Infectious diseases and STIs Flashcards
1
Q
Causes of non-falciparum malaria
A
Most common: Plasmodium vivax- Central America, indian subcontinent
Plasmodium ovale - Africaand Plasmodium malariae
Plasmodium knowlesi is another non-falciparum species which causes clinical pathology, found predominantly in South East Asia.
2
Q
Features of non-falciparum malaria
A
general features of malaria: fever, headache, splenomegaly
Plasmodium vivax/ovale: cyclical fever every 48 hours. Plasmodium malariae: cyclical fever every 72 hours
Plasmodium malariae: is associated with nephrotic syndrome.
Ovale and vivax malaria have a hypnozoite stage and may therefore relapse following treatment.
3
Q
Treatment of non-falciparum malaria
A
in areas which are known to be chloroquine-sensitive then WHO recommend either an artemisinin-based combination therapy (ACT) or chloroquine
in areas which are known to be chloroquine-resistant an ACT should be used
ACTs should be avoided in pregnant women
patients with ovale or vivax malaria should be given primaquine following acute treatment with chloroquine to destroy liver hypnozoites and prevent relapse
4
Q
Features of infectious mononucleosis
Triad
A
The classic triad of sore throat, pyrexia and lymphadenopathy is seen in around 98% of patients:
sore throat
lymphadenopathy: may be present in the anterior and posterior triangles of the neck, in contrast to tonsillitis which typically only results in the upper anterior cervical chain being enlarged
pyrexia
5
Q
Other features of infectious mononucleosis
A
malaise, anorexia, headache
palatal petechiae
splenomegaly - occurs in around 50% of patients and may rarely predispose to splenic rupture
hepatitis, transient rise in ALT
lymphocytosis: presence of 50% lymphocytes with at least 10% atypical lymphocytes
haemolytic anaemia secondary to cold agglutins (IgM)
a maculopapular, pruritic rash develops in around 99% of patients who take ampicillin/amoxicillin whilst they have infectious mononucleosis
6
Q
Diagnosing infectious mononucleosis
A
heterophil antibody test (Monospot test) - NICE guidelines suggest FBC and Monospot in the 2nd week of the illness to confirm a diagnosis of glandular fever.
7
Q
Management of infectious mononucleosis
A
rest during the early stages, drink plenty of fluid, avoid alcohol
simple analgesia for any aches or pains
consensus guidance in the UK is to avoid playing contact sports for 8 weeks after having glandular fever to reduce the risk of splenic rupture
8
Q
Overview of Hep E
A
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 us
9
Q
Difference between falciparum and non-falciparum malaria
A
plasmodium falciparum is more deadly
Plasmodium vivax is more easily transmissable
10
Q
What is mycoplasma pneumoniae?
A
Mycoplasma pneumoniae is a cause of atypical pneumonia which often affects younger patients. It is associated with a number of characteristic complications such as erythema multiforme and cold autoimmune haemolytic anaemia. Epidemics of Mycoplasma pneumoniae classically occur every 4 years. It is important to recognise atypical pneumonia as it may not respond to penicillins or cephalosporins due to it lacking a peptidoglycan cell wall.
11
Q
Features of mycopplasma pneumoniae
A
the disease typically has a prolonged and gradual onset
flu-like symptoms classically precede a dry cough
bilateral consolidation on x-ray
complications may occur as below
12
Q
Complications of mycoplasma pneumoniae
A
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
13
Q
Diagnosis of mycoplasma pneumoniae
A
mycoplasma serology
positive cold agglutinins
14
Q
Management of mycoplasma pneumoniae
A
doxycycline or a macrolide (e.g. erythromycin/clarithromycin)
15
Q
Common features of legionella and mycoplasma pneumoniae
A
atypical pneumonia
flu like symptoms
derranged LFTs
Treat with macrolide
16
Q
GI Abx
Salmonella (non-typhoid)
A
Ciprofloxacin
17
Q
GI abx
Shigella
A
Ciprofloxacin
18
Q
GI Abx
Campylobacter
A
Clarithromycin
19
Q
What is cytomegalovirus
A
Cytomegalovirus (CMV) is one of the herpes viruses. It is thought that around 50% of people have been exposed to the CMV virus although it only usually causes disease in the immunocompromised, for example people with HIV or those on immunosuppressants following organ transplantation.
