Infectious Diseases Flashcards
1
Q
What is the first line treatment for salmonella (non typhoid)?
A
Ciprofloxacin
2
Q
What is the most common cause of traveller’s diarrhoea?
A
E.coli
3
Q
What bacteria typically cause acute food poisoning?
A
Staph aureus
Bacillus cereus
Clostridium perfringens.
4
Q
What organism causes Syphilis?
A
Treponema pallidum (spirochaete)
5
Q
What is the incubation period for syphilis?
A
9-90days
6
Q
What are the features of primary syphilis?
A
- chancre - painless ulcer at the site of sexual contact
- local non-tender lymphadenopathy
- often not seen in women (the lesion may be on the cervix)
7
Q
What are the features of secondary syphilis?
A
- Occurs 6-10 weeks following primary contact
- systemic symptoms: fevers, lymphadenopathy
- rash on trunk, palms and soles
- buccal ‘snail track’ ulcers (30%)
- condylomata lata (painless, warty lesions on the genitalia )
8
Q
What are the features of tertiary syphilis?
A
- gummas (granulomatous lesions of the skin and bones)
- ascending aortic aneurysms
- general paralysis of the insane
- tabes dorsalis
- Argyll-Robertson pupil
9
Q
What are the features of congenital syphilis?
A
- blunted upper incisor teeth (Hutchinson’s teeth), ‘mulberry’ molars
- rhagades (linear scars at the angle of the mouth)
- keratitis
- saber shins
- saddle nose
- deafness
10
Q
What is the first line treatment for Syphilis?
A
Benzylpenicillin usually IM
Doxycycline is alternative
11
Q
What is Jarisch-Herxheimer reaction?
A
- Reaction following treatment of syphilis.
-Fever, rash, tachycardia after the first dose of antibiotic.
-No wheeze or hypotension. - due to the release of endotoxins following bacterial death and typically occurs within a few hours of treatment.
- no treatment is needed other than antipyretics if required.
12
Q
What is used to assess the response to treatment of syphilis?
A
- nontreponemal (rapid plasma reagin [RPR] or Venereal Disease Research Laboratory [VDRL]) titres should be monitored after treatment to assess the response.
- a fourfold decline in titres is often considered an adequate response to treatment.
13
Q
What are the CSF findings in bacterial meningitis?
A
- Cloudy appearance
- Low glucose (<half of plasma)
- High protein (>1g/l)
- 10-5000 polymorphs/mm3 (neutrophils).
14
Q
What are the CSF findings in viral meningitis?
A
- Clear/cloudy appearance
- High glucose (60-80% of plasma)
- Normal/raised protein
- 15 - 1,000 lymphocytes/mm³
15
Q
What are the CSF findings in Tuberculous meningitis?
A
- Slightly cloudy/fibrin web
- Low glucose (<half of plasma)
- High protein (>1g/l)
- 30 - 300 lymphocytes/mm³
16
Q
What are the CSF findings in Fungal meningitis?
A
- Cloudy appearance
- Low glucose (<half plasma)
- High protein (>1g/l)
- 20 - 200 lymphocytes/mm³
17
Q
What virus can be associated with a low glucose on CSF?
A
Mumps
18
Q
What is infectious mononucleosis?
A
- Commonly known as glandular fever
- Epstein-Barr virus
19
Q
What are the common features of infectious mononucleosis?
A
- sore throat
- lymphadenopathy: may be present in the anterior and posterior triangles of the neck
- pyrexia
20
Q
How is infectious mononucleosis diagnosed?
A
- heterophil antibody test (Monospot test)
- NICE recommend FBC + mono spot test in 2nd week of illness for diagnosis.
21
Q
What is the treatment for infectious mononucleosis?
A
- Supportive management of rest during the early stages, drink plenty of fluid, avoid alcohol
- simple analgesia for any aches or pains
- avoid playing contact sports for 4 weeks after having glandular fever to reduce the risk of splenic rupture
22
Q
What is the treatment for uncomplicated falciparum malaria?
A
Oral artemisinin-based combination therapies
23
Q
What is the first line treatment for non-gonococcal urethritis?
A
Doxycycline or azithromycin
24
Q
What is non-gonococcal urethritis?
A
Urethritis with no gonorrhea found on swabbing.
- Often presents with purulent discharge and dysuria.
25
What are some possible causes of non-gonococcal urethritis?
- Chlamydia trachomatis
most common cause
- Mycoplasma genitalium
thought to cause more symptoms than Chlamydia.
less common causes:
- Ureaplasma urealyticum
- Trichomonas vaginalis
- Escherichia coli
26
What is the first line treatment of chlamydia?
Doxycycline or azithromycin
27
What are the key features of CNS cryptococcal infection?
- HIV
- Neurological symptoms
- Headache
- CSF india stain positive
28
What are the adverse affects of aminoglycosides?
Nephrotoxicity
Ototoxicity
29
What is the mechanism of action of aminoglycosides?
Binds to 30S subunit causing misreading of mRNA
30
What are the adverse effects of Tetracyclines?
Discolouration of teeth photosensitivity
31
What is the mechanism of action of tetracyclines?
Binds to 30S subunit blocking binding of aminoacyl-tRNA
32
What is the mechanism of action of chloramphenicol?
Binds to 50S subunit, inhibiting peptidyl transferase
33
What are the adverse effects of chloramphenicol?
Aplastic anaemia
34
What is the mechanism of action of clindamycin?
