Travel conditions Flashcards
1
Q
Tests used in HIV diagnosis
A
A) Antibody test: antibodies against HIV
B) Antibody/antigen test: antibodies against HIV and HIV antigen (virus itself)
C) RNA/DNA test: screen for viral RNA -> detects virus directly & DNA -> copies of viral
RNA
• Antibody/antigen test is recommended for screening purposes -> better for identifying
early infection
• The other tests are recommended as confirmatory tests (as follow up after positive result
of antibody/antigen test)
2
Q
HIV diagnostic workout
A
3
Q
Aims of HIV management with anti-retroviral therapy
A
4
Q
What tests are involved in Dx of Malaria?
A
5
Q
Why it’s important to know % of RBCs infected by parasite? (in malaria)
A
% of RBCs infected by parasites is
important -> patients with >5% parasitemia can have worse outcome
6
Q
Common lab findings in malaria
A
Common lab findings:
- thrombocytopenia -> low platelet count
- elevated lactate levels -> due to hemolysis
- anaemia: normochromic (normal colour) and normocytic (normal size) BUT anaemia = low RBCs number
7
Q
Management algorithm in ‘suspected’ malaria case
A
8
Q
Types of malaria treatment (4)
A
- Suppressive treatment = Chemoprophylaxis is aimed to kill sporozoites before they infect hepatocytes -> given to travellers that go to endemic malaria countries
• Therapeutic treatment: to eliminate merozoites that are in erythrocytic phase -> given during active infection
- Gametocidal treatment - to kill gametocytes -> prevent spread of diseases
• Radical treatment - to kill hypnozoites in the liver (P. Vivax and P . Ovale infections)
9
Q
Name (2) agents used to treat malaria
A
chloroquine, quinine
10
Q
(2) options for malaria prevention - environmental
A
- to prevent mosquitoes from biting -> sprays, full body clothing, sleeping in the nets
- to remove containers with water -> as mosquitoes like to lay their eggs there (to control
mosquitoes population)
11
Q
What virus family causes Viral Haemorrhagic Fever?
A
Flaviviridae virus family
12
Q
What is the danger of viral haemorrhagic fever?
A
They can cause fever and bleeding disorders -> possible progression into shock and deaths
13
Q
Pathogenesis of viral haemorrhagic fever
A
14
Q
Symptoms of viral haemorrhagic fever
A
15
Q
What are general blood test findings in a person with viral hemorrhagic fever?
A
- decrease in total WBC (particularly in the lymphocytes)
- decrease in platelet count
- increase in blood serum liver enzymes
- reduced clotting ability -> measured as increased PT and PTT times
- hematocrit may be elevated
- urea and creatinine may be raised (depends on hydration status of the patient)
- prolonged bleeding time
16
Q
What is hematocrit?
A
*hematocrit - volume in % of RBCs; normally is around 47% (+/-5%) for men & 42% (+/- 5%) for women)
17
Q
management of viral hemorrhagic fever
A
- may require intensive support care
- antiviral therapy -> IV ribavirin (useful in some cases of VHF)
18
Q
Why do deaths usually occur in Ebola?
A
death occurs usually from low BP from fluid loss
- usually 6-16 days after the symptoms appear
- 50% of infected people die
19
Q
Simple pathology of Ebola
A
- Ebola virus enters the immune cells -> infects it -> inflammatory molecules are secreted from an infected cell -> inflammatory process starts; also virus replicated within the cell (as per normal viral mechanism -> hijacking the cell to make new viruses)
- inflammatory molecules -> damage to vascular integrity -> hemorrhagic fever
20
Q
Signs and symptoms of Ebola
A
Start usually 2 days - 3 weeks after contracting the virus
A. Early: fever, headache, muscle pain, sore throat (initially remains of a flu-like illness)
B. Later: vomiting, diarrhoea, rash and decreased renal and liver function *
* at later stage -> possible internal and external bleeding
21
Q
Complications of Ebola
A
- progression into disseminated intravascular coagulation (DIC) -> presents as low platelet count and elevated D-dimer
- diffuse /rozproszony/ haemorrhage -> shock
- multi-organ dysfunction
- renal and hepatic dysfunction -> elevated creatinie and liver enzymes
22
Q
How to make a diagnosis of Ebola from the results?
A
A. History, S&S
B. Decreased WBC -> then elevated WBC
C. D-Dimer -> elevated
D. platelet count decreased (DIC)
E. Prolonged PT and PTT (due DIC)
F. Liver enzymes -> elevated (hepatic dysfunction)
G. Urea and creatinine -> elevated (renal dysfunction)
E.ELISA (antigen recognition test) and PCR
23
Q
IgM and IgG detection in Ebola (timeframes)
A
- IgM detected 2 days after symptom onset
- IgG antibodies 6- 18 days after symptom onset
24
Q
Management of a patient with Ebola
A
* prevention measures (washes,disinfection, contact tracing, isolation, protective equipment, safe disposal, safe burial etc.)