20
Q
Histological features of cytomegalovirus
A
infected cells have a ‘Owl’s eye’ appearance due to intranuclear inclusion bodies
21
Q
Congenital cytomegalovirus
A
features include growth retardation, pinpoint petechial ‘blueberry muffin’ skin lesions, microcephaly, sensorineural deafness, encephalitiis (seizures) and hepatosplenomegaly
22
Q
Cytomegalovirus infectious mononucleosis
A
infectious mononucelosis-like illness
may develop in immunocompetent individuals
23
Q
CMV retinitis
A
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
24
Q
HIV neurocomplications
Focal Lesions
Toxoplasmosis
A
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
25
HIV neurocomplications
Focal Lesions
Primary CNS lesions
accounts for around 30% of cerebral lesions
associated with the Epstein-Barr virus
CT: single or multiple homogenous enhancing lesions
treatment generally involves steroids (may significantly reduce tumour size), chemotherapy (e.g. methotrexate) + with or without whole brain irradiation. Surgical may be considered for lower grade tumours
26
HIV neurocomplications
Focal Lesions
TB
much less common than toxoplasmosis or primary CNS lymphoma
| CT: single enhancing lesion
27
HIV neurocomplications
General neurological disease
Encephalitis
may be due to CMV or HIV itself
HSV encephalitis but is relatively rare in the context of HIV
CT: oedematous brain
28
HIV neurocomplications
General neurological disease
Cryptococcus
most common fungal infection of CNS
headache, fever, malaise, nausea/vomiting, seizures, focal neurological deficit
CSF: high opening pressure, India ink test positive
CT: meningeal enhancement, cerebral oedema
meningitis is typical presentation but may occasionally cause a space occupying lesion
29
HIV neurocomplications
General neurological disease
Progressive multifocal leukoencephalopathy (PML)
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
30
HIV neurocomplications
General neurological disease
AIDs Dementia Complex
caused by HIV virus itself
symptoms: behavioural changes, motor impairment
CT: cortical and subcortical atrophy§
31
Management of Gonorrhoea
IM ceftriaxone - first line
32
Typical presentation of E Coli
Common amongst travellers
Watery stools
Abdominal cramps and nausea
33
Typical presentation of Giardia
Prolonged, non-bloody diarrhoea
34
Typical presentation of cholera
Profuse, watery diarrhoea
Severe dehydration resulting in weight loss
Not common amongst travellers
35
Typical presentation of shigella
Bloody diarrhoea
| Vomiting and abdominal pain
36
Typical presentation of staph aureus
Severe vomiting
| Short incubation period
37
Typical presentation of campylobacter
A flu-like prodrome is usually followed by crampy abdominal pains, fever and diarrhoea which may be bloody
May mimic appendicitis
Complications include Guillain-Barre syndrome
38
Typical presentation of bacillus cereus
Two types of illness are seen
vomiting within 6 hours, stereotypically due to rice
diarrhoeal illness occurring after 6 hours
39
Typical presentation of amoebiasis
Gradual onset bloody diarrhoea, abdominal pain and tenderness which may last for several weeks
40
What is rubella
Rubella, also known as German measles, is a viral infection caused by the togavirus. Following the introduction of the MMR vaccine it is now rare. If contracted during pregnancy there is a risk of congenital rubella syndrome. Remember that the incubation period is 14-21 days and individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash.
41
Risk of Rubella in Pregnancy
in first 8-10 weeks risk of damage to fetus is as high as 90%
damage is rare after 16 weeks
42
Features of congenital rubella
```
sensorineural deafness
congenital cataracts
congenital heart disease (e.g. patent ductus arteriosus)
growth retardation
hepatosplenomegaly
purpuric skin lesions
'salt and pepper' chorioretinitis
microphthalmia
cerebral palsy
```
43
Diagnosis of rubella in pregnancy
suspected cases should be discussed immediately with the local Health Protection Unit (HPU) as type/timing of investigations may vary
IgM antibodies are raised in women recently exposed to the virus
it should be noted that it is very difficult to distinguish rubella from parvovirus B19 clinically. It is therefore important to also check parvovirus B19 serology as there is a 30% risk of transplacental infection, with a 5-10% risk of fetal loss
44
Management of rubella in pregnancy
suspected cases of rubella in pregnancy should be discussed with the local Health Protection Unit
since 2016, rubella immunity is no longer routinely checked at the booking visit
if a woman is however tested at any point and no immunity is demonstrated they should be advised to keep away from people who might have rubella
non-immune mothers should be offered the MMR vaccination in the post-natal period
MMR vaccines should not be administered to women known to be pregnant or attempting to become pregnant
45
Treatment of chlamydia
doxycyline or azithromycin
46
Treatment of syphilis
Benzathine benzylpenicillin or doxycycline or erythromycin
47
Treatment of bacterial vaginosis
Oral or topical metronidazole or topical clindamycin
48
Treatment of pelvic inflammatory disease
Oral ofloxacin + oral metronidazole or intramuscular ceftriaxone + oral doxycycline + oral metronidazole
49
Anti-fungals
Azoles
Inhibits 14α-demethylase which produces ergosterol Adverse effects:
P450 inhibition
Liver toxicity
50
Anti-fungals
Amphotericin B - used for systemic infections
Binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
Adverse effects- nephrotoxicity, flu-like symptoms, hypokalaemia, hypomagnaseamia
51
Anti-fungals
Terbinafine
Inhibits squalene epoxidase
| Commonly used in oral form to treat fungal nail infections
52
Anti-fungals
Griseofulvin
Interacts with microtubules to disrupt mitotic spindle Induces P450 system, teratogenic
53
Anti-fungals
Flucytosine
Converted by cytosine deaminase to 5-fluorouracil, which inhibits thymidylate synthase and disrupts fungal protein synthesis
S/E: Vomiting
54
Anti-Fungals
Caspofungin
Inhibits synthesis of beta-glucan, a major fungal cell wall component
S/e: Flushing
55
Anti-fungals
Nystatin
Binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
As very toxic can only be used topically (e.g. for oral thrush)
56
Cause of Lyme Disease
spirochaete Borrelia burgdorferi and is spread by ticks
57
Early features of Lyme Disease
Erythema migrans
'bulls-eye' rash is typically at the site of the tick bite
typically develops 1-4 weeks after the initial bite but may present sooner
usually painless, more than 5 cm in diameter and slowlly increases in size
present in around 80% of patients.
