Differential Diagnosis for Headache in Pregnancy at 14 Weeks

• Single most likely diagnosis
  • Tension headache: This is the most common type of headache and can be exacerbated by stress, lack of sleep, and environmental factors such as a warm day. The brief worsening with vomiting could be due to increased intrathoracic pressure, but the mild and persistent nature of the headache is more suggestive of a tension headache.
• Other Likely diagnoses
  • Migraine: Although migraines are often unilateral and can be triggered by environmental factors, the lack of other migraine-specific features (such as aura, phonophobia, or photophobia) makes this less likely. However, migraines can occur without these features, and the patient's symptoms could still be consistent with a migraine.
  • Dehydration headache: Given the warm day and the fact that the headache briefly worsened with vomiting, dehydration could be a contributing factor. Dehydration headaches are common, especially in pregnancy, where fluid balance can be more delicate.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Preeclampsia: Although less likely at 14 weeks, preeclampsia can occur and is a condition that must be considered in any pregnant patient with a new-onset headache. The presence of hypertension and proteinuria would support this diagnosis, but their absence does not rule it out.
  • Subarachnoid hemorrhage or other intracranial hemorrhages: These are rare but potentially life-threatening conditions that could present with a sudden, severe headache. The fact that this headache is described as mild and persistent makes this less likely, but it cannot be entirely ruled out without further evaluation.
  • Venous sinus thrombosis: This is a rare condition that can occur in pregnancy due to hypercoagulability. It typically presents with a severe, progressive headache, but early stages might be less severe.
• Rare diagnoses
  • Idiopathic intracranial hypertension (IIH): Also known as pseudotumor cerebri, this condition can cause headaches that worsen with maneuvers that increase intrathoracic pressure, such as vomiting. It is more common in obese women of childbearing age but is still relatively rare.
  • Arteriovenous malformation (AVM) or aneurysm: These vascular abnormalities can cause headaches if they bleed or if they exert mass effect on surrounding structures. They are rare and usually present with more severe symptoms, but they must be considered in the differential diagnosis of any new, unexplained headache in pregnancy.