Approach to shock (pediatrics): Clinical sciences

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Introduction0:00–1:12

Shock is a condition characterized by circulatory failure that impairs the delivery of oxygen and nutrients to peripheral tissues.
In the early stages, the human body activates compensatory mechanisms to maintain tissue perfusion and oxygen delivery. However, these mechanisms can fail.
So, if not recognized and treated on time, shock can progress to organ failure and death. Now, based on the systemic vascular resistance and cardiac output, shock can be classified as warm or cold shock.
Depending on the underlying cause, shock can also be subdivided into four main categories: distributive, hypovolemic, cardiogenic, and obstructive.
Now, here’s a high-yield fact! Sometimes, you might hear of a fifth category of shock called dissociative shock, which occurs when oxygen is not appropriately bound to or released from hemoglobin, causing inadequate tissue oxygenation.
Important examples of this type include carbon monoxide poisoning or methemoglobinemia. Now, if a pediatric patient presents with chief concerns suggesting shock, your first step is to perform an ABCDE assessment to determine if they are stable or unstable.

Unstable Patient1:12–1:55

Most patients in shock will be unstable, so be sure to initiate acute management by stabilizing the airway, breathing, and circulation.
Sometimes, you might even need to intubate your patient and start mechanical ventilation. Next, obtain intravenous or intraosseous access and begin fluid resuscitation.
Finally, put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry, and if needed, don’t forget to provide supplemental oxygen.

Focused H&P1:55–2:12

Once you’ve provided acute management, perform a focused history and physical examination. Patients usually report weakness, fatigue, lethargy, and dizziness, while their physical exam might reveal tachycardia, hypotension, tachypnea, and altered mental status.

Undifferentiated shock2:12–2:28

With these findings, consider shock, and assess the patient’s skin temperature, capillary refill, peripheral pulses, and pulse pressure.
These findings will help you determine whether your patient is dealing with warm or cold shock! In warm shock, the skin and extremities are warm and flushed, capillary refill is normal or rapid, pulses are bounding, and pulse pressure is widened.

Distributive shock2:28–2:52

In these individuals, you should consider distributive shock, which can be further subdivided into septic, anaphylactic, or neurogenic shock.
Let’s start with septic shock. In this case, the patient will usually have temperature instability and symptoms of infection.

Septic shock2:52–3:50

Their physical exam will typically reveal either elevated temperature or hypothermia, as well as tachycardia and tachypnea.
With these findings, consider septic shock and order CBC, lactate, and inflammatory markers such as CRP, ESR, and procalcitonin.
Next, obtain blood and urine cultures, and if safe to do so, consider obtaining cerebrospinal fluid cultures, especially in neonates!
Lab results typically reveal elevated white blood cells and low platelets, in combination with elevated lactate and inflammatory markers.
Finally, cultures might reveal a causative pathogen, but they could also be sterile with no pathogens! These results support the diagnosis of septic shock.

Anaphylactic shock3:50–4:17

Next, let’s discuss anaphylactic shock. Your patient will often report an exposure to a known or suspected allergen, followed by itching, a rash, and shortness of breath.
They could also experience gastrointestinal symptoms, like abdominal pain, vomiting, or diarrhea. If the physical examination reveals urticaria, angioedema, wheezing, or stridor, the diagnosis is anaphylactic shock.

Neurogenic shock4:17–4:51

Finally, let’s discuss neurogenic shock. These patients often report recent trauma with a brain or spinal cord injury, or possibly recent administration of spinal or epidural anesthesia.
If the physical exam reveals bradycardia, paralysis, or paresis, consider neurogenic shock, and perform an MRI or CT scan of the head or spine.
Imaging might reveal a skull or vertebral fracture, intracranial bleeding, or a spinal cord injury, which confirms the diagnosis of neurogenic shock.

