🌬️ Normokalemic Periodic Paralysis Exists
Why “Normal Potassium” Does Not Rule
Out Periodic Paralysis
By Susan Q. Knittle-Hunter
Founder, Periodic Paralysis Network, Inc.
Author, Advocate, and Patient Living With Periodic Paralysis
Introduction: The Myth That Won’t Die
People with Periodic Paralysis are still being told—often
emphatically—that Normokalemic Periodic Paralysis (NormoKPP) does not exist.
This claim is usually delivered with confidence, citations to older conference
talks, and the assertion that “normal potassium means it must be something
else.”
That position is incomplete—and increasingly incorrect.
Normokalemic PP is not a misunderstanding by patients. It is a real
clinical presentation, documented for decades, explained by ion-channel
dysfunction, and supported by both historical and modern research,
including identified genetic mutations.
This article exists so patients can finally say, “Here is the
evidence.”
⚡ What Is
Normokalemic Periodic Paralysis?
Normokalemic Periodic Paralysis describes episodic weakness or paralysis occurring without
serum potassium levels leaving the laboratory reference range.
Key point:
Periodic Paralysis is a channelopathy—not a potassium disorder.
Potassium shifts may modulate attacks, but they are not
required for paralysis to occur.
Core features may include:
- Episodic weakness or paralysis
- “Spellish” prodromes (fog,
heaviness, shakiness)
- Cold sensitivity
- Post-exertional weakness
- Normal potassium during attacks
- Normal EMG or ECG between attacks
- Missed or negative genetic tests
This presentation has been documented since the 1940s and 1950s,
long before modern genetics—and continues to be documented today.
🧠 Why Normal
Potassium Does NOT Exclude PP
Multiple authoritative sources confirm:
Potassium does not have to leave the normal range to cause serious or
life-threatening paralysis.
From Muscular Dystrophy UK:
“It has recently been discovered that it is not the change in blood
potassium level that is the primary problem… other factors separate from blood
potassium can also worsen the function of the pores, so a change in blood
potassium is not essential.”
From Talbot (1941) and later reviews of 400+ cases:
- Paralysis occurred with
consistently normal potassium
- ECGs could remain normal during
attacks
- Severity did not correlate
with potassium level
- Death was reported in extreme
paralysis without hypokalemia
From modern summaries:
“The total body store of potassium is usually normal; it is just in the
wrong place.”
🧬 Yes — There IS a
Genetic Basis for NormoKPP
A common claim is that NormoKPP “was really just HyperKPP.”
That claim fails when newer genetics are considered.
🔬 Calcium
Channel–Related Normokalemic PP
A landmark study by Fan et al., including Lehmann-Horn, identified
a calcium channel mutation causing complicated normokalemic periodic
paralysis:
Gene: CACNA1C / CaV1.1
Mechanism: Omega-pore current through mutant calcium channels
Conclusion (authors’ words):
“This study shows for the first time… the first calcium channel mutation
for complicated normokalaemic periodic paralysis.”
📌 This alone disproves the claim that
NormoKPP “does not exist.”
🧠 Normokalemia Occurs
Across PP Subtypes
Normokalemic attacks are documented in:
- Hyperkalemic PP
- Hypokalemic PP
- Andersen-Tawil Syndrome
- Paramyotonia Congenita
- Calcium-channel–related PP
From ATS literature:
“Attack frequency, duration and severity may not correlate with ictal
serum potassium levels, which may be reduced, normal, or elevated.”
This is why serum potassium alone is an unreliable diagnostic
gatekeeper.
⚠️ Why Testing Often
Fails These Patients
Genetic Testing
- Current panels do not cover
all pathogenic variants
- Many patients have variants of
unknown significance
- Negative testing ≠ no
channelopathy
EMG / Long Exercise CMAP
- Sensitivity ~60% at best
- Can be normal between attacks
- Normal results do not exclude
metabolic or channel myopathies
As stated in Electrodiagnostic Evaluation of Myopathies:
“Normal EDX studies do not necessarily rule out the presence of a
myopathy.”
