Hypovolemic Shock
This 6-month-old infant is in hypovolemic shock (≥10% fluid deficit) and requires immediate intravenous resuscitation. 1
Clinical Reasoning
The constellation of findings definitively indicates severe dehydration progressing to shock:
- Cold extremities indicate poor peripheral perfusion and impending circulatory collapse 1
- Tachycardia with hypotension (75/45 mmHg is low for a 6-month-old) represents hemodynamic instability 1, 2
- Decreased skin turgor and sunken eyes are classic signs of moderate-to-severe dehydration 1, 3
- 7-day duration of diarrhea has allowed progressive volume depletion 1
Dehydration Classification Framework
The CDC and AAP classify dehydration severity as follows 1, 2, 4:
- Mild (3-5% deficit): Increased thirst, slightly dry mucous membranes
- Moderate (6-9% deficit): Loss of skin turgor, dry mucous membranes, sunken eyes
- Severe (≥10% deficit): Lethargy/altered consciousness, prolonged skin tenting, cool and poorly perfused extremities, decreased capillary refill, signs of shock
Why This is Hypovolemic Shock, Not Moderate Dehydration
Cool extremities are the critical distinguishing feature that elevates this from moderate to severe dehydration with shock 1. The CDC explicitly states that "cool and poorly perfused extremities" indicate severe dehydration (≥10% fluid deficit) requiring emergency intervention 1. The presence of hemodynamic compromise (tachycardia with hypotension) further confirms shock state 1.
While sunken eyes and decreased skin turgor alone might suggest moderate dehydration 1, 3, the addition of poor perfusion signs (cold extremities) and cardiovascular instability mandates classification as severe dehydration/hypovolemic shock 1, 5.
Immediate Management Required
Severe dehydration constitutes a medical emergency requiring immediate IV boluses of 20 mL/kg of Ringer's lactate or normal saline 1, 2. Treatment should continue until pulse, perfusion, and mental status normalize 1. This may require multiple IV lines or alternate access sites 1.
Once the patient stabilizes and consciousness returns to normal, transition to oral rehydration solution to replace remaining deficit 1.
Common Pitfall
The most dangerous error would be classifying this as moderate dehydration and attempting oral rehydration therapy alone. The presence of cold extremities and hemodynamic instability absolutely contraindicate oral rehydration as initial therapy 1, 2. Delayed recognition of shock significantly increases morbidity and mortality in infants 1.