On last Thursday’s episode of Grey’s Anatomy (titled “Poker Face”), new mom Mary has a brain tumor called “butterfly tumor” (or Astrocytoma) and only 6 months left to live. Meredith thinks differently and tries to change the course of Mary’s disease.

Danger Level: High

What is it?

Astrocytoma is a type of brain tumor which tends to spread inside the brain ignoring anatomical borders. That causes it to be present on both sides of the brain (and sometimes look life a butterfly – hence the name).

Who gets it?

Astrocytomas are rare – in the United States, every year there are 5.4 new cases per 100,000 people. They are a little more common in men, and most cases appear around ages 20-45.

What causes it?

Astrocytes are star-shaped brain cells located between nerve cells (astro=star, cyte=cell). They are actually part of a larger group of cells in the brain called glia cells – which support the nerve cells and glue them together.

Photo by Neurorocker

When astrocytes start dividing without control, they create a tumor called astrocytoma. These tumors come in different grades (1 to 4) – low grade tumors are slow-growing while high-grade tumors can be very aggressive (on the Grey’s Anatomy episode, Mary had a grade-4 tumor which is the most aggressive type).

The reason for astrocytoma is unknown, but scientists have found that it can be related to radiation to the head at young age, and there are several genes that are also related to this tumor.

How does it feel?

The symptoms of astrocytoma are related to its location – almost any neurological symptom is possible, including changes in mental status, seizures, and movement or sensory problems. These symptoms appear because the tumor puts pressure on brain tissue or ruins it while growing. Symptoms like these are called focal neurological symptoms.

Besides that, astrocytoma (and any other brain tumor) can increase the pressure inside the skull (called intra-cranial pressure) – this causes symptoms like headaches, nausea and vomiting as well as decreased alertness.

How is it discovered?

When someone comes to the doctor with the symptoms described above, the doctor will order a scan – a CT or an MRI (MRI is the best option). Sometimes doctors can guess the type of the tumor according to the way it looks on MRI – but final diagnosis can be made only when checking the tumor under a microscope after it’s removed in surgery.

This is a part of a brain with a grade 4 astrocytoma which spread to both sides of the brain.

How is it treated?

Aggressive astyrocytomas are treated with surgery to remove the tumor, radiation and chemotherapy. Steroids sometimes help with the symptoms, and so do anti-epileptic drugs (for patients with seizures).

What happens after treatment?

Even with treatment, astrocytoma can be deadly. Patients with low-grade tumors can survive for an average of 6-8 years, but with high-grade aggressive disease, average survival is less that 1 year.

The story of Jodi Fenton who recovered from grade-3 astrocytoma

The bottom line – how do I avoid it

Unfortunately, there is no known way to avoid astrocytoma.

Related posts:

1. As Seen on Grey’s Anatomy – Tay-Sachs Disease – Fat Accumulating in The Brain
2. Nesidioblastoma – A Tumor of the Pancreas That Can Secrete Hormones (As Seen on House MD)
3. As Seen on Grey’s Anatomy – Normal Pressure Hydrocephalus (NPH)

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!) On episode 1 of season 7 (named “Now What”), the hospital’s only neurosurgeon, Dr. Richardson, has a severe nausea which doesn’t respond to strong anti-nausea drugs. The team treats him with stronger medications for his nausea – it passes but he starts to hallucinate and behave oddly. At first, the team thinks his behavior is a side effect of the drugs they gave him and test for a bunch of diseases like hepatitis and peptic ulcer. Only when they start to think of his behavior as a new symptom, and after they find out he was at a sea-food festival several days before, they diagnose him with toad egg poisoning

[Photo from episode]

Photo by Fox

Danger Level: High

What is it?

The poison in toad eggs is the venom of the Cane Toad. The venom is usually located in the salivary glands of the frog and on the skin, and rarely it can also pass to the eggs. The toad venom is also used in Chinese medications, so consuming these medications might also cause poisoning: it is the main ingredient in a medicine called Chan-Su which is used mostly as a topical aphrodisiac (and was banned from the Uniter States after four men died after trying to swallow it), and is also an ingredient of Kyushin, which is used in Chinese medicine to treat heart problems.

What causes it?

The toad poison contains a substance called Bufotenin, which is very similar to a cardiac medication called Digoxin (used to treat heart failure and certain abnormal heart rhythms). Digoxin can be toxic in high doses, and the toad venom causes symptoms similar to an overdose.

How does it feel?

