Approach to shock (pediatrics): Clinical sciences

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. 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.

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.

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. 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. 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.

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.

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.

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. 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. 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. 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.