Infectious Diseases Flashcards
1
Q
What is candidiasis?
A
thrush
2
Q
Features of candidiasis
A
- ‘Cottage cheese’, non-offensive discharge
- Vulvitis: superficial dyspareunia, dysuria
- Itch
- Vulval erythema
3
Q
Investigations for vaginal candidiasis
A
a high vaginal swab is not routinely indicated if the clinical features are consistent with candidiasis
4
Q
Management of vaginal candidiasis
A
1st line = single dose oral fluconazole
if contraindicated = intravaginal pessary clotrimazole
Vulval symptoms - topical imidazole with oral or intravaginal antifungal
5
Q
What is cryptococcosis?
A
Opportunistic fungal infection
- Caused by environmental fungus found worldwide
- often found in soil contaminated with bird droppings
6
Q
How does cryptococcosis infection present?
A
- Meningitis is the most frequently seen presentation
- Clinical manifestation can vary:
- Headache
- Lethargy
- Pyrexia
- Productive cough
- SOB
- personality changes will develop over 2-4 weeks (sometimes months)
7
Q
Investigation for cryptococcosis
A
- Lumbar puncture will feature high opening pressure, lymphocytic CSF, high protein and low glucose
- CSF CrAg: Sensitivity 93 - 100%, Specificity 93 - 98%
- Gold standard diagnostic test is culture*
2. Serum Cryptococcal Antigen (CrAg) also used
3. India ink stain: round, encapsulated yeast
8
Q
Gold standard diagnostic test for cryptococcosis
A
Culture!
9
Q
Management of cryptococcosis
A
mild to moderate disease:
1st line = fluconazole (6-12 months)
Severe disease and CNS involvement:
Amphotericin B + Flucytosine followed by fluconazole
10
Q
What is histoplasmosis?
A
Histoplasma capsulatum - another environmental fungus
- found worldwide
but most commonly America in soil with bird/bat droppings
11
Q
How is histoplasmosis transmitted?
A
Via inhalation of microscopic spores, incubation 3-17d
12
Q
Features of histoplasmosis
A
- Flu-like (fever/cough/lethargy/headache)
- Consider in patients with pneumonia and mediastinal LN, pulmonary nodule, pericarditis with LN, pulmonary manifestations with arthralgia
- Severity depends on host immunity and intensity of exposure
13
Q
Investigations for histoplasmosis
A
1st line = CXR common findings for histoplasmosis pneumonia: - nodules - mediastinal or hilar lymphadenopathy - cavitary lesions - pleural effusions
Gold standard /Diagnostic:
Culture of pulmonary secretions
Other: Histoplasma antigen on serum or urine
14
Q
Management of histoplasmosis
A
Asymptomatic, Mild + immunocompetent = observe
Mild + immunocompromised =
itraconazole (azole antifungals)
Severe (for acute pulmonary cases) = Amphotericin B followed by itraconazole
15
Q
What is pneumocystis jiroveci pneurmonia also known as?
A
Pneumocystis carinii pneumonia (PCP)
- common opportunistic infection in AIDS
16
Q
Featues of pneumocystis jiroveci
A
dyspnoea
dry cough
fever
very few chest signs
17
Q
Investigations for pneumocystis jiroveci
A
- CXR:
- bilateral interstitial
pulmonary infiltrates
- lobar consolidation.
- May be normal - exercise-induced desaturation
- sputum often fails to show PCP
- bronchoalveolar lavage (BAL) = silver stain shows characteristic cysts
18
Q
Most common complication of pneumocystis jiroveci
A
Pneumothorax
19
Q
Management of pneumocystis jiroveci
A
- co-trimoxazole
- IV pentamidine in severe cases
- alternative: aerosolized pentamidine (less effective in pneumothorax) - steroids if hypoxic
20
Q
What is Epstein-Barr virus?
A
Infectious mononucleosis (glandular fever)
EBV, also known as human herpesvirus 4, HHV-4
21
Q
Features of EBV
A
Classic triad of :
- sore throat
- pyrexia
- lympadenopathy
- Symptoms typically resolve after 2-4 weeks
22
Q
Diagnostic test for EBV
A
heterophil antibody test (Monospot test)
23
Q
Management of EBV
A
- Management is supportive and includes:
o rest during the early stages, drink plenty of fluid, avoid alcohol
o simple analgesia for any aches or pains
o avoid playing contact sports for 8 weeks after having glandular fever to reduce the risk of splenic rupture
24
Q
Types of herpes simplex virus
A
HSV-1 : oral lesions (cold sores)
HSV-2 for genital herpes
25
Features of HSV
- primary infection: may present with a severe gingivostomatitis
- cold sores
- painful genital ulceration
26
Management of HSV
1. gingivostomatitis: oral aciclovir, chlorhexidine mouthwash
2. cold sores: topical aciclovir
3. genital herpes: oral aciclovir.