systemic features
headache
lethargy
fever
arthralgia
58
Later features of Lyme Disease
```
cardiovascular
heart block
peri/myocarditis
neurological
facial nerve palsy
radicular pain
meningitis
```
59
Investigation of Lyme Disease
enzyme-linked immunosorbent assay (ELISA) antibodies to Borrelia burgdorferi are the first-line test
Clinica diagnosis is erythema migrans
60
Management of Lyme Disease
Doxycyline (1st Line)
Amoxicillin (2nd line when Doxy contra-indicated)
IV ceftriaxone if disseminated disease
Jarisch-Herxheimer reaction is sometimes seen after initiating therapy: fever, rash, tachycardia after first dose of antibiotic (more commonly seen in syphilis, another spirochaetal disease)
61
Pott's disease
Vertebral TB
62
Extra pulmonary TB
```
central nervous system (tuberculous meningitis - the most serious complication)
vertebral bodies (Pott's disease)
cervical lymph nodes (scrofuloderma)
renal
gastrointestinal tract
```
63
Strongyloides stercoralis - what is it
Nematodes (roundworms)
Strongyloides stercoralis is a human parasitic nematode worm. The larvae are present in soil and gain access to the body by penetrating the skin. Infection with Strongyloides stercoralis causes strongyloidiasis.
64
Features of strongyloides stercoralis
| Nematodes (roundworms)
diarrhoea
abdominal pain/bloating
papulovesicular lesions where the skin has been penetrated by infective larvae e.g. soles of feet and buttocks
larva currens: pruritic, linear, urticarial rash
if the larvae migrate to the lungs a pneumonitis similar to Loeffler's syndrome may be triggered
65
Management of strongyloides sterocoralis
ivermectin and albendazole are used
66
```
Enterobius vermicularis (pinworm)
Nematodes (roundworms)
```
Threadworm infestation is asymptomatic in around 90% of cases, possible features include perianal itching, particularly at night; girls may have vulval symptoms
Diagnosis may be made by the applying sticky plastic tape to the perianal area and sending it to the laboratory for microscopy to see the eggs
67
Treatment for enterobius vermicularis
| Nematodes (roundworms)
-bendazoles
68
Ancylostoma duodenale, Necator americanus (hookworms)
| Nematodes (roundworms)
Larvae penetrate skin of feet; gastrointestinal infection → anaemia
Thin-shelled ova
69
Ancylostoma duodenale, Necator americanus (hookworms) Treatment
-bendazoles
70
Loa loa- what are they
Nematodes (roundworms)
Transmission by deer fly and mango fly
Causes red itchy swellings below the skin called 'Calabar swellings', may be observed when crossing conjunctivae
71
Loa loa treatment
Diethylcarbamazine
72
Trichinella spiralis
| Nematodes (roundworms)
Typically develops after eating raw pork
Features include fever, periorbital oedema and myositis (larvae encyst in muscle)
73
Treatment for trichinella spiralis
-bendazoles
74
Onchocerca volvulus
| Nematodes (roundworms)
Causes 'river blindness'. Spread by female blackflies
Features include blindness, hyperpigmented skin and possible allergic reaction to microfilaria
75
Onchocerca volvulus- treatment
Ivermetcin - 'river blindness= ivermetcin'
76
Wuchereria bancrofti
| Nematodes (roundworms)
Transmission by female mosquito
Causes blockage of lymphatics → elephantiasis
77
Wuchereria bancrofti- treatment
Diethylcarbamazine
78
```
Toxocara canis (dog roundworm)
Nematodes (roundworms)
```
Transmitted through ingestion of infective eggs.
Features include visceral larva migrans and retinal granulomas
VISCious dogs → blindness
79
Toxocara canis (dog roundworm) - treatment
Diethylcarbamazine
80
```
Ascaris lumbricoides (giant roundworm)
Nematodes (roundworms)
```
Eggs are visible in faeces
May cause intestinal obstruction and occasional migrate to lung (Loffler's syndrome)
81
Ascaris lumbricoides (giant roundworm) - treatment
-bendazoles
82
Cestodes (tapeworms)
| Echinococcus granulosus
Transmission through ingestion of eggs in dog faeces. Definite host is dog, which ingests hydatid cysts from sheep, who act as an intermediate host. Often seen in farmers.
Features include liver cysts and anaphylaxis if cyst ruptures (e.g. during surgical removal)
83
Cestodes (tapeworms)
Echinococcus granulosus
Treatment
-bendazoles
84
Cestodes (tapeworms)
| Taenia solium
Often transmitted after eating undercooked pork. Causes cysticercosis and neurocysticercosis, mass lesions in the brain 'swiss cheese appearance'
85
Cestodes (tapeworms)
Taenia solium
Treatment
-bendazoles
86
Trematodes (flukes)
| Schistosoma haematobium
Hosted by snails, which release cercariae that penetrate skin.
