Infectious Diseases Flashcards
(100 cards)
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
What is cryptococcosis?
A
Opportunistic fungal infection
- Caused by environmental fungus found worldwide
- often found in soil contaminated with bird droppings
5
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)
6
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
7
Q
Gold standard diagnostic test for cryptococcosis
A
Culture!
8
Q
What is histoplasmosis?
A
Histoplasma capsulatum - another environmental fungus
- found worldwide
but most commonly America in soil with bird/bat droppings
9
Q
How is histoplasmosis transmitted?
A
Via inhalation of microscopic spores, incubation 3-17d
10
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
11
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
12
Q
What is pneumocystis jiroveci pneurmonia also known as?
A
Pneumocystis carinii pneumonia (PCP)
- common opportunistic infection in AIDS
13
Q
Featues of pneumocystis jiroveci
A
dyspnoea
dry cough
fever
very few chest signs
14
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
15
Q
Most common complication of pneumocystis jiroveci
A
Pneumothorax
16
Q
What is Epstein-Barr virus?
A
Infectious mononucleosis (glandular fever)
EBV, also known as human herpesvirus 4, HHV-4
17
Q
Features of EBV
A
Classic triad of :
- sore throat
- pyrexia
- lympadenopathy
- Symptoms typically resolve after 2-4 weeks
18
Q
Diagnostic test for EBV
A
heterophil antibody test (Monospot test)
19
Q
Types of herpes simplex virus
A
HSV-1 : oral lesions (cold sores)
HSV-2 for genital herpes
20
Q
Features of HSV
A
- primary infection: may present with a severe gingivostomatitis
- cold sores
- painful genital ulceration
21
Q
What is mumps?
A
Mumps is a caused by RNA paramyxovirus and tends to occur in winter and spring
22
Q
How do mumps spread?
A
- 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
23
Q
Symptoms of mumps
A
- fever
- malaise, muscular pain
- parotitis (‘earache’, ‘pain on eating’): unilateral initially then becomes bilateral
24
Q
Investigations of mumps
A
- Serum mumps IgM – Positive igM confirms diagnosis.
- Negative IgM does not rule out mumps infection
- Serum Mumps IgG
- Viral culture (Saliva)
- Consider CT Head if there are focal neurological symptoms
25
What is roseola infantum?
AKA as exanthem subitum is a common disease of infancy caused by the human herpes virus 6 (HHV6).
26
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
27
How is Roseola infantum diagnosed?
Clinical diagnosis
28
Treatment of Roseola infantum
Self-limiting
29
What is rubella AKA and causative organism?
AKA German measles, is a viral infection caused by the togavirus.
30
When is rubella infectious?
infectious from 7 days before symptoms appear to 4 days after the onset of the rash
31
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
32
Gold standard for rubella
Serological and/or polymerase chain reaction (PCR) testing is the gold standard.
33
Causative organism of Measles
RNA paramyxovirus
34
Transmission of Measles
1. spread by droplets
2. infective from prodrome until 4 days after rash starts
3. incubation period = 10-14 days
35
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
36
Investigation of Measles
IgM antibodies can be detected within a few days of rash onset
37
Causative organism of Erythema Infectiosum
Parvovirus B19 is a DNA virus which causes a variety of clinical presentations.
38
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
39
Investigations of Erythema Infectiosum
Only done in pregnant/immunocompromised patients = serology
40
Causative organism of rabies
Rhabdoviridae family
41
What is rabies?
viral disease that causes an acute encephalitis
42
Features of rabies
1. Prodrome: headache, fever, agitation
2. Hydrophobia
3. hypersalivation
43
Investigations for rabies
1. Clinical suspicion
| 2. immunofluorescence from saliva/CSF or anti- rabies antibodies
44
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
45
Define Cytomegalovirus Infections
Cytomegalovirus is part of the Herpesvirus family
| - Primary infection presentation = EBV
46
How CMV transmitted?
Sex/close contact (URT & Urine) / blood/transplant
47
Features of CMV
Manifest as colitis, hepatitis, encephalitis, pneumonitis, retinitis
48
Investigations for CMV
Serology (IgM & IgG), CMV DNA PCR, Histology (‘inclusions’)
49
Treatment of CMV
1. Supportive in immunocompetent
| 2. Antiviral in immunocompromised (Cidofovir/Foscarnet/Ganciclovir)
50
What pathogen causes influenza?
