Specific pathogens and their disease Flashcards
1
Q
Toxoplasma gondii
A
- Protozoa infects the body via the GI tract, lung or broken skin. O
- ocysts release trophozoites ->migrate widely around the body including to the eye, brain and muscle. Animal reservoir is the cat but other animals also such as rats.
- Most infections are asymptomatic.
- Symptomatic patients usually have a self-limiting infection, often having clinical features resembling infectious mononucleosis (fever, malaise, lymphadenopathy).
- Other less common manifestations include meningioencephalitis and myocarditis.
- Investigation: antibody test + Sabin-Feldman dye test
- Treatment is usually reserved for those with severe infections or patients who are immunosuppressed -> pyrimethamine plus sulphadiazine for at least 6 weeks
2
Q
Congenital toxoplasmosis
A
- Transplacental spread from the mother -> causes a variety of effects to the unborn child including microcephaly, hydrocephalus, cerebral calcification and choroidoretinitis
3
Q
Glandular fever
A
- EBV aka HHV-4
- Classic triad of sore throat, pyrexia and lymphadenopathy is seen in around 98% of patients,
-
Other features include:
- 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
- Symptoms typically resolve after 2-4 weeks
- Diagnosis - heterophil antibody test (Monospot test)
4
Q
Leprosy - Mycobacterium leprae.
A
- Features: patches of hypopigmented skin typically affecting the buttocks, face, and extensor surfaces of limbs with sensory loss
- The degree of cell mediated immunity determines the type of leprosy a patient will develop.
- Management with triple therapy: rifampicin, dapsone and clofazimine
5
Q
Zika
A
- Mosquito borne, majority of infected have no symptoms.
- Those with symptoms, Zika virus tends to cause a mild, short-lived (2 to 7 days) febrile disease.
- Zika is linked with microcephaly and other congenital abnormalities therefore wait 6 months after possible exposure to concieve
6
Q
Dog bite
A
- Pasteurella multocida is a gram-negative coccobacillus which is the most likely organism to be isolated after a dog bite.
- Co-amoxiclav is recommended OR if penicillin-allergic then doxycycline + metronidazole is recommended
7
Q
TB meninigitis ?steroids
A
- use of steroids in patients with tuberculous meningitis is supported by a Cochrane review in 2008
8
Q
Active TB treatment
A
Active tuberculosis:
- Initial phase - first 2 months (RIPE) Rifampicin Isoniazid, Pyrazinamide and Ethambutol
- Continuation phase - next 4 months: Rifampicin Isoniazid
9
Q
Latent TB treatment
A
- 3 months of isoniazid (with pyridoxine) and rifampicin
- OR 6 months of isoniazid (with pyridoxine)
10
Q
Meningeal tuberculosis
A
- Prolonged period (at least 12 months) with the addition of steroids
11
Q
Leptospirosis
A
- Sewage workers, farmers, vets or people who work in an abattoir.
- Pathogen: spirochaete Leptospira interrogans (serogroup L icterohaemorrhagiae),
- Features: fever, flu-like symptoms renal failure (50% pts), jaundice, subconjunctival haemorrhage headache, may herald the onset of meningitis
- *the term Weil’s disease is sometimes reserved for the most severe 10% of cases that are associated with jaundice.
- Management: high-dose benzylpenicillin or doxycycline
12
Q
Gram-negative cocci
A
- Neisseria meningitidis
- Neisseria gonorrhoeae,
- Moraxella catarrhalis
13
Q
Gram-positive rods (bacilli)
A
ABCD L
- Actinomyces
- Bacillus anthracis (anthrax)
- Clostridium
- Diphtheria: Corynebacterium diphtheriae
- Listeria monocytogenes
14
Q
Gram -negative rods
A
- Escherichia coli
- Haemophilus influenzae
- Pseudomonas aeruginosa
- Salmonella sp.
- Shigella sp.
- Campylobacter jejuni
15
Q
Cat scratch disease
- *-Bartonella spp infection
- Most important species
- Disease and vector
- classic immunocompetent presentation
- Best initial test if suspected
- Treatment**
A
- Gram negative rod
- Bartonella henselae
- Features: fever, hx of a cat scratch tender regional lymphadenopathy, headache, malaise
- Immunocompromised develop bacillarly angiomatosis and get benign papular vascular lesions
16
Q
Legionella
A
- Legionella pneumophilia.
- water tanks, air-conditioning systems or foreign holidays.