The venom of the toad causes several symptoms:

• Nausea with vomiting and possible abdominal pain.
• Cardiac symptoms – mostly problems with the heart rate (which are called arrhythmias), which can be deadly. You might feel heart palpitations.
• Mental symptoms, such as hallucinations. The cane toad is also known as the “hallucinogenic toad” – licking its skin can cause hallucinations which last for about an hour. However, mental symptoms are less described in toad venom poisoning.

Photo by Doug Greenberg

How is it discovered?

The doctors will suspect this if there is a story of eating certain foods such as toad soup, toad cake or toad eggs, or if the patient uses one of the Chinese medications mentioned above. They will test your blood for potassium levels (if it’s high – this is usually a bad sign, since it may cause the heart rhythm problems mentioned above) and for the level of Digoxin (this test can also identify the poison). They will also do an ECG to look for problems with the heart rate.

How is it treated?

There is an antibody for Digoxin which can be used to treat toad venom poisoning as well and has been proved to save lives. Besides that, the treatment focuses on stopping the symptoms.

The bottom line – how do I avoid it?

It’s important to be aware of the possibility of poisoning, and seek medical help if you start feeling nausea or have heart palpitations after eating foods which contain toad. Also, avoid topical aphrodisiacs containing Chan-Su, which are marketed as “Rockhard”, “Love Stone”, or “chan su” – and are forbidden to import to the United States.

Related posts:

1. Radiation Poisoning– What it Can Do To You (As Seen on House MD)
2. Organophosphate Poisoning – Getting Poisoned by Pesticides (As Seen on House MD)
3. Naphthalene Poisoning – When Mothballs Kill More Than Just Moths (As Seen on House MD)

This week, more than 1,000 people got sick and 16 died in an outbreak of HUS – a disease related to the bacteria E. coli. Initially cucumbers imported from Spain were blamed to be contaminated with the bacteria, but today this theory was proved wrong, and the source of the infection remains a mystery. What exactly is HUS, and what can you do to avoid it?

Initially, Germans have been warned not to eat cucumbers. (Photo by kobiz7)

Danger Level: High

What is it?

Hemolytic Uremic Syndrome (HUS) is a disease that causes anemia, renal failure and a low platelet count in the blood.

Who gets it?

Most cases of HUS develop in young children, but it can certainly happen in adolescents and adults as well.

It can affect men and women alike.

It’s usually not very common, occurring to 0.5-2 people out of 100,000 in the US per year.

What causes it?

The most common cause for HUS is infection with E. Coli bacteria. E. coli (or by its full name, Escherichia coli) is actually a large group of germs, some of them live in the intestines of healthy people. The type of E. coli which causes HUS is a violent type, which produces a toxin called Shiga-Like Toxin. The toxin is absorbed to the blood through the intestines, and damages the cells that create the most internal layer of blood vessels – especially in the kidney but also in other organs. This damage causes all the symptoms of HUS.

You can get infected with this type of E. coli by eating contaminated and undercooked meat or produce, drinking unpasteurized contaminated milk or swimming in contaminated pools and lakes. It can also be transferred by contact with infected people, for example – in day-cares.

E. coli (Photo by Phil Moyer)

There are other not-common causes for HUS, including:

• Other infections: Some other bacterial and viral infections can also cause HUS, but this is much less common.
• Medications: Several medications can (rarely) cause HUS, including birth control pills, some chemotherapy drugs and cyclosporine – which is used to suppress the immune system (for example after an organ transplant).
• Other diseases: Systemic Lupus Erythematosus (SLE), Preeclampsia and inflammation in the kidneys after radiation treatments.
• Some cases are genetic.

How does it feel?

1. Food Poisoning: The first symptoms are food-poisoning symptoms caused by the E. coli bacteria themselves. This can include abdominal pain, a fever, vomiting and diarrhea which usually becomes bloody at some point. these symptoms appear 5-10 days before all the other symptoms.
2. Anemia: This causes the sick person to look pale and be pretty tired, weak and irritable.
3. Bleeding: There might be external bleeding (from the nose of mouth) or bleeding under the skin, which looks like small unexplained bruises. this is caused by a low number of platelets, which are the cells in our body responsible for blood clots.
4. Kidney Failure: Can cause the body to produce less urine.

The story of 16-year-old Aly, who recovered from HUS

How is it discovered?

When suspecting HUS, the doctors will draw some blood. They will check several things: Complete Blood Count will let them know if there is anemia or low platelets, and kidney function tests will determine if there is kidney failure. They will also look at the blood under a microscope. Other tests that might be needed are a urine test (to look for blood in the urine) and a stool sample (to look for the germs).