- Supportive care as no specific treatments are available
- No licensed vaccine or anti-Ebola products developed
Supportive:
- Rehydration via oral or IV route
- analgesia
- nausea, fever and anxiety treatments
- blood products (fresh frozen plasma, RBCs, platelets)
- Heparin -> in effort to prevent DIC
- Clotting factors -> to decrease haemorrhage
Intensive care in developed worlds: maintaining blood volume and electrolytes (salt) balance, treating any bacterial infections that may develop
25
What meds and why to avoid in Ebola
\*avoid ***ibuprofen*** or ***aspirin*** -\> as risk of bleeding
26
How to distinguish Dengue from Ebola?
They are both types of viral haemorrhagic fever
distinction from Ebola: no renal/hepatic failure, no DIC
27
WHat virus causes Dengue?
mosquito-borne, tropical disease -\> caused by ***dengue virus*** (enveloped, single stranded, positive sense, RNA virus)
28
Symptoms of Dengue infection
\*start 3 - 14 days after infection
High fever, headache, vomiting, muscle and joint pain, characteristic skin rash
29
What's prognosis in Dengue?
* Recovery usually takes \<2 - 7 days
* Complication (in small proportion of cases), potentially fatal:
A. Dengue hemorrhagic fever -\> bleeding, low platelet count, blood plasma leakage
B. Dengue shock -\> extremely low BP
30
Diagnosis of Dengue
Diagnosis made on basis of S&S and physical examination -\> however early manifestationsare difficult to be differentiated from other viral diseases/infections
Number of different tests available for diagnosis:
- detection of antibodies to the virus
- detection of viral RNA
31
Management of Dengue
No specific anti-viral drug is available
Rx depends on a status of a person:
* those whose hydration status is OK (drinking and passing urine) and are otherwise healthy (no warning signs) -\> can be managed at home with daily follow-up and oral rehydration therapy
* patients with hydration and other health problems -\> need to be hospitalised for a regular follow up
A. Preventative: vaccine available, reduction mosquito habitat, limitation of exposure to bites
B. Acute dengue fever -\> supportive treatment:
- fluids (oral or IV) - mild to moderate disease
- blood transfusion - for severe forms of disease (if haematocrit is decreasing and vital signs are unstable)
32
What to avoid in pt with Dengue?
To avoid:
- invasive medical procedures e.g. NG tube, IM injections etc -\> as risk of bleeding
- Do not use NSAIDs as they may increase risk of bleeding
\*use Paracetamol (acetaminophren) instead (for fever and pain relief)
33
What's atypical pneumonia?
***Atypical pneumonia*** aka *walking pneumonia*
- pneumonia that is not caused by one of commonly pneumonia causing organisms
- different clinical presentation to that of a typical pneumonia
34
Difference between typical vs atypical pneumonia
- antibiotics used to Rx
- appearance on X ray
35
Difference between typical vs atypical pneumonia
- clinical presentation
36
Cause of ***Ameobic Abscess***
* liver abscess caused by amebiasis -\> as liver tissue is involved in the infection by thropozoites of ***Entamoeb histolytica*** -\> abscess due to necrosis
37
Symptoms and signs of amoebic abscess
_Symptoms:_
- pain in R hypochondriac area (referred to R shoulder)
- pyrexia
- sweating and rigors
- loss of weight
- earthy complexion - patchy pigmentation of the face
_Signs:_
- pallor
- tenderness in R hypochondriac area
- palpable liver
- intercostal tenderness
- basal lung signs
38
Management of amoebic abscess
A.Abscess aspiration
B.Repeated liver imaging
C.***Metronidazole*** - antibiotic and antiprotozoal medication
39
What is the cause of ***Leptospirosis***?
