Infectious diseases for AMC MCQ

A 29 year old man presents with five days of high fever, shaking chills, drenching sweats, headache and muscle aches, two weeks after returning from a month in rural sub-Saharan Africa. He took no antimalarial prophylaxis. He is febrile with a palpable spleen but is alert and haemodynamically stable, and his thick and thin films show Plasmodium falciparum at a low parasite count. What is the most likely diagnosis?

1. Sepsis Fever and feeling very unwell from a different infection somewhere in the body. It does not fit the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs.
2. Amoebic liver abscess Fever and pain in the upper right side of the tummy after travel, from a liver infection. Here, the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs points elsewhere.
3. Malaria correct Correct. Fever with shaking chills and sweats in someone back from travel, with falciparum seen on the blood film, means malaria.
4. Influenza A feverish illness from a flu virus. But the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs does not point to it.
5. Viral hepatitis Fever with yellow skin (jaundice) and abnormal liver blood tests. That does not match the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs.

The point: Think of malaria in anyone with a fever who has come back from a country where malaria is common. The golden rule: fever after travel is malaria until you prove otherwise. Malaria is spread by mosquito bites, from tiny parasites called Plasmodium. Plasmodium falciparum is the dangerous type. It can cause severe illness and can kill fast. It usually shows up within a month of coming home. Two other types, Plasmodium vivax and ovale, can hide in the liver and cause fever again months later. The symptoms are not specific to malaria. There is fever, which may come and go in a pattern, with chills, shaking, sweats, headache and muscle aches. Some people also get diarrhoea or yellow skin (jaundice). On examination there may be just fever and a big spleen. To diagnose it, doctors look at a drop of blood under a microscope (a blood film) to see the parasite, its type, and how many there are. If the first film is clear, it is repeated up to three times, because malaria can still be there. A rapid test strip can help too. Severe falciparum malaria means one or more of these: confusion, shock, acid in the blood, low blood sugar, severe anaemia, kidney failure, fluid on the lungs, or a high parasite count. This is an emergency, treated with artesunate given through a drip. Malaria with no danger signs is treated with tablets, chosen by the type of parasite and local drug resistance. Vivax and ovale malaria need an extra tablet to clear the hiding parasites in the liver, but only after checking for a blood condition called G6PD deficiency, because the tablet can be unsafe without that check. To prevent malaria, avoid mosquito bites and take preventive tablets before travel.

Source: Therapeutic Guidelines (Australia) — Antibiotic: malaria Therapeutic Guidelines (Australia) · tier 3, national formulary

A 29 year old man presents with five days of high fever, shaking chills, drenching sweats, headache and muscle aches, two weeks after returning from a month in rural sub-Saharan Africa. He took no antimalarial prophylaxis. He is febrile with a palpable spleen but is alert and haemodynamically stable, and his thick and thin films show Plasmodium falciparum at a low parasite count. What is the most appropriate next step in management?

1. Appropriate oral regimen for uncomplicated malaria correct Correct. He is alert, his observations are stable, and the parasite count is low. This is malaria with no danger signs, so tablets are right.
2. Exclude co-infection and other travel illness Check for other infections picked up at the same time. That does not match the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs.
3. Liver-stage treatment for vivax and ovale after G6PD testing A tablet to clear hiding parasites from the liver, given only after checking G6PD, to stop the fever coming back. Here, the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs points elsewhere.
4. Admit and monitor falciparum malaria Keep the patient in hospital and watch closely in case they get worse. It does not fit the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs.
5. Bite avoidance and chemoprophylaxis advice for prevention Advice on avoiding bites and taking preventive tablets before the next trip. But the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs does not point to it.

