Diagnosis of Secondary Headache Based on Causes, Symptoms and Investigations

Headaches are a common occurrence, experienced by anyone and they appear in various forms. Secondary headache is a condition, when headache is result of another underlying condition. Tension headaches, migraines and other types of headaches are considered primary headache. But when headache occurs due to presence of other medical conditions, it is termed as secondary headache. As there are several medical conditions casing headache, diagnosis of secondary headache is challenging and needs thorough investigation and understanding of the condition.

It is believed that primary headaches are less serious, however, secondary headache, depending on the underlying cause can have serious complications and can even be life-threatening at times. Diagnosis of secondary headache is crucial and the physician often considers the patient’s history, clinical symptoms and evaluates all possible causes of secondary headache.

Secondary headache can be a result of various medical conditions and it is important to evaluate all possible causes for the diagnosis of secondary headache. Some of the important causes of secondary headache include:

1. Diagnosing Secondary Headache Secondary to Inflammation and Infections

   Conditions causing inflammatory reactions in the body or infections can cause secondary headaches:

   • Sinusitis – Inflammation and infections of the sinuses or pockets in the skull can lead to secondary headache. This is mostly accompanied with running or blocked nose, pain in the frontal sinuses or the area above the eyes, maxillary sinuses or the cheek bones and pain may also extend to the ears.
   • Upper respiratory infections – Upper respiratory infections that cause running nose, ear infections, otitis media, throat infections like laryngitis, pharyngitis can present specific symptoms and also result in secondary headache.
   • Influenza and flu-like fevers – Influenza and other viral fevers, often result in body ache, joint pain, weakness, fever and secondary headache.
   • Meningitis – Inflammation of the meninges or the covering of the brain and the spinal cord, or infections affecting the lining can cause secondary headache. It may be accompanied with vomiting, stiffness of neck and fever. Meningitis presents itself with secondary headache.
   • Encephalitis – Inflammation in the brain is encephalitis or inflammation in the brain and spinal cord, which is encephalomyelitis, can cause secondary headache. These inflammations are often caused by bacterial, viral or other infections and can result in secondary headaches.
   • Brain abscess – Brain abscess is an inflammatory condition, caused by an abscess or infected material collected in the brain or nearby structures, like an ear infection, dental abscess, sinus infection, epidural abscess, mastoid bone infection or any infection in another location like the lungs or the kidneys. It can cause secondary headache.
   • Giant cell arteritis – It is an inflammatory vasculitis, occurring in older people, above 50 years and presents with secondary headache, joint pain, facial pain, vision difficulties and sometimes, fever.
   • Toxoplasmosis – It is a parasitic infection, caused by Toxoplasma gondii parasite. Toxoplasmosis occurs due to feces of cat and some other animals, which can spread through contaminated food and water. When symptoms are present, the person may have flu-like symptoms, fever, body pain and secondary headache.
   • Trigeminal neuralgia – Trigeminal nerve is a nerve carrying signals from the face to the brain. When this nerve gets affected, injured or damaged, it can result in pain in trigeminal nerve, called trigeminal neuralgia. It often presents with increased sensitivity in facial areas, sudden episodes of facial pain. It also causes pain in and around the cheeks, jaws, lips, eyes or forehead. It can also result in secondary headache.
   • Dental infections – Tooth decay, eruption of wisdom tooth, or abscess can result in secondary headache.

2. Diagnosing Secondary Headache Caused Due to Space Occupying Diseases and Lesions

   Conditions that are space occupying diseases and lesions usually create pressure in the neighboring areas, resulting in secondary headache. These include:

   • Brain Tumor – A tumor is an extra growth in brain cells or in closely associated structures. The growing tumor exerts pressure on the surrounding structures and results in secondary headaches. Symptoms of brain tumor include headache, convulsions, changes in sensation, nausea and vomiting.
   • Hydrocephalus – While normally cerebrospinal fluid is present in the brain, excessive accumulation of fluid in the brain is called hydrocephalus. It may be present since birth or may be acquired later on. The excess fluid accumulation exerts pressure on surrounding parts and results in secondary headache.
   • Arterial Aneurysm – Arterial aneurysms are an abnormal bulge in the arterial walls, which can occur in any part of the body. This condition can occur due to entrapment, infections or septic emboli, etc. Aneurysms occurring around head, face and neck area, can cause secondary headache and may be associated with malaise and fever.
   • Sub-Dural bleeding and hematoma – Subdural hematoma is a type of brain injury, which occurs from serious head injury. It commonly presents with secondary headache and associated symptoms like difficulty in balance and co-ordination, vision and speech difficulties, confusion and sometimes weakness.
   • Arteriovenous Malformation – This condition is a defect in the vascular system that causes tangled arteries and veins and commonly occurs in the brain and spinal cord region. It interferes with blood circulation and can result in secondary headache.
   • Chiari Malformation – It is a condition, in which there are structural defects in the part of the brain, called cerebellum that controls balance. It affects the brain and spinal cord and can cause secondary headache.

3. Diagnosing Secondary Headache Caused Due to Injuries

   Injuries to the head, face, neck region or any part can sometimes affect the brain and result in secondary headache, depending on the type of injury.

   The commonest injuries that can cause secondary headache include:

   • Brain Concussion – It is a type of brain injury, occurring due to fall or blow on the head or an injury that shakes the brain inside the skull. It may or may not cause loss of consciousness, but often results in secondary headache and other symptoms depending on the person and the severity of the injury.
   • Brain Contusion – It is a bruise or contusion in the tissues of the brain, usually occurring due to a severe impact on the brain. It can occur due to sports injuries, falls or during car accidents and the prominent ridges in the skull commonly get bruised. Secondary headache is a result of such an injury.
   • Whiplash Injury – Commonly known as whiplash is a neck strain, usually occurring during vehicular accidents and rear end collisions. In this, the neck is thrusted back and forth, causing damage to the neck muscles and soft tissues. It can cause neck pain, pain and limited movements in the area of strained muscles and ligaments and sometimes secondary headache, depending on the impact of the injury.

4. Diagnosing Secondary Headache Caused Due to Systemic Disorders

   Certain conditions affecting other systems of the body and metabolism can cause secondary headaches. Some of the common conditions include:

   • Stroke – Stroke is a condition resulting from interruption or reduction in the blood supply to the brain. It occurs suddenly, affecting one side of the body, slurring of speech, affects arms and can result in severe headache.
   • Hypothyroidism – This is underactive thyroid, when the thyroid gland does not produce adequate hormones and results in various systemic problems, including secondary headache.
   • High blood pressure – Blood pressure readings above 140/90 mm of Hg are considered high, but sometimes the pressure increases to very high levels and increase the risk of stroke and heart attack. It can also cause secondary headache.
   • Anemia – Anemia is having low hemoglobin levels, which can result in feeling tired, fainting and secondary headache.
   • Spinal headache – Certain procedures like spinal tap, epidural block, performed as diagnostic or therapeutic procedures, can result in secondary headache.
   • Systemic infection – Conditions and infections affecting other systems like respiratory infections, gastrointestinal infections, typhoid, malaria, etc. often cause fever and secondary headaches.
   • HIV/AIDS – Infections like HIV and AIDS can cause secondary headache, associated with other symptoms.

5. Diagnosing Secondary Headache Caused Due to Substance Abuse and Withdrawal Symptoms

   Use or consumption of certain substances or their withdrawal can cause undesirable effects and secondary headache is one of the symptoms. These conditions include

   • Carbon monoxide poisoning – Carbon monoxide is a poisonous gas released by burning at fireplaces, furnaces, stoves, etc. If the gas gets built up inside a room and people breathe it, it can result in dizziness, stomach pain and secondary headache.
   • Alcohol – Excessive alcohol intake can cause secondary headache. Also, withdrawal of alcohol in regular drinkers too can cause secondary headache.
   • Medicine overuse – Secondary headache can be a result of chronic medication. Also, withdrawal of such medicines or medicines that cause dependence, those containing opiates, too can cause secondary headache.
   • Others – Other substances that cause dependence, stimulants like tea, coffee or anything a person is specifically habituated to, when withdrawn can cause secondary headache.