Binds to 50S subunit, inhibiting translocation (movement of tRNA from acceptor site to peptidyl site)
35
What is the adverse effects of clindamycin?
Common cause of C-difficile diarrhoea
36
What is the mechanism of action of macrolides?
Binds to 50S subunit, inhibiting translocation (movement of tRNA from acceptor site to peptidyl site)
37
What are the adverse effects of macrolides?
Nausea (especially erythromycin), P450 inhibitor
Prolonged QT interval
38
What are the features of Mycoplasma pneumoniae?
- disease typically has a prolonged and gradual onset.
- flu-like symptoms classically precede a dry cough
- bilateral consolidation on x-ray
- complications common
39
What are the complications associated with Mycoplasma pneumoniae?
- Cold agglutins (IgM): may cause an haemolytic anaemia, thrombocytopenia.
- Erythema multiforme, erythema nodosum.
- Meningoencephalitis, Guillain-Barre syndrome and other immune-mediated neurological diseases.
-Bullous myringitis: painful vesicles on the tympanic membrane.
-Pericarditis/myocarditis.
- Gastrointestinal: hepatitis, pancreatitis
- Renal: acute glomerulonephritis
40
How is mycoplasma pneumoniae diagnosed?
- Mycoplasma serology
- positive cold agglutination test → peripheral blood smear may show red blood cell agglutination
41
What is the management of mycoplasma pneumoniae?
- Doxycycline or a macrolide (e.g. erythromycin/clarithromycin).
42
What are the features of legionella?
- Flu-like symptoms including fever
- Dry cough
- Relative bradycardia
- Confusion
- Lymphopaenia
- Hyponatraemia
- Deranged LFTs
- Pleural effusion
43
What investigations should be carried out in suspected legionella infection?
- Urinary antigen (diagnostic)
- CXR - mid/lower zone patchy consolidation and pleural effusions.
44
What is the treatment for legionella?
Erythromycin/clarithromycin
45
How is legionella transmitted?
- Typically colonizes water-tanks so typically transmitted via particles in air-condition systems or water abroad.
- Person to person transmission is NOT seen.
46
What are the two main forms of trypanosomiasis?
- African trypanosomiasis (sleeping sickness)
- American trypanosomiasis (Chagas' disease)
47
How is African trypanosomiasis spread?
Tsetse fly
48
What are the features of African trypanosomiasis?
- Trypanosoma chancre (painless subcutaneous nodule at site of infection)
- Intermittent fever
- Enlargement of posterior cervical lymph nodes
- CNS involvement in later stages e.g. somnolence, headaches, mood changes, meningoencephalitis
49
What is the management for African trypanosomiasis?
Early disease: IV pentamidine or suramin
Later disease/CNS involvement: IV melarsoprol
50
What organism causes Chagas' disease?
Trypanosoma cruzi
51
What are the features of Chagas' disease?
- 95% asymptomatic in acute phase
- Chagoma (erythematous nodule at site of infection)
- periorbital oedema
- myocarditis/ dilated cardiomyopathy
- Megaoesophagus / megacolon
52
What is the management of Chagas' disease?
Early disease: Azole or nitroderivatives e.g. benznidazole or nifurtimox.
Later disease: Treat complications
53
What is the mechanism of action of sulphonamides?
Inhibition of dihydropteroate synthetase
54
What are some examples of antibiotic sulphonamides?
- Sulfamethoxazole
- Co-trimoxazole (sulfamethoxazole + trimethoprim).
- Sulfadiazine
- Sulfisoxazole
55
What are some side effects of co-timoxazole?
- Hyperkalaemia
- Headache
- Rash including Steven-Johnson Syndrome
56
What organism causes Lyme disease?
Borrelia Burgdorferi
(spread by ticks)
57
What are the early features (first 30 days) of Lyme disease?
- Erythema migrans (bulls-eye rash at tick bite site, 1-4 weeks after initial bite, usually painless, slowly increases in size).
- Headache
- Lethargy
- Fever
- Arthralgia
58
What are the later features (>30 days) of Lyme disease?
- Cardiovascular - heart block, peri/myocarditis
- Neurological - facial nerve palsy, radicular pain, meningitis
59
What investigations are required for Lyme diease?
- Clinical diagnosis if erythema migrans present.
- ELISA antibodies
- Immunoblot test if ELISA positive
60
What is the management of Lyme disease?
- Doxycycline in early disease (amoxicillin if contraindicated)
- Ceftriaxone in disseminated disease
-
61
What are some factors that reduce vertical transmission of HIV?
- Maternal antiretroviral therapy
- Mode of delivery (c-section)
- Neonatal antiretroviral therapy
- Infant feeding (bottle)
62
What should be commenced when a HIV positive woman undergoes a caesarean section?
- IV zidovudine infusion commenced 4 hrs prior to c-section.
63
What neonatal antiviral therapy is used in babies who are born to HIV positive mothers?
- Zidovudine: orally if maternal viral load <50 copies/ml.
- Triple ART if viral load higher. 4-6 week duration.
64
What organisms commonly cause celluitis?
Streptococcus pyogenes
Staphylococcus aureus
65
What are the features of Eron class I cellulitis?
- No systemic toxicity
- No uncontrolled comorbidities
66
What are the features of Eron class II cellulitis?
- Systemically unwell or well but with a comorbidity which may complicate or delay resolution of infection
67
What are the features of Eron class III cellulitis?