The point: Think of malaria in anyone with a fever who has come back from a country where malaria is common. The golden rule: fever after travel is malaria until you prove otherwise. Malaria is spread by mosquito bites, from tiny parasites called Plasmodium. Plasmodium falciparum is the dangerous type. It can cause severe illness and can kill fast. It usually shows up within a month of coming home. Two other types, Plasmodium vivax and ovale, can hide in the liver and cause fever again months later. The symptoms are not specific to malaria. There is fever, which may come and go in a pattern, with chills, shaking, sweats, headache and muscle aches. Some people also get diarrhoea or yellow skin (jaundice). On examination there may be just fever and a big spleen. To diagnose it, doctors look at a drop of blood under a microscope (a blood film) to see the parasite, its type, and how many there are. If the first film is clear, it is repeated up to three times, because malaria can still be there. A rapid test strip can help too. Severe falciparum malaria means one or more of these: confusion, shock, acid in the blood, low blood sugar, severe anaemia, kidney failure, fluid on the lungs, or a high parasite count. This is an emergency, treated with artesunate given through a drip. Malaria with no danger signs is treated with tablets, chosen by the type of parasite and local drug resistance. Vivax and ovale malaria need an extra tablet to clear the hiding parasites in the liver, but only after checking for a blood condition called G6PD deficiency, because the tablet can be unsafe without that check. To prevent malaria, avoid mosquito bites and take preventive tablets before travel.

Source: Therapeutic Guidelines (Australia) — Antibiotic: malaria Therapeutic Guidelines (Australia) · tier 3, national formulary

A 29 year old man presents with five days of high fever, shaking chills, drenching sweats, headache and muscle aches, two weeks after returning from a month in rural sub-Saharan Africa. He took no antimalarial prophylaxis. He is febrile with a palpable spleen but is alert and haemodynamically stable, and his thick and thin films show Plasmodium falciparum at a low parasite count. What is the most likely complication?

1. Acute respiratory distress and pulmonary oedema Fluid on the lungs and severe breathing trouble in bad disease. It does not fit the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs.
2. Acute kidney injury Sudden kidney failure from severe malaria. Here, the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs points elsewhere.
3. Hypoglycaemia Low blood sugar from the infection itself or its treatment. But the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs does not point to it.
4. Cerebral malaria Confusion and fits from malaria affecting the brain. That does not match the picture of fever with shaking chills in someone back from travel, with a low falciparum count and no danger signs.
5. Severe anaemia correct Correct. The infection can break down red blood cells and cause severe anaemia, so this is watched for.

The point: Think of malaria in anyone with a fever who has come back from a country where malaria is common. The golden rule: fever after travel is malaria until you prove otherwise. Malaria is spread by mosquito bites, from tiny parasites called Plasmodium. Plasmodium falciparum is the dangerous type. It can cause severe illness and can kill fast. It usually shows up within a month of coming home. Two other types, Plasmodium vivax and ovale, can hide in the liver and cause fever again months later. The symptoms are not specific to malaria. There is fever, which may come and go in a pattern, with chills, shaking, sweats, headache and muscle aches. Some people also get diarrhoea or yellow skin (jaundice). On examination there may be just fever and a big spleen. To diagnose it, doctors look at a drop of blood under a microscope (a blood film) to see the parasite, its type, and how many there are. If the first film is clear, it is repeated up to three times, because malaria can still be there. A rapid test strip can help too. Severe falciparum malaria means one or more of these: confusion, shock, acid in the blood, low blood sugar, severe anaemia, kidney failure, fluid on the lungs, or a high parasite count. This is an emergency, treated with artesunate given through a drip. Malaria with no danger signs is treated with tablets, chosen by the type of parasite and local drug resistance. Vivax and ovale malaria need an extra tablet to clear the hiding parasites in the liver, but only after checking for a blood condition called G6PD deficiency, because the tablet can be unsafe without that check. To prevent malaria, avoid mosquito bites and take preventive tablets before travel.

Source: Therapeutic Guidelines (Australia) — Antibiotic: malaria Therapeutic Guidelines (Australia) · tier 3, national formulary