- Person-to-person transmission is not seen.
- Features flu-like symptoms including fever (present in > 95% of patients), dry cough, relative bradycardia confusion, lymphopaenia hyponatraemia, deranged LFTs, pleural effusion: seen in around 30% of patients
- Diagnosis: urinary antigen
- Tx: erythromycin/clarithromycin
17
Q
Legionella vs Mycoplasma penumonia
A
- COMMON: atypical, fly like sx, dry cough, deranged LFTs, macrolide tx.
- MYCOPLASMA: haemolytic anaemia/ITP, erythema multiforme, encephalities/GBS, peri/myocarditis. Dx with serology
- LEGIONELLA: lymphopenia, hyponatremia, dx with urinary Ag
18
Q
Lyme disease: features
A
- Early features: erythema migrans small papule often at site of the tick bite -> larger annular lesion with central clearing, ‘bulls-eye’ 70% of patients.
- Systemic symptoms: malaise, fever, arthralgia
- Later features: CVS: heart block, myocarditis neurological: cranial nerve palsies, meningitis polyarthritis
19
Q
Bacillus anthracis
A
- Gram positive rod.
- Clinical fx: Painless black eschar, may cause marked oedema, can cause GI bleeding
- Tx: ciprofloxacin
20
Q
Enteric fever (typhoid/paratyphoid)
A
- Spread via F-O route.
- Aerobic, Gram-negative rods which are not normally present as commensals in the gut,
- Presentation: initially systemic upset as above relative bradycardia, abdominal pain, distension constipation:
- although Salmonella is a recognised cause of diarrhoea, constipation is more common in typhoid
- rose spots: present on the trunk in 40% of patients, and are more common in paratyphoid
- Complications: OM (especially in sickle cell disease where Salmonella is one of the most common pathogens), GI bleed/perforation, meningitis, cholecystitis, chronic carriage
21
Q
Schistosoma haematobium
A
- It commonly presents with terminal hematuria, due to bladder wall inflammation and ulcer, urinary calcifications, obstruction, and bladder cancer may eventually develop.
- “Swimmers itch” and Acute schistomiasis syndrome (Katayama fever)
22
Q
Strongyloides stercoralis
A
- The larvae are present in soil and gain access to the body by penetrating the skin.
- Infection with Strongyloides stercoralis causes strongyloidiasis.
- Features 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
- Treatment ivermectin and albendazole are used
23
Q
clostridium botulinum,
A
- Sx produced by botulinum toxin: afebrile, descending, flaccid paralysis.
- Features typically include difficulty speaking or slurred speech, blurred or double vision, and/or dysphagia.
- Other features of bulbar palsy include ptosis and facial muscle weakness.
- Without treatment, paralysis may progress to the upper limbs, trunk, lower limbs and respiratory muscles. The treatment of botulism - supportive care and botulism antitoxin.
- Clostridium botulinum is sensitive to benzylpenicillin, and therefore this is also administered in patients with abscess formation at the injection site.
24
Q
Acute schistomiasis syndrome
A
- Acute manifestations may include: swimmers’ itch acute
- schistosomiasis syndrome (Katayama fever) include: fever, urticaria/angioedema, arthralgia/myalgia, cough, diarrhoea,eosinophilia
25
Q
Chagas’ disease (Trypanosoma cruzi)
A
- American trypanosomiasis, 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.
- Cardiomyopathy is the most frequent and most severe manifestation of chronic Chagas’ disease
- GI features includes megaoesophagus and megacolon causing dysphagia and constipation
- Management: 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., cardiomyopathy
26
Q
African trypanosomiasis (sleeping sickness)
A
- Trypanosoma gambiense in West Africa and Trypanosoma rhodesiense in East Africa
- Clinical features include:
- Trypanosoma chancre - painless subcutaneous nodule at site of infection intermittent fever, enlargement of posterior cervical lymph nodes
- later: central nervous system involvement e.g. somnolence, headaches, mood changes, meningoencephalitis
- Management:
- early disease: IV pentamidine or suramin
- later disease or central nervous system involvement: IV melarsoprol
27
Q
Listeria monocytogenes
A
- Gram-positive bacillus which has the unusual ability to multiply at low temperatures.
- Spread via contaminated food, typically unpasteurised dairy products.
- Infection is particularly dangerous to the unborn child where it can lead to miscarriage.
