Myasthenia gravis

The decisive clue is not tiredness as such but that strength declines with exertion and recovers with rest — and that evenings are worse than mornings. That is how it should be described.

Especially if both fluctuate through the day, it is a strong clue. Such complaints deserve a neurological work-up rather than being dismissed as tiredness.

Numerous agents, including certain antibiotics and magnesium given as an infusion, can markedly worsen myasthenia. The diagnosis therefore belongs everywhere — including the dentist and the pharmacy.

If weakness increases rapidly and affects breathing or swallowing, that is a myasthenic crisis — call for help at once (144). Triggers are often infections or stopping medication.

Because strength declines with exertion, breaks spread across the day often help more than any extra effort. Doing demanding things early uses the best phase.

High temperatures and febrile infections often intensify the weakness. Reacting early and having infections treated consistently prevents deterioration.

In a large proportion the thymus is altered. Imaging belongs to the initial work-up, because a treatment option of its own can follow from it.

A threadworm can stay silent in the gut for decades and, under cortisone, biologicals or other immune suppression, flood lung and bloodstream. Anyone who ever went barefoot in the tropics or subtropics is looked for beforehand with a blood test — one effort, and it prevents the worst course this worm has.

Pyridostigmine leaves more messenger at the muscle plate — it works within thirty to sixty minutes and lasts three to four hours. It treats the sign, not the cause. For the cause there is cortisone and other drugs that slow the immune system; they need weeks to months, and cortisone can temporarily worsen the weakness in the first weeks — which is why it is started low. Removing the thymus comes into question for some.

About fifteen to twenty per hundred thousand people are affected, with two peaks: young women under forty and older men over sixty. Typically the weakness increases through the day and improves after rest — that daily course is the identifying mark. In about two out of three it begins in the eyes. In about one in ten a thymoma is found; which is why the chest is imaged once.

In the morning everything works, in the evening nothing does. After a rest it briefly gets better. This swing across the day is the hallmark — and it sets the picture apart from ordinary exhaustion.

In about half it starts at the eye: a drooping upper lid, often alternating between left and right, and double vision that gets worse when reading or in the evening.

At meals chewing becomes an effort, the voice grows quiet or nasal after longer speaking, food goes down the wrong way. The smile too can look different than before.

Combing hair, hanging washing, filling a shelf, climbing stairs — the muscles close to the body tire first. Heat, infections and certain antibiotics make the picture worse.

Autoimmune diseases often occur together — thyroid involvement is common and sometimes explains part of the symptoms.

Usually normal in myasthenia — this helps distinguish it from muscle diseases with muscle breakdown.

Relevant especially if longer-term cortisone is needed — bone protection and vitamin D then belong to the picture.

Without B12 the insulating layer of the nerves is not maintained. A lack causes tingling, numbness and unsteadiness in the dark — and it is one of the few reasons for nerve trouble that can be fully undone if found early.

The nerves cover their energy needs through thiamine. It runs short with alcohol, after stomach operations, with long-lasting vomiting and under water tablets.

Here both count: a lack harms the nerves, and too high an intake over months harms them as well. Supplements therefore belong taken in a dose that has a reason.

Works together with B12. Given alone, folate can improve the blood count while the B12 deficiency goes on damaging the nerves — which is why both are looked at together.

The most important pointer here, and one of the least known: magnesium in high dose — above all as an infusion, but also as a hefty effervescent powder — damps transmission at the muscle further and can worsen a weakness. Magnesium from food is not the issue; the amount makes it.

Treatment runs in many through cortisone, often over years — and then bone is the organ affected alongside. Vitamin D and calcium belong from the start, not only after the first bone density measurement.

Under cortisone and water tablets potassium falls, and low potassium on its own already causes muscle weakness — here the two add up to a picture easily taken for a worsening of the condition. The laboratory value separates them.

Clearly worthwhile and well supported when deficient — vegan, older adults, certain drugs. No energy boost without a deficiency.

In pregnancy clearly established against neural-tube defects, otherwise mainly with deficiency. Can mask a B12 deficiency — watch both.

About one in ten of those affected also has a thyroid condition — mostly Graves’. Both are autoimmune, and the muscle weakness of overactivity can blur the picture.

Cortisone is a pillar of the treatment — with one peculiarity: at the start the weakness can increase for one to two weeks before it improves. This is why it is worked up slowly and not begun at full dose.

The condition often begins before thirty in women and after fifty in men. Fluctuations across the cycle and in pregnancy are regularly reported — the course in pregnancy is not predictable.

Strength fades during the meal. So the most important food comes first, softer food is preferred and the main meal is placed at the time of day when the medication works best.

Treatment often runs for years. Bone protection from the start and keeping an eye on potassium is the usual approach.

Formerly advised against. Today studies show that moderate training is tolerated and improves strength — the effort is placed at the time of day when the medication works.

Here as a warning: magnesium in high doses, especially by infusion, can worsen the muscle weakness. Certain antibiotics do too — the list belongs to the treatment.

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