Causes 'swimmer's itch' - frequency, haematuria. Risk factor for squamous cell bladder cancer
87
Trematodes (flukes)
Schistosoma haematobium
Treatment
Praziquantel
88
Trematodes (flukes)
Paragonimus westermani
Caused by undercooked crabmeat, results in secondary bacterial infection of lungs
89
Trematodes (flukes)
Paragonimus westermani
Treatment
Praziquantel
90
Trematodes (flukes)
| Clonorchis sinensis
Caused by undercooked fish
Features include biliary tract inflammation. Known risk factor for cholangiocarcinoma
91
Trematodes (flukes)
Clonorchis sinensis
Treatment
Praziquantel
92
```
Trematodes (flukes)
Fasciola hepatica (the liver fluke)
```
May cause biliary obstruction
93
Trematodes (flukes)
Fasciola hepatica (the liver fluke)
Treatment
Triclabendazole
94
Gram negative cocci
Neisseria gonorrhoeae
Moraxella catarrhalis
Neisseria meningitidis
95
gram positive rods
| mnemonic = ABCD L
```
Actinomyces
Clostridium
Listeria monocytogenes
Bacillus anthracis
Corynebacterium diphtheriae
```
96
Live attenuated vaccines
```
BCG
measles, mumps, rubella (MMR)
influenza (intranasal)
oral rotavirus
oral polio
yellow fever
oral typhoid
```
97
Inactivated vaccine preparations
rabies
hepatitis A
influenza (intramuscular)
98
Toxoid (inactivated toxin) vaccines
tetanus
diphtheria
pertussis
99
Conjugate/ sub unit vaccines
```
pneumococcus (conjugate)
haemophilus (conjugate)
meningococcus (conjugate)
hepatitis B
human papillomavirus
```
100
Plasmodium malariae
associated with nephrotic syndrome
| cyclical fever every 72 hours
101
Rickettsiae
Rickettsiae are Gram-negative obligate intracellular parasites. Types of rickettsiae cause a variety of diseases that are typically characterised by fever, headache and rash.
The Weil-Felix reaction is positive except in Q fever. Rickettsial diseases are all treated with tetracyclines.
102
Rocky Mountain spotted fever
| Rickettsia ricketsii
Headache and fever are common
Rash starts on the peripheries (wrist, ankles) before spreading centrally. It is initially maculopapular before becoming vasculitic
Endemic to east coast of US
103
Q fever
| Coxiella burnetti
No rash but causes pneumonia
104
Endemic typhus
Rickettsia typhi
Flea
Rash starts centrally then spreads to the peripheries
105
Complications of chronic Hep C
rheumatological problems: arthralgia, arthritis
eye problems: Sjogren's syndrome
cirrhosis (5-20% of those with chronic disease)
hepatocellular cancer
cryoglobulinaemia: typically type II (mixed monoclonal and polyclonal)
porphyria cutanea tarda (PCT): it is increasingly recognised that PCT may develop in patients with hepatitis C, especially if there are other factors such as alcohol abuse
membranoproliferative glomerulonephritis
106
Management of chronic Hep C
currently a combination of protease inhibitors (e.g. daclatasvir + sofosbuvir or sofosbuvir + simeprevir) with or without ribavirin are used
107
Complications of chronic Hep C Treatment
ribavirin - side-effects: haemolytic anaemia, cough. Women should not become pregnant within 6 months of stopping ribavirin as it is teratogenic
interferon alpha - side-effects: flu-like symptoms, depression, fatigue, leukopenia, thrombocytopenia
108
History of Toxocara canis
a man develops visceral larva migrans. During the work-up he is noted to have developed some retinal granulomas
109
History of loa loa
a man develops episodic angioedema whilst in west Africa. On one occasion he noticed a 'worm moving across the left eye'
110
What is polyarteritis nodosa
Polyarteritis nodosa (PAN) is a vasculitis affecting medium-sized arteries with necrotizing inflammation leading to aneurysm formation. PAN is more common in middle-aged men and is associated with hepatitis B infection.
111
Features of polyarteritis nodosa
fever, malaise, arthralgia
weight loss
hypertension
mononeuritis multiplex, sensorimotor polyneuropathy
testicular pain
livedo reticularis
haematuria, renal failure
perinuclear-antineutrophil cytoplasmic antibodies (ANCA) are found in around 20% of patients with 'classic' PAN
hepatitis B serology positive in 30% of patients
112
stereotypical history of Taenia solium (helminth)
a recent immigrant from Latin America presents to the Emergency Department following a seizure. A CT head shows multiple cystic lesions
113
Stereotypical history of Schistosoma haematobium
a man develops haematuria and frequency after visiting Malawi
114
Causes of genital herpes
Genital herpes is most often caused by the herpes simplex virus (HSV) type 2 (cold sores are usually due to HSV type 1). Primary attacks are often severe and associated with fever whilst subsequent attacks are generally less severe and localised to one site. There is typically multiple painful ulcers.
115
STI: Ulcers - syphilis
Syphilis is a sexually transmitted infection caused by the spirochaete Treponema pallidum. Infection is characterised by primary, secondary and tertiary stages. A painless ulcer (chancre) is seen in the primary stage. The incubation period= 9-90 days.
116
what is chancroid
a tropical disease caused by Haemophilus ducreyi. It causes painful genital ulcers associated with unilateral, painful inguinal lymph node enlargement. The ulcers typically have a sharply defined, ragged, undermined border.
