When a headache is a pain! About primary and secondary headaches

When a headache is a pain! About primary and secondary headaches

Nitin K. Sethi, MD

Assistant Professor of Neurology

New York-Presbyterian Hospital

Weill Cornell Medical Center

New York, NY 10065



Headaches are a very common reason that patients consult a neurologist like me.  The intensity of the headache, its character and duration are some of the factors which determine if and when patients seek medical attention. So in this post I shall go over the different types of headaches and list their main differentiating features.

Broadly speaking we can divide headaches into primary and secondary headaches. Primary headaches are those headaches for which there is no structural/ secondary cause.  For example a migraine headache is an example of a primary headache. The migraine may be severe and frequently disabling but if you scan (CT or MRI) the patient’s brain no underlying structural lesion like a tumor is found. Secondary headaches as the name implies are secondary to a another cause. For example headache due to a large brain tumor or headache due to an infection (meningitis) represent secondary headaches.

Types of primary headaches:

1)      Migraine: common migraine and classical migraine

2)      Tension type headache

3)      Cluster headache

Types of secondary headaches:

1)      Headache secondary to a brain tumor or other masses (space occupying lesions) in the brain

2)      Headache secondary to an infectious and inflammatory process in the brain (example headache associated with meningitis)

Headaches can be a cause of concern and distress. Patients frequently worry that may have a brain tumor. So let us go over some of the signs and symptoms which suggest that the headache is due to a secondary cause . These are the signs and symptoms which should make you seek urgent medical attention:

  1. Sudden onset of severe headache. When asked patients rate their headache as the “worse headache of their lives”. I shall be concerned if I encounter such as patient in the ER, more so if the patient tells me that they have never had a  headache in their life before. When accompanied with other signs such as nuchal (neck) rigidity and depressed sensorium (level of alertness), the question of subarachnoid hemorrhage (SAH) comes to mind. A common cause of non-traumatic SAH is the rupture of an aneurysm or arteriovenous malformation (AVH) in the brain. SAH is associated with high morbidity and mortality especially if the patient presents to medical attention late.

Caveat: Not all “worse headaches of my life” are due to SAH due to rupture of an intracranial aneurysm. Many times (especially if there is a past history of migraine headaches) these patients are suffering from a particularly debilitating/ severe attack of migraine. Thunderclap/ explosive headaches have also been reported at the time of coitus. They are referred to as post coital or orgasmic headache.

  1. Headaches in extreme of ages:  headaches which occur in the extreme of ages (such as in a young child or after middle age especially if there is no past history of headaches) deserve a more closer look. Signs such as neck stiffness or depressed level of sensorium may be masked or difficult to elicit in these age groups. As a neurologist my threshold of investigating these patients with tests such as MRI of the brain and more invasive tests such as spinal tap (lumbar puncture) is lower.

Caveat: small children frequently cannot express headache (meaning they cannot tell you that they are bothered by headache).  Primary headaches such as migraine may be missed in children as a result. The child may be agitated and parents may think he is acting up. So a high index of suspicion has to maintained by the physician to timely identify migraines in small children. Also it is well known that migraine is not “typical” in the pediatric age group. Various migraine variants have been identified in children such as abdominal migraine (the child complains of episodic abdominal pain), cyclical vomiting and so forth.

  1. Onset of headache in middle age (especially if there is no prior history of headaches): when a middle aged patient comes to me and says he is bothered by headaches for the past 3-4 months, never had headaches when he was in his teens, I pay close attention to him. A thorough neurological examination shall frequently tell me if there is anything “brewing” inside the brain aka does he have a mass lesion/ tumor? As a neurologist I have several tools to help me in this endeavor. I can look for signs of asymmetry: weakness/ numbness on one side of the body, problems with coordination on one side of the body, is the gait steady, are the reflexes symmetrical and so forth. I can further look into his eyes with an ophthalmoscope to see if there is increased pressure inside the brain (remember the eyes are the window into the brain).  Based on my exam, I may or may not order a MRI scan or CT scan to confirm my suspicion.
  2. Headaches associated with fever: are always a cause of concern. Various disease processes such as meningitis (bacterial, viral or fungal), brain abscesses and so forth come into the differential. Patients are admitted into the hospital and further management depends upon the underlying etiology.
  3. Recent onset of headache in an immunocompromised patient: recent onset of headache in a patient who is immunocompromised (example a HIV positive patient or a patient who is receiving chemotherapy for cancer) always warrant a thorough work-up. Such patients are frequently found to have a secondary cause for their headaches. So again my threshold for imaging such patients is low.  My threshold for doing a spinal tap in these patients is also low (provided I am confident that the pressure in the brain is normal).
  4. Headache/ temporal pain  in a patient past 65: temporal arteritis (Giant cell arteritis) is a disease entity which is seen in the elderly and is due to inflammation of the temporal arteries. Patients may not complain of headache per-se. When you examine them you find they have tenderness over the temporal arteries and the artery may feel beaded and thickened.  It is imperative that temporal arteritis be identified in a timely fashion and treated otherwise the patient may suffer loss of vision.