- Significant systemic upset - confusion, tachycardia, hypotension
- Significant unstable co-morbidities
- Limb threatening infection due to vascular compromise
68
What are the features of Eron class IV cellulitis?
- Sepsis syndrome
- Necrotising fasciitis
69
Which patients with cellulitis should be admitted for IV antibiotics?
- Eron class III or IV
- Severe/ rapidly deteriorating cellulitis
- Significant lymphoedema
- Young or frail
- Immunocompromised
- Facial or periorbital cellulitis.
70
How is cellulitis managed?
- Flucloxacillin 1st line
- Clarithromycin, erythromycin or doxycycline in patients allergic to penicillin
- For severe cellultis (class III or IV) then IV co-amoxiclav, clindamycin, cefuroxime or ceftriaxone may be used.
71
What is the most common organism found in central line infections?
Staphylococcus epidermidis
72
What are the characteristics of staphylococcus aureus?
- Gram-positive cocci
- Coagulase positive
- Skin infections, abscesses, osteomyelitis, toxic shock syndrome.
73
What are the characteristics of staphylococcus epidermidis?
- Gram positive cocci
- Coagulase negative
- Central line infections, infective endocarditis
74
What is leprosy?
- Granulomatous disease primarily affecting the peripheral nerves and skin.
- Mycobacterium leprae
75
What are the features of leprosy?
- Patches of hypopigmented skin typically affecting buttocks, face and extensor surfaces of limbs.
- Sensory loss
76
What are the two different types of leprosy?
Lepromatous leprosy: low degree of cell mediated immunity, extensive skin involvement, symmetrical nerve involvement
Tuberculoid leprosy: high degree of cell mediated immunity, limited skin disease, asymmetric nerve involvement leading to hypesthesia, hair loss.
77
What is the management of leprosy?
Triple therapy:
- Rifampicin
- Dapsone
- Clofazimine
78
What is mycobacterium avium complex?
- Atypical mycobacterium infection seen in HIV patients.
- Caused by mycobacterium avium and mycobacterium intracellulare.
- MAC is usually seen when CD4 count is <50 cells/mm3.
79
What are the features of mycobacterium avium complex (MAC)?
- fever / sweats
- abdominal pain
- diarrhoea
- dyspnoea
- cough
- anaemia
- lymphadenopathy
-hepatomegaly
- deranged LFTs
80
What is the prophylactic treatment for mycobacterium avium complex?
Clarithromycin or azithromycin ( when CD4 count < 100 cells/mm3.
81
What is the management of mycobacterium avium complex?
Rifampicin + ethambutol + clarithromycin
82
What is the mechanism of action of bictegravir?
- Blocks enzymatic insertion of the viral genome into host DNA.
83
What is the ART used in HIV managment?
At least 3 drugs: 2 nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a non nucleoside reverse transcriptase inhibitor (NNRTI).
To be commenced ASAP following diagnosis, regardless of CD4 count.
84
What are some HIV entry inhibitors?
- Maraviroc
- Enfuvirtide
85
What are some side effects of nucleoside analogue reverse transcriptase inhibitors (NRTI)?
- Peripheral neuropathy
- tenofovir : renal impairment, osteoporosis
- zidovudine : anaemia, myopathy, black nails
- didanosine : pancreatitis
85
What are examples of nucleoside analogue reverse transcriptase inhibitors (NRTI)?
Zidovudine (AZT)
Abacavir
Emtricitabine
Didanosine
Lamivudine
Stavudine
Zalcitabine
Tenofovir
86
What are some examples of non-nucleoside reverse transcriptase inhibitors (NNRTI)?
- Nevirapine
- Efavirenz
87
What are some side effects of non-nucleoside reverse transcriptase inhibitors (NNRTI)?
P450 enzyme interaction
Rashes
88
What are some examples of protease inhibitors?
Indinavir
Nelfinavir
Ritonavir
Saquinavir
89
What are the side effects of protease inhibitors?
- Diabetes
- Hyperlipidaemia
- Buffalo hump
- Central obesity
- P450 enzyme inhibition
Indinavir: renal stones, asymptomatic hyperbilirubinaemia
Ritonavir: potent P450 inhibition
90
What are some examples of integrase inhibitors?
Raltegravir
Elvitegravir
Dolutegravir
91
What are the common cause of meningitis in children ages 0-3months?
Group B streptococcus
E.coli
Listeria monocytogenes
92
What are the common causes of meningitis in 3months - 6 years?
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
93
What are the common causes of meningitis between 6 - 60 years?
Neisseria meningitidis
Streptococcus pneumoniae
94
What are the common causes of meningitis >60years?
Streptococcus pneumoniae
Neisseria meningitidis
Listeria monocytogenes
95
What are the features of chlamydia?
Asymptomatic
Cervicitis (discharge, bleeding)
Dysuria
Urethral discharge in men
96
What are potential complications of chlamydia?
Epididymitis
Pelvic inflammatory disease
Endometritis
Ectopic pregnancy
Infertility
Reactive arthritis
Perihepatitis (Fitz-Hugh-Curtis syndrome)
97
What is the investigation of choice in identifying chlamydia?
Nuclear acid amplification tests (NAATs).
First void urine, vulvovaginal and cervical swabs can be tested using NAATs.
Testing should be carried out 2 weeks post exposure.
98
What are the 3 main types of schistosomiasis?
S. mansoni, S. japonicum and S. haematobium
99
What are the features of acute schistosomiasis?