- how is it spread
- who is at risk
Caused by a bacteria called ***Leptospira***
- spread by wild and domestic animals (rodents e.g. rats, mice, hamsters, squirrels)
\*in developing world - farmers and low-income people living in the cities and slums
\* in the developed world - outdoor activities in warm and wet areas
40
Signs and symptoms of ***leptospirosis***
_S&S may range from:_
A) none to mild: headaches, muscle pains, fevers
B) severe: bleeding from the lungs or meningitis
41
(2) serious complications of Leptospirosis
* Weil’s disease -\> when a person infected with leptospira turns yellow, have kidney failure and bleeding (death rate \>10%)
* Severe pulmonary haemorrhage syndrome -\> bleeding into the lungs (death rate \>50%)
42
Diagnosis/Ix of *Leptospirosis*
Early diagnosis - test blood and urine:
- blood and CSF -\> infection can be found within first 10 days
- after 10 days -\> infection moves to kidney -\> can be found in fresh urine
- U&Es and LFTs, creatinine and nitrogen
- enzyme- linked immunosorbent assay (ELISA) and PCR -\> confirm diagnosis
- MAT (microscopic agglutination test) -\> gold standard in diagnosis of leptospirosis
43
Occupations at risk of Leptospirosis
_Occupations at risk_: vets, slaughterhouse workers, farmers, sailors, waste disposal
workers
_Adventure tourism_: kayakers, rowers, canoeists
44
Treatment of Leptospirosis
A. Usually effective antibiotics - *Penicillin G, ampicillin, amoxicillin, deoxycline*
B. More severe cases: cefotaxime or ceftriaxone
C. Glucose and salt infusions
D. Dialysis - if kidney affected severly
E. Measure potassium (as elevation is common)
45
Cause of *Schistosomiasis*
*Schistosomiasis* aka ‘snail fever’
* disease caused by parasitc flatworms (schistosomes)
* Parasites infect fresh water snails
46
***Schistosomiasis***
- site of infection
- long- term complications
* Sites of infection: urinary tract or intestine
* long time infection may result in: liver damage, kidney failure, bladder cancer, infertility
47
Risk groups of schistosomiasis
* Disease is particularly common among children in developing countries -\> as they play a lot in fresh water (water is contaminated with shistosomes)
* farmers, fishermen, people using unclean water
48
Symptoms of ***schistosomiasis***
**Symptoms**: abdominal pain, diarrhoea, bloody stool, blood in the urine
**Children**: poor growth and learning difficulties
49
Dx / Ix of schistosomiasis
- finding eggs of the parasite in a person’s urine or stool
- finding antibodies against the disease in the blood
50
Prevention of Schistosomiasis
- improving access to clean water
- reduction of water snail population
- meds ***Praziquantel*** (drug against some parasites) given once yearly to the populations at risk
51
Treatment of *Schistosomiasis*
All cases of schistosomiasis should be treated regardless of presentation -\> as parasite can live in host for years
Preferably use ***Praziquantel*** (drug against some parasites) and combination of other
drugs (mostly these used to treat malaria as anti-parasitic activity)
52
**Exotoxin** mechanism of diarrhoea + bacteria causing it
* ***exotoxins*** -\> effect on the stomach, small bowel -\> mucosal inflammation symptoms of food poisoning (*Bacillus Cereus* and *Staphylococus Aureus*)
53
***Enterotoxin*** mechanism of diarrhoea + bacteria causing it
**enterotoxins** -\> watery diarrhoea without fever *(E. Coli*) - usually no blood or mucous
54
***Enteroinvasive*** mechanism of diarrhoea + bacteria causing it
***enteroinvasive*** -\> invade intestinal mucosa (*Enteroinvasive E. Coli, Shigella and Campylobacter*) -\> fewer, lower abdominal pain, bleeding diarrhoea + fever (dysentery)
55
Possible complications of diarrhoea
electrolyte imbalances, renal impairment, dehydration, defective immune responses, inefficiency of administrated drug -\> as medication travels too quickly through digestive tract
56
Medical management of diarrhoea
* Oral rehydration therapy -\> slightly sweetened and salty water -\> used to prevent dehydration; it can be given via NG tube; usually include zinc
supplementation
* Medication: antibiotics used only in certain cases of diarrhoea (bacterial) - \> beneficial in resource poor countries; antibiotics may contribute to diarrhoea
**Other medications** (used only if the bloody diarrhoea is not present):
* ***Bismuth compounds*** (Pepto-Bismol) -\> decreases number of bowel movements in traveler’s diarrhoea but do not decrease length of illness
* ***Loperamide*** -\> anti motility agent -\> to reduce number of stools but again, not the illness duration
* **Bile acid sequestrants** (bile reabsorption prevented from the gut) -\> for those with chronic diarrhoea due to bile acid malabsorption
* **Zinc supplementation** -\> beneficial for children over 6 months old
* **Probiotics** -\> reduce duration of symptoms by one day + reduce chance of symptoms lasting longer than 4 days (by 60%)
57
Diet recommendation in diarrhoea
* Fluid and food: Replacing lost fluids (usually by oral rehydration therapy), in severe cases IV
* diet restrictions are not recommended (even for babies and children; including those breast fed) -\> as nutrient is usually still absorbed and support children with growth and also eating as usual has an effect on speed up of recovery as support normal intestinal functioning; limitation of food has no effect on duration of diarrhoea
58
**Antibiotic-associated diarrhoea**
- common bacteria
- severe form (names )
- age groups at risk
- when develops
* bacterial overgrowth with ***C. Difficile***
* severe -\> can lead to ***acute colitis/ pseudomembranous colitis***
* common in young and elderly
* diarrhoea develops 2 days - 4 weeks after taking antibiotics
59
Risk factors for C Diff infection
_Risk factors:_ Prolonged hospital stay, multiple or prolonged antibiotic therapy, GI surgery, proton pump inhibitor use
60
Ix and what can be seen in ***C Diff***
* detection of C.Diff toxins (in stool by enzyme-linked immunosorbent assay ELISA)
* stool culture -\> C diff isolation (in 30%)
* sigmoidoscopy -\> ulceration and a white pseudomembrane
61
Management of C Diff infection
- antibiotics should be stopped
- to treat dehydration (oral, IV fluids)
- infection control measures) -\> barrier nursing and hand washing
- antibiotics against C.Diff (***metronizadole*** or oral vancomycin) should be started following a diagnosis
- more severe in the elderly -\> colectomy may be required for toxic megacolon
