Medical Fun Facts Podcast

MFF0031: A pussy’s pussy pussy

I love the word pus. I know just the very mention of the word can make some people gag, just like when I say moist or yeast to a friend, she starts to have a visceral reaction

So what is pus? Pus is essentially neutrophil debris. Neutrophils are the attack dogs of the cellular immune system. When a foreign protein, especially a pathogenic bacterium is in the wrong place, neutrophils surge forth to meet the alien and attempt to destroy invading bacteria by three mechanisms which include, 1. phagocytising them, 2. releasing deadly granules, and 3. trapping them in neutrophil extracellular traps (NETs). As you’d expect such vigorous activity takes a toll on each cell and cell turnover is high. The bacteria also release toxins that kill neutrophils. As the neutrophils die, they break apart and other cells like macrophages need to mop up the cellular debris.

Small amounts of pus can be walled off in say a pimple or furuncle. Any bigger and it may be an abscess. Sometimes carbuncles form. Carbuncles are really cool abscesses which contain small sacs filled with pus. And then, you get collections of pus that develop and grow larger as loosely formed cavities in the body give way to the accumulating fluid. A good example of such a cavity is the ischiorectal fossa. I remember as a young resident assisting a surgeon drain pus from an ischiorectal abscess. There were 2 litres of pus. It was pretty foul-smelling too. It had a typically anaerobic odour to it.

Most of the time, the pus is walled up in a sort of capsule. So long as the pus remains walled off, it remains relatively contained. As you can imagine, while pus is mostly a soup of dead and dying neutrophils, it also contains lots of viable bacteria. Imagine you have an abscess forming in your appendix. While the abscess gets bigger it poses a danger because of its mass effect and because of the risk of rupture. At the surface of the appendix, as the abscess grows, the blood supply thins, this may lead to the death of the connective tissue and smooth muscle in the bowel wall and abscess capsule. This leads to gangrene and necrosis. Necrotic tissue is inherently weak and a gangrenous appendiceal abscess left for a short time untreated will result in a burst appendix and the contamination of the peritoneum. This results in peritonitis which is inflammation and infection of the entire peritoneal surface. Bacterial peritonitis is a medical emergency.  Basically, you now have bowel contents in what is normally a nearly sterile site most of the time. The vast surface area of the peritoneum means you have a huge amount of infection. Without surgical intervention, death is around the corner.

So let’s get back to pus and its various forms.

Pus can have many consistencies, sometimes it can be thin and oozy like a light jus or gravy, or it can be like a lovely pouring custard just coating the back of a spoon, and at other times it can be thick and gluggy almost like porridge or rolled oats. Did you enjoy my use of cooking metaphors in describing pus? Let me know in the comments.

Pus is often white and sometimes a light yellow. Occasionally it can be a yellow-brown colour too.

If you see green pus it may be due to the pyocyanin elaborated by Pseudomonas aeruginosa. If the pus is from a liver abscess and it looks like anchovy paste, you need to think about Entamœba histolytica as a potential cause of what is likely to be an amœbic abscess.

Really foul-smelling pus, especially if it smells of death or someone’s guts being split open often signifies an anaerobic abscess.

Have you ever gone to YouTube and searched for “incision and drainage of pus”? It’s amazing what you can watch these days on YouTube. Did you know I have a YouTube channel? I’ll leave a link in the show notes https://www.youtube.com/c/YummyLummyBlog Rest assured you won’t find any incision and drainage of pus videos on my YouTube channel. You won’t even find any custard videos.

Bacteria that create purulent infections are known as pyogenic bacteria. Different bacteria can have different pyogenic potential. For example, the golden staph, that is, Staphylococcus aureus tends to create abscesses while Streptococcus pyogenes tends to cause cellulitis. Both produce pus but of different consistency. The coagulase of the golden staph tends to coagulate plasma and bind things together, while the streptokinase, acts to break down protein and connective tissue to facilitate spreading cellulitis.

Now, is pussy a word? My favourite pathologist, Professor Richard Steele who was a pulmonary pathologist and taught medical students about inflammation would exclaim there is no such word as pussy. If he saw pussy on an examination paper, he would write comments about cats.  He also had nasty things to say when he read canon ball lesion rather than cannonball lesion. As a result, I’ve always tried to avoid the word pussy. Sometimes though it can’t be helped. For example, I remember a patient from whom we received a vaginal swab that was covered in pus. The clinical notes included, “intimate with cat”. In that situation, it can’t be helped but to say “Pussy caused a pussy pussy”. And yes, we grew feline oral flora from the vaginal swab.

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