- Swimmers itch
- Katayama fever (fever, urticarial rash, hepatosplenomegaly, bronchospasm)
- Cough
- Arthralgia
- Diarrhoea
- Eosinophilia
100
What causes the swimmer's itch in schistosomiasis?
S. Haematobium worms deposit egg clusters (pseudopapillomas) into the bladder causing inflammation.
This can cause obstructive uropathy and kidney damage leading to swimmer's itch.
This is a risk factor for squamous cell bladder cancer.
101
What are the investigations used in schistosomiasis?
Asymptomatic: serum schistosome antibodies
Symptomatic: Urine/stool microscopy
102
What is the treatment of schistosomiasis?
Single oral dose praziquantel
103
What is hepatitis B?
Double stranded DNA hepadnavirus and is spread through exposure infected blood or bodily fluids. Vertical transmission also possible.
6-20 week incubation period.
104
What are the features of hepatitis B?
Fever
Jaundice
Elevated liver transaminases
105
What are the complications of hepatitis B infection?
Chronic hepatitis
Fulminant liver failure
Hepatocellular carcinoma
Glomerulonephritis
Polyarteritis nodosa
Cryoglobulinaemia
106
What do anti-HBs levels >100 indicate?
Adequate response to hepatitis B immunisation, no further testing required.
Booster in 5 years.
107
What do anti-HBs levels 10 -100 indicate?
Suboptimal response - 1 addition vaccine dose required.
No further testing if not immunocompromised.
108
What do anti-HBs levels <10 indicate?
Non-responder.
Test for current and past infection.
Give 3 further vaccine doses and testing afterwards.
If remains to not respond then HBIG needed if exposed.
109
What is the treatment of Hepatitis B?
Pegylated interferon 1st line
Other antivirals 2nd line e.g. tenofovir, entecavir, telbivudine
110
What are the features of toxocara canis?
- Commonest cause of Visceral larva migrans (condition caused by migration of larvae from parasites through the body).
- Eye granulomas
- Liver/lung involvement
111
Who should be screened for Methicillin-resistant Staphylococcus aureus (MRSA)?
- All patients awaiting elective admissions (except day patients having terminations/ophthalmic surgery)
- All emergency admissions
112
How is MRSA screened?
Nasal swab and skin lesion or wounds
5 seconds for nasal swab
113
What antibiotics are commonly used in the treatment of MRSA infections?
Vancomycin
Teicoplanin
Linezolid
114
How is MRSA suppressed if identified from a carrier?
Nose: Mupirocin 2% in white soft paraffin TDS 5/7.
Skin: Chlorhexidine gluconate OD 5/7. All over but particular care to axilla, groin and perineum
115
Which type of pneumonia is associated with cold sores?
Streptococcus pneumoniae.
(reactivates herpes simplex)
116
What is the treatment for genital warts?
- Multiple, non-keratinised warts: topical podophyllum
- Solitary, keratinised warts: cryotherapy
117
What most commonly causes genital warts?
Human papillomavirus (HPV) types 6 and 11
118
What is the mechanism of action of amantadine (antiviral)?
Inhibits uncoating (M2 protein) of virus in cell. Also releases dopamine from nerve endings
119
What is amoebiasis?
Caused by Entamoeba histolytica (an amoeboid protozoan) and spread by the faecal-oral route.
Infection can be asymptomatic, cause mild diarrhoea or severe amoebic dysentery. Amoebiasis also causes liver and colonic abscesses.
120
What are the features of amoebic dysentery?
- Profuse bloody diarrhoea
- Long incubation period
- Trophozoites on hot stool sample
121
What is the treatment for amoebic dysentery and amoebic liver abscesses?
- Oral metronidazole
- Luminal agent to target intraluminal cysts e.g. diloxanide furoate
122
What are the features of an amoebic liver abscess?
-Usually a single mass in the right lobe (may be multiple). The contents are often described as 'anchovy sauce'
- fever
- right upper quadrant pain
- systemic symptoms e.g. malaise
- hepatomegaly
123
What is Dengue fever?
Viral infection that can progress to viral haemorrhagic fever.
-RNA virus of the genus Flavivirus
-Transmitted by the Aedes aegypti mosquito
-Incubation period of 7 days
124
What are the features of dengue fever?
-Fever
-Headache (often retro-orbital)
-Myalgia, bone pain and arthralgia ('break-bone fever')
-Pleuritic pain
- Facial flushing (dengue)
-Maculopapular rash
- Haemorrhagic manifestations e.g. positive tourniquet test, petechiae, purpura/ecchymosis, epistaxis
'Warning signs' include:
-abdominal pain
-hepatomegaly
-persistent vomiting
-clinical fluid accumulation (ascites, pleural effusion)
125
What are the investigations for Dengue fever?
Bloods : leukopenia, thrombocytopenia, raised aminotransferases.
serology
nucleic acid amplification tests for viral RNA
NS1 antigen test
126
What is the treatment for Dengue fever?
Entirely symptomatic
No antivirals currently available.
127
What is the treatment for campylobacter infection?
Usually self limiting after 7 days
Oral clarithromycin first line in severe cases.
Azithromycin and erythromycin are suitable alternatives.
128
What is leprosy?
Granulomatous disease primarily affecting the peripheral nerves and skin. It is caused by Mycobacterium leprae.
129
What are the features of leprosy?
-Patches of hypopigmented skin typically affecting the buttocks, face, and extensor surfaces of limbs
-Sensory loss
130
What is leptospirosis?
