Distinguishing SAH, Caput Succedaneum, and Cephalohematoma
These are three completely different conditions affecting different age groups and anatomical locations: SAH is a life-threatening intracranial hemorrhage in adults requiring emergency neurosurgical evaluation, while caput succedaneum and cephalohematoma are benign birth-related scalp injuries in newborns that resolve spontaneously.
Subarachnoid Hemorrhage (SAH) - Adult Emergency
Population and Presentation
- Adults presenting with sudden-onset severe headache described as "the worst headache of my life" (80% of cases), reaching maximal intensity immediately (thunderclap pattern) 1
- Associated with nausea/vomiting (77%), loss of consciousness (53%), and nuchal rigidity (35%) 1
- Mortality is 45% at 30 days, with 12% dying before reaching medical attention 2
Anatomical Location
- Bleeding occurs in the subarachnoid space between the arachnoid mater and pia mater, surrounding the brain 1
- Most commonly caused by ruptured intracranial aneurysm (80% of cases) 2
Diagnostic Approach
- Non-contrast head CT is the cornerstone: 98-100% sensitive within first 12 hours, declining to 93% at 24 hours 1
- If CT negative and high clinical suspicion: perform lumbar puncture looking for xanthochromia and elevated red blood cells 1
- Digital subtraction angiography to identify aneurysm source 2
Management
- Immediate neurosurgical consultation - this is a medical emergency 1
- Maintain systolic blood pressure <160 mmHg to prevent rebleeding 2
- Nimodipine 60 mg every 4 hours for 21 days to improve neurological outcomes 2
- Early aneurysm repair (endovascular or surgical) to prevent rebleeding, which has 70% case fatality 2
Caput Succedaneum - Benign Newborn Scalp Edema
Population and Presentation
- Newborns immediately after delivery, particularly following vacuum-assisted or prolonged vaginal delivery 3
- Presents as soft, pitting edema of the scalp visible at birth 3
Anatomical Location
- Superficial to the periosteum in the subcutaneous tissue layer 3
- Crosses suture lines freely - this is the key distinguishing feature 3
- Located above the galea aponeurotica
Clinical Course
- Benign and self-resolving within 24-48 hours without intervention 3
- No risk of significant blood loss or complications
- No treatment required
Cephalohematoma - Subperiosteal Blood Collection
Population and Presentation
- Newborns, typically becoming apparent hours to days after delivery (not immediately visible like caput) 3
- More common with vacuum or forceps-assisted delivery 4
- Presents as firm, non-pitting swelling that may enlarge over first 24-48 hours 3
Anatomical Location
- Subperiosteal hemorrhage - blood collection between skull bone and periosteum 3
- Does NOT cross suture lines because periosteum is tightly adherent at sutures - this is the critical distinguishing feature 3
- Most commonly affects parietal bones
Clinical Course and Complications
- Resolves spontaneously over weeks to months (typically 2-3 months) 3
- May be associated with hyperbilirubinemia (40% of cases) as blood resorbs 4
- Can coexist with more serious intracranial injuries: subdural hemorrhage (50%), subarachnoid hemorrhage (15%), or skull fracture (30%) 4
- Monitor for severe metabolic acidosis (pH <7.0), which is the only prognostic factor associated with mortality 4
Management
- No intervention required for isolated cephalohematoma 4
- Monitor hemoglobin if large - 60% required transfusion in one series when associated with subgaleal hemorrhage 4
- Phototherapy if hyperbilirubinemia develops (mean total bilirubin 13.1 mg/dL) 4
- Never aspirate - risk of infection and reaccumulation
Critical Distinguishing Features Summary
| Feature | SAH | Caput Succedaneum | Cephalohematoma |
|---|---|---|---|
| Age | Adults | Newborns | Newborns |
| Location | Intracranial (subarachnoid space) | Scalp (subcutaneous) | Subperiosteal |
| Crosses sutures | N/A | YES | NO |
| Timing | Sudden onset | Present at birth | Hours to days after birth |
| Texture | N/A | Soft, pitting | Firm, non-pitting |
| Mortality | 45% | 0% | <1% (only if severe acidosis) |
| Treatment | Emergency neurosurgery | None | Observation only |
Common Pitfall
Caput succedaneum and cephalohematoma can coexist - if swelling crosses suture lines, do not assume it is only caput succedaneum, as you may miss an underlying cephalohematoma 3. MRI can distinguish if clinically important 3.