Differential Diagnosis of Intractable Headache in 3rd Trimester Pregnancy

Single Most Likely Diagnosis

• Tension Headache: This is often the most common type of headache in pregnancy, including the third trimester. It can be exacerbated by stress, fatigue, and the physical strain of late pregnancy.

Other Likely Diagnoses

• Migraine: Migraines can occur at any stage of pregnancy, including the third trimester. They are often severe and can be triggered by various factors, including hormonal changes.
• Cervicogenic Headache: This type of headache is caused by referred pain from the cervical spine and can be more common in late pregnancy due to the increased strain on the neck and back.
• Sinusitis: Pregnancy can increase the risk of sinusitis due to nasal congestion and immune system changes, leading to headaches.

Do Not Miss Diagnoses

• Preeclampsia: A condition characterized by high blood pressure and often accompanied by protein in the urine, preeclampsia can cause severe headaches. It is a medical emergency that requires immediate attention.
• Posterior Reversible Encephalopathy Syndrome (PRES): Associated with preeclampsia and eclampsia, PRES can cause severe headaches, seizures, and visual disturbances.
• Subarachnoid Hemorrhage: Although rare, this condition can occur in pregnancy and is often associated with severe, sudden-onset headache (often described as "the worst headache of my life").
• Venous Sinus Thrombosis: A blood clot in the venous sinuses of the brain, which can cause headache, among other symptoms, and is more common in pregnancy due to hypercoagulability.

Rare Diagnoses

• Pituitary Apoplexy: A rare condition where there is bleeding into the pituitary gland, which can cause sudden, severe headache, often accompanied by visual disturbances and acute endocrine deficiencies.
• Arteriovenous Malformation (AVM) or Arterial Aneurysm: These vascular abnormalities can rupture during pregnancy, leading to subarachnoid hemorrhage and severe headache.
• Idiopathic Intracranial Hypertension (IIH): Also known as pseudotumor cerebri, this condition can cause increased intracranial pressure, leading to headaches, often with visual disturbances, and is more common in obese women, a growing demographic in pregnancy.