27
What is mumps?
Mumps is a caused by RNA paramyxovirus and tends to occur in winter and spring
28
How do mumps spread?
* by droplets
* respiratory tract epithelial cells → parotid glands → other tissues
* infective 7 days before and 9 days after parotid swelling starts
* incubation period = 14-21 days
29
Symptoms of mumps
- fever
- malaise, muscular pain
- parotitis ('earache', 'pain on eating'): unilateral initially then becomes bilateral
30
Investigations of mumps
1. Serum mumps IgM – Positive igM confirms diagnosis.
2. Negative IgM does not rule out mumps infection
3. Serum Mumps IgG
4. Viral culture (Saliva)
5. Consider CT Head if there are focal neurological symptoms
31
Management of mumps
1. Self-limiting - rest
2. paracetamol for high fever/discomfort
3. notifiable disease
32
What is roseola infantum?
AKA as exanthem subitum is a common disease of infancy caused by the human herpes virus 6 (HHV6).
33
Features of Roseola infantum
1. high fever: lasting a few days, followed later by a
2. maculopapular rash
3. Nagayama spots: papular enanthem on the uvula and soft palate
4. febrile convulsions
5. diarrhoea and cough
34
How is Roseola infantum diagnosed?
Clinical diagnosis
35
Treatment of Roseola infantum
Self-limiting
36
What is rubella AKA and causative organism?
AKA German measles, is a viral infection caused by the togavirus.
37
When is rubella infectious?
infectious from 7 days before symptoms appear to 4 days after the onset of the rash
38
Features of rubella
1. prodrome, e.g. low-grade fever
2. rash: maculopapular, initially on the face before spreading to the whole body, usually fades by the 3-5 day
3. lymphadenopathy: suboccipital and postauricular
39
Gold standard for rubella
Serological and/or polymerase chain reaction (PCR) testing is the gold standard.
40
Management of Rubella
Self-limiting
41
Causative organism of Measles
RNA paramyxovirus
42
Transmission of Measles
1. spread by droplets
2. infective from prodrome until 4 days after rash starts
3. incubation period = 10-14 days
43
Features of Measles
1. prodrome: irritable, conjunctivitis, fever
2. Koplik spots (before rash): white spots ('grain of salt') on buccal mucosa
3. rash: starts behind ears then to whole body, discrete maculopapular rash becoming blotchy & confluent
4. diarrhoea
44
Investigation of Measles
IgM antibodies can be detected within a few days of rash onset
45
Management of Measles
1. mainly supportive
2. admission may be considered in immunosuppressed or pregnant patients
3. notifiable disease → inform public health
46
Causative organism of Erythema Infectiosum
Parvovirus B19 is a DNA virus which causes a variety of clinical presentations.
47
Symptoms of Erythema Infectiosum
1. ‘slapped cheek’ rash
2. An erythematous maculopapular rash on the trunk, back, and limbs may develop a few days after the facial rash
3. This then fades to produce a lace-like, reticular rash.
4. low-grade fever
5. Prodromal viral infection prior to onset of rash
48
Investigations of Erythema Infectiosum
Only done in pregnant/immunocompromised patients = serology
49
Management of Erythema Infectiosum
Self-limiting
50
Causative organism of rabies
Rhabdoviridae family
51
What is rabies?
viral disease that causes an acute encephalitis
52
Features of rabies
1. Prodrome: headache, fever, agitation
2. Hydrophobia
3. hypersalivation
53
Investigations for rabies
1. Clinical suspicion
| 2. immunofluorescence from saliva/CSF or anti- rabies antibodies
54
Treatment of rabies
1. Contact PHE
2. Late-stage Rx:
- Symptomatic Mx:
Quiet
private room
benzodiazepines
haloperidol
analgesia
anti-cholinergics
3. At risk countries:
- HRIG
55
Define Cytomegalovirus Infections
Cytomegalovirus is part of the Herpesvirus family
| - Primary infection presentation = EBV
56
How CMV transmitted?
Sex/close contact (URT & Urine) / blood/transplant
57
Features of CMV
Manifest as colitis, hepatitis, encephalitis, pneumonitis, retinitis
58
Investigations for CMV
Serology (IgM & IgG), CMV DNA PCR, Histology (‘inclusions’)
59
Treatment of CMV
1. Supportive in immunocompetent
| 2. Antiviral in immunocompromised (Cidofovir/Foscarnet/Ganciclovir)
60
What pathogen causes influenza?
