This document discusses diagnosing and differentiating between primary and secondary headache disorders. It begins by explaining that headache is a common symptom neurologists evaluate and can be caused by many underlying diseases. The challenges are that primary headaches are prevalent, so secondary headaches may co-occur with primary types. Various classification systems and criteria for primary vs. secondary headaches are reviewed. Causes of secondary headaches like subarachnoid hemorrhage, cerebral vasoconstriction syndrome, spontaneous intracranial hypotension, and idiopathic intracranial hypertension are then discussed in detail, including related symptoms, imaging findings, diagnostic criteria and management considerations.

1. Diagnosing Secondary
Headache
By
Dr Mohammud Ibraheem

2. Headache is the most common symptom
neurologists are asked to evaluate.
Headache is a common and often cardinal
manifestation of a myriad of diseases, and may
be a disease unto itself.
The challenge is made more difficult because
primary headache disorders are highly
prevalent; therefore, it is common for patients
with a secondary cause of headache to also have
a long-standing history of a primary headache
disorder.

3. The International Classification of
Headache Disorders 3rd edition
The primary headaches
1. Migraine
2. Tension type headache
3. Trigeminal autonomic
cephalagias (TACs)
4. Other primary headache
disorders
The secondary headaches
5. Headache attributed to trauma or
injury to the head and/or neck
6. Headache attributed to cranial or
cervical vascular disorder
7. Headache attributed to non-vascular
intracranial disorder
8. Headache attributed to a substance
or its withdrawal
9. Headache attributed to infection
10. Headache attributed to disorder of
homoeostasis
11. Headache or facial pain attributed to
disorder of the cranium, neck, eyes,
ears, nose, sinuses, teeth, mouth or
other facial or cervical structure
12. Headache attributed to psychiatric
disorder

4. Epidemiology
Worldwide, almost 3 billion people have a
headache; of those, approximately 1.89 billion have
TTH and 1.04 billion have migraine.
For TTH, the global sex standardized prevalence is
30.8% for women and 21% for men, whereas the
prevalence rates for migraine are 19% for women
and 10% for men.
About 2% of those with headache have a secondary
cause for headache, up to 18% of patients
presenting with headache to tertiary care centers
harbor an underlying secondary cause

5. SECONDARY HEADACHE DISORDERS
The index of suspicion for a secondary cause of
headache can be effectively raised by identifying
historical data and examination red flags.
The acronym SNOOP4 is useful as a memory
aid to ensure that warning signals for sinister causes
of headache that are associated with serious
morbidity and mortality are not overlooked.
This acronym was expanded to SNNOOP10.

8. Points to detect secondary cause
A single episode of headache as opposed to recurrent
or persistent.
Headache that is substantially different from previous
headaches.
Asking about whether a headache is sudden in onset
is not sufficient to determine whether a headache is
thunderclap in onset. Ask whether the headache go
from 0 to 10 in intensity within seconds or 1 minute
or using a hand gesture, such as a clap.
Ask what the patient was doing when the headache
began (eg, during sexual intercourse, during
defecation)

9. NEUROIMAGING FOR HEADACHE
CT of the head has a very limited role in the evaluation
of secondary headache disorders. Head NCCT is useful
to exclude
A. SAH
B. Epidural or subdural hematoma
C. Intraparenchymal hemorrhage
D. Identifying skull fractures
80 million CT scans are performed annually in the US
and 50% are medically unnecessary.
In children, Epidemiologic studies have demonstrated an
increased cancer risk associated with CT scans
performed during childhood

10. Contrast
Gadolinium is helpful in characterizing parenchymal
brain lesions associated with:
1) Pachymeningeal pathology (CSF leak/intracranial
hypotension, granulomatous pathology as
sarcoidosis and granulomatosis with polyangiitis)
2) Leptomeningeal pathology (leptomeningeal
carcinomatosis )
3) Intracranial tumors
4) Infections
5) Postconcussion
6) RCVS.