How is it treated?

The treatment is given in the hospital, and the goal is to relieve the symptoms:

• The most important part of the treatment is dialysis treatments until the kidneys start working again. If the disease is diagnosed early enough, dialysis might not be needed. The doctors can save the kidneys from failing by giving a lot of fluids.
• The anemia is treated with blood transfusions, and the bleeding problems with platelet transfusions.
• Another possible treatment is plasma-exchange (also called plasmapheresis) – in which blood is removed from the body and blood from a donor is returned back. This is used to remove elements that cause the disease from the blood.

Although the cause is an infection, antibiotics are not part of the treatment.

Dialysis treatment.

What happens after treatment?

In most cases (about 90%, and especially in children), if the disease is discovered early enough and treated correctly, the patient recovers. The other 10% might die or remain with chronic kidney failure which will require dialysis treatments for the rest of their life or a kidney transplant. Some of the people who recover will develop kidney problems or hypertension later in life.

The bottom line – how do I avoid it?

The best way to avoid HUS is to avoid food-poisoning with E. coli – this can be done in several ways:

• Treating foods carefully: You should wash hands often when cooking, keep meat in the refrigerator or freezer, wash fruit and vegetables under running water, cook meat thoroughly without leaving pink areas (if you have a thermometer for cooking, cook to a temperature of at least 160°F [70°C]).
• Avoiding certain foods: Especially undercooked meat, unpasteurized milk and cider. Drink only clean water. Remember that the contaminated food will not necessarily look spoiled of taste bad.
• Avoid swimming in dirty lakes and pools.
• If you have diarrhea – wash hands often.

Related posts:

1. Everything You Need To Know About Fast Food – An Infographic
2. In the News – Hodgkin’s Disease
3. Naphthalene Poisoning – When Mothballs Kill More Than Just Moths (As Seen on House MD)

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)
On episode 23 of season 7 (the season finale, named “Moving On”), Afsoun Hamidi, a performance artist, collapses during filming one of her projects. Later she has pancreatitis, something resembling a tumor in her brain, and a skin rash. Biopsy of the rash reveals that her symptoms are related to a condition called Wegener’s granulomatosis.

Photo by NBCUniversal

Danger level: High

What is it?

Wegener’s Granulomatosis (WG for short) is an inflammation of blood vessels, restricting blood flow to various organs in the body.

Who gets it?

WG is quite rare. In the United States, for example, it’s estimated that about 3 out of every 100,000 people are sick with it. It’s more common in people of Northern European origins, and is less common in black people. It can occur in any age, but is most common in middle age (the average age when it appears is around 40). Men and women are affected equally.

What causes it?

In WG there is an inflammation of blood vessels in the body, meaning it’s a vasculitis (the medical term for inflammation of blood vessels. There are other diseases in this group – such as temporal arteritis and kawasaki, which we covered before).

Our blood vessels generally come in 3 sizes, much like clothing. Small, medium and large. WG is an inflammation of small and medium sized blood vessels.

It happens because the body actually attacks its own blood vessels. The process isn’t completely understood, but probably involves a change in the body’s immune system which triggers the body destroying its own blood vessels.

WG tends to affect mostly 3 systems in the body: The upper airways, the kidney, and the lungs. They are affected since the arteries that supply them with blood are damaged in the disease.

How does it feel?

There are some general symptoms in WG which include loss of appetite, fever, fatigue, and even weight loss.

Usually the first specific symptoms involve the upper airways and can include nosebleeds, nasal congestion, collapse of the bridge of the nose (causing a deformity called saddle nose, seen in this picture), a hole in the nasal septum (which separates our right side of the nose from the left), inflammation of the sinuses (sinusitis), ear infections, difficulty breathing, and coughing (sometimes a bloody cough).

When the disease is in the lungs people may feel shortness of breath (which may be caused by bleeding in the lungs), or cough. When the kidneys are involved, kidney failure can occur, which may be life threatening.

Other organs may be involved, such as the skin (a rash may appear, like the one on House), the joints – which can become inflamed as well, and the nerves (something which can also affect vision – like the patient on House told that had happened to her).

Believe it or not, but there are even more possible symptoms, into which we won’t get here (including, rarely, pancreatitis, which for some reason was a main manifestation on House).

How is it discovered?

The disease resembles many other diseases, making the diagnosis difficult. A blood test checking for a component in the body called ANCA can be used, since it’s elevated in the disease. A physical exam, x-ray, and urine test, among others, can help with the diagnosis. The definitive way is performing a biopsy (taking a piece of an organ to look at under a microscope) on one of the involved organs, which will show something like this:

WG under a microscope. The round area on the left is called a granuloma, which is a mass of immune cells (that’s how the disease got its name). Photo by Nephron.

