Sepsis and Septic Shock: Sources & Diagnosis

00:01 So what's the diagnostic algorithm for sepsis? Very simply, it all starts with suspected infection.

00:08 So your patient has signs or symptoms suggestive of infection.

00:12 You're gonna get a qSOFA on them, and you're gonna wanna know if their qSOFA is greater than two because that predicts the need for prolonged hospitalization or bad outcomes.

00:22 If the qSOFA is less than two, you might still suspect sepsis and the patient might definitely still have an infection that needs to be treated so you're gonna just monitor their clinical condition, provide them with conventional treatment for their infection just like you would for a non-septic patient and really kind of keep an eye on things and see if they develop sepsis over time.

00:45 For the patient who does have a high qSOFA, you wanna be aware that this is a high risk patient, so these are patients in whom you're gonna get laboratory studies that are gonna look for all the types of organ dysfunction that we discussed in the beginning.

00:59 You're gonna wanna check their kidney function, their liver function, their blood counts, all of those kinds of things to see if they have evidence of evolving organ dysfunction, and that's gonna allow you to calculate a full SOFA.

01:13 If their SOFA is greater than two, that's when you need to really diagnose them with sepsis and that's when you're in the realm of having to treat them aggressively and recognize that their outcomes are gonna be dependent upon how effective you are in managing their physiologic derangements.

01:32 When do you develop septic shock? Well, like we said, if we need vasopressors to maintain an adequate blood pressure, or if we have elevated serum lactate, that's when we are in the realm of septic shock and our morbidity and mortality becomes even higher.

01:47 So we just wanna be aware of the risks associated with septic shock, and when we do identify them in one of our patients we wanna be really aggressive about treating them.

01:56 So what causes sepsis? Basically, any infection can do it.

02:00 Bacterial, viral, fungal.

02:02 Although by far, bacterial are the most common.

02:06 There's a number of infection sources that commonly lead to sepsis.

02:10 Lung being the most common, followed by urinary tract.

02:14 And like I said, the vast majority of these are gonna be bacterial.

02:19 Whenever we have a patient in whom we suspect sepsis, we wanna be really thorough in our history and physical exam because we wanna get into the bottom line of what's causing their sepsis so we can treat it effectively.

02:30 What we're really doing is searching for a source.

02:33 So we wanna always get a chest x-ray on these patients to look for the possibility of pulmonary infection.

02:38 We wanna get urinalysis to look for possibility of urinary tract infection.

02:43 We always wanna get blood cultures to identify the subset of patients who are bacteremic.

02:48 And we always wanna get a lactate level because we wanna know if they are tethering over that border into septic shock.

02:56 Not every patient is gonna have a sepsis source that is readily apparent on their history and physical and their basic work-up.

03:03 So when we get the test that I just described and we are still scratching our heads about why the patient is septic, we wanna think about moving on to more sophisticated and or invasive tests.

03:15 So we can think about chest or abdominal CT.

03:17 Chest CT is much more sensitive for pneumonia than chest x-ray is and might be warranted in a septic patient.

03:24 Abdominal CTs could help potentially identify bacterial infections in the abdomen such as appendicitis, diverticulitis, or other processes that would merit treatment.

03:36 Lumbar puncture is something to consider, especially if the patient has headache or altered mental status.

03:42 And then there are other body fluids that might need to be sampled.

03:46 Patients with liver disease could have spontaneous bacterial peritonitis and need a paracentesis to evaluate the peritoneal fluid as a source of sepsis.

03:55 Maybe your patient has pleural effusions and you need to see if that's actually an empyema.

04:00 Maybe they have evidence of aseptic joint and you wanna know if that could potentially be the source of their sepsis.

04:07 So you need to take the work-up beyond the basics in order to really rigorously identify the underlying cause whenever possible.

04:16 There are some causes of sepsis that are commonly missed.

04:19 Skin infections are notorious, and I hate to say this, but especially patients who were unable to give their own histories and or are debilitated, a lot of times decubitus ulcers, perineal lesions, cellulitis on the buttocks or back, it's missed because we simply don’t roll the patient over after we undress them.

04:41 So we need to again, be thorough and meticulous in our physical exam to make sure we don’t miss these causes of sepsis.

04:47 ENT infections can lead to sepsis and are often missed again, in patients who are unable to report to you that they have congestion, pain in their throat or neck, etc.

04:58 Endocarditis is a common source of sepsis.

05:01 We always think about it in our injection drug use patients, but it can also be present sub-acutely in patients who have other etiologies of bacteremia such as dental infections.

05:12 Intra-abdominal processes can be missed sources of sepsis and might require advanced imaging to diagnose.

05:19 And again, the CNS, is a place where you can have infection and the only way you're gonna know about it is by performing a lumbar puncture.

05:27 So you wanna really consider all the potential sources on the table and work your patient up appropriately to identify those sources even the subtle and hard to find ones.

05:38 The patients who are unable to give their own histories because of dementia, stroke, mental retardation, or just, you know, very young age, these are the patients who are at highest risk of having their sepsis sources overlooked.

05:53 So whenever you take care of a debilitated patient or a non verbal patient who's not able to explain their own history to you, you wanna be really, really careful in your search for a source.

06:05 Why is this so important? Well, first and foremost, there are some sources of sepsis that will need treatment above and beyond antibiotics.

06:14 We all know to give antibiotics to septic patients and if they have pneumonias or urinary tract infections that's typically gonna be adequate to control their infection.

06:23 However, there are some infections that require invasive procedures to control.

06:28 For example, if you’ve got aseptic joint, the joint space doesn’t have adequate blood supply to deliver antibiotics there so you're gonna need surgical intervention to drain and wash that joint out if you're gonne cure it.

06:41 If you have an intra-abdominal infection, you might need a surgical procedure to take care of that source.

06:48 So you really wanna make sure that you know what's causing the sepsis because you wanna know that you're treating it adequately and not every cause of sepsis can just be treated with broad spectrum antibiotics.

07:01 So really this is a top priority in sepsis management.

07:05 Why do we check lactate? We all associate that in our minds with sepsis but what's the physiologic basis for it? Like we said before, cellular hypoxia is what really drives shock, and when the cells are hypoxic at the tissue level that forces them into an anaerobic metabolic state.

07:23 You probably remember that the by-product of anaerobic metabolism is lactate.

07:29 So as you develop tissue hypoxia, you're gonna develop more and more lactate production as you force yourselves to make energy using non-aerobic means.

07:42 Lactate is a surrogate marker for the adequacy of tissue perfusion, so basically, if your tissues are well perfused, they will be using the aerobic metabolic pathway and you won't build up much lactate.

07:53 Whereas if they are hypoperfused, they're gonna be forced down the anaerobic pathway and you will develop lactate.

07:59 And this is often the earliest clue of sepsis in patients who are well-compensated.

08:04 So remember I said before, not every patient in shock is gonna be hypotensive.

08:10 If you have a patient with infection and a significant lactic acidosis, they might be maintaining their blood pressures through physiologic compensation, but that lactate is telling you that their tissue level perfusion is not adequate, and you wanna make sure that you address that very aggressively.

08:27 So lactate has very good sensitivity for detection of cellular level hypoxia but it's only moderately specific for sepsis.

08:37 There are a lot of things that can cause lactic acidosis including simple dehydration.

08:42 So not every patient with a high lactate is gonna be septic but in the right clinical setting, where they have infection and you're concerned about the development of septic shock, it's a very useful tool to look at the adequacy of tissue perfusion.