Caused by the spirochaete Leptospira interrogans (serogroup L. icterohaemorrhagiae)
Classically being spread by contact with infected rat urine.
131
What people are more commonly infected with leptospirosis?
Sewage workers
Farmers
Vets
Abattoir workers
Those returning from tropics
132
What are the features of Leptospirosis?
-Early phase is due to bacteraemia and lasts around a week:
may be mild or subclinical
fever
flu-like symptoms
subconjunctival suffusion (redness)/haemorrhage
-Second immune phase may lead to more severe disease (Weil's disease):
acute kidney injury (seen in 50% of patients)
hepatitis: jaundice, hepatomegaly
aseptic meningitis
133
What investigations should you perform for Leptospirosis?
-Serology: antibodies to Leptospira develop after about 7 days
-PCR
-Culture:
growth may take several weeks so limits usefulness in diagnosis
blood and CSF samples are generally positive for the first 10 days
urine cultures become positive during the second week of illness
134
What is the treatment for Leptospirosis?
high-dose benzylpenicillin or doxycycline
135
Which species of malaria parasite has the shortest erythrocytic replication cycle?
Plasmodium knowlesi
136
What are the most common cause of non-falciparum malaria?
- Plasmodium vivax is most common
- Plasmodium ovale and Plasmodium malariae accounting for the other cases.
137
What is Chikungunya?
Alphavirus disease caused by infected mosquitoes.
Areas affected are Africa, Asia and Indian subcontinent but in recent years there has been seen in a few cases in Southern Europe
138
What are the features of Chikungunya?
Prominent symptoms:
- severe joint pain
-abrupt onset of high fever.
-general flu-like illness of muscle ache, headache, and fatigue.
The disease shares its symptoms with dengue but tends to have more joint pain which can be debilitating.
139
What is Trichomonas vaginalis?
Trichomonas vaginalis is a highly motile, flagellated protozoan parasite. Trichomoniasis is a sexually transmitted infection (STI).
140
What are the features of Trichomonas vaginalis?
- Vaginal discharge: offensive, yellow/green, frothy
- Vulvovaginitis
- strawberry cervix
- pH > 4.5
- in men is usually asymptomatic but may cause urethritis
141
What is the treatment for Trichomonas vaginalis?
oral metronidazole for 5-7 days, although the BNF also supports the use of a one-off dose of 2g metronidazole
142
What is Tularaemia?
Zoonotic infection involving the microorganism F. tularensis Commonly transmitted through lagomorphs such as rabbits, hares and pikas but also in aquatic rodents - beavers and muskrat - and ticks.
143
What are the features of Tularaemia?
-Erythematous papulo-ulcerative lesion at the site of the bite
-Reactive and ulcerating regional lymphadenopathy.
144
What is the treatment for Tularaemia?
It is treated with antibiotics such as doxycycline.
145
What is the most commonly isolated organism in animal bites?
Pasteurella multocida.
146
What are examples of gram negative cocci?
Neisseria meningitidis
Neisseria gonorrhoeae
Moraxella catarrhalis
147
What are examples of gram positive cocci?
staphylococci + streptococci (including enterococci)
148
What are examples of gram positive bacilli?
- Actinomyces
- Bacillus anthracis (anthrax)
- Clostridium
- Diphtheria: Corynebacterium diphtheriae
- Listeria monocytogenes
149
What are examples of gram negative bacilli?
- Escherichia coli
- Haemophilus influenzae
- Pseudomonas aeruginosa
- Salmonella sp.
- Shigella sp.
- Campylobacter jejuni
150
What are the features of PCP?
dyspnoea
dry cough
fever
very few chest signs
rarely: hepatosplenomegaly
lymphadenopathy
choroid lesions
151
What is the management of PCP?
- co-trimoxazole
- IV pentamidine in severe cases
aerosolized pentamidine is an alternative treatment for Pneumocystis jiroveci pneumonia but is less effective with a risk of pneumothorax
- steroids if hypoxic (if pO2 < 9.3kPa then steroids reduce risk of respiratory failure by 50% and death by a third)
152
What are the features of Legionnaire's disease?
flu-like symptoms including fever (present in > 95% of patients)
dry cough
relative bradycardia
confusion
lymphopaenia
hyponatraemia
deranged liver function tests
pleural effusion: seen in around 30% of patients
153
What is Legionnaire's disease?
intracellular bacterium Legionella pneumophilia.
colonizes water tanks and hence questions may hint at air-conditioning systems or foreign holidays.
154
What are the investigations for Legionnaire's disease?
- diagnositic test of choice:urinary antigen
- chest x-ray findings are non-specific but may include:
a mid-to-lower zone predominance of patchy consolidation
- pleural effusions in around 30%
155
What is the management of Legionnaires disease?
erythromycin/clarithromycin
156
What are the key features of hepatitis E?
- RNA hepevirus
- spread by the faecal-oral route
- incubation period: 3-8 weeks
- common in Central and South-East Asia, North and West Africa, and in Mexico
- causes a similar disease to hepatitis A, but carries a significant mortality (about 20%) during pregnancy
- does not cause chronic disease or an increased risk of hepatocellular cancer
- a vaccine is currently in development, but is not yet in widespread use
157
What are potential complications of Chlamydia?
