AUTHOR'S NOTE: This short story was written and first published in 2010, while I was in my 3rd year of medical school. It was written to be a whimsical summary and educational tool for my tutorial group about Deep Vein Thromboses (DVTs) and Pulmonary Emboli (PEs) which we were studying at the time. The bolded and italicised sections were the key bits of medical information my classmates were supposed to glean from this maniacal story. Some inspirations that (obviously) made it's way into the story were the TV shows, 'Lost' and 'The Magic School Bus', and the movie 'Back to the Future' - as well as a few other pop-culture references scattered throughout. It is presented below, in full, uncut, and largely unedited. Please pardon spelling, grammar and medical inaccuracies.

PART 1: THE RISKS (Risk Factors)

Meet Mary Clump, a well to-do lady with a very interesting life’s story; one that would take a whole novel to outline and explore. However, we’re concerned with only one chapter of her life, only one story; the story of her clot.

It all begins one rainy afternoon at half-past 10. Mary’s getting dressed hurriedly, desperately trying to avoid missing her flight which boards in 25mins and 5secs.

Now I know what you’re thinking, ‘what a silly and absent-minded lady to be so unorganized for a flight’. But in her defense, she normally isn’t like this. In fact, her whole life has revolved around being organized, and this is just a lapse in a stellar record. From taking her Oral Contraceptive Pills, to arriving to work, she’s almost always on time. You see, Mary is a spy. Granted, only an ASIO operative, but a spy nonetheless. Therefore, routines, schedules, and strict discipline are completely ingrained into her character.

Before you all start imagining Mary to be a sultry and athletic brunette with disarming eyes, I must remind you that she is an ASIO operative. And ASIO spies, unlike CIA, MI6, and Mossad operatives, tend to be more… lax. More like glorified police officers than your clichéd Bonds or Bournes. In other words, Mary has a desk job; and like most long-hour working desk jockeys, she’s fueled by unhealthy eating habits, and sub-zero exercise levels (even when factoring in her walks to the water-cooler). In saying that, it should also be noted that Mary’s time is also absorbed with periods of prolonged standing, during briefings and stake-out surveillance missions etc. This has given her a bad case of varicose veins, which she is very self-conscious of.

Mary is also a very anxious person. It’s unclear if her job caused her anxiety or simply exacerbates it from time to time. All I know is that she’s fallen on the crutch of cigarettes to help ease her stress.

And so she lights one up now as she shuts her briefcase and runs out the door, worrying about what will happen to her if she misses her plane.

I won’t bore you with her drive to the airport. All you need to know is that Mary made it on board the plane with 3 seconds to spare, and at the cost of 4 human lives (and one parakeet’s ... you don’t want to know).

It is now, as she buckles her seat belt (after loosening it considerably), and consumes a sleeping pill to avoid human contact for the next 14 hours, that our true story begins.

The loud-speaker chimes to life as the voice of a flight stewardess announces “Welcome to Oceanic Airlines flight 815, non-stop from Sydney to Los Angeles. As we prepare for take off please secure your luggage....”

The flight attendant’s voice trails off faintly in Mary’s mind as she falls asleep in her economy class seat. The next time Miss Mary Clump wakes up, she won’t be feeling very well.

PART 2: THE CLOT THICKENS (Pathophysiology)

It’s my job as your trusty narrator to ensure you’re entertained, and that’s why we’ll let Mary sleep on, alone. The real drama is occurring deep inside Mary’s leg, at a microscopic level. Let’s take a look.

Here we are, the left posterior tibial vein, Mary’s left posterior tibial vein. Beyond that valve leaflet up ahead is what we’re here for; please no flash photography. We’ll be swimming with the current so no need to panic. Watch your step, there’s that micro-chip transponder that was injected into Mary last week; she still doesn’t know about that yet...

Ahh, there, see? attatched to that valve leaflet and extending upwards along the lumen (in the direction of the blood flow). That’s the clot; the DVT.

A big old ball of fibrin, thrombin and red cells, with a smidgeon of platelets. It took a whole extrinsic pathway; complete with factors, enzymes and vitamins to bring about this bad boy. When exactly it started to grow is nearly impossible to determine, even for your omnipotent, omnipresent narrator. What is clear, however, is what brought it about in the first place, and why it’s growth is especially accelerated now.

