Category Archives: Brain

Sentinel Headache: Subarachnoid Hemorrhage

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A 25 year old male college student presents to the ER with complaint of sudden severe headache with an episode of vomiting. On exam he looks uncomfortable but is neurologically normal, that is, he is awake, oriented fully, moving arms and legs without weakness or neglect. Pupils are 3 mm and reactive. A head CT is ordered:

Sudden, severe headache

Sudden, severe headache

The verbal report is “normal,” and he is discharged home.

One week later the same patient arrives at the ER by ambulance, non arousable, with decerebrate (extensor) posturing to deep pain stimulus, no verbalizations, and non reactive pupils measuring 5 mm. A CT scan is again ordered:

Devastating subarachnoid hemorrhage

Devastating subarachnoid hemorrhage

This devastating subarachnoid hemorrhage was preceded a week earlier by a tiny bleed in the region of the left posterior cerebral artery, a hemorrhage so small in fact that is was not identified on the radiologist’s formal reading. The patient experienced a sentinel headache that heralded the aneurysm rupture that took his life a week later. In the case of a suspected subarachnoid hemorrhage with a negative head CT, consider lumbar puncture to look for RBCs or xanthochromia in the CSF.  

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Cranial fossae: Anterior, middle and posterior

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How would you describe the location of this mass?Describe the location

a. Cerebellar

b. Infratentorial

c. Posterior fossa

d. Suboccipital

Answer: All of the above.

All these terms refer to the same space. The cerebellum resides in the posterior cranial fossa, in a location that is infratentorial or suboccipital.

Please note the “occipital” and “suboccipital” are NOT synonymous. (“Occipital” refers to the occipital lobe which is a part of the cerebrum and is supratentorial.)

The term “fossa” refers to a “scooped out” space, like the palm of your cupped hand. There are three fossa of the skull base: anterior, middle and posterior.

Cranial fossae

The anterior fossa (green) is where the frontal lobe is located.

The middle fossa (purple) is where the temporal lobe is located.

The posterior fossa (orange) is where the cerebellum is located.

The mass presented above is a tumor of the posterior fossa, that is, in an infratentorial location. It abuts the cerebellum. Surgical resection may be achieved through a suboccipital craniectomy.

Pituitary Adenoma

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Pituitary Adenoma

Tumors at the pituitary are classified by SIZE and by SECRETIONS. They are treated with medication, surgery, or active surveillance.

Size

A MICROadenoma is less than 1 cm and is often an incidental finding on an MRI of the brain done for other reasons, like workup of a headache. Unless it is secreting active hormone, a small adenoma is asymptomatic and will not cause visual disturbance or headache.

A MACROadenoma is larger than 1 cm and often presents with visual field cut due to compression of the optic chiasm. This produces tunnel vision, with a loss of peripheral vision called bitemporal hemianopsia.Pituitary macroadenoma. MRI T1 with contrast

Secretions

Pituitary tumors are also classified by secretions.

A “non-functioning” adenoma does not secrete active hormone. It may actually suppress the production of normal hormones, with TSH, LH, and FSH being most vulnerable. Paradoxically it can result in *mild* elevation of PRL to about 20-100. It is often discovered by visual field loss caused by compression of the optic chiasm causing bitemporal hemianopsia.

“Functioning” pituitary adenomas secrete active hormone. These tumors may secrete any hormone, but PRL, GH, and ACTH are by far the most common.

A PRL secreting tumor mimics the postpartum state in females, with amenorrhea and galactorrhea.  In males it’s even worse: impotence and poor libido! A prolactinoma can be quite large on initial presentation, and the serum PRL may measure in the several hundreds. Fortunately, these are nicely responsive to dopaminergic drugs like bromocriptine and cabergoline, shrinking the tumor dramatically within a few weeks.

A GH secreting tumor causes acromegaly in adults and giantism in children. Acromegaly in adults can occur insidiously, barely noticed by the patient and close family. On questioning the patient may admit enlarged hands and feet such that rings and shoes have been resized. Other stigmata include an enlarged brow, protruding jaw, or enlargement of the cartilaginous nose. One patient noticed that he could floss easier as his teeth separated due to elongation of the jaw! Surgery is needed to remove this tumor.

