Differential Diagnosis for Primary Cough Headache and Chiari Malformation Headache

When differentiating between primary cough headache and Chiari malformation headache, it's crucial to consider various diagnoses based on their likelihood and potential impact on patient outcomes. The following categorization helps in systematically approaching these conditions:

• Single Most Likely Diagnosis
  • Primary cough headache: This is a likely diagnosis if the headache is triggered solely by coughing and other Valsalva maneuvers, without any evidence of structural lesions. The headache typically resolves within minutes after the precipitating event.
• Other Likely Diagnoses
  • Chiari malformation type I: Characterized by the herniation of the cerebellar tonsils into the foramen magnum, which can cause headaches that worsen with coughing or straining. Neuroimaging, particularly MRI, is diagnostic.
  • Secondary cough headache: This could be due to various causes such as a Chiari malformation, but also includes conditions like space-occupying lesions or other structural abnormalities that cause increased intracranial pressure.
• Do Not Miss Diagnoses
  • Subarachnoid hemorrhage: Although less common, a sudden, severe headache (often described as "the worst headache of my life") could be indicative of a subarachnoid hemorrhage, especially if accompanied by other symptoms like vomiting, altered consciousness, or focal neurological deficits.
  • Brain tumor: Any new onset of headache, especially if worsening over time or associated with neurological deficits, warrants investigation for a possible brain tumor.
  • Arteriovenous malformation (AVM): An AVM could cause headaches and might be suspected if there are associated neurological symptoms or if the headache is unusually severe or persistent.
• Rare Diagnoses
  • Spontaneous intracranial hypotension: This condition, characterized by low cerebrospinal fluid pressure, can cause headaches that might worsen with coughing or straining, although it's less common.
  • Cervicogenic headache: Although not directly related to coughing, if the headache is referred from the cervical spine, it could potentially worsen with certain movements or maneuvers, including coughing.

Each of these diagnoses requires careful consideration of the patient's history, physical examination, and appropriate diagnostic tests to accurately differentiate between primary cough headache and Chiari malformation headache, as well as to identify other potential causes.