6. Diagnosing Secondary Headache Based on Other Causes

   While most of the causes are categorized in the list above, there are some other causes, which can cause secondary headache.

   • Glaucoma – Glaucoma is a condition caused due to increased intraocular pressure. While there are many types of glaucoma, certain types may present with severe headache as a symptom, which is secondary headache.
   • TMJ – Temporomandibular joint disorders often leads to jaw pain, pain in facial muscles, difficulty in making jaw movements and secondary headache. It can be associated with injury or arthritis of the jaw joint.
   • Optic neuritis – Optic neuritis is the inflammation of the optic nerve and can affect either of the eyes, causing eye symptoms and secondary headache.
   • Low blood sugar – When sugar levels drop down, it can cause fainting, discomfort and headache.
   • Errors of refraction – Refractive errors commonly called short-sightedness (myopia), long-sightedness (hyperopia), sight problems with aging (presbyopia), astigmatism and others, may result in secondary headache if not appropriately managed with the use of spectacles and any treatment, as required.
   • Changes in routine – Lack of sleep, skipping meals, over exertion, or any other changes in a person’s daily routine can lead to secondary headache.

Symptoms of secondary headache often vary with the underlying cause. It may be commonly seen in middle-aged people, however, children and teens are also vulnerable and any atypical symptoms should immediately receive medical attention.

Secondary headache presents with the following symptoms, based on the cause

Secondary headache can be of sudden onset in conditions like trauma to the brain, brain hemorrhage, meningitis, encephalitis or hypertension. However, slow progression and buildup of secondary headache can be seen in brain abscess, tumors, hydrocephalus, neck and facial muscle pain or dehydration.

Secondary headache in case of encephalitis, meningitis, aneurysm, brain hemorrhage can be continuous, while it may be intermittent in pregnancy, dehydration or hypertension. Recurrent type of secondary headache can be seen in substance and medication withdrawal or hypertension.

The intensity of secondary headache can vary with the severity of the underlying condition. Secondary headaches originating from fasting, inadequate sleep, sinusitis or other upper respiratory illnesses, flu-like conditions are often mild and may last for a short period. Whereas secondary headache due to meningitis, hypertension, brain tumor, hemorrhage, brain aneurysm, abscess, etc. may be moderate to severe in nature and may be present for a longer period.

Depending on the underlying condition, secondary headache may be associated with some other complaints like:

• Nausea and vomiting
• Loss of desire to eat and indigestion.
• Stiffness of neck
• Pain in jaw, face or neck
• Numbness or tingling in neck, arms or hands
• Weakness
• Confusion and impaired cognitive function
• Difficulty in sleeping
• Seizures
• Difficulty in vision, speech or hearing.

Diagnosis of secondary headache needs evaluation of all symptoms, their frequency, severity and overall nature of the headache, along with associated symptoms. In addition, some signs associated with secondary headache are related to the possibility of certain condition. These too need to be studied and evaluated to aid the diagnosis of secondary headache.

Certain signs and symptoms that may accompany secondary headache include

• Neuro-deficiency, numbness or weakness in the regions around the head, neck, arms or hands. These may be seen in brain tumor, hematoma, abscess, brain aneurysm or stroke.
• Associated visual symptoms or swelling of optic nerve must be assessed, which could point towards tumor, abscess, malformation, hematoma or hydrocephalus.
• Any possibility of brain injury, concussion or contusion must be suspected if there are signs of trauma, history of fall, accident or sports injury.
• Signs of stroke must be looked for which could be loss of consciousness, numbness, tingling, weakness or difficulty in balance and co-ordination.
• Abnormally high blood pressure or hypertension should raise the suspicion of intracranial hemorrhage.
• Possibility of dehydration can be ruled out by checking for other signs of dehydration like dry, lax skin, dry mouth, low blood pressure and increased heart rate.