11. For the majority of secondary intracranial causes of
headache, MRI is the imaging of choice.
The acronym PIN is helpful in diagnoses that are
best visualized by brain MRI:
1. Pressure abnormalities: intracranial
hypertension (IIH and secondary), intracranial
hypotension
2. Infection: meningitis, encephalitis, cerebritis,
sphenoid sinusitis
3. Neoplastic disease: parenchymal and extraaxial
neoplasms, meningeal carcinomatosis, pituitary
tumor, brain metastases

12. When ordering an MRI for a presumed secondary cause for headache,
it is important to know the correct sequences to request

13. When the index of suspicion for cerebrovascular
pathology is high, especially in context of a
thunderclap headache, MRA and
MRV or CTA and CTV is essential.
MRI is necessary to rule out early changes that is
consistent with certain secondary disorders, as
PRES, or subclinical infarction in patients with
arterial dissection.

14. Thunderclap headache
TCH is defined as a high-intensity headache of
abrupt onset. The severity itself is not
diagnostically helpful, it is the rapidity of onset,
with pain developing from zero to maximum in
seconds to minutes.
Patients presenting with a thunderclap TCH may
describe their pain as "the worst headache ever"
or "worst headache of my life“ or “like a
hammer hitting my head”

15. Types of TCH
1. Primary thunderclap headaches, followed
by primary sexual headache, bath-related
headache and exertional headache and
combinations of the aforementioned.
2. Secondary thunderclap headache
Primary and secondary thunderclap headache,
however, cannot be reliably diferentiated
clinically thus, all patients should be
investigated.

16. The other primary headache
1) Primary cough headache
2) Primary exercise headache
3) Primary headache associated with sexual activity
4) Primary thunderclap headache
5) Cold stimulus headache
6) External-pressure headache
7) Primary stabbing headache
8) Nummular headache
9) Hypnic headache
10)New daily persistent headache

17. Disorders Associated With Thunderclap
Headache
Vascular
1. Subarachnoid hemorrhage
2. Arterial dissection
3. Cerebral venous sinus
thrombosis
4. Reversible cerebral
vasoconstriction syndrome
Nonvascular
1. Spontaneous intracranial
hypotension
2. Idiopathic Intracranial
Hypertension
3. Pituitary apoplexy
4. Colloid cyst of the 3rd
ventricle
5. Acute hypertensive crisis

18. Subarachnoid Hemorrhage
Nontraumatic (or spontaneous) SAH occurs in the
setting of a ruptured cerebral aneurysm or AVM.
80% of cases of SAH result from ruptured
aneurysms.
The central feature of classic SAH is sudden onset of
severe headache (thunderclap headache), Less
severe hemorrhages may cause headache of
moderate intensity, neck pain, and nonspecific
symptoms.
Absence of headache in the setting of a ruptured
intracranial aneurysm is rare and probably
represents amnesia for the event.

19. When evaluating CT for possible SAH, it is important to
identify the locations where subarachnoid blood is less
obvious.
The acronym PITS (parenchymal, intraventricular, truncal,
sulci) is useful in making certain these locations:
1. Parenchymal blood, especially when the sylvian fissure is
compressed, may obscure the subarachnoid blood and a
MCA aneurysm that ruptured
2. Intraventricular blood, especially a small amount of blood
layering the dependent and posterior portion of the lateral
ventricle
3. Truncal (pons) SAH may be present in the prepontine,
perimesencephalic or interpeduncular cisterns
4. Subarachnoid blood may be limited to the sulci
particularly after trauma or in those with RCVS

21. Reversible cerebral vasoconstriction
syndrome
RCVS is a group of disorders characterized by severe headaches and a
narrowing of the blood vessels in the brain
SYMPTOMES
1) Recurrent thunderclap headaches. The thunderclap headaches
tend to recur over a span of days to weeks.
2) Vomiting, photophobia, phonophobia, confusion, and blurred
vision
3) Seizures and focal neurological deficits
4) History of potential triggers
5) Family history to identify inheritable conditions associated with
RCVS, such as pheochromocytoma and porphyria
6) Nonaneurysmal SAH

22. Distinguishing between certain secondary
headaches is challenging. For example, the
diffuse multifocal vasoconstriction associated
with RCVS may be difficult to distinguish from
other arteriopathies, as CNS vasculitis, primary
angiitis of the central nervous system (PACNS).
Diagnosis depends primarily on radiological
imaging. The diagnosis of RCVS requires the
radiological findings of vasospasm on cerebral
angiogram features. Vasospasm in RCVS is more
widespread, symmetric, severe and includes
involvement of the proximal arteries.

