Guillain-Barre Syndrome/acute inflammatory demyelinating polyradiculopathy; proximal muscle weakness; inability to ambulate; Dysphagia; could not lift his arms above his head; Pain; deep tendon reflexes; diffuse hypokinesis; non-ischemic cardiomyopathy; Mild dysarthria; sensorimotor polyneuropathy; silent aspiration; This case was reported in a literature article and described the occurrence of guillain barre syndrome in a 79-year-old male patient who received Flu unspecified (Influenza vaccine) for prophylaxis.   On an unknown date, the patient received Influenza vaccine. On an unknown date, 2 weeks after receiving Influenza vaccine, the patient experienced guillain barre syndrome (serious criteria hospitalization and GSK medically significant), proximal muscle weakness (serious criteria hospitalization), unable to walk (serious criteria hospitalization), dysphagia (serious criteria hospitalization), mobility decreased (serious criteria hospitalization), pain (serious criteria hospitalization), tendon reflex decreased (serious criteria hospitalization), hypokinesia (serious criteria hospitalization), non-ischemic cardiomyopathy (serious criteria hospitalization and GSK medically significant), dysarthria (serious criteria hospitalization), mixed sensory & motor neuropathy (serious criteria hospitalization) and silent aspiration (serious criteria hospitalization and GSK medically significant). The patient was treated with immunoglobulins nos (Ivig). On an unknown date, the outcome of the guillain barre syndrome, proximal muscle weakness, unable to walk, dysphagia, mobility decreased, pain, tendon reflex decreased, hypokinesia, non-ischemic cardiomyopathy, dysarthria, mixed sensory & motor neuropathy and silent aspiration were recovering/resolving.   The reporter considered the guillain barre syndrome, proximal muscle weakness, unable to walk, dysphagia, mobility decreased, pain, tendon reflex decreased, hypokinesia, non-ischemic cardiomyopathy, dysarthria, mixed sensory & motor neuropathy and silent aspiration to be possibly related to Influenza vaccine.  Additional details were reported as follows: This case was reported in a literature article and described the occurrence of Guillain-Barre Syndrome in a 79-years old male patient, who was vaccinated with unspecified influenza vaccine (manufacturer unknown) for prophylaxis. The patient had no medical history or recent illness. No information on patient's family history, concurrent condition or concomitant medication was provided. On an unspecified date, the patient received double dose of unspecified influenza vaccine (administration route and site unspecified; batch number not provided). The age of vaccination was not provided. [Eventually, the patient reported receiving a double dose influenza vaccine 2 weeks prior to symptom onset]. On an unspecified date, 2 weeks after the vaccination, the patient presented after overnight onset of proximal muscle weakness and inability to ambulate. Over two days, the patient developed dysphagia and could not lift his arms above his head. Physical exam demonstrated diminished vibration and pain in his lower limbs and 0 to 1+ deep tendon reflexes throughout without myalgias. CBC/BMP were unremarkable. Notable labs included creatinine kinase 274 U/L (30-170 U/L), lactate 2.4 mmol/L (0.67-1.8 mmol/L), and troponin 0.33 ug/L (0-0.5 ug/L). Infectious workup was negative. Family was unaffected. A lumbar puncture revealed protein 45 mg/dL (15-60 mg/dL). Head and spine imaging were unremarkable. Transthoracic echocardiogram (TTE) showed left ventricular ejection fraction (EF) of 20-25% and apical, anterolateral, anteroseptal and inferoseptal wall motion abnormalities. Electromyography (EMG) suggested an axonal demyelinating polyneuropathy but was not diagnostic. The patient received 2 doses of IVIG for presumed Guillain-Barre Syndrome (GBS) without improvement and transferred to the institution. Autoimmune workup was negative. Repeat EMG showed a sensorimotor polyneuropathy with demyelination without myopathic components, confirming acute inflammatory demyelinating polyradiculopathy. Cardiac MRI with gadolinium revealed diffuse hypokinesis without infarction, scarring, or infiltrate, suggesting potential for functional recovery. Guideline directed medical therapy was initiated for non-ischemic cardiomyopathy with reduced EF. Mild dysarthria with silent aspiration required a nasogastric tube. After resuming IVIG for 5 total days of treatment, the patient displayed improvement and transferred to inpatient rehabilitation 15 days after symptom onset. The authors commented, "This case illustrates an unusual presentation of GBS and the need to rapidly initiate appropriate treatment. Proximal weakness remains atypical. Rapidly developing profound weakness is also uncharacteristic, as maximum disability typically takes weeks. Mechanism of myocyte injury in rhabdomyolysis from GBS is unclear. Myocardial involvement varies in severity and appears reversible. Cardiomyopathy in GBS appears rare and incidence remains unknown. Proposed mechanisms for GBS-related cardiomyopathy include autonomic and nervous dysfunction from immune-mediated nerve damage. GBS and influenza vaccinations have been temporally correlated, but little evidence supports a causal relationship. It is unclear if a double-dose vaccination confers greater risk. Mainstay of GBS treatment is prompt IVIG infusion." The authors concluded, "Clinicians should be aware that hyperacute onset of proximal weakness, myositis, and cardiomyopathy are atypical features of GBS. Cardiovascular involvement of GBS may be severe yet reversible with appropriate treatment." This article corresponding to this case is not available for regulatory submission due to copyright restriction.