05 Aug Kids Korner: The False Brain Tumor
By A. David Rothner, M.D.
Director of the Pediatric/Adolescent Headache Clinic and Chairman Emeritus of Child Neurology at the Cleveland Clinic Foundation in Cleveland, Ohio
It’s not uncommon to worry that headaches are being caused by a tumor. Fortunately, they rarely are. Another condition, however, can mimic a tumor, causing similar symptoms but different concerns. This is pseudotumor cerebri, Latin for false brain tumor. It’s also known as idiopathic intracranial hypertension, which means that, for unknown reasons, there is an increase in intracranial pressure with a blockage of spinal fluid flow. This rare condition is more common in adolescents than children (though most common in adults).
To understand how pseudotumor cerebri works, it’s useful to visualize how tumors exert pressure or block spinal fluid flow. A tumor acts like a beaver’s dam—if you block the creek, the pond gets bigger and higher. Spinal fluid usually passes into the fourth ventricle (one of the four connected fluid-filled cavities within the human brain) and is then absorbed over the brain. But when there is a block, the ventricles get bigger and cause pressure. A similar phenomenon happens in pseudotumor cerebri, but there is no actual tumor or blockage.
The symptoms of pseudotumor cerebri are headache, blurred vision, fatigue, and, sometimes, balance and coordination difficulty or problems with nausea and vomiting. The headache is not usually an acute episodic headache such as that seen with migraine. Rather, it is frontal in nature and seems to increase in severity over time and become a chronic headache. It can be confused with tension-type headache, but the fact that it gets worse over time differentiates it.
If a child comes into our clinic who has had a headache over the last two to four weeks, and perhaps some sleepiness or morning vomiting, we will check for papilledema using an ophthalmoscope (the instrument used to see the backs of the eyes). Papilledema, or swelling of the head of the optic nerve, is a sign of increased intracranial pressure. If papilledema is present, we will do an MRI scan to look for the presence of a tumor. If the scan is normal, there is no tumor. In that case, we need to measure the intracranial pressure using a lumbar puncture (also called a spinal tap). If the pressure is too high, then we have a tentative diagnosis of pseudotumor cerebri. We may also lower the spinal fluid pressure by removing some of the spinal fluid.
The primary concern with pseudotumor cerebri is its effect on vision. It can cause progressive and permanent visual loss. It’s important to work in conjunction with a pediatric ophthalmologist to verify the papilledema, and get visual acuities, fields and blind spots checked.
Treating Pseudotumor Cerebri
While it’s not entirely clear why pseudotumor cerebri happens, we do know that it is more common in women, in obese people with a BMI over 30 and in youngsters who exhibit some of the symptoms of polycystic ovarian syndrome—acne, obesity, facial hair and menstrual irregularities. Another major cause is a rare reaction to medications used to treat acne, including the antibiotics minocycline and tetracycline, steroids and excessive use of vitamin A or Retin-A.
If one of these agents is identified as a cause, it should be discontinued immediately. This usually results in significant improvement.
The most common drug treatment for pseudotumor cerebri is acetazolamide (Diamox®). Diuretics may also decrease production of spinal fluid. A weight loss program may need to be initiated. Patients should be followed closely.
Most cases of pseudotumor cerebri usually resolve using this approach. If vision is worsening, which happens very rarely, one of two surgical procedures can be considered. The first is an optic sheath, which takes the pressure off the optic nerve. The second is a shunt, which diverts spinal fluid and lowers the pressure. These procedures are typically successful.