Can Valsalva Maneuver Cause Severe Headache and Altered Mental Status with Normal CT?
Yes, intense Valsalva maneuvers can cause severe headache and altered mental status without visible abnormalities on CT imaging, most commonly due to cerebral venous thrombosis (CVT) or benign Valsalva-related headache, both of which frequently show normal initial CT scans.
Primary Diagnostic Consideration: Cerebral Venous Thrombosis
The most critical diagnosis to exclude is CVT, which can present with headache as the sole manifestation in 40% of cases and frequently shows no blood or parenchymal lesion on initial CT scan 1.
Key Clinical Features of CVT:
- Headache worsened by Valsalva maneuvers, straining, sleep/lying down occurs in the majority of CVT patients presenting with headache alone 1
- Altered mental status occurs in 8% of CVT cases 2
- Normal neurological examination does not exclude CVT 1
- CT without contrast has very limited sensitivity for detecting CVT—the diagnosis requires CT venography or MRI with venography 1
Critical Pitfall:
A normal non-contrast CT does not rule out CVT. Patients with headache worsened by Valsalva maneuvers require dedicated venous imaging (CTV or MRV) even when initial CT appears normal 1.
Secondary Consideration: Benign Valsalva-Related Headache
If venous imaging excludes CVT, benign Valsalva-related headache is the likely diagnosis 3.
Characteristics:
- Presents between ages 49-67 years 3
- Variable location and duration, mostly global and short-lasting 3
- MRI shows no structural abnormality in the majority of cases (75% in one series) 3
- Can improve spontaneously or respond to indomethacin or propranolol 3
Imaging Algorithm
Initial Imaging:
Non-contrast CT is appropriate as first-line imaging but has limited diagnostic yield 2. The ACR Appropriateness Criteria recommend CT head without contrast as the first-line test for altered mental status, with yield of acute findings ranging from 2-45% depending on risk factors 2.
When CT is Normal but Suspicion Remains High:
MRI brain without and with contrast plus MR venography is mandatory when:
- Headache worsened by Valsalva maneuvers 2, 1
- Altered mental status persists 2
- Headache is recent, persistent, or thunderclap in nature 1
The Headache Consortium guidelines specifically identify "headache worsened by Valsalva maneuver" as a clinical feature associated with increased likelihood of abnormality on neuroimaging, though they note insufficient evidence to make definitive recommendations 2.
Physiologic Mechanism
Valsalva maneuvers cause significant increases in intracranial pressure and reductions in cerebral perfusion pressure 4. This can precipitate:
- Venous stasis leading to CVT 1
- Transient intracranial pressure elevations causing headache 3, 4
- In rare cases, intracranial hemorrhage (though this would be visible on CT) 2
Risk Factors Requiring Imaging:
Based on ACR guidelines, the following increase likelihood of positive findings 2:
- Anticoagulation therapy
- History of malignancy
- Older age
- Impaired consciousness or unresponsiveness
- Nausea or vomiting
Management Approach:
- Obtain non-contrast CT initially to exclude hemorrhage and mass effect 2
- If CT is normal but clinical suspicion remains (Valsalva-triggered headache with altered mental status), proceed immediately to MRI brain with and without contrast plus MR venography 2, 1
- Do not be falsely reassured by normal CT—CVT is the diagnosis that cannot be missed and requires dedicated venous imaging 1
- If all imaging including venous studies is normal, consider benign Valsalva-related headache and trial of indomethacin or propranolol 3