I’m about to get all Sherlock Holmes on you, so get ready. Notice the damaged appearance of the valve, how it’s bent out of shape, with a friable surface. Furthermore, note the lumen’s surface, also damaged. This, ladies and gentlemen, is how the clot came to be. The damaged surfaces demand repair, and your body is only too ready to oblige, however, it’s not so good at knowing when to stop. As the patch-up work grows larger, it bulges out into the lumen. Here, further debris manages to stick, thus the bulge grows larger and larger, particularly in the direction of blood flow as you can see. Ah, but why is it that the thrombus grows now at an accelerated rate? For two very simple reasons; 1. Mary’s lifestyle, gender and age all impact on her blood’s affinity to clot, and Mary is what we would call ‘hypercoaguable’ and 2. In Mary’s current unconscious state, she has become flaccid. The lack of muscle activity (particularly in the legs) reduces venous flow rate, and this haematological stasis exacerbates coagulation. This Terrible (Virchow’s) Triad of vein wall damage, hypercoagulability and stasis have caused and accelerated the growth of Mary’s clot.

PART 3: GREAT SCOTT! (Signs/Symptoms & Investigations)

10 hours have elapsed, and Mary hasn’t moved an inch. Our big old DVT has begun to irritate and inflame the vein walls. Pain is starting to register, and the sleeping pill is wearing off.

Mary’s eyes flutter open. She yawns and slowly stretches. As she extends her legs, she feels a twinge of pain. Strange. She turns on the reading light above her and takes a good look at her legs.

Her left calf has swollen up to almost twice the size of her right, and its red. She touches it gently and winces.

“Great Scott!” exclaims a voice behind Mary.

Mary jumps and turns around. The man in the seat behind her is standing and unabashedly staring at Mary’s left calf.

“My dear woman,” exclaimed the man, “that does not look good at all.”

Poor old Mary doesn’t know what to say or do; for one thing, her mind is still foggy from the sleeping pill, and for another, the man behind her is... strange...to put it mildly. And that’s not just because he’s standing behind her, looking at her leg, and shouting at her. He looked strange; mad-scientist type strange, with the crazy white hair and big round eyes. He looked like he’d just traveled through time in a Delorean he invented.

Needless to say, the man’s shouting brought an attendant to the scene.

“Is everything all-right sir?” she asked with forced politeness. The man simply stood appalled, mouth somewhat open, and slowly pointed at Mary’s calf. The flight attendant looked, and shrieked in horror.

A moment of delerium and panic passed through the plane as people began to suspect a bomb was on-board... but I won’t bore you with the details...

We pick up the story now with the mad-scientist, who calls himself Doc Emmett Brown, taking charge of the situation.

“It seems that you have what they call a Deep Vein Thrombosis” he absent-mindedly rants to Mary.

“How do you know?” asks the poor frightened Mary, “are you a medical doctor.”

“Oh God no,” Doc Brown exclaims.

“Inside voice,” advises the stewardess.

“Very well,” whispers the mad man.

“So how do you know?” asks Mary, desperate for some sanity.

“We’re on a plane for an extended period of time, you’re obese, you stink of cigarette smoke, and you have a swollen, red, tender leg.” His eyes were bulging as he spoke. “If the scenario was anymore perfect I’d believe it to be contrived.”

“But how can you be sure?” Mary’s fear had reached a new peak.

“Well if you have the resources for me to take some blood tests like a D-dimer, coagulation profile, and inflammatory markers, not to mention a venous doppler ultrasound machine to image your lower leg, then I’m sure we could confirm your diagnosis. But we have no time to waste.”

“What are we going to do?” Mary asks, frightened.

“We are going to send a team of highly specialized scientists inside your veins to neutralize the thrombus.”

“WHAT?! HOW?!” Mary did indeed think that this man was insane, but she couldn’t help but trust him; he had an enduring ‘mad charm’ about him. It’s difficult to explain.

“I’ve invented a tiny school bus equipped with all sorts of mechanisms and gadgets. We will miniaturize the team of scientists, insert them into this ‘magic school bus (TM)’ as I like to call it, and hey presto, clot gone.”

10 minutes later, after asking all the passengers, Mary and the Doc discover that there are no science teams present. But there is a grade 6 science class on board who are on excursion to LA for some unknown, unimportant reason. The teacher, Ms Frizzle, announces that she and her class would be delighted to help Mary.

Without discussing this highly unethical, highly immoral and irresponsible decision, Ms Frizzle and her class are miniaturized and then injected into Mary’s left posterior femoral vein. They take a path similar to the one we took earlier, until they find the thrombus.

Impertinent and obvious questions are asked by the children, to which Ms Frizzle answers in a very over-simplified manner. One child falls out of the bus, and is promptly attacked by macrophages. Further mishaps transpire until something truly horrible occurs. The turbulence caused by the bus manages to dismember a sizable embolus from the whole. It hurtles down the lumen, weaving its way through valves.

“Buckle up children!” shouts Ms Frizzle, the enormity of the situation bearing down upon her. The magic school bus (TM), along with Ms Frizzle and all 15 children rush after the embolus.