🌀 The “Spellish”
Prodrome: Early Warning, Not Anxiety
Patients often describe:
- Fog or disconnection
- Shakiness or coldness
- Sudden fatigue
- A sense that “something is
coming”
These are early ion-channel destabilizations, not psychological
symptoms.
Importantly:
- Lying down or resting can worsen
attacks
- Gentle activity or mental
engagement may abort them
- Cold exposure frequently triggers
symptoms
This pattern is classic PP physiology.
❌ Why Dismissing
NormoKPP Causes Harm
When doctors insist NormoKPP “doesn’t exist,” patients are:
- Misdiagnosed with FND or anxiety
- Given contraindicated medications
- Denied anesthesia precautions
- Left untreated for a genetic
channelopathy
The cost is real morbidity—and sometimes death.
🧾 Clinical Bottom
Line for Physicians
- Periodic Paralysis is a mineral
metabolic channelopathy
- Normal potassium does not exclude
PP
- Normokalemic attacks are
well-documented historically and currently
- Calcium channel mutations do
cause normokalemic PP
- Testing limitations are real
- Clinical pattern matters
The correct response is not dismissal, but clinical humility.
📚 Selected References
- Fan C. et al. Complicated
normokalaemic periodic paralysis due to a Ca(v)1.1 mutation. PubMed:
24240197
- Talbot JH. Studies in
Disorders of Muscle. JCI 1941
- Tyler FH et al. Periodic
Paralysis Without Hypopotassemia. JCI 1951
- Muscular Dystrophy UK. Periodic
Paralyses Overview
- Oxford Brain Journal. Andersen-Tawil
Syndrome
- Medscape: Periodic Paralysis
Workup
- Paganoni & Amato. Electrodiagnostic
Evaluation of Myopathies
(Full reference list available via Periodic Paralysis Network, Inc.)
📚 Appendix: Key
Evidence Supporting Normokalemic Periodic Paralysis
1️⃣ Historical Clinical Documentation (Pre-Genetic Era)
These papers document classic periodic paralysis with normal potassium,
long before modern genetic testing:
- Talbot JH (1941) – Review of >400 cases
showing paralysis without hypokalemia
- Tyler FH et al. (1951) – Periodic paralysis without
hypopotassemia
- JAMA Neurology (1963) – Normokalemic PP identified as
a muscle disorder, not psychiatric
👉 These papers establish
Normokalemic PP as a clinical entity independent of lab potassium.
2️⃣ Modern Channelopathy Understanding
These sources explain why potassium may remain normal:
- Muscular Dystrophy UK – PP as an
ion-channel disorder, not a potassium disease
- Wikipedia (summary of
peer-reviewed literature) – Potassium distribution vs serum levels
- Medscape – PP workup
acknowledging normal potassium during attacks
👉 Mechanism matters more than serum
potassium.
3️⃣ Genetic Evidence (Calcium Channel Involvement)
- Fan C. et al., including
Lehmann-Horn F.
First calcium-channel mutation linked to complicated normokalemic PP
PubMed ID: 24240197
👉 Direct refutation of the claim
that no genetic basis exists.
4️⃣ Normal Testing Does NOT Exclude PP
- Paganoni & Amato – Normal EMG
does not rule out metabolic myopathies
- MDA Quest Magazine – PP described
as an endocrine/metabolic myopathy
👉 Negative tests ≠ absence of
disease.
5️⃣ Normokalemia Across PP Subtypes
- Andersen-Tawil Syndrome
literature – Attacks occur with low, normal, or high K
- HyperPP and HypoPP studies –
Potassium may stay in normal range during attacks
👉 Normokalemia is a phenotype, not a
diagnosis error.
💙 Final Word to
Patients
If your potassium is normal and your body is failing you anyway—you are not
wrong, not imagining it, and not alone.
Normokalemic Periodic Paralysis exists.
And your lived experience already proved it—long before medicine caught up.
With warmth and resolve,
Susan Q. Knittle-Hunter
