Parasitic Diseases - Malaria, Schisosomiasis, Trpanosomiasis/Chagas disease, Amebiasis

Question 1

Schistosomiasis
-causative organism
-presentation
-investigations
-management

Answer 1

Parasitic flatworm living in freshwater snails

Acute infection
-swimmers itch
-fever, arthralgia, myalgia
-urticaria, angiodema => eosinophilia
-diarrhoea

Chronic infection - worms deposit egg clusters in bladder => inflammation and calcification
-frequency
-hematuria
-bladder calcification

Asymptomatic - schistosome AB
Symptomatic - urine/stool MCS for eggs

1 dose of praziquantel

Question 2

Malaria
-species causing infection
-protective factors
-investigations

Answer 2

Severe malaria - plasmodium falciparum (MOST COMMON)
Benign malaria - plasmodium vivax, ovale, malariae

Sickle cell
G6PD - high oxidative stress has antimalarial action

GOLD STANDARD - thick and thin blood films
FBC
-low PLT
-normochromic normocytic anemia
-normal WCC
-high retics

Question 3

Malaria falciparum
-presentation
-management

Answer 3

48hr cycle of fever + chills + sweating

GI - N+V, abdo pain, mild jaundice and itch
MSK - aches and pains
SPLENOMEGALY
Resp - cough
Neuro - headache

Severe features
-schizont on blood film
-parasitemia 2%+
-hypoglycemia
-acidosis
-HEMOLYTIC ANEMIA
-acute renal failure
-ARDS
-cerebral malaria
-DIC
-39C+

Uncomplicated - artemisin combination therapy (ACT)
Severe - IV artesunate

Question 4

Malaria - non-falciparum
-causes and location
-features
-treatment

Answer 4

General features - fever, headache, splenomegaly

Vivax + ovale - 48hrs
-have dormant stage in liver (hypnozoite) => may relapse
Malariae - 72hrs + nephrotic

ACT or chloroquine
-ACT should not be used in pregnancy
Ovale + vivax - primaquine should be given in addition to destroy liver hypnozoites

Question 5

Trypanosomiasis - African/Sleeping sickness
-cause and location
-presentation
-management

Answer 5

Trypanosoma gambiense - West Africa
Trypanosoma rhodesiense - East Africa

Spread by tsetse fly

Early disease
-trypanosoma chancre - painless SC nodule at infection site
-intermittent fever
-enlargement of posterior cervical LN

Late disease - CNS involvement
-sleepiness
-headache
-mood changes
-meningoencephalitis

Light microscopy of blood (thick and thin) or other fluid samples

Early - IV pentamdine/suramin
Late/CNS involvement - IV melarsoprol

Question 6

Trypanosomiasis - American/Chagas diseases
-cause and location
-presentation
-investigations
-management

Answer 6

Trypanosoma cruzi - majority of cases in Latin America

Acute phase - majority asymptomatic
-chagoma - red hardened lesion at insect bite site
-periorbital edema

Chronic phase
-myocarditis => dilated cardiomyopathy, arrythmias
-megaesophagus and megacolon => dysphagia, constipation

Acute - -azoles or nitroderivatives
Chronic - treat complications

Question 7

Amebiasis
-cause and location
-presentation
-investigations
-management

Answer 7

Entamoeba histolytica
Poor sanitation, crowded => fecal-oral spread
India, Indonesia, Mexico

CAN HAVE VERY LONG INCUBATION PERIOD

Dysentery - profuse bloody diarrhoea

Stool microscopy within 15mins/kept warm - trophozoites

Amebic liver abscess - fever + RUQ pain + systemic upset + hepatomegaly
-often in right liver lobe -supplied by portal vein
-anchovy sauce

Liver US
Serology

Management for both - PO metronidazole + luminal agent (diloxanide furoate)

Question 8

Chikingunya
-causative organism
-presentation
-investigations
-management

Answer 8

Aedes mosquito
Africa, Southeast Asia, Central and South America

Fever + JOINT PAIN + rash

Serum PCR

Symptomatic management