I am not a doctor, I am most certainly not your doctor, and this is not medical advice.

Usually on this blog, I write about questionable depictions of cryptography in fiction, but today it was a questionable depiction of medicine that caught my attention.

Lost in Space is a science fiction television series based on the 1965 series of the same name, following a family of space colonists whose journey goes off course.

In episode 2 of season 2, ‘Precipice’, one of the crew members, Don, is attacked by some kelp-like alien flora, which paralyzes his leg. The crew's medic, Judy, surmises that this is due to a ‘toxin’, and begins removing the kelp. Don, however, soon begins deteriorating, saying ‘Something's happening, I can't feel my head’, and develops a lisp. Soon after, we hear:

JUDY: Don, I think you're going into anaphylactic shock. I need to mitigate the spread of the toxin before it reaches your brain, so I'm going to give you a blood transfusion.

Oestensibly, this is an excuse to manufacture a situation where Don requires a blood transfusion, which is relevant to the plot. Medically, however, this seems a little out of left field.

Anaphylaxis is ‘an acute, potentially life-threatening, multisystem syndrome caused by the sudden release of mast cell mediators into the systemic circulation’ [UTD]. Anaphylactic shock is a complication of anaphylaxis characterised by low blood pressure, and therefore inadequate blood flow to body tissues.

Anaphylaxis is most commonly due to an allergic reaction, and would usually be unrelated to a ‘toxin’ of the leg-paralyzing variety per se.1 However, anaphylaxis can be caused by non-immunological processes [UTD], and if we were to be generous, we might theorise it would be possible for an alien toxin to cause anaphylaxis, for example, by directly inducing mast cell degranulation.

It is unclear, however, how Judy has reached the conclusion that Don's deteriorating condition is a result of anaphylaxis. The relevant clinical criteria in Don's case for anaphylaxis are:

Acute onset of an illness (minutes to several hours) involving the skin, mucosal tissue, or both (eg, generalized hives, pruritus or flushing, swollen lips-tongue-uvula) and at least one of the following:

  • Respiratory compromise (eg, dyspnea, wheeze/bronchospasm, stridor, reduced peak expiratory flow, hypoxemia); OR
  • Reduced blood pressure (BP) or associated symptoms and signs of end-organ malperfusion (eg, hypotonia [collapse], syncope, incontinence) [UTD]

His deterioration is indeed rapid, but this could be due to some other toxin-mediated pathology. He does display a lisp, which could be due to angioedema, a sign of anaphylaxis, but he does not appear to have any respiratory distress per se.

More concerningly, Judy does not appear to have performed a physical examination2 – including to measure Don's pulse and respiratory rate, which could give an indication as to the severity of his condition. The ship, at this point in the episode, has limited power, and although the lights are on, no medical equipment is powered on, so computerised monitoring appears to be unavailable, but Judy does not take a manual blood pressure measurement either. In the absence of evidence of reduced blood pressure, it is by definition particularly difficult to see how Judy has leapt to the diagnosis of anaphylactic shock.

Judy's sole management for Don's anaphylactic shock, it appears, is the aforementioned blood transfusion. The immediate emergency management of anaphylaxis would more usually include, among other things, intramuscular/intravenous injection of adrenaline (epinephrine), supplemental oxygen and volume resuscitation with intravenous saline [UTD]. Blood transfusion is not part of the usual management of anaphylaxis, and it is indeed unclear how exactly a blood transfusion would ‘mitigate the spread of the toxin before it reaches [Don's] brain’.

Edit/Bonus: The next episode features this follow-up:

JUDY: You are on bed rest until the parenthesia wears off.

DON: What? Can't a man stretch his legs?

JUDY: Yes, but a man has to be able to use them first.

DON: I can use them. It's not— (His leg gives way)

‘Parenthesia’ is not a word. Presumably, Judy was thinking of ‘paraesthesia’, meaning perception of abnormal sensations such as pins and needles. But Don's ongoing issue in this scene appears to be one of weakness, not sensation, and would be more correctly described as ‘myasthenia’ (or simply ‘weakness’).

What's this? Another Bonus? In episode 5, another person falls victim to the ‘toxin’, and is placed into a medically-induced coma because ‘his brain won't stop swelling’ – describing a case of cerebral oedema. Allergic cerebral oedema has been described in the literature, but is very rare, and it remains unclear how exactly a blood transfusion would help in this case. Indeed, in the case of cerebral oedema, treatments such as diuretics are designed to remove fluid from the body rather than, as a transfusion would do, increase fluid.


  1. Indeed, since allergic anaphylaxis is mediated by immunoglobulin E (IgE) antibodies, this would require Don's immune system to have previously produced IgE antibodies against the ‘toxin’ in the first place, which would not be expected to have already been the case in a first exposure to the ‘toxin’. 

  2. The episode does cut away between Don's condition deteriorating and Judy announcing her diagnosis, but we leave the two with Judy cutting the kelp away, and return to Judy still cutting the kelp away, so this seems like a reasonable inference.