Tropical Medicine Course At Cu Som

Front 1

What is another name for onchocerciasis?

Back 1

River Blindness

Front 2

What is the causative agent of onchocerciasis? What type of organism is it?

Back 2

Onchocerca volvulus, a filarial nematode

Front 3

Name the vector for onchocerciasis.

Back 3

the black fly (Simulium sp.)

Front 4

What are the top two causes of infectious blindness?

Back 4

(1) Trachoma (C. trachomatis)
(2) Onchocerciasis

Front 5

What are the clinical manifestations of onchocerciasis?

Back 5

Possibly no symptoms. Skin rash (usually itchy), eye disease, and nodules under the skin. The most serious is lesions in the eye that can lead to visual impairment and blindness.

Front 6

What is the medication to prevent onchocerciasis?

Back 6

Trick question. No such medication exists.

Front 7

How soon after infection will a pt have symptoms of onchocerciasis?

Back 7

It can take up to one year for the larvae (also called microfilariae) to develop into an adult inside the human body and between 10 and 20 months before larvae can be found in the skin. Each adult female worm, which can live from 10-15 years, can produce millions of larvae during her lifetime. As it is the larvae that cause most of the symptoms of onchocerciasis, most people feel well until after the adults start producing large numbers of new larvae.

Front 8

How is Onchocerciasis diagnosed?

Back 8

• The most common method of diagnosis is the skin snip. A 1- to 2- mg shaving or biopsy of the skin is done to identify larvae, which emerge from the skin when it is put in physiologic solutions (e.g. normal saline). Typically 6 snips are taken from different areas of the body. Polymerase chain reaction (PCR) of the skin can allow for diagnosis if the larvae are not visualized.
• In patients with nodules in the skin, the nodule can be surgical removed and examined for adult worms.
• Infections in the eye can be diagnosed with a slit-lamp examination of the anterior part of the eye where the larvae or the lesions they cause are visible.
• Mazzotti test - A test for onchocerciasis using an oral test dose of diethylcarbamazine (50 or 100 mg), resulting in the appearance of an acute rash in 2 to 24 hours from death of microfilariae in the skin. Not necessarily well tolerated by patients. Considered a reaction by many, rather than a test.

Front 9

What is the treatment for onchocerciasis?

Back 9

There are treatments, such as ivermectin, available to kill the larvae in your body and thus prevent the symptoms of the disease, such as skin rash and blindness. Needs to be repeated every 6-12 months for 10+ years. Promising treatments, such as doxycycline, to kill the adult worms are currently being studied.

Front 10

What are the causative agents of filariasis?

Back 10

Three nematodes species
Wuchereria bancrofti, Brugia malayi, and Brugia timori.

Front 11

What is the vector for filariasis (lymphatic filariasis)?

Back 11

Multiple species of mosquito

Front 12

Describe the pathology of lymphatic filariasis.

Back 12

People get lymphatic filariasis from the bite of an infected mosquito. The microscopic worms pass from the mosquito through the skin, and travel to the lymph vessels. In the lymph vessels they grow into adults. An adult worm lives for about 5-7 years. The adult worms mate and release millions of microscopic worms, called microfilariae, into the blood. As these worms mature the cause blockage of the lymphatics. This leads to lymphedema and difficulty fighting infections.
Other symptoms include thickening of the skin (elephantiasis.)

People with the worms in their blood can give the infection to others through mosquitoes.

Front 13

What is Tropical Pulmonary Eosinophilia?

Back 13

It is a syndrome associated with filariasis and presents like asthma. Signs include high IgE, eosinophilia, abnormal CXR.

Front 14

How is lymphatic filariasis diagnosed?

Back 14

Blood microscopic examination from nocturnal blood draws (10p-2a.)

Serum Antigen test may be more useful (cards available for use in the field.)

Ultrasound – “Filarial Dance Sign”

Front 15

What is the treatment for lymphatic filariasis?

Back 15

DEC (diethylcarbamazine citrate) – Kills microfilariae and “damages” adults
Ivermectin – Kills microfilariae but not adult worms.
Albendazole – Affects adults but not microfilariae
Doxycycline – For co-infection with Wolbachia bacteria
Combos of meds a good idea with particular recommendations.
Surgery for hydrocele and lymphedema

Front 16

What is infectious agent of Chagas disease?

Back 16

Trypanosomiasis cruzi

Front 17

What is the vector of the Chagas disease?

Back 17

riduviid bug (aka kissing bug, a triatomine insect.)

Front 18

What is the mode of transmission of Chagas Disease?

Back 18

Elimination/defecation by the bug and then inoculation by person scratching the skin.

Front 19

What are the most common complications of Chagas disease (chronic phase)?

Back 19

Cardiac complications, which can include an enlarged heart (cardiomyopathy), heart failure, altered heart rate or rhythm, and cardiac arrest (sudden death); and/or
Intestinal complications, which can include an enlarged esophagus (megaesophagus) or colon (megacolon) and can lead to difficulties with eating or with passing stool.

Front 20

How is Chagas disease diagnosed?

Back 20

(1) Detection of parasite in wet prep/blood smear (during acute phase)
OR
(2) • apply two or more tests that use different techniques and/or that detect antibodies to different antigens (i.e., ELISA and IFA)

Front 21

Name 2 drugs that are used to treat Chagas Disease.

Back 21

nifurtimox
benznidazole
(Neither are FDA approved.)
• Efficacy of these drugs is on the order of 50-70%

Front 22

Name the infectious agent of ascariasis.
What type of organism is it?

Back 22

Ascaris Lumbricoides
Soil transmitted helminths (a nematode in this case.)

