October 2003 PES Bulletin

Testing for Porphyric Peripheral Neuropathy

Peripheral neuropathy is one of the biggest problems that porphyria patients face on a continual basis long after acute attacks are in remission.

And most porphyria patients know that it takes testing and repeated testing to confirmed their PN in relationship to porphyria. Often it is mistakened as being early MS or another affliction.

For determing Peripheral Neuropathy [PN] testing by a neurologist must be undertaken. Such tests include:(1) the simple pin sticking checking for nerve impulse; (2) the rubber tipped hammer to check for tendon reflexes; and (3) an EMG [Electromyography].

Electromyography is a diagnostic neurolic test to study the potential [electrically measured activity] of muscle at rest, the reaction to contraction, and the response of muscle to insertion of a needle. The test is an aid in ascertaining whether a patient's illness is directly affecting the spinal cord, muscles or peripheral nerves.

When EMG testing the patient lies at rest while the peripheral nerves in various locations are stimulated through electrodes, and the electrical activity in the muscle at rest, on insertion of the needle, and during the muscle contraction. The test is sometimes employed as a measure of the muscle tension produced by nercous stress, usually, the muscles of the forehead are tested, since they can indicate relaxation of generalized body tension.

Electromyoneurogra[hy is the combined use of electromyography and neurography. The two tests offer a more precise means of finding the exact location of nerve damage or disorder.

Dynomometry testing uses a dynomometer [most often a dial guage attached to a spring mechanism that measures the strength of muscles] to ascertain certain physical abilities such as holding an object in the hand. It helps detect diseases of the nerves from the spinal cord to the muscle.

There is negligible risk factor in running this test. All that is involved is the catheter and needle insertion along with the elctrical instruments.

The pain and discomfort from the test focuses on the needle insertion, which is usually done without local anesthesia. This can be quite uncomfortable and at times even very painful.

Intrepretation of the tests must be made by a neurologist. In the normal values, when the muscle is at rest, no electrical activity is observed. When the muscles contract, the elctromyograph will show a smooth graphic wavelike respresentation of each contraction. The graph lines are amplified with the increase in strength of each contraction.

When the values are abnormal,muscle disease will produce a spiked wave pattern. The shape of the spike depends on the particular disease.

Muscle weakness produces a diminished wave. With myasthenia gravis, for instance, the waves disappear for a few minutes. Nerve involvement, as opposed to muscle involvement, usually shows a decreased frequency of contractions.

Neurologist consider the test quite reliable and rate it as 90 percent accurate. As stated by a neurologist, "it is quite quite difficult for a pretender /malingerer to fake to have muscle pathology when muscles respond to electric stimulation."

Robert Johnson, M.D.
Retired Clinician

Latex Sensitivity Needs to Put Porphyria Patients on Alert

While most hospitals and medical clinics have changed over to non-latex gloves and other medical equipment, the incidence of latex allergy continues to be documented. Among those reporting reactions to the use of latex are many porphyria patients.

Medical history citing latex allergy is quite extensive. Beginning in the fall of 1989, the Food and Drug Administration (FDA) started receiving medical reports of patients going into anaphylactic shock while receiving barium enemas. It was soon found that the latex-cuffed enema tip was the cause of a total of 16 deaths. That was soon remedied and this began an increased awareness of latex allergy.

The prevalence of latex allergy in porphyria patients ranges much higher. Porphyria patients with cutaneous symptomology or those with MCS exacerbation need to be especially aware of the problems with latex. Many porphyria patients using intervenous treatments have noted alergic reaction to latex products used. Caretaker who wear latex gloves for prolonged periods of time also noted allergic reactions to the latex.

Patients with atrophy have higher risk for latex allergy which has been cited.

The reasons for latex allergy has to do with the processing and source of latex. Latex is the milky sap obtained by tapping the rubber tree. The raw product is mixed with a preservative, such as ammonia. It is processed and it is concentrated.

Numerous chemical accelerators reduce the temperature and time required. These accelerators can cause allergic reactions and are responsible for many cases of contact dermatitis.

Chemically, latex contains proteins, cis-polyisoprene, water, and lipids. The proteins cause the severe immediate hypersensitivity reactions. More than 50 different proteins have been implicated in the allergic response, with up to a total of 240 different proteins found in latex.

Coated or very soft rubber products appear to have the highest content of latex proteins and, therefore, have the greatest allergenic potential.

Medical devices that have been reported to trigger serious systemic reactions by cutaneous exposure include anesthetic masks, tourniquets, electrocardiogram electrodes, adhesive tapes, condom catheters, and ileostomy bags.

The symptoms of such a latex reaction can include redness, cracks, fissures, and scaling. Another type is that of allergic contact dermatitis. There is also a delayed hypersensitivity, which has an onset 6 to 48 hours after contact. Another name for this reaction is "Type 4".

Symptoms, which are also caused by the accelerators and chemicals, include erythema, vesicles, papules, pruritus, blisters, and crusting. These lesions can resemble those caused by poison ivy or poison oak. Approximately 80 percent of the immunologic reactions are type 4.

The third type of reaction is immediate hypersensitivity, or type 1-IgE mediated reaction, which is caused by the latex proteins. Its onset occurs, within minutes and rarely lasts longer than 2 hours. These symptoms include local and generalized urticaria, light-headedness, angioedema, nausea, vomiting, abdominal cramps, rhinoconjunctivitis, bronchospasm, and anaphylactic shock. It is possible to have used latex for years without problems and suddenly progress to systemic symptoms. Anaphylactic reactions to latex have been reported in persons who had previously experienced only irritant or allergic contact dermatitis.