In the next post I shall talk about the primary headaches.

Meningitis or encephalitis?

Let us discuss viral encephalitis in this post. First what do we mean when we say a patient has encephalitis and how does encephalitis differ from meningitis.

Meningitis is inflammation of the meninges of the brain. The meninges are the thin layers which cover the brain and include from inwards outwards pia mater, arachnoid mater and dura mater. When they get inflammed usually due to an infectious etiology a patient develops meningitis. There are numerous causes of meningits and they can be classified as bacterial causes (common bacteria which cause meningits include Haemophilus Influenzae type B, Nesseria meningitidis, Streptococcus pneumoniae, Listeria), viral causes (most of the viruses which cause meningitis are seasonal viruses and usually it is hard to isolate them. We do not try too hard to find out the particular virus causing the meningits as viral meningitis is usually self limited and has a good outcome with most patients recovering completely), fungal causes, parasitic causes and so on. So how does meningits present clinically? Patients usually have complaint of fever, headache and stiff neck. They feel tired and listless and may also have nausea and vomiting. Patients who have meningitis are bothered by bright light (we call this photophobia and hence they prefer to lie in a quiet dark room), loud sounds are also bothersome (we call this phonophobia). When we assess such patients clinically we look for tell-tale signs of meningitis: namely we check for neck stiffness (neck stiffness in a febrile patient is quite sensitive for meningitis). Patients with meningitis at least initially in their disease course are awake and alert and do not present with seizures (remember it is the meninges which are involved not the brain itself at least initally). Later on if the meningitis remains untreated patients become stuporous and comatosed. Bacterial meningitis as compared to viral meningitis is more fulminant and if untreated can prove fatal (bacterial meningitis patients usually look more “sick” as compared to those with viral meningitis). Once the diagnosis of meningitis is entertained we usually admit these patients to the hospital (some patients with viral meningitis may be managed on an outpatient basis if close supervision can be ensured). A CT scan is usually done next followed by a spinal tap to get some cerebrospinal fluid. This fluid is then sent for various tests. The diagnosis is confirmed if the spinal fluid shows inflammatory cells. On the basis of tests on the spinal fluid we can determine whether the patient has bacterial, viral, fungal or tubercular meningitis (each type has its own spinal fluid characteristic. Moreover we examine the fluid under the microscope and further culture it to isolate the organism). As you can imagine, it takes time for some of these tests to come back, so patients may be empirically started on antibiotics pending CSF culture results. Once the CSF results come back, the antibiotics can be changed depending upon which organism is isolated from the CSF.

So then what is encephalitis and how does it differ from meningitis. Encephalitis simply put is inflammation of the brain itself (not the meninges). Usually the term is used in connection with a viral etiology. The common causes of encephalitis include viruses like herpes simplex, cytomegalovirus, West Nile, flaviviruses to name a few and the common encephalitis are: herpes simplex encephalitis, Japanese encephalitis, Eastern Equine and Western Equine encephalitis, California encephalitis and tick-borne and arthropod borne encephalitis (such as Lyme encephalitis). Since in encephalitis the brain parenchyma is involved, these patients may present with depressed level of consciousness, altered personality, abnormal behavior and seizures. Usually in encephalitis the brain MRI is abnormal and gives us a hint to the extent of brain parenchymal involvement. The spinal fluid may show inflammatory cells (some patients have a component of meningitis along with their encephalitis: MENINGOENCEPHALITIS). Doctors may also order other tests like EEG to rule out seizures. The treatment of encephalitis varies. In the case of herpes encephalitis we use anti-viral drugs like acyclovir. In other encephalitis the treatment is more supportive. Some patients recover (those detected and treated in time), others are left behind with devastating neurological sequelae


Nitin Sethi, MD