How is it treated?

Drugs that suppress the immune system (which attacks the body here) are used in WG. This includes steroids and chemotherapy.

What happens after treatment?

With treatment given on time, symptoms may disappear altogether. Still, in about half of patients, the disease may return. Before the disease was understood and the right treatments were given, about half of all patients died within 5 months. Today more than 75% get to live longer.

The bottom line – How do I avoid it?

Unfortunately, there is no known way to prevent WG.

Related posts:

1. Behçet’s Disease – Inflammation of Your Blood Vessels, Throughout the Body (As Seen on House MD)
2. Waldenström’s macroglobulinemia – A Rare Blood Cancer That Can Lead To Strokes
3. Peripheral Arterial Disease – A Narrowing of Blood Vessels that Will Shorten Your Life

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)


On episode 19 of season 7, called “Last Temptation”, a 16 years old patient named Kendall Pierson collapses while embarking on a boat trip. Later her hand turns blue while running on a treadmill and her pineal gland is found to be calcified. Later she collapses due to a hypertensive crisis. An MRI of her arm discovers that she has a tumor called lymphoid sarcoma in the arm. As hard as we tried, we couldn’t really find enough data about lymphoid sarcoma. Seems the writers went a little too rare with the disease, or that a more likely diagnosis is in place here: osteosarcoma.

Photo by NBCUniversal

Danger level: High

What is it?

Osteosarcoma is the most common type of bone cancer is children.

Who gets it?

In the United States, about 400 children  and adolescents (under age 20) are diagnosed with osteosarcoma each year. 

It’s a little more common in black people and in males. It’s also more common as a child ages – quite rare under the age of 5, but becoming more common towards age 20 (it’s more common at the age when a child is growing faster).

What causes it?

The exact reason for the development of osteosarcoma isn’t known. There are, though, some risk factors which increase a child’s risk of developing the tumor:

1. Rapid bone growth: As mentioned above, at times when the child grows faster, their chances of developing an osteosarcoma increase.
2. Exposure to radiation
3. A genetic problem: For example, children with retinoblastoma (more on that in a future post) are more likely to develop osteosarcoma. (other genetic diseases associated with it include Li-Fraumeni syndrome, and Rothmund-Thomson syndrome – more on those in the future).

How does it feel?

Any bone may be involved in the disease, but it’s more common in areas of bone which grow faster, such as the end of the thigh bone, the beginning of the shinbone, or the beginning of the arm bone.

Usually the child will feel pain in the area, and a swelling may also be felt there. Sometimes the child may limp as a result of the pain.

How is it discovered?

Usually an x-ray is performed first on the area. It will show an area of destroyed bone (called in medicine a “lyric lesion”). An example for that can be seen in this x-ray.

Photo by bc the path

In order to diagnose osteosarcoma for sure, a piece of the bone is needed (a process called a biopsy). It is then looked at under a microscope. This is how it looks:

There are many types of cells in this picture, which we can’t explain here. There is also a clear pink area, created by the tumor. Photo by Nephron.

CT and/or MRI are usually also needed, to see if the tumor has spread to other areas in the body (it tends to spread to the lungs and to other bones).

How is it treated?

Osteosarcoma is usually treated with chemotherapy, after which surgery is performed, which either removes the tumor or involves an amputation of the limb in which the tumor exists (like the case on the House episode). After that, more chemotherapy is usually used.

What happens after treatment?

The most important way to answer that depends on whether the tumor has spread to other areas, a fact which worsens the outcome.

About 60-70% of children with a tumor that hasn’t spread are cured thanks to treatment. Those with metastasis have a worse outcome – only 30-35% of them will survive.

There is currently no known way to prevent osteosarcomas.

The following video is about Bianca Bresadola, who died of osteosarcoma. May she rest in peace.

Related posts:

1. Neuroblastoma – The Most Common Cancer in Infants
2. Paget Disease of Bone – Bone Deformity For An Unknown Reason
3. Necrotizing Fasciitis Revisited, Osteosarcoma, and Aneurysms – (As Seen on House MD)

This is a guest post by Ashley Warner. Ashley is a graduate student working toward her Masters in Conservation Biology. She currently resides in Washington state and is a part-time content creator for Online Biology Degree.

Danger level: High

What is it?