117
what is Lymphogranuloma venereum (LGV)
caused by Chlamydia trachomatis. Typically infection comprises of three stages
stage 1: small painless pustule which later forms an ulcer
stage 2: painful inguinal lymphadenopathy
stage 3: proctocolitis
LGV is treated using doxycycline.
118
Gram +ve rods
```
Actinomyces
Bacillus anthracis (anthrax)
Clostridium
Diphtheria: Corynebacterium diphtheriae
Listeria monocytogenes
```
119
Gram -ve rods
```
Escherichia coli
Haemophilus influenzae
Pseudomonas aeruginosa
Salmonella sp.
Shigella sp.
Campylobacter jejuni
```
120
Gram-positive cocci
staphylococci + streptococci (including enterococci)
121
Gram negative cocci
Neisseria meningitidis + Neisseria gonorrhoeae, also Moraxella catarrhalis
122
HIV Management: Protease Inhibitor side effects
diabetes, hyperlipidaemia, buffalo hump, central obesity, P450 enzyme inhibition
indinavir: renal stones, asymptomatic hyperbilirubinaemia
ritonavir: a potent inhibitor of the P450 system
123
HIV management: Integrase Inhibitors
block the action of integrase, a viral enzyme that inserts the viral genome into the DNA of the host cell
examples: raltegravir, elvitegravir, dolutegravir
124
HIV Management: Non-nucleoside reverse transcriptase inhibitors (NNRTI)
examples: nevirapine, efavirenz
| side-effects: P450 enzyme interaction (nevirapine induces), rashes
125
HIV Management: Nucleoside analogue reverse transcriptase inhibitors (NRTI)
examples: zidovudine (AZT), abacavir, emtricitabine, didanosine, lamivudine, stavudine, zalcitabine, tenofovir
general NRTI side-effects: peripheral neuropathy
tenofovir: used in BHIVAs two recommended regime NRTI. Adverse effects include renal impairment and ostesoporosis
zidovudine: anaemia, myopathy, black nails
didanosine: pancreatitis
126
HIV Management: Entry Inhibitors
maraviroc (binds to CCR5, preventing an interaction with gp41), enfuvirtide (binds to gp41, also known as a 'fusion inhibitor')
prevent HIV-1 from entering and infecting immune cells
127
HIV Management: Basics
ART = 3 drugs:
2x nucleoside reverse transcriptase inhibitors (NRTI)
+
1 x Protease inhibitor OR 1 x non-nucleoside reverse transcriptase inhibitor (NNRTI)
127
HIV Management: Basics
ART = 3 drugs:
2x nucleoside reverse transcriptase inhibitors (NRTI)
+
1 x Protease inhibitor OR 1 x non-nucleoside reverse transcriptase inhibitor (NNRTI)
128
First line treatment for acute prostatitis
Quinolone or trimethoprim
129
Examples of quinolone antibiotics
Ciprofloxacin, levofloxacin
130
First line treatment for dental abcess
Amoxicillin
131
What is trichomonas vaginalis
Trichomonas vaginalis is a highly motile, flagellated protozoan parasite. Trichomoniasis is a sexually transmitted infection (STI).
132
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
133
Investigations of trichomonas vaginalis
microscopy of a wet mount shows motile trophozoites
134
Management of trichomonas vaginalis
oral metronidazole for 5-7 days, although the BNF also supports the use of a one-off dose of 2g metronidazole
135
Treatment of severe falciparum malaria
Parasite count > 2% IV artesunate
| Parasite count >10% plasma exchange
136
Features of severe falciparum malaria
```
schizonts on a blood film
parasitaemia > 2%
hypoglycaemia
acidosis
temperature > 39 °C
severe anaemia
complications as below
```
137
Complications of severe malaria
cerebral malaria: seizures, coma
acute renal failure: blackwater fever, secondary to intravascular haemolysis, mechanism unknown
acute respiratory distress syndrome (ARDS)
hypoglycaemia
disseminated intravascular coagulation (DIC)
138
Management of uncomplicated malaria falciparum
Asia/Africa- strains resistant to chloroquinolone - artemisinin-based combination therapies
e.g artemether plus lumefantrine, artesunate plus amodiaquine, artesunate plus mefloquine, artesunate plus sulfadoxine-pyrimethamine, dihydroartemisinin plus piperaquine
139
Non-gonococcal uretheritis - causes
Chlamydia trachomatis - most common cause
| Mycoplasma genitalium - thought to cause more symptoms than Chlamydia
140
Stereotypical history of non-gonococcal urethritis
male who presented to a GUM clinic with a purulent urethral discharge and dysuria. A swab would be taken in clinic, microscopy performed which showed neutrophils but no Gram negative diplococci (i.e. no evidence of gonorrhoea)
141
Management of non-gonococcal urethritis
contact tracing
| the BNF and British Association for Sexual Health and HIV (BASHH) both recommend either oral azithromycin or doxycycline
142
amphotericin B mechanism of action
Binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
143
Terbinafine mechanism of action
Inhibits squalene epoxidase
144
CD 4 200-500 -opportunistic infections
oral thrush, hairy leukoplakia, shingles, karposi's sarcoma (HHV 8)
145
CD 4 count 100-200 opportunistic infections
Cryptosporidiosis- usually self limiting
Cerebral toxoplasmosis
Progressive multifocal leukoencephalopathy- 2 to JC virus
Pneumocystis jirovecii pneumonia
HIV dementia
146