RNA virus - orthomyxoviridae
51
What are the symptoms of influenza?
- Coryzal symptoms
- Fever
- Headache
- Non-productive cough
- Sore throat
52
How is influenza diagnosed?
Clinical diagnosis
| - viral culture - PCR
53
What is varicella-zoster infection?
Chickenpox
| - shingles is reactivation of VZV (herpes zoster)
54
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.
55
Facts about salmonellosis
Leading cause of foodborne illness
(poultry, eggs, milk products)
- Incubation period 8-72h post exposure (ingestion of contaminated food/water)
56
Features of salmonellosis
1. Diarrhoea
2. Nausea
3. Vomiting
4. Fever
5. abdo cramps
57
Investigation for salmonellosis
Stool Microscopy, Culture & Sensitivities (MCS)
58
What is shigellosis?
Shigella species cause a diarrhoeal illness
59
Transmission of shigellosis
Faeco-oral transmission, can be sexually acquired
60
Features of shigellosis
- Diarrhoea (often bloody)
- fever
- abdominal pain
61
Investigation for shigellosis
Stool MCS
62
Causative organism of tetanus
tetanospasmin exotoxin released from Clostridium tetani
63
How does tetanus affect the body?
Prevents release of GABA
64
How is tetanus transmitted?
Spores of the bacteria enter the body through a wound
65
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)
66
Diagnosis of tetanus
clinical
67
What is cholera?
Acute diarrhoeal illness caused by toxin-producing strains of gram negative Vibrio cholerae.
68
How is cholera transmitted?
ingesting contaminated food or water
69
Features of cholera
1. Diarrhoea - profuse ‘Rice water stool’
2. Dehydration
3. hypoglycaemia
70
Investigation for cholera
1. Largely clinical
| 2. Stool MCS
71
Causative organism for diphtheria
Gram-positive bacillus Corynebacterium diphtheriae
72
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
73
Investigation for diphtheria
Culture of throat swab: uses tellurite agar or Loeffler's media
74
What is botulism?
Rare, but potentially life-threatening neuroparalytic syndrome caused by a neurotoxin of Clostridium botulinum
75
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
76
Investigation for botulism
Clinical suspicion, anaerobic culture
77
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
78
Transmission of Atypical Mycobacterial Disease
Transmission occurs via the respiratory or GI tract
79
Features of Atypical Mycobacterial Disease
1. fever, night sweats, weight loss, lymphadenopathy, hepatomegaly
2. Anaemia, leucopenia, hypoalbuminaemia
80
Investigation for Atypical Mycobacterial Disease
Mycobacterial cultures (blood/bone marrow/lymph node/ sputum/stool)
81
Causative organis of threadworks
Infestation with threadworms (Enterobius vermicularis, sometimes called pinworms) is extremely common amongst children in the UK.
82
Transmission of threadworms
Infestation occurs after swallowing egg
83
Features of threadworms
Usually asymptomatic
- perianal itching, particularly at night
- girls may have vulval symptoms
84
How do you diagnose threadworms?
Cellophane test/ Clinical suspicion
85
Treatment for threadworms
1st line = Mebendazole with repeat dose in 2/52
- Treat entire family, hygiene measures
86
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
87
Transmission of hookworm
Mainly acquired through walking barefoot in contaminated soil
88
Features of hookworm
- Majority asymptomatic
- Some GI symptoms
- anaemia
- mild cough
- serum eosinophilia
89
Investigation for hookworm
Stool Ova, Cysts and Parasites
90
Treatment of hookworm
Albendazole or Mebendazole
91
Causative organism of amoebiasis
Entamoeba histolytica
92
Transmission of amoebiasis
Spread by the faecal-oral route
93
Symptoms of amoebiasis
- Infection can be asymptomatic
- cause mild diarrhoea
- severe amoebic dysentery
94
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
95
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
96
Features of malaria
1. Fever, arthralgia, headache, nausea, abdominal pain (often non-specific symptoms)
2. Signs: Tachycardia, tachypnoea, fever, anaemia, thrombocytopenia, transaminitis, splenomegaly
97
Causative organism of toxoplasmosis
Infection with a worldwide distribution caused by Toxoplasma gondii
98
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
99
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
100
Investigations of toxoplasmosis
*Serology*