Chagas disease (also called “American trypanosomiasis”) is an infection that eventually causes potentially fatal heart and digestive problems in 20-40 percent of infected humans.

Who gets it?

The parasite responsible for the disease, Trypanosoma cruzi (T. cruzi), exists mostly in central and south America and in Mexico, although a small number of infections documented in the southern United States indicate that the disease has spread into the north. Similarly, recent population movements have led to cases as far afield as Europe. Anyone living in one of these regions, particularly in a rural area, could potentially become infected.

What causes it?

T. cruzi lives in wild mammals such as opossums, armadillos, rats and raccoons and may inhabit domestic animals as well. The disease is transmitted to humans by triatomines (also called reduviid bugs), insects that feed on the blood of vertebrate animals. Often biting the faces of human victims, triatomines are commonly called “kissing bugs.”

A kissing bug. Photo by Fernando Otálora Luna

These insects defecate while feeding, and if one is carrying T. cruzi from a previous meal, the parasites will be in the feces. When human victims scratch at the bite, the infected feces enter the blood through the bite wound itself. The parasites can also pass through other places, such as the eye.

T. cruzi can also be transmitted by consumption of contaminated food (including breast milk), through transfusion of infected blood or transplantation of infected organs, and from an infected mother to her unborn child.

How does it feel?

Chagas disease proceeds in two phases.

The initial, acute phase, lasts for weeks or months. It usually brings about mild symptoms, if any, beyond swelling at the site of infection. The most recognizable symptom of acute infection, called Romaña’s sign, is swelling around the eye where the parasites reside.

A child with a Romana’s sign.

After several weeks, the infection proceeds to the chronic phase. In most cases, the parasites’ presence will cause no symptoms. This is known as indeterminate chronic Chagas disease. However, when symptoms do develop, they severely affect the heart and digestive system.

Cardiomyopathy (damage to the heart muscle) can lead to sudden death, while megacolon and megaesophagus (dilation and enlargement of the intestines and throat) cause difficulty swallowing, loss of weight and malnutrition and other life-threatening complications. In some cases chronic Chagas disease also affects the nervous system, impairing reflexes and sense perception.

How is it discovered?

Because it often presents no distinct symptoms (or no symptoms at all), Chagas disease can be difficult to detect. Diagnosis depend on detecting T. cruzi in the blood or the presence of antibodies specific to the parasite (antibodies are molecules the body produces to fight an infection).

How is it treated?

Acute cases respond well to antiparasitic drugs, and are often completely curable. In general, the younger the patient and the sooner treatment is received, the better the odds that the parasites can be eliminated.

However, in its chronic phase, Chagas disease becomes more and more incurable. In determinate chronic cases (where symptoms do appear), currently available antiparasitic treatments are not effective.

What happens after treatment?

If the disease is effectively treated with antiparasitic drugs, the parasite infection has been completely cured and the patient should suffer no further ill effects. Damage to the body in chronic cases may be irreversible even if a the parasites have been eliminated.

The bottom line — How do I avoid it?

Although research to develop one is underway, there is no vaccine for Chagas disease. The surest way to avoid infection is to avoid travel in regions where the disease is common. If you do spend any time in areas known to harbor T. cruzi and the kissing bugs that transmit it, avoid sleeping outdoors or in rural areas where the insects may inhabit buildings. Sleeping under a mosquito net is also advisable.

Related posts:

1. Leprosy – The Biblical Disease is Still With Us (As Seen On House MD)
2. Malaria – A Deadly Infection Passed On By Mosquitoes (As Seen on House MD)
3. Syphilis – The 4 Stage Disease That Will Make You Want To Wear A Condom

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)


On last night’s episode of House (season 7, episode 14, called “Recession Proof”) a man working as a janitor on crime scenes develops a set of symptoms which contain a rash, fever (which goes up pretty quickly), swollen joints, conjunctivitis (an inflammation of the eye), hearing loss, and kidney failure. All of these appear when he is cold. His set of symptoms fits a condition called Muckle-Wells syndrome, yet the diagnosis arrives too late…

Photo by Fox

Danger level: High

What is it?

Muckle-Wells syndrome (MWS) is a condition in which there are spells of a skin rash, fever, and joint pain. With time, hearing is impaired, and kidney function deteriorates.

Who gets it?

MWS is a rare disorder. Even though it’s been encountered throughout the world, no one knows exactly how common it is, and who’s more prone to get it.

What is known is that it’s genetic, and can be passed on in families.

What causes it?

MWS is caused by a mutation in one of the genes in our body, called NLRP3 (or, by another code name, CIAS1). Genes in our body serve as the blueprint for our body’s various functions and structures. This gene tells our body how to make a certain protein named cryopyrin.