- epididymitis
- pelvic inflammatory disease
- endometritis
- increased incidence of ectopic pregnancies
- infertility
- reactive arthritis
- perihepatitis (Fitz-Hugh-Curtis syndrome)
158
What is the 1st line investigation for Chlamydia?
for women: the vulvovaginal swab is first-line
for men: the urine test is first-line
nuclear acid amplification tests (NAATs) are now the investigation of choice (used during swab testing)
159
What is amoebiasis?
- caused by Entamoeba histolytica (an amoeboid protozoan)
- spread by the faecal-oral route.
160
What are the features of amoebic dysentery?
- profuse, bloody diarrhoea
- there may be a long incubation period
- stool microscopy may show trophozoites if examined within 15 minutes or kept warm (known as a 'hot stool')
- treatment
oral metronidazole
a 'luminal agent' (to eliminate intraluminal cysts) is recommended usually as well e.g. diloxanide furoate
161
What are the features of amoebic liver abscesses?
- usually a single mass in the right lobe (may be multiple). The contents are often described as 'anchovy sauce'
- features: fever, RUQ pain, systemic symptoms e.g. malaise, hepatomegaly
- Investigations
ultrasound
serology is positive in > 95%
- Management
oral metronidazole
a 'luminal agent' (to eliminate intraluminal cysts) is recommended usually as well e.g. diloxanide furoate
162
What is the most common organism isolated in animal bites?
Pasteurella multocida.
163
What is the management for animal bites?
- cleanse wound. Puncture wounds should not be sutured closed unless cosmesis is at risk
- co-amoxiclav
if penicillin-allergic then doxycycline + metronidazole is recommended
164
What organisms are commonly found following human bites?
- Streptococci spp.
- Staphylococcus aureus
- Eikenella
- Fusobacterium
- Prevotella
165
What is the management for human bites?
Co-amoxiclav
need to consider HIV/hep C risk
166
What is anthrax?
- caused by Bacillus anthracis, a Gram positive rod
- spread by infected carcasses.
- produces a tripartite protein toxin:
protective antigen
oedema factor: a bacterial adenylate cyclase which increases cAMP
lethal factor: toxic to macrophages
167
What are the features of anthrax?
- causes painless black eschar (cutaneous 'malignant pustule', but no pus)
- typically painless and non-tender
- may cause marked oedema
- can cause GI bleeding
168
What is the management of Anthrax?
- Ciprofloxacin for cutaneous
- expert advice if further rx required
169
What are examples of bactericidal antibiotics?
- penicillins
- cephalosporins
- aminoglycosides
- nitrofurantoin
- metronidazole
- quinolones
- rifampicin
- isoniazid
170
What are examples of bacteriostatic antibiotics?
- chloramphenicol
- macrolides
- tetracyclines
- sulphonamides
- trimethoprim
171
Which antibiotics inhibit cell wall formation?
- penicillins: binds transpeptidase blocking cross-linking of peptidoglycan cell walls
- cephalosporins
172
Which antibiotics inhibit protein synthesis?
- Bacteriostatic abx
- aminoglycosides (cause misreading of mRNA)
- chloramphenicol
- macrolides (e.g. erythromycin)
- tetracyclines
- fusidic acid
173
Which antibiotics inhibit DNA synthesis?
- quinolones (e.g. ciprofloxacin)
- metronidazole
- sulphonamides
- trimethoprim
174
Which antibiotics inhibit RNA synthesis?
rifampicin
175
What is an aspergilloma?
a mycetoma (mass-like fungus ball) which often colonises an existing lung cavity (e.g. secondary to tuberculosis, lung cancer or cystic fibrosis).
176
What are the features of an aspergilloma?
- cough
- haemoptysis
- rounded opacity with crescent sign on CXR
- high titres Aspergillus precipitins
177
What is bacterial vaginosis?
- overgrowth of predominately anaerobic organisms such as Gardnerella vaginalis.
- leads to a consequent fall in lactic acid producing aerobic lactobacilli resulting in a raised vaginal pH.
178
What is the criteria used to diagnose BV?
- Amsel's criteria for diagnosis of BV - 3 of the following 4 points should be present:
- thin, white homogenous discharge
clue cells on microscopy:
- stippled vaginal epithelial cells
- vaginal pH > 4.5
- positive whiff test (addition of potassium hydroxide results in fishy odour)
179
What is the management for BV?
- asymptomatic usually doesn't require rx
- symptomatic oral metronidazole 5-7 days
180
What risks are associated with BV in pregnancy?
preterm labour
low birth weight chorioamnionitis
late miscarriage
181
Who should be given the BCG vaccine?
- all infants living in area of UK with annual incidence of TB is 40/100,000 or greater
- all infants with parent/grandparent born in country with annual incidence of TB is 40/100,000 or greater
- previously unvaccinated tuberculin-negative contacts of cases of respiratory TB
- previously unvaccinated, tuberculin-negative new entrants under 16 years of age who were born in or who have lived for a prolonged period (at least three months) in a country with an annual TB incidence of 40/100,000 or greater
- healthcare workers
- prison staff
- staff of care home for the elderly
- those who work with homeless people
182
How is the BCG vaccination administered?
- any person being considered for the BCG vaccine must first be given a tuberculin skin test. The only exceptions are children < 6 years old who have had no contact with tuberculosis
- given intradermally, normally to the lateral aspect of the left upper arm
- BCG can be given at the same time as other live vaccines, but if not administered simultaneously there should be a 4 week interval
183
What are contraindications to the bcg vaccine?
- previous BCG vaccination
- a past history of tuberculosis
- HIV
- pregnancy
- positive tuberculin test (Heaf or Mantoux)
184
What is botulism?
