaxis of contacts
What are symptoms of meningococcal sepsis/meningitis?
Headache Fever NV Photophobia Drowsiness Seizures
What are signs of meningococcal sepsis/meningitis?
Neck stiffness
Purpuric rash