Cryopyrin helps to regulate our body’s inflammation process. When it’s damaged, like in this disease, it can work overtime, and so our body reacts by causing inappropriate inflammation, leading to a rise in temperature and damage to the body’s cells and tissues.

The inflammation can cause our body’s temperature to rise.
Photo by Andres Rueda

How does it feel?

People with MWS have recurrent episodes of the disease. Those can begin during infancy or early childhood. They may appear out of nowhere, or have certain triggers that can cause their appearance. Examples of such triggers include cold (like the trigger on House), heat, dampness, or fatigue.

The episodes contain a rash, fever, painful and swollen joints, and conjunctivitis – an eye inflammation. With time, hearing loss also appears. It’s caused by a continuous damage to the nerves responsible for hearing (which makes the situation shown on House, in which the patient lost his hearing within a day or two, unlikely…).

There is also damage to the kidneys in the disease. It’s caused by the deposition of a substance called amyloid, which also appears in other diseases. This is also progressive (and again, the picture on the House episode doesn’t make much sense).

How is it discovered?

The symptoms give a clue to the condition. To be sure, genetic testing is done, which shows the mutation in the NLRP3 gene (although not all patients have the mutation).

How is it treated?

Until 2008, no specific drug was used for this condition. Hearing aids were used for the hearing impairment, anti-inflammatory drugs and steroids were used for the joint pain.

In 2008, a drug called Arcalyst (or rilonacept) was approved for use in MWS (it’s also mentioned on House). It blocks our inflammatory response, helping the body fight the disease. In 2009, another drug, named Canakinumab, was also approved for this condition.

What happens after treatment?

The condition can lead to deafness and to kidney failure with time. The kidney failure can lead to death.

The bottom line – How do I avoid it?

MWS is a genetic disease. There is nothing that is known which can prevent this condition.

Related posts:

1. Common Variable Immunodeficiency (CVID)–When a Cold Can Threaten Your Life (As Seen on House MD)
2. Cushing’s Syndrome – Could You Be Exercising and Dieting and Still Be Fat? (As Seen On House MD)
3. Treacher-Collins Syndrome – Being Born Without Cheek Bones (As Seen on Grey’s Anatomy)

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)


On episode 10 of season 2, named “Failure To Communicate”, a reporter named Fltecher Stone collapses and hits his head on a desk. After that he has aphasia – a condition in which a person speaks but doesn’t know they speak the wrong words. He also can’t write properly (a condition called dysgraphia). After trial and error (lots of it, as usual), it’s discovered the patient has cerebral malaria, meaning he has an infection called malaria, that has also reached his brain, causing his symptoms. He got that when going to an exotic place in order to get a brain surgery for a different disease he has.

Danger level: High

What is it?

Malaria is an infection of red blood cells caused by a parasite that’s transmitted by mosquitoes. It kills about 1 million people each year worldwide.

Who gets it?

Modern medicine has made malaria quite rare in the United States and most other developed countries. In other places, though, it still remains common. Worldwide, about 300-500 million people are infected with malaria, with 1-2 million dying of it each year (most of them African children under 5 years of age).

This doesn’t mean you can’t see malaria in your neighborhood if you live elsewhere. Visitors from other places, immigrants, and even plain travelers (like the one on the House episode) can have the disease.

Map of malaria spread around the world (from the WHO website). Areas in shades of blue are those with active malaria spread.

If you visit these areas, you’re naturally more prone to get infected. Some people are at risk of having a severe case of malaria:

• Young children and infants
• Travelers from a place where there is no malaria (that’s because there is some immunity to malaria in people living in malaria-infected places)
• Pregnant women and their fetus

What causes it?

Malaria is caused by a bite from a female mosquito infected with germs (or, more correctly, parasites).

There are 4 types of parasites that can cause malaria. They are called: Plasmodium falciparum (the most common one – accounting for 80% of cases), plasmodium vivax, plasmodium ovale, and plasmodium malariae.

Image by the country of Los Angeles public health website

Once a female mosquito bites a person with malaria, the parasite gets into its blood stream. Once inside the mosquito, the parasite reproduces and migrates to its salivary glands. Now, when the mosquito bites another person, parasites are injected along with its saliva.

Inside the infected person, the parasites move to the liver, where they multiply and mature. This takes about 1-3 weeks. Then they leave the liver and get into the infected person’s blood cells, where they multiply again, causing the cells’ rupture. The parasite is then free to infect more red blood cells.