Assess for volume loss4:51–5:19

Now, let’s go back to our assessment of skin temperature, capillary refill, peripheral pulses, and pulse pressure. In contrast to warm shock, in cold shock the skin and extremities are cold and clammy, the capillary refill is delayed, peripheral pulses are diminished, and pulse pressure is narrow!
In this case, your next step is to assess the patient for evidence of volume loss. If there’s evidence of volume loss, your patient is experiencing hypovolemic shock, which can be further classified as non-hemorrhagic and hemorrhagic.

Hypovolemic shock5:19–6:04

In this case, your next step is to order a CBC and determine whether or not the patient is losing blood! Now, here’s a clinical pearl!
In addition to a CBC, always order a basic metabolic panel! In shock.
Hypoperfused organs switch from aerobic to anaerobic metabolism and begin to produce lactate as a byproduct, eventually increasing blood lactate levels.
Additionally, renal and hepatic hypoperfusion often result in elevated BUN, creatinine, and transaminases. First, let’s take a look at non-hemorrhagic causes of volume loss.

Non-hemorrhagic hypovolemic shock6:04–6:55

In this case, history often reveals signs of gastrointestinal infection, like prolonged vomiting, diarrhea, and poor fluid intake.
Diarrheal illness is the most common cause of pediatric hypovolemic shock worldwide, but other significant causes include burns and diabetic ketoacidosis!
Next, the physical exam will demonstrate signs of dehydration, such as dry mucous membranes and skin tenting, usually in combination with decreased urine output.
However, keep in mind that in diabetic ketoacidosis, the urine output is excessively increased, not decreased! Finally, the CBC typically reveals elevated hemoglobin levels due to hemoconcentration, which confirms a diagnosis of non-hemorrhagic hypovolemic shock.
Now let’s move on to hypovolemic shock due to blood loss. Most patients have a history of trauma or bleeding, and their physical exam typically reveals superficial or overt bleeding.

Hemorrhagic shock6:55–7:45

In some cases, you might notice superficial bruising, or abdominal tenderness with rebound or guarding. The CBC will likely demonstrate a decreased hemoglobin, but remember that during an acute bleed, the red cell count may not reflect blood loss due to equilibration.
With these findings, consider hemorrhagic shock and consider imaging, like a CT scan, to assess for internal hemorrhage.
The scan may reveal evidence of intracranial, thoracic, abdominal, or pelvic bleeding, which confirms the diagnosis of hemorrhagic shock.
On the other hand, if there’s no evidence of volume loss, consider cardiogenic or obstructive shock. In this case, your next step is to assess myocardial function using a bedside cardiac point-of-care ultrasound.

No evidence of volume loss7:45–7:59

If the ultrasound demonstrates reduced myocardial function, your patient is experiencing cardiogenic shock, which is caused by ineffective myocardial contractility.

Cardiogenic shock7:59–8:20

Next, be sure to assess the underlying cause, which is most commonly supraventricular tachycardia or myocarditis. First, let’s focus on supraventricular tachycardia or SVT for short.

Sustained SVT8:20–9:13

Verbal patients commonly report palpitations and shortness of breath, while the physical exam exhibits tachycardia. In this case, consider SVT and obtain a 12-lead electrocardiogram, or ECG, to look for a heart rate consistently above 220 in infants or above 180 in children.
Additionally, if the QRS complexes are narrow, often without visible P waves, you can diagnose SVT, which is the most common pediatric dysrhythmia.
This type of dysrhythmia can be triggered by a variety of conditions, including drug use, infection, electrolyte or metabolic disturbances, structural heart lesions, or even aberrant electrical pathways such as Wolff-Parkinson-White syndrome.