Other systems that need to be examined and assessed include:

Examining the oral cavity to determine the possibility of dental caries, abscess or disorders of the jaw joint. Eye examination must be done to rule out disorders of the eye and any conditions that can cause visual symptoms. All functions including speech, hearing, cognition, muscle control, balance and co-ordination needs to be assessed.

Secondary headache or any type of headache can be a matter of concern if certain warning signs are present. Red flags of headache, which may need immediate medical attention include SNOOP

• S – Systemic symptoms like weight loss, fever or risk factors of secondary headache like HIV or systemic cancer.
• N – Neurological symptoms or atypical signs like impaired alertness, confusion, loss of consciousness
• O – Onset, which is usually sudden and abrupt or split-second.
• O – Older, particularly in older people, above 50 years, new onset of headache or progressive headache, like in giant cell arteritis.
• P – Previous history of headache or progression of headache, which can be first headache or a previous headache now appearing with change in frequency of episodes, difference in severity or clinical symptoms.

The physician would like to consider the pattern of headache to be able to understand whether it is secondary headache. This includes, episode of headache being the first or the worst type in a person’s life, sudden onset without any buildup, radical change in the pattern of previously occurring headaches, presence of associated problems like seizures, fainting or aggravation on exertion, abnormality found during physical examination and presence of other conditions, pregnancy, cancer or HIV.

While assessing symptoms and signs of secondary headache can help to understand the possible causes of secondary headache, investigations can help to confirm the underlying cause.

Some investigations commonly performed for diagnosis of secondary headache include:

Blood tests can be performed to rule out various common conditions to a range of serious infections. Some of the blood tests performed for diagnosis of secondary headache include:

• Hemoglobin levels to rule out anemia.
• Complete blood picture – To check for elevated white blood cells (WBCs), which occurs in infections like abscess, sinusitis, meningitis, encephalitis or other systemic infections. To check platelet count, which may be reduced in certain infections, hematoma or intracranial bleeding.
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) – To check the trend and severity of inflammatory conditions like autoimmune disorders, temporal arteritis and other infections.
• Serum calcium – Increased calcium levels associated with headaches need to be assessed.
• Venereal Disease Research Laboratory (VDRL) – To evaluate increased levels in venereal diseases and tuberculosis, when associated with headaches.
• HIV/AIDS – To assess presence of HIV infection or AIDS disease.

To check for systemic functions:

• Serum creatinine – These levels may be raised in case of renal conditions or renal failure if associated with headaches.
• Liver function tests – To check for liver function to rule out metastasis of brain tumors.
• Thyroid function tests – To assess thyroid hormone levels as low levels can cause secondary headache.

Imaging and radiological studies can help to diagnose the underlying condition causing secondary headache and assess the impact and severity of the condition.

• X-ray – X-rays of the affected area considering the history of complaints is ordered. X-rays of the sinuses to assess sinusitis, dental areas for dental abscesses and caries, skull in case of injuries may be performed.
• CT scan – CT scan of brain is often performed to evaluate hemorrhage, hematoma, aneurysm, injuries, tumors, malformation or hydrocephalus in the brain. CT scan of neck may be done to rule out conditions affecting the neck, whiplash injuries, etc.
• MRI – MRI brain may also be performed to assess various conditions affecting the brain that can lead to secondary headache. Brain contusion, concussion and all other severe forms of brain disorders can be assessed.
• Electroencephalogram (EEG) – EEG test is mainly done to evaluate the cause of seizures and assess brain activity to rule out certain brain disorders, causing secondary headache.
• Spinal tap – Spinal tap is a procedure performed to aspirate cerebrospinal fluid, which is sent for laboratory analysis. Conditions like infections, tumor, abscess, hematoma, etc. of the brain and spinal cord can be diagnosed with this test.

• System specific investigations may be ordered, depending on the body part or system involved.
• Ophthalmoscopy evaluation, optic nerve scanning, glaucoma tests, etc. may be done to rule out eye related conditions, glaucoma or optic neuritis.
• Ear and hearing evaluation may be done using otoscope or tests like impedance audiometry to evaluate possibility of middle ear effusion, which could be a cause of secondary headache.