This video shows the process using beautiful animation:

In rare cases, there’s no need for a mosquito in order for the infection to pass form one person to another. Examples of such rare cases are transmission of the infection from a mother to her fetus, transfusion of blood contaminated with malaria, or injection with a needle that was used by a malaria infected person.

How does it feel?

Symptoms usually take a few weeks to a few months to appear after the infection, but they may also appear after years.

Once red blood cells begin to rupture and release parasites into the blood stream, a shaking chill appears, followed by high fever. Once body temperature falls again, the person sweats profusely. This ritual of shaking, fever, and sweating repeats in attacks.

Other things that can be felt are fatigue, headaches, body aches, and nausea.

If you’re infected with the plasmodium falciparum type of parasite, the infection can be more dangerous. Since here the infected red blood cells stick to the walls of small blood vessels and clog them, blood supply to organs in the body is interrupted, causing damage to these organs. Examples of such organs include the brain (causing cerebral malaria – like was seen on House), lungs, kidneys, and gastrointestinal tract.

How is it discovered?

When a doctor suspects a person has malaria, a blood sample is taken from them and looked at under a microscope to see the parasites, like can be seen in this picture:

How is it treated?

There are drugs that when taken kill the plasmodium parasites. The type of drug given depends on which of the four types of plasmodium parasites the person got infected with. An example of such a drug is chloroquine.

What happens after treatment?

Most people improve within 24-48 hours of starting taking the drugs, although with plasmodium falciparum, fever can persist for 5 days. Without treatment, malaria can be deadly.

The bottom line – How do I avoid it?

If you know you’ll be travelling to a place where there’s malaria, consult your doctor a few months ahead about drugs you can take before, during and after your trip, that can help protect you.

When you are in one of those countries, you should take measures to avoid contact with mosquitoes. This includes sleeping under a net (preferably sprayed with permethrin, an insecticide), covering your skin (especially from dusk till dawn, the most active mosquito times), spraying your clothing and skin with permethrin, and treating the home you live in with insecticides and with screens on the doors and windows.

Related posts:

1. Amebiasis– A Very Common Infection You May Not Even Have Heard of (As Seen on House MD)
2. Gas Gangrene – An Infection That Can Rapidly Kill Your Muscles (As Seen on House MD)
3. Meningitis – The Brain Infection That Could Kill You, and How To Recognize It

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)


On episode 9 of season 2, called “Deception”, A woman named Anica has a seizure and arrives at the hospital. She also has a bruise on her stomach. She has had Cushing’s syndrome in the past, caused because she was faking it (she has Munchausen syndrome – a condition in which people fake diseases to get attention). After House smells a fruity smell in her bed, he arrives at the conclusion that she has an infection with a bacteria called clostridium perfringens, that used her stomach bruises as a safe house in which to grow.

Danger level: High

What is it?

Gas gangrene is a life-threatening infection of muscle. It’s usually caused by a germ called clostridium perfringens.

Who gets it?

In the US, about 3000 of these infections occur each year. Estimates are that outside the US it is more common.

What causes it?

Gas gangrene is an infection of the muscle caused by a germ named clostridium perfringens (although it may be caused by other bacteria as well).

It usually occurs at the site of an injury in the body, or in a surgical wound. Clostridium perfringens is a type of bacteria that belongs to the anaerobic type, which means it lives best when the level of oxygen is low. This makes deep wounds, in which there isn’t much oxygen, an excellent area for them to grow and prosper.

Clostridium perfringens. These guys cause all the trouble.

The bacteria then produce toxins. These eventually cause the death of the tissue (hence the name gangrene = tissue death). As a result of the toxins gas is produced, and it becomes trapped in the infected tissue.

The time between the infection and the symptoms is very short, since these bacteria grow very fast. The average time is less than 24 hours.

As a result of this process, tissue destruction occurs rapidly – muscle and fat in the area are destroyed, and blood vessels get clogged. The whole process affects the whole body pretty fast, causing destruction of blood cells, possible kidney failure, and then shock. Eventually, death can occur if the condition isn’t treated.

How does it feel?

The infected area will be very painful. At the beginning it may be swollen and pale, but it then turns red, then bronze, and then a blackish green. Large blisters also appear in the area.

Gas bubbles may be felt under the skin, as a result of the gas produced by the bacteria.

As mentioned above, without treatment death can occur pretty fast, usually within 48 hours.

Behind this link is an image showing a leg with gas gangrene. Please be warned – the image is very graphic. (photo by Engelbert Schröpfer, Stephan Rauthe and Thomas Meyer).