CD 4 count 50-100 opportunistic infections
Aspergillosis
Oesophageal candidiasis
Cryptococcal meningitis
Primary CNS lymphoma
147
CD 4 count <50 opportunistic infections
cytomegalovirus retinitis
| Mycobacterium avium-intracellulare infection
148
Gardnerella vaginalis
cause of bacterial vaginitis
| clue cells found on microscopy
149
Features of tertiary syphilis
```
granulomatous lesions of the skin and bones
tabes dorsalis
Argyll-Robertson pupil
gummas
ascending aortic aneurysm
```
150
Features of congenital syphilis
Hutchinson's teeth
saddle nose
linear scars at the angle of the mouth
mulberry molars
151
Aciclovir - mechanism of action
Guanosine analog, phosphorylated by thymidine kinase which in turn inhibits the viral DNA polymerase
152
Aciclovir adverse effects
Crystalline nephropathy
153
Live attenuated vaccines
```
oral typhoid
MMR
influenza (intranasal)
oral polio
oral rotavirus
yellow fever
BCG
```
154
ganciclovir mechanism of action
Guanosine analog, phosphorylated by thymidine kinase which in turn inhibits the viral DNA polymerase
155
Ganciclovir side effects
Myelosuppression/agranulocytosis
156
First line treatment for animal/human bite
Co-amoxiclav
157
Foscarnet mechanism of action
Pyrophosphate analog which inhibits viiral DNA polymerase
158
Foscarnet adverse effects
Nephrotoxicity, hypocalcaemia, hypomagnasaemia, seizures
159
Initial empirical therapy aged < 3 months
Intravenous cefotaxime + amoxicillin (or ampicillin)
160
Pneumocystis jiroveci- what is it
unicellular eukaryote, generally classified as a fungus but some authorities consider it a protozoa
PCP is the most common opportunistic infection in AIDS
all patients with a CD4 count < 200/mm³ should receive PCP prophylaxis
161
Features of pneumocystis jiroveci
```
dyspnoea
dry cough
fever
very few chest signs
Extrapulmonary manifestations are rare (1-2% of cases), may cause
hepatosplenomegaly
lymphadenopathy
choroid lesions
```
162
Investigations for pneumocystis jiroveci
CXR: typically shows bilateral interstitial pulmonary infiltrates but can present with other x-ray findings e.g. lobar consolidation. May be normal
exercise-induced desaturation
sputum often fails to show PCP, bronchoalveolar lavage (BAL) often needed to demonstrate PCP (silver stain shows characteristic cysts)
163
Management of pneumocystis jiroveci
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)
164
Stereotypical history of strep pyogenes
a 10-year-old presents with fever and a sore throat. Today they have a developed a fine, erythematous, 'sand-paper' rash which is more prominent in flexural areas.
165
Erythema infectiosum
Associated with slapped cheek syndrome
Parvovirus B19
Barely noticeable mild feverish illness
Teratogenic in first 20 weeks of pregnancy
166
Clostridia
Clostridia are gram-positive, obligate anaerobic bacilli
167
Clostridium perfringens
produces α-toxin, a lecithinase, which causes gas gangrene (myonecrosis) and haemolysis
features include tender, oedematous skin with haemorrhagic blebs and bullae. Crepitus may present on palpation
168
Clostridium botulinum
```
typically seen in canned foods and honey
prevents acetylcholine (ACh) release leading to flaccid paralysis
```
169
Clostridium difficile
causes pseudomembranous colitis, typically seen after the use of broad-spectrum antibiotics
produces both an exotoxin and a cytotoxin
170
Clostridium tetani
produces an exotoxin (tetanospasmin) that prevents the release of glycine from Renshaw cells in the spinal cord causing a spastic paralysis
171
Cause of syphilis
Syphilis is a sexually transmitted infection caused by the spirochaete Treponema pallidum. Infection is characterised by primary, secondary and tertiary stages. The incubation period is between 9-90 days
172
Primary features of syphilis
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)
173
Secondary features of syphilis - usually 6-10 weeks post infection
systemic symptoms: fevers, lymphadenopathy
rash on trunk, palms and soles
buccal 'snail track' ulcers (30%)
condylomata lata (painless, warty lesions on the genitalia)
174
Tertiary features of syphilis
```
gummas (granulomatous lesions of the skin and bones)
ascending aortic aneurysms
general paralysis of the insane
tabes dorsalis
Argyll-Robertson pupil
```
175
Overview of Measles
RNA paramyxovirus
spread by droplets
infective from prodrome until 4 days after rash starts
incubation period = 10-14 days
176
Features of measles
prodrome: irritable, conjunctivitis, fever
Koplik spots (before rash): white spots ('grain of salt') on buccal mucosa
rash: starts behind ears then to whole body, discrete maculopapular rash becoming blotchy & confluent
diarrhoea occurs in around 10% of patients
177
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
178
Sub-unit/congugate vaccines
```
meningococcus
hepatitis B
haemophilus
pneumococcus
human papillomavirus
```
179
Toxoid vaccines
pertussis
diphtheria
tetanus
180
Management of malaria:non-falciparum malaria (preventing relapse)
Primaquine
181
CSF: tuberculos menigitis
