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When the Diaphragm Fails: Visual Hallucinations Due to Isolated Respiratory Muscle Weakness as a First Manifestation
Caroline Van Lierde1, Mathieu Brancaleone1, Tom Cornelis2
1Department of Internal Medicine, UZ Leuven, Leuven, Belgium.
Background:
Late-onset Pompe disease (LOPD) is a rare autosomal recessive disorder caused by a deficiency of acid alpha-glucosidase (GAA), leading to progressive skeletal and respiratory muscle weakness. In about 10% of cases, diaphragmatic weakness may be the sole presenting feature. Early diagnosis is crucial, as ventilatory support improves outcomes and enzyme replacement therapy can slow disease progression.
Case Presentation:
A 60-year-old male with a medical history of heart failure presented with dyspnoea, orthopnoea and fluctuating visual hallucinations. Initial metabolic alkalosis, presumed secondary to diuretics, masked chronic hypercapnic respiratory failure. Despite optimised heart failure treatment, symptoms persisted. Pulmonary function tests showed a restrictive pattern with preserved diffusion. Hypercapnic respiratory failure prompted admission to the intensive care unit and invasive ventilation. A significant drop in vital capacity between upright and semi-recumbent positions and absent phrenic nerve responses indicated diaphragmatic weakness. Low GAA activity and genetic testing confirmed the diagnosis of LOPD. Neurological and immunological work-up excluded alternative causes. Non-invasive ventilation improved symptoms, and enzyme replacement therapy with avalglucosidase alfa was initiated.
Conclusion:
This case illustrates the diagnostic challenge of isolated respiratory failure due to LOPD when early signs are masked by comorbidities and metabolic disturbances. Nocturnal hypoventilation may cause atypical symptoms such as hallucinations. Systematic neuromuscular evaluation is essential to enable timely ventilatory support and disease-specific treatment.
Learning Points:
Isolated respiratory failure due to diaphragm weakness can be the first manifestation of late-onset Pompe disease.Diagnosing diaphragmatic weakness is challenging in cardiopulmonary disease, as symptoms may be misattributed.Visual hallucinations are a rare symptom of nocturnal hypoventilation.
Insights
Late-onset Pompe disease (LOPD) can present solely as respiratory failure due to diaphragmatic weakness, challenging diagnosis. Early identification and treatment, including ventilatory support and enzyme replacement therapy, are crucial for managing this rare condition.
Area of Science:
- Neurology
- Rare Diseases
- Pulmonology
Background:
- Late-onset Pompe disease (LOPD) is a rare genetic disorder causing progressive muscle weakness due to acid alpha-glucosidase (GAA) deficiency.
- Diaphragmatic weakness can be the primary symptom in 10% of LOPD cases, impacting respiratory function.
- Timely diagnosis and intervention, including ventilatory support and enzyme replacement therapy (ERT), are vital for improving patient outcomes.
Purpose of the Study:
- To highlight the diagnostic challenges of LOPD presenting as isolated respiratory failure.
- To emphasize the importance of systematic neuromuscular evaluation in patients with unexplained respiratory symptoms.
- To illustrate how comorbidities and metabolic disturbances can mask LOPD symptoms.
Main Methods:
- Case presentation of a 60-year-old male with heart failure, dyspnea, and visual hallucinations.
- Diagnostic work-up included pulmonary function tests, assessment of diaphragmatic function, GAA activity measurement, and genetic testing.
- Exclusion of alternative neurological and immunological causes.
Main Results:
- The patient presented with masked chronic hypercapnic respiratory failure, initially attributed to heart failure and metabolic alkalosis.
- Pulmonary function tests revealed a restrictive pattern with preserved diffusion, and diaphragmatic weakness was confirmed.
- Diagnosis of LOPD was established via low GAA activity and genetic testing, leading to initiation of non-invasive ventilation and ERT.
Conclusions:
- Isolated diaphragmatic weakness can be the sole presenting feature of LOPD, often masked by other conditions.
- Misattribution of symptoms like dyspnea and visual hallucinations (a rare sign of nocturnal hypoventilation) can delay LOPD diagnosis.
- Systematic neuromuscular assessment is essential for early diagnosis and management of LOPD.
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