An ACTH secreting adenoma causes Cushing’s disease, named for Harvey Cushing, the father of neurosurgery. ACTH production in the pituitary stimulates production of cortisol in the adrenal gland. This produces clinical hallmarks of Cushing’s: moon face, buffalo hump, abdominal obesity with striae, wasting of arms and legs, and easy bruising. This, too, is a surgical condition.

Treatment

Non-functioning MICROadenomas: No intervention needed, just periodic MRIs to check for growth, and periodic labs to check endocrine function.

Non-functioning MACROadenoma: Check endocrine labs, especially thyroid and sex hormones which can be diminished in the presence of a tumor. Check visual fields for bitemporal hemianopsia. Transphenoidal adenomectomy surgery can remarkably restore visual fields.

Prolactinoma: Pro-dopamine drugs like bromocriptine or cabergoline shrink the tumor dramatically and help with symptoms in males and females.

GH or ACTH secreting tumors usually need surgical resection to correct the harmful effects of these excess hormones.

Glioblastoma: Growth rate

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Glioblastoma: How fast do they grow?

A 57 year old female presented with new onset seizure. An MRI was obtained showing a lesion in the right frontal/parietal region. You can see there is some mass effect, slight effacement of the ventricle, and a whiff of enhancement. Needle biopsy returned astrocytoma, WHO Grade 3.Astrocytoma WHO Grade 3

Surgical resection was recommended, but the patient chose instead to pursue external beam radiation and oral chemotherapy in the form of temozolomide.

Unfortunately, she now presents three months later with confusion, agitation, and left arm weakness. An MRI is again obtained. The tumor shows marked growth and different signal characteristics. You see that the mass is inhomogeneously enhancing, with marked mass effect, surrounding edema, ventricular effacement, and minimal midline shift.

Glioblastoma, WHO Grade 4

At this time the patient requests craniotomy for surgical debulking. The final pathologic diagnosis is Glioblastoma, WHO Grade 4.

This shows how rapidly a glioma can grow and transform to a higher grade, in this case just three months.

Brown-Sequard Syndrome: Hemisection of the Cord

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Brown-Sequard syndromeBrown-Sequard Syndrome

Injury to half the spinal cord, or “hemisection of the cord,” can occur with trauma, tumor, or disc herniation. But most often it is seen in textbooks and in med school exams! The injury produces a unique constellation of findings: loss of motor and fine touch on the same side as the injury, and loss of pain/temperature on the opposite side. This is the Brown-Sequard syndrome.

Here’s how it happens.

First to orient you to the cartoons. We all know what this is.

The Brain, actually!

The brain, actually!

And now the brain with the brainstem and spinal cord.

Brain, brainstem, spinal cord

Of all the tracts in the spinal cord, there are really only three you need to know to get started. There is one efferent pathway, the corticospinal tract that carries motor signals from the brain to the body. There are two afferent pathways that carry sensory information to the brain, the dorsal columns which carry proprioception and fine touch, and the spinothalamic tract which transmits pain and temperature.

Note the location of the “crossover” of these tracts. This crossover point is the key to understanding the clinical features of the Brown-Sequard syndrome. The corticospinal tract and the dorsal columns cross over in the medulla, at the “decussation of pyramids.”

Corticospinal tract

Dorsal columns

By contrast, the spinothalamic tract doesn’t cross to the opposite side until it exits from the cord.

Spinothalamic tract

So what if you have an injury to the left side of the cord. What will be the expected clinical findings? What neuro deficits will result?

Left hemisection of the cord

This is the Brown-Sequard syndrome. Loss of motor and fine touch ipsilateral to the lesion, and contralateral loss of pain and temperature.Ipsilateral loss of motor and fine touch

Subdural Hematoma: When to Cut

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Subdural Hematoma: When to Cut

Subdural hematoma is a common neurosurgical problem. A subdural usually occurs in patients with significant brain atrophy, such as the elderly or alcoholic. Even minor trauma can injure the bridging veins between the brain and the dura. Bleeding into the subdural space can occur rapidly, causing death in a matter of hours, or gradually over a period of weeks. The surgical management depends on whether the hemorrhage is acute or chronic.