slightly cloudy appearance with fibrin web, glucose 25% of plasma, protein 4 g/l, WCC 500 per mm^3 (lymphs)
182
CSF: bacterial meningitis
cloudy appearance, glucose 25% of plasma, protein 1.5 g/l, WCC 2,000 per mm^3 (neuts)
183
Presentation of diptheria
recent visitors to Eastern Europe/Russia/Asia
sore throat with a 'diphtheric membrane' - grey, pseudomembrane on the posterior pharyngeal wall
bulky cervical lymphadenopathy
may result in a 'bull neck' appearanace
neuritis e.g. cranial nerves
heart block
184
Pathophysiology of diptheria
Gram positive bacterium Corynebacterium diphtheriae
releases an exotoxin encoded by a β-prophage
exotoxin inhibits protein synthesis by catalyzing ADP-ribosylation of elongation factor EF-2
185
Management of diptheria
intramuscular penicillin
| diphtheria antitoxin
186
Stereotypical history of rubella
a child develops a pink maculopapular rash, initially on the face before spreading to the whole body. Suboccipital and postauricular lymphadenopathy is present
187
Stereotypical history of measles
a child presents with fever, conjunctivitis and being irritable. He has also developed a maculopapular rash which started behind ears before spreading and becoming blotchy & confluent
188
Cat scratch disease
```
fever
history of a cat scratch
regional lymphadenopathy
headache, malaise
Gram negative rod Bartonella henselae
```
189
erysipelas
infection of the upper layers of the skin (superficial). The most common cause is group A streptococcal bacteria, especially Streptococcus pyogenes
Rx: Flucloxacillin
190
Stereotypical history of Onchocerca volvulus
a man develops hyperpigmented skin and blindness after being bitten by a fly
191
Stereotypical history of Ancylostoma duodenale
a man develops abdominal pain after a holiday where he was walking barefoot in northern Africa. Bloods show an iron deficiency anaemia
192
Mechanism of action: amantidine
```
Inhibits uncoating (M2 protein) of virus in cell. Also releases dopamine from nerve endings
Used in influenza (rarely due to resistance) and parkinsonism
```
193
Chancroid
caused by Haemophilus ducreyi. It causes painful genital ulcers associated with unilateral, painful inguinal lymph node enlargement. The ulcers typically have a sharply defined, ragged, undermined border
194
Stereotypical history of Loa loa
a man develops episodic angioedema whilst in west Africa. On one occasion he noticed a 'worm moving across the left eye'
195
Conditions that can be caused by Hep B
- erythema nodosum
- cryoglobulinaemia
- hepatic cirrhosis
196
American trypanosomiasis, or Chagas' disease
caused by the protozoan Trypanosoma cruzi
chagoma (an erythematous nodule at site of infection) and periorbital oedema are sometimes seen.
Chronic Chagas' disease mainly affects the heart and gastrointestinal tract-
myocarditis may lead to dilated cardiomyopathy (with apical atophy) and arrhythmias
gastrointestinal features includes megaoesophagus and megacolon causing dysphagia and constipation
197
Management of Chagas disease
treatment is most effective in the acute phase using azole or nitroderivatives such as benznidazole or nifurtimox
chronic disease management involves treating the complications e.g., heart failure
198
mechanism of action: terbinafine
inhibits squalene epoxidase
199
melioidosis
Severe, bacterial infection caused by Burkholderia pseudomallei and is common in East Asia and Northern Australia
Risk factor: diabetes
Rx - IV ceftazidime
200
Sub-unit and conjugate vaccines
```
use polysaccarides to make them more immunogenic pneumococcus (conjugate)
haemophilus (conjugate)
meningococcus (conjugate)
hepatitis B
human papillomavirus
```
201
Management of PCP
Oral co-trimoxazole
202
Management of Schistosomiasis
Praziquantel
203
Cat scratch disease
Bartonella henselae
204
Q fever causative organism
Coxiella burnetii
205
Carbapenem resistance
New Delhi metallo-beta-lactamase 1
typically found in klebsiella, e coli, Enterobacter cloacae
Treat with tigercycline or colistin
206
Vancomycin resistance
D-alanyl-D-lactate variation leading to loss of affinity to antibiotics is the mechanism of VRE (vancomycin resistant enterococci). Vancomycin binds to D-ala-D-ala.
207
Pseudomonas resistance
MexAB-OprM efflux pumps is one of the mechanisms by which pseudomonas aeruginosa is resistant to -lactams, chloramphenicol, fluoroquinolones, macrolides, novobiocin, sulfonamides, tetracycline, and trimethoprim.
208
Diagnosis of intestinal ameobias
'hot' stool sample - microscopy within 15 mins
209
Animal bites (dogs)
Pasteurella multocida
210
C.diff
gram positive bacilli
211
gram negative cocci
Neisseria meningitidis + Neisseria gonorrhoeae, also Moraxella catarrhalis
212
Cryptosporidium staining
Modified Ziehl-Neilson
213
Features of Zika virus
```
fever
rash
arthralgia/arthritis
conjunctivitis
myalgia
headache
retro-orbital pain
pruritus
```
214
tuberculoid leprosy
recent onset of hypopigmented skin lesions, sensory peripheral neuropathy and thickened peripheral nerves having come from an endemic region.