- gram positive anaerobic bacillus
- 7 serotypes A-G
- produces botulinum toxin, a neurotoxin which irreversibly blocks the release of acetylcholine
- may result from eating contaminated food (e.g. tinned) or intravenous drug use
- neurotoxin often affects bulbar muscles and autonomic nervous system
185
What are the features of botulism?
- patient usually fully conscious with no sensory disturbance
- flaccid paralysis
- diplopia
- ataxia
- bulbar palsy
186
What is the treatment for botulism?
- botulism antitoxin and supportive care
- antitoxin is only effective if given early - once toxin has bound its actions cannot be reversed
187
What is brucellosis?
- a zoonosis more common in the Middle East and in farmers, vets and abattoir workers.
- Four major species cause infection in humans: B. melitensis (sheep), B. abortus (cattle), B. canis and B. suis (pigs).
- Brucellosis has an incubation period 2 - 6 weeks.
188
What are the features of brucellosis?
- non-specific: fever, malaise
- hepatosplenomegaly
- sacroiliitis: spinal tenderness may be seen
- complications: osteomyelitis, infective endocarditis, meningoencephalitis, orchitis
- leukopenia often seen
189
How is brucellosis diagnosed?
- the Rose Bengal plate test can be used for screening but other tests are required to confirm the diagnosis
- Brucella serology is the best test for diagnosis
- blood and bone marrow cultures may be suitable in certain patients, but these tests are often negative
190
What are the features of progressive multifocal leukoencephalopathy (PML)?
- Caused by JC virus, commonly affects HIV patients
- widespread demyelination
due to infection of oligodendrocytes by JC virus (a polyoma DNA virus)
- symptoms, subacute onset : behavioural changes, speech, motor, visual impairment
- CT: single or multiple lesions, no mass effect, don't usually enhance.
- MRI is better - high-signal demyelinating white matter lesions are seen
191
What is measles?
- RNA paramyxovirus
- one of the most infectious known viruses
- spread by aerosol transmission
- infective from prodrome until 4 days after rash starts
- incubation period = 10-14 days
192
What are the features of measles?
- prodromal phase
* irritable
* conjunctivitis
* fever
- Koplik spots
* typically develop
before the rash
* white spots ('grain
of salt') on the
buccal mucosa
- rash
* starts behind ears
then to the whole
body
* discrete
maculopapular rash
becoming blotchy &
confluent
* desquamation that
typically spares the
palms and soles
may occur after a
week
- diarrhoea occurs in around 10% of patients
193
What are the investigations for measles?
IgM antibodies detected within a few days of rash onset
194
What is the management of measles?
- mainly supportive
- admission may be considered in immunosuppressed or pregnant patients
- notifiable disease → inform public health
195
What are the complications of measles?
- otitis media: the most common complication
- pneumonia: the most common cause of death
- encephalitis: typically occurs 1-2 weeks following the onset of the illness)
- subacute sclerosing panencephalitis: very rare, may present 5-10 years following the illness
- febrile convulsions
- keratoconjunctivitis
- corneal ulceration
- diarrhoea
- increased incidence of appendicitis
- myocarditis
196
What vaccinations should individuals with hyposplenism receive?
pneumococcal, Haemophilus type B and meningococcus type C
197
What is the schedule of vaccinations post splenectomy?
- Men C and Hib at two weeks post-splenectomy.
- MenACWY vaccine one month later.
- Children under 2 may need a booster at 2 years.
- Pneumococcal vaccines
- Annual influenza vaccination for all patients
198
What are the features of toxoplasmosis?
- accounts for around 50% of cerebral lesions in patients with HIV
- constitutional symptoms, headache, confusion, drowsiness
- CT: usually single or multiple ring enhancing lesions, mass effect may be seen
- management: sulfadiazine and pyrimethamine
199
Which antibiotic promotes the acquisition of MRSA?
Ciprofloxacin
200
What is the management of meningeal TB?
Initial phase - first 2 months (RIPE)
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
Continuation phase - next 10 months
Rifampicin
Isoniazid
Prednisolone is added in CNS TB
201
What are the features of cat scratch disease?
- caused Gram negative rod Bartonella henselae
- fever
- history of a cat scratch
- regional lymphadenopathy
- headache, malaise
202
What is the mechanism of action of macrolides and clarithromycin?
Inhibition of 50S subunit of ribosomes
203
What is the diagnostic criteria for staphylococcus toxic shock syndrome?
- Fever: temperature > 38.9ºC
- hypotension: systolic blood pressure < 90 mmHg
- diffuse erythematous rash
- desquamation of rash, especially of the palms and soles
- involvement of three or more organ systems: e.g. gastrointestinal (diarrhoea and vomiting), mucous membrane erythema, renal failure, hepatitis, thrombocytopenia, CNS involvement (e.g. confusion)
204
What is Linezolid highly effective at treating?
Gram positive organisms including:
- MRSA (Methicillin-resistant Staphylococcus aureus)
- VRE (Vancomycin-resistant enterococcus)
- GISA (Glycopeptide Intermediate Staphylococcus aureus)
205
What are some adverse effects of linezolid?
- thrombocytopenia (reversible on stopping)
- monoamine oxidase inhibitor: avoid tyramine containing foods
206
Which vaccines should not be given to immunocompromised patients?
Live attenuated vaccines:
BCG
Yellow fever
Oral polio
Intranasal influenza
Varicella
Measles, mumps and rubella (MMR)
207
What staining should be added to cells from BAL to show PCP infection?