Acute Subdural Hematoma

An acute subdural may result from trauma or in a patient on antiplatelet or anticoagulant drugs. Symptoms often include headache, hemiparesis or alteration of consciousness like agitation, lethargy, or coma. If the acute subdural is small, it can be managed non-surgically. Antiplatelet drugs are stopped, and coagulation is corrected. Careful clinical observation is imperative. The subdural may expand as it becomes chronic, as the osmotic effect of the blood products draws free CSF into the subdural space. All this to say, if a small, acute subdural isn’t surgical today, it may be in two weeks!

Here a moderate sized, acute subdural is seen. You will notice a hyperdense (white) mass over the cortical surface of the brain (arrow), with effacement of the gyral pattern adjacent to the subdural, along with asymmetry of the lateral ventricles and midline shift.

Acute subdural hematoma

This patient was taken to surgery for a craniotomy. In the craniotomy, a large section of the skull was removed. This is called “turning a flap.” It allows the evacuation of the blood clot. At surgery, the clot was so tenacious it could be picked up with forceps. This, by the way, is the reason that an acute subdural cannot be drained with a bur hole. The blood is congealed. It cannot be drained with a bur hole any more than a cup of Jello can be eaten with a straw: it is solid. Air is introduced into the head at the time of surgery. It appears jet black on CT (arrow).

Acute subdural hematoma post op

Chronic Subdural Hematoma

On CT, a chronic subdural is hypodense (dark). It represents old blood in a liquid state. How old is old? It takes about two weeks for an acute subdural to liquefy, and the CT appearance will evolve from hyperdense to hypodense as the hemorrhage becomes chronic. Symptoms include headache on the same side as the subdural. Hemiparesis may be mild or well compensated as weakness occurs gradually. Many patients experience hemiparesis as gait imbalance, or veering to one side. As the patient worsens, frank lethargy or coma may ensue.

Here is a chronic, subacute subdural hematoma. You see a hypodensity over the cerebral convexity anteriorly (double arrow), with a hyperdense component posteriorly (arrow). There is effacement of the gyral pattern, ventricular asymmetry and midline shift.

Subacute chronic subdural hematomaChronic subacute subdural hematoma with labels

This patient was taken to the operating room for bur-hole evacuation of the subdural. The liquefied blood was removed with a simple bur hole. Going back to the Jello analogy: If you leave Jello at room temperature, it turns to liquid; in this case you CAN drink it with a straw. Or drain a chronic subdural with a bur hole!

Here you can see postoperative air in the head (jet black, see arrow), with a mix of residual chronic and subacute blood, with improved mass effect. A drain is present (double arrow).

Chronic subdural hematoma post opChronic subdural hematoma post op with labels

To summarize, an acute subdural is a life threatening emergency, often requiring craniotomy within hours. The chronic subdural can be life threatening as well, but over a period of weeks, often treated with simple bur hole drainage.

When to get a CT Head

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When to get a head CT?

How do you know when to order a head CT? A patient presents with headache or confusion: should you get a scan now? Here is a mnemonic that can help you know when to get a head CT on a patient with neurological symptoms.

SCAN – NOW. Get a CT Head if . . .

Seizure: new onset seizure

Confusion, or any change in mental status

Acute onset: a “new and different” headache

Nuchal rigidity: the stiff neck of meningitis or subarachnoid hemorrhage

Neuro deficit: any focal neuro change, like unequal pupils or pronator drift

Optic papilledema: a sign of increased intracranial pressure

Worrisome history: like malignancy, anticoagulants, or prior bleed or known lesion

For the patient with complaint of headache, always ask, “Is this the same old headache that’s bothered you so long … or IS THIS NEW AND DIFFERENT?” The “new and different headache” needs a CT.

For the headache patient, always perform a funduscopic exam, looking for optic papilledema, a sign of increased intracranial pressure. Every headache workup needs a funduscopic exam!

Nuchal rigidity is a classic sign of meningitis and is caused by the irritation of the meninges caused by bacteria and white blood cells in the CSF. This irritation is heightened by flexion of the neck, as the meninges are stretched. In a subarachnoid hemorrhage, red blood cells in the CSF cause a similar irritation of the meninges, aggravated by neck flexion. This nuchal rigidity is also associated with Kernig’s sign and Brudzinski’s sign. Any patient with headache and nuchal rigidy requires an immediate CT of the head. (And in the presence of acute illness or fever suggesting meningitis, immediate administration of antibiotics, even before the diagnostic workup is completed.)