RNA virus - orthomyxoviridae
61
What are the symptoms of influenza?
- Coryzal symptoms
- Fever
- Headache
- Non-productive cough
- Sore throat
62
How is influenza diagnosed?
Clinical diagnosis
| - viral culture - PCR
63
Management of influenza and indication for medication
Antivirals:
Selective use of antivirals : oral oseltamivir and inhaled zanamivir
Indication:
1) if able to start treatment within 48 hours of symptoms onset
2) Known circulation of virus in community
3) High-risk : pregnant, obese, > 65 + < 6 y.o, immunocompromised, comorbidities
Conservative:
- analgesia
- increase fluid intake
- rest
64
What is varicella-zoster infection?
Chickenpox
| - shingles is reactivation of VZV (herpes zoster)
65
Symptoms of shingles
prodromal period
1. burning pain over the affected dermatome for 2-3 days
2. fever, headache, lethargy
rash
1. initially erythematous, macular rash over the affected dermatome
2. quickly becomes vesicular
3. does not cross the midline.
66
Management of shingles
1. Anti-viral if you are seeing the patient within 72 hours of the onset of the rash
2. Acyclovir 800 mg po 5 times per day x 7d
3. Pain control
- Opiates
- Anticonvulsants
- Tramadol
- ? steroids
67
Facts about salmonellosis
Leading cause of foodborne illness
(poultry, eggs, milk products)
- Incubation period 8-72h post exposure (ingestion of contaminated food/water)
68
Features of salmonellosis
1. Diarrhoea
2. Nausea
3. Vomiting
4. Fever
5. abdo cramps
69
Investigation for salmonellosis
Stool Microscopy, Culture & Sensitivities (MCS)
70
Management of salmonellosis
1. Often self-limiting, 4-10d. <5% develop bacteraemia
2. Supportive (hydration
3. if severe – Ciprofloxacin/Azithromycin
4. Isolate until 48 hours after the last episode of diarrhoea or vomiting
5. Notifiable disease
71
What is shigellosis?
Shigella species cause a diarrhoeal illness
72
Transmission of shigellosis
Faeco-oral transmission, can be sexually acquired
73
Features of shigellosis
- Diarrhoea (often bloody)
- fever
- abdominal pain
74
Investigation for shigellosis
Stool MCS
75
Management of shigellosis
1. Cipro/Azithro if unwell
| 2. Hand hygiene, Notify
76
Causative organism of tetanus
tetanospasmin exotoxin released from Clostridium tetani
77
How does tetanus affect the body?
Prevents release of GABA
78
How is tetanus transmitted?
Spores of the bacteria enter the body through a wound
79
Features of tetanus
1. painful muscle contractions esp Masseter and neck muscles
2. prodrome: fever, lethargy, headache
3. trismus (lockjaw)
4. risus sardonicus (distorted grin)
5. opisthotonus (arched back, hyperextended neck)
6. spasms (e.g. dysphagia)
80
Management of tetanus
1. Supportive: ventilatory support, muscle relaxants
2. wound debridement
3. Metronidazole
4. NB Tetanus does not confer immunity post infection, re-vaccinate every 10 years
81
Diagnosis of tetanus
clinical
82
What is cholera?
Acute diarrhoeal illness caused by toxin-producing strains of gram negative Vibrio cholerae.
83
How is cholera transmitted?
ingesting contaminated food or water
84
Features of cholera
1. Diarrhoea - profuse ‘Rice water stool’
2. Dehydration
3. hypoglycaemia
85
Management of cholera
1. Aggressive volume repletion (oral or IV)
2. adequate nutrition
3. antibiotics for severe cases = doxycycline, ciprofloxacin
86
Investigation for cholera
1. Largely clinical
| 2. Stool MCS
87
Causative organism for diphtheria
Gram-positive bacillus Corynebacterium diphtheriae
88
Features of diphtheria
1. sore throat --> with diphtheric membrane' : grey pseudomembrane on the posterior pharyngeal wall
2. bulk cervical lymphadenopathy --> 'bull neck'
3. low-grade fever
89
Investigation for diphtheria
Culture of throat swab: uses tellurite agar or Loeffler's media
90
Management of diphtheria
1. intramuscular penicillin
- Erythromycin
2. diphtheria antitoxin
- Notify
- Contact trace + prophylaxis
91
What is botulism?