How is it discovered?

Usually a doctor suspects the condition just by seeing the patient and the infected area. X-rays can be used to confirm the suspicion, as well as CT or MRI images. The images will show gas inside the muscle tissue.

To make sure this is gas gangrene, though, fluids from the wound have to be examined under a microscope to show the bacteria there (like in the picture above). Most times, when the condition is suspected, there isn’t much time for that, and sometimes the diagnosis is done in surgery.

How is it treated?

When gas gangrene is suspected, high doses of antibiotics are immediately given.

Then a procedure called debridement is performed, in which all dead and infected tissue is removed surgically. About 1/5 of people with the infection in a limb will have to undergo amputation.

What happens after treatment?

Even with treatment, about 1/8 of people with an infected limb, and about 2/3 of those with infection in the torso will die.

Any skin injury should be cleaned thoroughly. If you see any signs of infection (such as redness, pain, drainage, or swelling around a wound) consult your health care provider promptly.

Related posts:

1. Meningitis – The Brain Infection That Could Kill You, and How To Recognize It
2. Amebiasis– A Very Common Infection You May Not Even Have Heard of (As Seen on House MD)
3. Malaria – A Deadly Infection Passed On By Mosquitoes (As Seen on House MD)

This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)

On episode 8 of season 2, named “The Mistake”, a woman named Kayla suffers from a severe stomach pain while watching her daughters perform a school show. Later it’s found she also has uveitis (inflammation in the eye) and genital ulcers. A diagnosis is made of Behçet’s disease (the rest of the episode deals with the legal implications of a mistake Chase has made in her treatment).

Danger level: High

What is it?

Behçet’s disease is a rare disease in which inflammation of blood vessels leads to a group of symptoms, which can eventually also lead to death.

Who gets it?

As mentioned above, Behçet’s disease is quite rare. In North America and Europe it happens to about 1 out of 15,000 to 500,000 people. In other parts of the world it’s less rare. Turkey, for example, is where it’s most common – it happens to 420 people out of every 100,000. It’s also more common in Japan, Korea, China, Iran, and Saudi Arabia.

It’s more common in people of Middle Eastern and Japanese origin.

The disease tends to occur in people aged 20-40 years.

What causes it?

Behçet’s is caused by an inflammation in our blood vessels throughout the body. No one knows the exact cause, but it’s believed that the body attacks its own blood vessels. Our immune system, responsible for fighting infections, fights instead the cells of the blood vessels. This also happens in other types of diseases, making them belong to a group of diseases called autoimmune diseases (we covered some of them in the past here, including Hashimoto’s thyroiditis, Graves disease, vitiligo, and others).

Blood vessels. In Behçet’s disease, the body attacks them. Photo by Freya Mowat

How does it feel?

The most common thing in Behçet’s are mouth sores. They are painful and recurring. They can appear on the tongue, on the gums, or on the mouth’s lining.

The sores may also appear on the genital organs – the penis, scrotum, or vulva, where they tend to be painful. They may also appear in the vagina, where they are painless.

Since blood vessels throughout the body are damaged in the disease, a multitude of organs are affected. The eyes, for example, in which there is inflammation causing eye pain, redness, sensitivity to light and hazy vision. The skin can be involved as well, showing blisters or a very rapid reaction to a slight injury. The joints can become painful. Blood clots can form throughout the body, and may lead to a stroke. kidney or lung damage.

Even the digestive tract isn’t spared, possibly causing stomach cramps and diarrhea. One last organ that can be affected is the brain, causing headaches, confusion, and other things such as memory loss.

Athlete Sanya Richards describes her own experience with Behçet’s in this video:

How is it discovered?

There aren’t any lab tests that can confirm you have Behçet’s. The doctor determines a person has the disease based on their symptoms and their physical examination, and after ruling out other diseases.

How is it treated?

There is no cure for Behçet’s disease. Drugs such as steroids (and other drugs that suppress our immune system) are used to help deal with the inflammation and the symptoms.

What happens after treatment?

The disease tends to come and go. It may also result in death, but for many patients the severity of the disease usually abates with time.

Since the cause of Behçet’s disease isn’t known yet, no measures are known that can prevent the disease.

Related posts:

1. Wegener’s Granulomatosis–A Rare Inflammation in Blood Vessels that Can Lead to Death (As Seen on House MD)
2. Peripheral Arterial Disease – A Narrowing of Blood Vessels that Will Shorten Your Life
3. Familial Mediterranean fever – Fever and Inflammation Inside The Body