PART 4: THE FANTASTIC VOYAGE (Anatomy)

The embolus is far ahead, it seems almost hopeless for the bus to catch up.

Ms Frizzle hysterically cackles as they speed past the seemingly endless tunnel that we know as the tibial vein. “Isn’t this fun children?” she declares as little Billy throws up and Sally mourns the loss of her friend that was absorbed by the macrophage.

As they pass another valve Ms Frizzle turns around to announce “We’ve just entered the popliteal vein.” Ahead of them, the embolus bounces off the vein wall which manages to slow down it’s progress enough for the bus to catch up. “Children! There, over there, it’s the embolus, we’re close.” Embolus and bus alike hurtle the length of the popliteal vein.

It’s as they enter the femoral vein, where problems arise. White cells begin to attack the school bus. Adhering to its surface, slowing its progress down, and slowly phagocytosing the vehicle. The children scream in horror, but Ms Frizzle will have none of this. She urges the bus on, and something remarkable happens; the bus becomes sentient, or so it seems. It maneuvers its way out of the leukocytes and propels itself at break-neck speeds. Ms Frizzle resumes her cackling, the children remain terrified.

They’ve entered the external iliac vein, and by some miracle, the embolus is still within their sights.

The pursuit continues through to the common iliac vein.

They begin to climb as they enter the inferior vena cava. “You’re in for a real treat kids!” Frizzle proclaims, “we’re about to enter the heart!”

And enter the heart they do. As they burst into the right atrium, pressures disrupt their progress. The good news is, the embolus has experienced the very same, and is now within reach. The bus and the embolus are ejected through the tricuspid valve into the right ventricle. The bus deploys its claw-like clamps in the hopes of capturing the embolus and ending this nightmare. Just as the clamps enclose the embolus, the ventricles contract, ejecting them up towards the pulmonary valve. Embolus just ahead. The magic school bus’s clamps are fully extended, micrometers away from grabbing the embolus. “We’re almost there!” shouts Frizzle, and as the embolus passes through the pulmonary valve, it snaps shut, causing the bus to collide with it head-on and rebound it and all it’s occupants back against the right ventricle wall, where they smash on impact.

PART 5: LOST (PE - Signs/Symptoms, Management; Prevention)

Two things occur immediately to Mary as a result of the crash; 1. She feels a sharp chest pain with sudden shortness of breath as the embolism lodges in a distal branch of her pulmonary artery, 2. she experiences palpitations as a result of the bus colliding into her ventricular wall.

Doc Brown, still watching Mary, notices her discomfort. Mary begins to cough, covering her mouth politely as she does so. When her hands are withdrawn they are sprinkled with blood.

“Great Scott! It’s just as I feared! They’ve failed!”

“What?” Gasps Mary, “What’s happened?”

“You have a pulmonary embolism, this is serious, we need to treat you right away!”

“But what happened to the bus and the children? How do we get them out?”

“It’s too late, I assume they’re dead.”

“WHAT!?” Mary coughs up more blood and struggles to catch her breath.

“It’s ok Mary, you’ll be fine,” Brown reassures kindly, “I’ve got the medication you need here.”

“You do?! So why did we have to send the school bus in if you had medication?!”

“Mary, you need to calm down, I didn’t give you the medication because it carries some serious side-effects that I’d like to avoid if I can.” Explains Doc gently, smiling reassuringly as he prepares an injection.

“We just sent a grade 6 science class to their deaths and you’re talking about side effects! You’re insane.” Despite her outrage, and severe shortness of breath, Mary willingly accepts the injection from the certifiable old man. Doc Brown then administers therapeutic doses of enoxaparin injections, and gives her a warfarin pill to take.

The pilot also lowers Mary’s emergency oxygen mask, and soon, Mary starts to feel a whole lot better.

“Thank you,” Mary says gratefully.

“You know Mary, you should really take some preventative measures,” Doc fires back.

“Like what?”

“Well, for a start, change certain aspects of your lifestyle; stop smoking, lose some weight, eat right. Then you might want to wear some compression stockings next time you’re on a flight, and walk around a bit too. And you should probably see a doctor, to see whether you need to be on anticoagulant drugs.”

“Thanks Emmett, I’ll take your advice.”

Wasn’t that a heart-warming interaction dear reader? At this point in the flight, Doc Brown resumes his seat, Mary settles into hers; there are only 2 hours left till touch down. And then it hits: turbulence.

The plane is rocked hard by an invisible source, all the emergency air masks deploy, baggage begins to rain down from overhead compartments. Flight attendants are tossed down the aisles. The plane splits in half. Mary is in the front section of the plane. It crash-lands on a mysterious island, but Mary does not survive the impact.

THE END