Front 23

Describe the life cycle in brief of Ascariasis.

Back 23

Ingest eggs, they mature in GI tract and excrete eggs, they invade intestines, migrate to lungs, migrate up repsiratory tract over epiglottis, and repeat cycle.

Front 24

How is Ascariasis diagnosed?

Back 24

Stool O&P

Front 25

What is the treatment of ascariasis?

Back 25

Albendazole
Mebendazole

Front 26

What family of viruses does influenza belong to? Describe its genome (i.e ss vs ds, RNA vs DNA)

Back 26

Orthomyxoviridae
ssRNA

Front 27

Name two different important surface porteins important with influenza.

Back 27

Hemagglutinins (15 different known)
Neuraminidases (9 different known)
These are the 2 proteins used to name flu viruses (i.e. H1N1)

Front 28

Which types of flu are more likely to cause epidemic or pandemic (Influenza A or B)?

Back 28

Influenza A

Front 29

Why are children more likely to spread the flu?

Back 29

Children have higher influenza titers and shed more virus.

Front 30

In what area of the world does influenza occur year round

Back 30

SE asia

Front 31

How is a pandemic defined?

Back 31

3 criteria

Front 32

Name and describe two types of medicines that can be used to treat the flu.

Back 32

Adamantanes derivatives –
o Amantidine, rimantidine, etc. – interferes with M2 ion channel

Neuraminidase inhibitors
o Tamiflu (oseltamivir), Relenza (zanamivir)
o effective against both A & B
o Reminder: Neuraminidase – Important for cell escape

Front 33

Name the two types of influenza vaccines.

Back 33

Trivalent Inactivated Vaccine (TIV)
Live Attenuated Influenza vaccine (LAIV)

Front 34

Why is H5N1 so worrisome? In other words, why is it a potential for pandemic?

Back 34

Mutates and reassorts
Poosibly incorporate genes from other animal species
Severe disease in humans (50% fatality rate)
Surviving birds secrete virus for > 10 days
Person to person spread documented

Front 35

What is Reye Syndrome?

Back 35

Reye Syndrome – Associated with influenza and ASA use (or other salicylates as in peptobismol)
The disease causes fatty liver with minimal inflammation and severe encephalopathy (with swelling of the brain).

Front 36

Approximately how many people in the world have TB infection?

Back 36

~2 Billion

Front 37

Which class of medicine can lead to delay in Dx of TB?

Back 37

Fluoroquionlones lead to improvement in symptoms. Can lead to misdiagnosis if patient is presumed to have pna, uti, or other disease.

Front 38

Name risk factors for TB infection

Back 38

Born or lived in areas where TB is common
Close contact to persons with TB
Elderly US Born (>70 y.o.)

Front 39

Name some major risk factors for progression of TB.

Back 39

Risk factors for progression
HIV infection
Fibrotic CXR c/w prior TB
Diabetes
CRF (Chronic Renal Failure
Other immunosuppression (transplant, TNF-a inhibitors)
Leukemia, lymphoma
Others

Front 40

Briefly describe the TB pathogenesis.

Back 40

1. Droplet nuclei conaintin teubercle bacilli are inhaled, enter lungs, and travel to alveoli.
2. Tubercle Bacilli gets into lymphatics
3. Small number of tubercle bacilli enter bloodstream and spread throughout the body (frequently get trapped in granulomas.)

Front 41

A few of important acronyms:
PPD
TST
IGRA
BCG

Back 41

PPD = Purified Protein Derivative
TST = Tuberculin Skin Test
These are the same thing.

IGRA - Interferon Gamma Release Assay
BCG - Bacillus Calmette-Guérin

Front 42

Tests for TB infections?

Back 42

TST 70% sens
IGRA 85-90%sens
Sputum smear/culture - 50%sensitive

Front 43

Name the 2 types of IGRA?

Back 43

T-Spot and Quantiferon

Front 44

What is the HAIN Assay or Cepheid Gene Xpert?

Back 44

Tests for MDR TB.
Does require a specialized lab.
Not FDA approved tests.

Front 45

What are first line therpy for TB?

Back 45

INH, Rifampin
Pyrazinamide,
Ethambutol

Front 46

Side effect of Rifampin?

Back 46

P450 inducer
need to ask about other meds

Front 47

Side effects of Pyrazinamide?

Back 47

GI upset, rash, hepatitis, flare ups for gout pts.

Front 48

Describe 2 phases of TB treatment.

Back 48

Intensive phase - 4 drugs for 2 months, 1st 2-3 wks at home in isoation

Continuation phase - INH + Rifampin x4 more months

Front 49

Risk factors for TB relapse after treatment.

Back 49

Presence of cavitary TB
Positive culture at 2 months.
HIV infection.

Front 50

Define MDR TB vs XDR TB.

Back 50

MDR - Resistant INH + Rifampin
XDR - Resistant INH, Rifampin, + flouroquinolones and at least one second line injectable med (amikacin, kanamycin, or capreomycin)

Front 51

Name 4 ortho emergencies to consider in the developing world.

Back 51

Compartment Syndrome
Dislocations
Open Fractures
Septic Joints?

Front 52

Name some important ortho infections in the developing world.

Back 52

Osteomyelitis (chronic)
Pyomyositis (muscle abscess)
Septic Arthritis
Polio Residuals

Front 53

Name some important pediatric ortho conditions

Back 53

Club feet
Scoliosis
SCFE/Legg-Calves-Perthes
Hip Dysplasia

Front 54

What is the Ponsetti Project.

Back 54

Closed method of treatment for club feet.