For porphyric patients the exacerbation of reactions can increase dramatically and can triggers porphyric attacks as well.

Because any product containing latex can trigger a reaction, cautious investigation of products at home, in the workplace, and at sites of medical and dental care should occur. A thorough medical history is the cornerstone of the diagnosis of latex allergy.

If you are aware of itching or other allergic reaction to latex please notify your primary care provider. Please note this reaction in your medical records and carry this information in your wallet. Such reactions are as important to cite as those of an allergic reaction to penicillin.

Dr. Ernesto Gonzales MD

Chlorine Present in Many Pharmaceuticals

Chlorine is a product that is found just about everywhere these days. And chlorine is essential and is even beneficial overall. But unfortunately for most porphyria patients chlorine is considered a chemical toxin which can and does trigger acute porphyria attacks from time to time.

What is often unknown to many porphyria patients is that chlorine is lurking just about everywhere in the hospital or clinical medical setting.

Porphyria patients find themselves so often in a medical setting, and yet many are so unaware of that chlorine is lurking just about everywhere. This includes even the medications that most people take commonly and even on a daily basis.

One common drug is acetaminophen. Others include antibiotics. Chlorine is also found in anti-cancer drugs including cisplatin, and mintotane.

Other drugs containing chlorine include xanax, vancomycin, lorabid, ceclor, benedryl, chlor-trimeton.

In addition, almost one-third of central nervous system drugs contain chlorine, and 98 percent of gastrointestinal medications are made using chlorine.

At the same time chlorine is what makes our tap water safe and keeps our "whites white" during laundry.

Chlorinated compounds are essential to the development of potent new drug therapies. Of the nearly 400 new drugs approved for therapeutic use in humans since 1984, more than 60 are chlorinated compounds, and many others use chlorine's unique chemical properties in their production.

In the medical world chlorine does not just stop with the pharmaceuticals. Chlorine is essential to a wide variety of medical equipment. An estimated one-fourth of all medical devices in hospitals contain chlorine, ranging from some of the most commonly used to some of the most specialized and advanced.

X-ray and mammography films are made with silver chloride. Chlorine also is a basic building block in the silicon used to make the semiconductors upon which many electronic medical devices depend. And surgical sutures, artificial blood vessels, and osmotic membranes are all made with nylon, a product made using chlorine chemistry.

Chlorine-based plastics also are widely used in medical devices and equipment. Of the 14 families of plastics made using chlorine, the most common is polyvinyl chloride, a plastic known for being light, easy to bend and shape, and inexpensive.

As a porphyric if your are super sensitivity to chemical toxins including chloride be aware that the IV and blood bags are made of chloride. Same with the oxygen tents and even prescription eyewear.

Chlorine-based vinyl packaging also adds to the safety of medicine. Many pharmaceuticals also are supplied in vinyl packaging -- such as the "blister" packs that help extend the shelf life of tablets and capsules and make it easier for patients to take the proper dosage.

Much of the aforementioned is safe for porphyrics however if contact is limited. What is neeeded to be mindful of is the chlorination of drinking water, and especially chlorinated water in swimming pools. This has always been a problem for the general populous and with porphyrics it is even more so.

Skin irritation is a great concern for porphyrics with the cutaneous manifestations. However AIP also can be affected by chlorine.

Play it safe, read labels, ask questions, and do not be afraid to refuse use of some products.

Robert Johnson, MD
Retired Clinician

The Association of Vitamin B6 and Porphyria

During the past year or so many porphyria patients have concerned Vitamin B6 protocols for controlling their porphyria. As to date there has not been any scientific research that would point to this conclusion.

Proponents of the Vitamin B6 regiment often cite that porphyria PN is due in part to a defiency of Vitamin B6. However medical research has yet to make any findings to substantiate this theory.

Vitamin B6 comprises a group of closely related compounds: pyridoxine, pyridoxal, and pyridoxamine.

These chemical elements are metabolized and phosphorylated in the body to pyridoxal phosphate, which functions as a coenzyme in many reactions.

Such reactions include the decarboxylation and transamination of amino acids, deamination of hydroxyamino acids and cysteine, conversion of tryptophan to niacin, and metabolism of fatty acids.

Vitamin B6 components are important in blood, CNS(central nervous system) , and skin metabolism.

Vitamin B6 is an important factor in erythropoiesis because pyridoxal phosphate is needed in the formation of -aminolevulinic acid, (ALA) the rate-limiting step in heme biosynthesis.

The theory that B6 deficiency is the main cause of porphyric PN, really is not a consideration when you understand that primary deficiency is rare, because most foods contain vitamin B6.

Secondary deficiency of B6 may result from malabsorption, alcoholism, oral contraceptive use, chemical inactivation by drugs (eg, isonicotinic acid hydrazide, cycloserine, hydralazine, penicillamine), excessive loss, and increased metabolic activity. Malabsorption is found in many porphyria patients, however none of these patients show a deficit in B6.

Anticonvulsant drugs are the chief offenders, and these drugs are contraindicated for most porphyria patients.

In event of a B6 deficiency the vitamin B6 antagonist deoxypyridoxine produces seborrheic dermatosis, glossitis, cheilosis, peripheral neuropathy, and lymphopenia. Vitamin B6 deficiency can cause convulsions in infants and anemia in adults.

It is important to keep in mind that several recessive or X-linked states affect different vitamin B6 apoenzymes, producing symptoms such as convulsions, mental deficiency, cystathioninuria, sideroblastic (iron overload) anemia, urticaria, asthma, and xanthurenic aciduria.

Jeff Brown PhD
Pharmacology