Silver stain
208
What is Leishmaniasis?
- Intracellular protozoa Leishmania, which are spread by the bites of sandflies.
- Cutaneous, mucocutaneous leishmaniasis and visceral forms are seen
209
What are the features of cutaneous Leishmaniasis?
- caused by Leishmania tropica or Leishmania mexicana
- crusted lesion at the site of bite
- there may be an underlying ulcer
- diagnosed by doing a punch biopsy from the edge of the lesion allowing for both histology and culture
- cutaneous leishmaniasis acquired in South or Central America merits treatment due to the risk of mucocutaneous leishmaniasis whereas disease acquired in Africa or India can be managed more conservatively
210
What are the features of mucocutaneous leishmaniasis?
caused by Leishmania braziliensis
skin lesions may spread to involve mucosae of nose, pharynx etc
211
What is Chancroid?
- Tropical disease caused by Haemophilus ducreyi
- painful genital ulcers associated with unilateral, painful inguinal lymph node enlargement. The ulcers typically have a sharply defined, ragged, undermined border.
212
What are the features of congenital CMV infection?
growth retardation
pinpoint petechial 'blueberry muffin' skin lesions
microcephaly
sensorineural deafness
encephalitiis (seizures) hepatosplenomegaly
213
What are the features of CMV retinitis?
- common in HIV patients with a low CD4 count (< 50)
- presents with visual impairment e.g. 'blurred vision'.
- Fundoscopy shows retinal haemorrhages and necrosis, often called 'pizza' retina
- IV ganciclovir is the treatment of choice
214
What is the mechanism of action of oseltamivir?
inhibiting the activity of neuraminidase.
215
Bacterial vaginosis is an overgrowth of typically what organism?
Gardnerella vaginalis
216
What is used to treat immunocompromised patients with cryptosporidiosis?
Nitazoxanide
(broad-spectrum thiazolide anti-parasitic agent)
217
Which organism that commonly causes pneumonia has RBC agglutination on blood film?
Mycoplasma pneumoniae
218
What is the mechanism of action of terbinafine?
inhibits the fungal enzyme squalene epoxidase, causing cellular death
219
What is Listeria?
- Gram positive bacilli typically spread via contaminated food, typically unpasteurised dairy products.
- Infection is particularly dangerous to the unborn child where it can lead to miscarriage.
220
What are the features of Listeria?
- gastroenteritis
- diarrhoea
- bacteraemia
- flu-like illness
- central nervous system infection
meningoencephalitis
- ataxia
- seizures
221
What investigations would you carry out for listeria?
- Bloods cultures: 'tumbling motility' on wet mount
- cerebrospinal fluid findings:
pleocytosis, often lymphocytes (nontuberculous bacteria usually cause a rise in neutrophils)
raised protein
reduced glucose
222
What is the management for Listeria?
- Listeria is sensitive to amoxicillin/ampicillin (cephalosporins usually inadequate)
- Listeria meningitis should be treated with IV amoxicillin/ampicillin and gentamicin
223
What complications can occur if Listeria is contracted during pregnancy?
- fetal/neonatal infection can occur both transplacentally and vertically during childbirth
- complications include miscarriage, premature labour, stillbirth and chorioamnionitis
- Rx with amoxicillin
224
Which conditions are associated with rose spots?
Typhoid and paratyphoid
(salmonella group)
225
What is the first lime treatment for Lyme's disease?
14-21 day course of oral doxycycline
226
Which antiretroviral is associated with mephrolithiasis?
Indinavir
227
Which organism is associated with cavitating lesions when it causes pneumonia?
Staph aureus
228
Which organisms commonly cause PID?
- Chlamydia trachomatis: the most common cause
- Neisseria gonorrhoeae
- Mycoplasma genitalium
- Mycoplasma hominis
229
What is the treatment for PID?
- 1st line: stat IM ceftriaxone + followed by 14 days of oral doxycycline + oral metronidazole
- 2nd line: oral ofloxacin + oral metronidazole
230
What complications are associated with PID?
- perihepatitis (Fitz-Hugh Curtis Syndrome)
occurs in around 10% of cases
it is characterised by right upper quadrant pain and may be confused with cholecystitis
- infertility - the risk may be as high as 10-20% after a single episode
- chronic pelvic pain
- ectopic pregnancy
231
What is Lemierre's syndrome?
- Infectious thrombophlebitis of the internal jugular vein.
- often occurs secondary to a bacterial sore throat caused by Fusobacterium necrophorum leading to a peritonsillar abscess.
- history of bacterial sore throat followed by neck pain, stiffness and tenderness (may be mistaken for meningitis) and systemic involvement (fevers, rigors, etc).
- Septic pulmonary emboli may also occur.
232
What are the features of disseminated gonorrhoea?
tenosynovitis, migratory polyarthritis, dermatitis
233
What is the most common organism found in central line infections?
Staphylococcus epidermidis
234
Which organism typically causes gastroenteritis after eating rice?
Bacillus cereus
235
How does botulin toxin work?
Inhibits the release of acetylcholine at synapses
236
What is the causative organism in Q fever?
Coxiella burnetti
237
What is the Jarisch-Herxheimer reaction?
- phenomenon following syphilis treatment
- fever, chills, malaise, flushing, tachycardia and worsening of any existing skin lesions.
- occurs 1-12hrs after antibiotic administration
238
