Neuritis cordis due to the acute polyneuritis of the Guillain-Barré syndrome

[Neuritis cordis and myocarditis in rabies]

Once the rabies virus has spread through the central nervous system (CNS), the virus is also transported centrifugally along axons, especially of the autonomic nervous system, to a wide range of organs including the heart. In this case report of a 49-year-old man who had been bitten by a dog in Asia, the rabies infection of cardiac nerves and cardiac muscle fibres is shown by immunohistochemistry. The neuritis cordis and rabies myocarditis can have important clinical effects on the heart rate and myocardial function and lead to blood pressure crises which are typical for the clinical course of rabies in humans.

Assessment of coronary morphology and flow in a patient with Guillain-Barré syndrome and ST-segment elevation

Patients with Guillain-Barré syndrome often have cardiac disturbances as a manifestation of autonomic dysfunction. Such abnormalities consist of arrhythmias and disturbances of heart rate and blood pressure. We report a case of a patient with Guillain-Barré syndrome who developed ST-segment elevation in the inferolateral leads, suggestive of an acute coronary syndrome. Cardiac catheterization revealed angiographically normal coronary arteries. Intracoronary ultrasound was also normal. Intracoronary Doppler flow measurements revealed an elevated baseline coronary flow velocity of up to 41 cm/s and decreased coronary flow reserve, particularly in the left circumflex artery. Myopericarditis as cause of the electrocardiographic changes could be ruled out by echocardiography and endomyocardial biopsy. We postulate that the intracoronary Doppler findings are caused by autonomic dysfunction with decrease of coronary resistance and redistribution of the transmural myocardial blood flow.

[Cardiac involvement in neuromuscular diseases]

Many neuromuscular disorders involve the heart, occasionally with overt clinical disease. Muscular dystrophies (dystrophinopathies, limb girdle muscular dystrophy, Emery-Dreifuss muscular dystrophy, Steinert's myotonic dystrophy), congenital myopathies, inflammatory myopathies and metabolic diseases (glycogenosis, periodic paralysis, mitochondrial diseases) may produce dilated or hypertrophic cardiomyopathy and heart rhythm or conduction disturbances. Furthermore the heart is commonly involved in some hereditary and degenerative diseases (Friedreich's ataxia and Kugelberg-Welander syndrome) and acquired (Guillain-Barré syndrome) or inherited (Refsum's disease and Charcot-Marie-Tooth syndrome) polyneuropathies. A cardiologist's high clinical suspicion and a simple but systematic skeletal muscle and peripheral nerve investigation, including muscle enzymes quantification, neurophysiological study and muscle biopsy, are necessary for an accurate diagnosis. In selected patients, more sophisticated biochemical and genetic analysis will be necessary. In most cases, endomyocardial biopsy is not essential for the diagnosis.

Quantitative assessment of cardiovascular autonomic function in Guillain-Barre syndrome

To study the temporal course and the relationship between autonomic failure and motor weakness in Guillain-Barré syndrome (GBS), a total of 164 autonomic function tests were serially applied for up to 1 year in 13 consecutive patients. Results were compared with those obtained in 25 healthy volunteers and 13 patients with other neurological diseases. Parasympathetic function tests comprised heart rate responses to Valsalva maneuver, deep breathing, and active change of posture, whereas sympathetic vasomotor function was assessed by blood pressure responses to handgrip and standing. At the height of the disease, subclinical autonomic involvement of both parasympathetic and sympathetic arms was revealed in the vast majority of patients. Abnormalities of autonomic function tests improved gradually over time, paralleling the recovery of motor function, but were only partially related to clinically significant autonomic dysfunction. Correlation analysis suggested that tachycardia in the context of GBS might be caused by a reduction of sympathetically mediated peripheral vascular tone rather than by vagal failure.

Influenza virus and neurological diseases

Influenza viruses rarely cause acute encephalopathy. Post-influenzal encephalitis, which occurs a few weeks after recovery from influenza is thought to be an autoimmune process associated with demyelination and vasculopathy. It has been suggested that Economo lethargic encephalitis followed by postencephalitic Parkinsonism was associated with the influenza A epidemic of 1918 (Spanish flu). The incidence of Reye's syndrome has markedly decreased due to the avoidance of salicylates in the treatment of influenza or varicella. One inactivated flu vaccine is thought to have caused Guillain Barre syndrome due to molecular mimicry between viral protein and myelin, which triggered autoimmune responses. The persistence of influenza virus genes in neural cells as one of the causes of chronic degenerative diseases of the central nervous system by inducing apoptosis of the host cells is yet to be proven.