Rare, but potentially life-threatening neuroparalytic syndrome caused by a neurotoxin of Clostridium botulinum
92
Features of botulism
Acute onset bilateral cranial neuropathies with symmetric descending weakness
1. patient usually fully conscious with no sensory disturbance
2. flaccid paralysis
3. diplopia
4. ataxia
5. bulbar palsy
93
Investigation for botulism
Clinical suspicion, anaerobic culture
94
Management of botulism
Botulism antitoxin and supportive care
| - antitoxin is only effective if given early - once toxin has bound its actions cannot be reversed
95
What is Atypical Mycobacterial Disease?
Opportunistic infection
E.g. Mycobacterium avium and Mycobacterium kansasii
- context of HIV, CD4 <50 are at higher risk of disseminated disease
- environmental organism
96
Transmission of Atypical Mycobacterial Disease
Transmission occurs via the respiratory or GI tract
97
Features of Atypical Mycobacterial Disease
1. fever, night sweats, weight loss, lymphadenopathy, hepatomegaly
2. Anaemia, leucopenia, hypoalbuminaemia
98
Investigation for Atypical Mycobacterial Disease
Mycobacterial cultures (blood/bone marrow/lymph node/ sputum/stool)
99
Management of Atypical Mycobacterial Disease
Clari-/Azithromycin) + Ethambutol + Rifabutin for > 3mo
100
Causative organis of threadworks
Infestation with threadworms (Enterobius vermicularis, sometimes called pinworms) is extremely common amongst children in the UK.
101
Transmission of threadworms
Infestation occurs after swallowing egg
102
Features of threadworms
Usually asymptomatic
- perianal itching, particularly at night
- girls may have vulval symptoms
103
How do you diagnose threadworms?
Cellophane test/ Clinical suspicion
104
Treatment for threadworms
1st line = Mebendazole with repeat dose in 2/52
- Treat entire family, hygiene measures
105
What is hookworm?
Hookworm (Ancylostoma duodenale and Necator americanus) as well as Ascaris (up to 35mm) and Trichuris (whipworm) are all soil-transmitted helminths account for the majority of infection
106
Transmission of hookworm
Mainly acquired through walking barefoot in contaminated soil
107
Features of hookworm
- Majority asymptomatic
- Some GI symptoms
- anaemia
- mild cough
- serum eosinophilia
108
Investigation for hookworm
Stool Ova, Cysts and Parasites
109
Treatment of hookworm
Albendazole or Mebendazole
110
Causative organism of amoebiasis
Entamoeba histolytica
111
Transmission of amoebiasis
Spread by the faecal-oral route
112
Symptoms of amoebiasis
- Infection can be asymptomatic
- cause mild diarrhoea
- severe amoebic dysentery
113
Sx, Ix & Mx of amoebic dysentery
- profuse, bloody diarrhoea
Ix: stool microscopy may show trophozoites if examined within 15 minutes or kept warm (known as a 'hot stool')
Mx: metronidazole
114
Causative organism of malaria
Mosquito-borne infection caused by Plasmodium protozoa
Four kinds of malaria parasite: Plasmodium falciparum, P. vivax, P. ovale and P. malariae
115
Features of malaria
1. Fever, arthralgia, headache, nausea, abdominal pain (often non-specific symptoms)
2. Signs: Tachycardia, tachypnoea, fever, anaemia, thrombocytopenia, transaminitis, splenomegaly
116
Management of malaria
Urgent prompt IV therapy, inform senior, if DGH consider referral to Tertiary referral centre, inform ITU
Depends on severity of falciparum malaria
(CHECK NOTES)
117
Management of falciparum malaria
1st line = artemisinin-based combination therapies (ACTs)
Severe:
IV artersunate
? bacterial septicaemia if haemodynamic collapse
118
Management of non- falciparum malaria
1st line = artemisinin-based combination therapy (ACT) or chloroquine
Give Primaquine following acute treatment with chloroquine to destroy liver hypnozoites and prevent relapse.
119
Causative organism of toxoplasmosis
Infection with a worldwide distribution caused by Toxoplasma gondii
120
Transmission of toxoplasmosis
1. Ingestion of infectious oocysts from soil/water
2. Ingestion of tissue cysts in the meat of an infected animal
3. Vertical transmission
4. Transmission from organ transplantation from an infected donor
121
Features of toxoplasmosis
1. Immunocompetent person: primary infection usually asymptomatic
2. If symptomatic: fever, sweats, headache, myalgia, hepatosplenomegaly
3. Most common manifestation is bilateral, symmetrical non-tender cervical lymphadenopathy
4. Labs: Lymphocytosis, raised LFTs, moderate increase in CRP
122
Investigations of toxoplasmosis
*Serology*
123
Management of toxoplasmosis
no treatment unless severe infection or immunosuppressed
Tx: pyrimethamine and sulfadiazine
Advice: avoid raw/undercooked meat, avoid changing cat litter