- Management -> Listeria is sensitive to amoxicillin/ampicillin (cephalosporins usually inadequate)
- Listeria meningitis should be treated with IV amoxicillin/ampicillin and gentamicin
28
Q
Listeria monocytogenes in pregnant women
A
- Pregnant women are almost 20 times more likely to develop listeriosis compared with the rest of the population due to changes in the immune system
- fetal/neonatal infection can occur both transplacentally and vertically during child birth complications include miscarriage, premature labour, stillbirth and chorioamnionitis
- treatment is with amoxicillin
29
Q
Parovirus B19
A
- Erythema infectiosum (also known as fifth disease or ‘slapped-cheek syndrome’)
- they are no longer infectious by the time the rash occurs.
- virus can affect an unborn baby in the first 20 weeks of pregnancy.
- Infection in a pregnant woman can lead to fetal hydrops and spontaneous miscarriage, particularly in the first trimester.
- This can be managed with the use of fetal blood transfusion.
- Other presentations include:
- asymptomatic pancytopaenia in immunosuppressed patients aplastic crises e.g. in sickle-cell disease (parvovirus B19 suppresses erythropoiesis for about a week so aplastic anaemia is rare unless there is a chronic haemolytic anaemia)
30
Q
Hepatitis B
A
- dsDNA hepadnavirus spread through exposure to infected blood or body fluids - including vertical transmission.
- Incubation 6-20 weeks
-
Complications:
- chronic hepatitis (5-10%). ‘Ground-glass’ hepatocytes may be seen on light microscopy fulminant liver failure (1%) hepatocellular carcinoma, glomerulonephritis, polyarteritis nodosa, cryoglobulinaemia
35
Q
Active HBV infection
HBsAg =
HBeAg =
Anti HBc =
Anti HBs =
HBV DNA =
A
36
Q
Amoebiasis
- Cause
- Spread
- Risky occupation in the West
- Most common presentation
- Mx of the different forms
A
39
Q
Brucellosis
- Australian spp
- Main Aus RF
- Presentation
- Treatment
A
40
Q
Buzzword: Gram negative bacilli with safety pin appearance
- Bug and condition
- Initial therapy
- Follow up therapy
A
- Burkholderia pseudomallei (Melioidosis)
- Other buzzwords: North Australia/Asia pacific, alcoholics
- Tx as per eTG ->
- Followed by Bactrim (+Folate) for 3 month
- if can’t have Bactrim use doxycycline or Augmentin
41
Q
C. diff
- micro
- how it causes disease
- special strain - 4 features of it
- most important RF
A
42
Q
A
44
Q
Causes of eosinophilic meningitis
Role of prednisolone
A
46
Q
Variant Creutzfeldt Jakob Disease
A
47
Q
Haemolysis Test
A
48
Q
IRIS - Immune Reconstitution Inflammatory Syndrome
A
49
Q
Surveillance in HBV - who gets surveilled?
A
Also ATSI > 50
50
Q
Risk of HBV reactivation according to therapy
A
51
Q
Immunisation against HBV
HBsAg =
HBeAg =
AntiHBc =
AntiHBs =
HBV DNA =
A
52
Q
Empirical treatment of nosocomial meningitis
A
54
Q
Most common cause of viral encephalitis
A
56
Q
Markers of Severe Malaria
A
59
Q
Empirical therapy for febrile neutropenia
- when would you add Vancomycin
- when would you add anti-fungals
A
Consider gentamicin if concerns re resistance or critically unwell
Add vancomycin if fever persists > 48 hours
Add anti-fungal cover if fever persists > 96 hours
60
Q
Treatment of typhoid
A
65
Q
Phases of opportunistic infections among allogenic HCT recipients
A
67
Q
Stages of Hep B infection
- What are the 4 stages
- Which require treatment
A
68
Q
Ebola
- Region
- Incubation
- Management principles
A
69
Q
Treatment of C-diff
A
70
Q
Vaccines
A
74
Q
Dengue Warning Signs (7- Poor Prognostic Signs)
A
75
Q
Hospital Acquired Pneumonia
A
Definition - pneumonia in patient hsopitalised for > 48 hours
Pathogenesis - microaspiration of bacteria colonising oropharynx or upper GIT
RF - intubation, previous Abx use (for resistant organisms)
Pathogens - note atypicals rare:
- Aerobic GNB
- MRSA
- Resistant enterobacteriaceae
- Pseudomonas
- Acinteobacter
76
Q
Brucellosis
- Australian spp
- Main Aus RF
- Presentation
- Treatment
A
FERAL PIGS!