23. The RCVS2 score
The RCVS2 score is an algorithm, it demonstrate that a
score of 5 or more had 99% specificity and 90%
sensitivity for diagnosing RCVS, where a score of 2 or
less has 100% specificity and 85% sensitivity for
excluding RCVS.
Recurrent thunderclap headache over a period of days
to weeks is the sine que non of RCVS, makes up
half the total RCVS2 score, and will reliably distinguish
RCVS from CNS vasculitis, especially when associated
with a trigger (eg, sexual intercourse, straining,
bathing) and normal parenchymal brain imaging on
MRI.

25. Etiology of RCVS
1) RCVS can occur spontaneously
2) Vasoactive drugs, sympathomimetic drugs and migraine
abortive medications
3) Tetrahydrocannabinol, SSRIs, IVIG
4) NSAIDs, alcohol, amphetamines, cocaine, ecstasy, and
nicotine
5) Blood transfusions, erythropoietin
6) Migraines, certain tumors as pheochromocytoma and
paraganglioma, HELLP syndrome, antiphospholipid
antibody syndrome and TTP
7) Trauma, head and neck surgery, carotid dissection
8) Postpartum state (1 to 6 weeks)
9) Coughing, laughing

27. Spontaneous intracranial hypotension
SIH presents with:
1) Postural headache
2) Nausea, vomiting, hiccups
3) Neck pain, neck stiffness
4) Anorexia, diaphoresis
5) Diplopia, photophobia, blurred vision
6) Unsteady gait
7) Hyperacusis, tinnitus, dysgeusia
8) low CSF

28. The underlying cause is usually a CSF leak that is
caused by:
1) Congenital connective tissue disorders causing
structural abnormalities
2) Osteophyte protrusions
3) Herniation of the spinal disc
4) Focal weakness in the dura can be found
around the thoracic and lumbar spine
5) Arachnoid diverticula

29. Radiological features of SIH including:
1) Subdural fluid collections
2) Pachymeningeal enhancement
3) Venous distention sign is best seen on T1-weighted
sagittal imaging of the transverse sinus. the inferior
border takes on a distended appearance with a
convex bulging of its inferior border. The sensitivity
and specificity of the venous distention sign is
approximately 94%.
4) Brain sagging occurs in 18% to 61% of individuals
with intracranial hypotension. Findings of sagging;
Ventricular effacement, narrowing of the chiasmatic
cistern and the prepontine cistern, and cerebellar
tonsillar descent.

34. Imaging Features of Intracranial
Hypotension Using the Mnemonic SEEPS

35. Recently, a 9-point predictive scoring system
based on the 6 most discriminating imaging
features of SIH was developed and validated
The score is based on 3 qualitative and 3
quantitative signs and identifies a patient with a
high (score ≥5), intermediate (score 3 to 4), or
low (score ≤2).
This may guide the clinician’s diagnostic and
treatment decision making regarding
myelographic procedures and targeted
percutaneous or surgical dural sealing
treatments.

38. Idiopathic intracranial hypertension
The most common symptom is
1) An unbearably, frequent headache
2) Sometimes associated with nausea and
vomiting that is not relieved by medication
3) Papilledema
4) Stiff neck, back and arm pain
5) Exercise intolerance
6) Memory difficulties.

39. The diagnosis is confirmed by detecting a high
spinal CSF pressure, usually greater than 250
mmH2O or 25 cmH2O (200-250 mmH2O or 20-
25 cmH2O is considered borderline high)

40. Radiological findings of IIH:
Absence of mass occupying lesion or venous
thrombosis on neuro-imaging, normal CSF,
and no other secondary cause
Primary empty sella (PES) is the occurrence of
an empty sella without any known pathology
of the pituitary gland
Optic nerve protrusion, optic nerve tortuosity,
and optic nerve sheath (ONS) distension
Slit-like Lateral Ventricles

41. Imaging Features of Idiopathic
Intracranial Hypertension

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