Myocarditis9:13–10:21

Next, let’s take a look at individuals with myocarditis, who often report a recent viral illness, low-grade fever, and non-exertional chest pain.
Additionally, the physical examination typically reveals S3 or S4 gallop, as well as signs of heart failure, including jugular venous distention, hepatomegaly, and pulmonary crackles.
With these findings, consider myocarditis and order a chest X-ray, echocardiogram, and endomyocardial biopsy. Again, the chest X-ray will demonstrate signs of heart failure, like an enlarged cardiac silhouette and possibly a pleural effusion, while the echocardiogram shows reduced ejection fraction with ventricular dilation.
Finally, if the endomyocardial biopsy confirms the presence of inflammatory infiltration, diagnose myocarditis. Here’s a clinical pearl!
Many other conditions can cause cardiogenic shock, such as congenital heart lesions, hypoxic injury, cardiomyopathy, drug intoxication, and Kawasaki disease.

Obstructive shock10:21–10:39

Now, switching gears and moving on to obstructive shock. If the cardiac point-of-care ultrasound shows an obstruction of blood flow, consider obstructive shock, which occurs when there’s a mechanical obstruction of cardiac output.
First, let’s review congenital heart lesions associated with left ventricular outflow tract obstruction, or LVOTO. These patients are typically under two weeks old and may develop poor feeding and respiratory distress.

LVOTO10:39–11:39

The physical exam usually demonstrates a systolic murmur, possibly in combination with weak femoral pulses. Additionally, the lower extremity blood pressure might be less than the upper extremity blood pressure.
In this case, consider congenital LVOTO and obtain a chest X-ray and echocardiogram. The chest X-ray might show cardiomegaly and pulmonary edema, while the echocardiogram typically demonstrates critical narrowing of the aortic valve or aortic arch, which confirms the diagnosis.
Congenital conditions associated with LVOTO include critical aortic stenosis, interrupted aortic arch, and coarctation of the aorta.

Cardiac tamponade11:39–12:32

Next, let’s move on to cardiac tamponade. In this case, verbal patients usually report dyspnea as well as chest pain that decreases when upright or leaning forward.
If the physical exam reveals the Beck triad of hypotension, jugular venous distension, and muffled heart sounds; consider cardiac tamponade.
In most cases, you’ll need to proceed with an emergent percutaneous pericardiocentesis to relieve the pressure, but if you are not sure, order a chest X-ray and echocardiogram.
The chest X-ray will show a widened mediastinum and in some cases, you might even notice the characteristic water bottle sign.
If the echocardiogram reveals a pericardial effusion, possibly in combination with right atrial or ventricular collapse, diagnose cardiac tamponade.
Finally, let's discuss tension pneumothorax. Verbal patients may report chest or shoulder pain and severe shortness of breath.

Tension pneumothorax12:32–13:44

If the physical examination reveals a unilateral decrease or absence of breath sounds as well as unilateral hyperexpansion of the chest; consider a tension pneumothorax.
Keep in mind that tension pneumothorax is a clinical diagnosis, and emergent treatment with needle decompression should not be delayed while waiting for imaging results!
If you were to order a chest X-ray, you’d see a visceral pleural line with absent distal lung markings, and tracheal deviation or mediastinal shift to the contralateral side.
Here’s a final clinical pearl! Although the four types of shock can occur in isolation, in some conditions, one or more mechanisms can occur simultaneously.
For example, hypertrophic obstructive cardiomyopathy can cause both cardiogenic and obstructive shock. This inherited condition is associated with myocardial dysfunction and left ventricular hypertrophy, and in some cases, left ventricular outflow tract obstruction.

Review13:44–14:33

Alright, as a quick recap… Shock happens when oxygen and nutrient delivery fail to meet metabolic requirements. There are four main categories of shock: distributive, hypovolemic, cardiogenic, and obstructive, each of which is associated with various underlying conditions.
Distributive shock includes septic, anaphylactic, or neurogenic shock; while hypovolemic shock can be non-hemorrhagic or hemorrhagic.
Cardiogenic shock includes conditions associated with reduced myocardial contractility, such as sustained SVT or myocarditis.
Finally, obstructive shock is caused by obstruction to blood flow into or out of the heart; some causes include congenital heart lesions with LVOTO, cardiac tamponade,