FND Diagnosis Followed by Myasthenia Gravis and Respiratory Failure
Reddit Stories
A Reddit user, u/Flunose_800, documented a neurological illness that was attributed to Functional Neurological Disorder (FND) while they were also being investigated for myasthenia gravis (MG). The patient reported testing positive for LRP4 antibodies and repeatedly questioned whether FND could explain what was happening to them.
Later that month, they reported deteriorating to respiratory failure and requiring intubation in intensive care. A neuromuscular specialist subsequently diagnosed MG, according to the patient, and treatment included IVIG and plasma exchange. Several months later, the patient returned to Reddit and reported that an FND specialist had reassessed them and found no FND symptoms.
The account is the patient's own public description of events and has not been independently verified through medical records. However, much of the story was posted while events were still unfolding, giving us a useful chronology rather than a single retrospective claim of misdiagnosis.
Questioning the FND diagnosis
In July 2024, the patient was already publicly questioning the FND diagnosis. They reported progressive weakness and said that blood testing had found them positive for LRP4 antibodies, which have been identified in some patients with myasthenia gravis.
There was apparently disagreement between the doctors involved. The patient said inpatient neurologists continued to attribute their symptoms to FND, while a neuromuscular specialist who had seen them in intensive care thought they had either MG or a mitochondrial myopathy.
The picture was not quite as simple as one group saying FND and another saying MG. The patient also reported seeing an outpatient FND neurologist who believed some of their symptoms were functional, but considered those symptoms secondary to MG and possible small fiber neuropathy rather than an explanation for the entire illness.
Read the patient's July 2024 account on Reddit.
What were the positive FND signs?
This is where the story becomes difficult to reconstruct from Reddit alone. The patient clearly reports being diagnosed or treated as having FND, but their posts do not tell us what positive clinical signs were used to make that diagnosis.
There is no description in the available posts of Hoover's sign, entrainment, distractibility, give-way weakness or another specific positive rule-in sign being demonstrated. That does not mean none were found. It simply means we cannot establish from the patient's account what they were.
That becomes more relevant later because the patient says the FND specialist who had encountered them during an earlier hospital admission had not been able to perform a complete assessment because they were too unwell. When a fuller outpatient assessment was eventually performed, the patient says they were told that they showed no symptoms of FND.
Respiratory failure and intubation
On 29 July 2024, the patient posted another update. Their condition had deteriorated considerably. They reported developing respiratory failure, stopping breathing and requiring intubation in intensive care.
According to the patient, a neuromuscular specialist reviewed the clinical picture together with the LRP4 antibody result and diagnosed myasthenia gravis. They received MG-directed treatment including intravenous immunoglobulin (IVIG) and plasma exchange.
The patient said they had previously received five rounds of IVIG at another hospital and improved, but subsequently developed aseptic meningitis, reportedly confirmed by lumbar puncture. After returning to hospital again, they deteriorated further and reported stopping breathing during a transfer before being intubated.
What makes the chronology useful is that the earlier posts already show the patient discussing MG and disputing the FND explanation before this happened. The MG story did not first appear months later after the outcome was known.
Read the patient's 29 July 2024 update following respiratory failure and intubation.
"Confirmed not to have FND"
On 14 November 2024, the patient returned with another post, this time titled "Confirmed not to have FND." They reported having an outpatient assessment with an FND specialist who had previously encountered them during one of their hospital admissions.
According to the patient, the specialist found no FND symptoms during this assessment. They said the specialist explained that a full assessment had not been performed during the earlier admission because the patient had been extremely unwell at the time with blood clots, vertigo and migraines.
The patient also reported absent reflexes in their legs and said these had not been checked during the earlier assessment. Their account therefore describes a substantially different neurological examination from the one on which the earlier functional interpretation had apparently been based.
Read the November 2024 post, "Confirmed not to have FND".
So what happened?
Without the medical records, we cannot settle every part of this case. We cannot independently confirm the antibody result, exactly what happened during the hospital admissions, which FND signs were originally observed, or precisely what each neurologist concluded.
What we do have is a Reddit history written across several months. The patient questioned the FND diagnosis and discussed MG before the reported respiratory failure. They later reported being intubated, diagnosed with MG by a neuromuscular specialist and treated with IVIG and plasma exchange. Months afterwards, they reported that an FND specialist performed another assessment and found no FND symptoms.
There is also an unanswered question sitting in the middle of the story: what actually established the original FND diagnosis? The patient reports that at least one FND neurologist initially thought some symptoms were functional, but the available posts do not identify the positive signs behind that conclusion. The later assessment reportedly found none.
That is probably the most useful reason to document this case. A functional interpretation was present while another neurological diagnosis was still being investigated, the patient continued to deteriorate, and the clinical picture eventually became serious enough to require intensive care and ventilation. Whatever role FND was thought to play earlier in the illness, it clearly was not sufficient to explain what followed.
Further reading
For background on LRP4 antibodies and myasthenia gravis, see Zhang et al., "Autoantibodies to lipoprotein-related protein 4 in patients with double-seronegative myasthenia gravis" and Shen et al., "Antibodies against low-density lipoprotein receptor-related protein 4 induce myasthenia gravis."