215
Aspergilloma in previous TB
Occupies previous cavitating lesion
| chest x-ray containing a rounded opacity. A crescent sign may be present- air around the lesions
216
Brucellosis
luctuating temperatures, transient arthralgia and myalgia, hyperhidrosis with a 'wet hay' smell. unpasteurised cheese.
Brucella melitensis is the bacteria found in contaminated unpasteurised milk
217
Lemierre's syndrome
Lemierre's syndrome is an infectious thrombophlebitis of the internal jugular vein.
It most often occurs secondary to a bacterial sore throat caused by Fusobacterium necrophorum leading to a peritonsillar abscess. A combination of spread of the infection laterally from the abscess and compression lead to thrombosis of the IJV.
Patients will present with a 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.
218
Campylobacter
Unpasteurised milk, bloody diarrhoea and fevers
| Clarithromycin
219
mycoplasma and skin
associated with erythema multiforme
220
Linezolid- mechanism of action
type of oxazolidinone antibiotic
It inhibits bacterial protein synthesis by stopping the formation of the 50s initiation complex and is bacteriostatic in nature.
221
Linezolid- used to treat?
Spectrum, highly active against Gram positive organisms including:
MRSA (Methicillin-resistant Staphylococcus aureus)
VRE (Vancomycin-resistant enterococcus)
GISA (Glycopeptide Intermediate Staphylococcus aureus)
222
Linezolid adverse effects
thrombocytopenia (reversible on stopping)
| monoamine oxidase inhibitor: avoid tyramine containing foods
223
Features of anthrax
causes painless black eschar (cutaneous 'malignant pustule', but no pus)
typically painless and non-tender
may cause marked oedema
anthrax can cause gastrointestinal bleeding
224
Management of anthrax
Ciprofloxacin
225
HIV: Mycobacterium avium complex features
```
fever, sweats
abdominal: pain, diarrhoea
lung: dyspnoea, cough
anaemia
lymphadenopathy
hepatomegaly/deranged LFTs
```
226
HIV: Mycobacterium avium complex management
rifampicin + ethambutol + clarithromycin
226
HIV: Mycobacterium avium complex management
rifampicin + ethambutol + clarithromycin
227
Leptospirosis
Spirochete infected rat urine
sewage workers, farmers, vets or people who work in an abattoir
Treat with ben pen or doxycyline
228
VDRL (Venereal Disease Research Laboratory) & RPR (rapid plasma reagin)
Used to investigate syphyllis, can be falsely positive in antiphospholipid syndrome, pregnancy, SLE, TB, leprosy, malaria, HIV.
229
Dengue
Retro-orbital headache, fever, facial flushing, rash, thrombocytopenia in returning travelle
230
Basics of Dengue
transmitted by the Aedes aegypti mosquito
incubation period of 7 days
a form of disseminated intravascular coagulation (DIC) known as dengue haemorrhagic fever (DHF) may develop. Around 20-30% of these patients go on to develop dengue shock syndrome (DSS)
231
Treatment of Dengue
entirely symptomatic e.g. fluid resuscitation, blood transfusion etc
no antivirals are currently available
232
Low glucose CSF- viral
Mumps
| herpes encephalitis
233
indinavir
protease inhibitor associated with renal stones
234
Tetracyclines (doxycycline)
Inhibit 30s sub-units of ribosomes
235
CNS toxoplasma
ring enhancing lesion
| pyrimethamine plus sulphadiazine
236
Leprosy
Hypopigmentation
| Sensation loss
237
Staph aureus
Gram +ve
Coagulase +ve
Catalase +ve
238
Mechanism of action of Amphotericin B
binds to ergosterol, a component of fungal cell membranes, forming pores that cause lysis of the cell wall and subsequent fungal cell death
239
Sequelae of corynebacterum (diptheria)
Heart block
neuritis
Bulky lymphadenopathy
sore throat with diptheric (grey) membrane
240
IVDU with descending paralysis
Clostridium botulinum
241
Most common causes of viral meningitis (Adults)
Enterovirus e.g. Coxsackie B
242
African trypanosomiasis treatment
early disease: IV pentamidine or suramin
| later disease or central nervous system involvement: IV melarsoprol
243
Chagas disease
protozoan Trypanosoma cruzi. (95%) are asymptomatic in the acute phase although a chagoma (an erythematous nodule at site of infection) and periorbital oedema are sometimes seen. Chronic Chagas' disease mainly affects the heart and gastrointestinal tract
myocarditis may lead to dilated cardiomyopathy (with apical atophy) and arrhythmias
gastrointestinal features includes megaoesophagus and megacolon causing dysphagia and constipation
244
Management of chagas disease
treatment is most effective in the acute phase using azole or nitroderivatives such as benznidazole or nifurtimox
chronic disease management involves treating the complications e.g., heart failure
245
Urine dip - +ve for leucocytes, -ve for nitrates
Gram +Ve bacteria e.g. staph saprophyticus
246
Jarisch-Herxheimer reaction
Seen in management of syphillis - release of endotoxins
Flushing, rash and fever
No wheeze or hypotension - differentiates from anaphylaxis
247
URTI + amoxicillin --> rash
?Glandular fever
248
Chikungunya
alphavirus spread by infected bacteria
| Debilitating arthralgia, flu like illness
249
Second line management of genital warts (herpes simplex)
imiquimod
250
Amantadine
inhibits uncoating of viral M2
| increases dopamine release from neuronal synapses
