An 85-year-old woman’s inability to remain standing was ultimately connected to an undiagnosed congenital defect. The patient was admitted to the geriatric unit of a university hospital for new frequent falls and subacute delirium, both of which began 1 month before presentation. Her medical history included ischemic stroke 10 years earlier, mild neurocognitive impairment, and Von Recklinghausen neurofibromatosis with isolated skin involvement.
Assessment
On examination the patient’s blood pressure was 104/70 mm Hg, heart rate was 100 beats per minute, oxygen saturation was 85%, and body temperature was 98.8°F (37.1°C). She weighed 99.2 lb (45 kg). Her breathing was normal while she was in the dorsal decubitus position. Findings from a lung examination and heart auscultations were within normal limits, but she had a distended jugular vein and peripheral cyanosis.
A neuropsychological examination confirmed that her confusion, marked by anxiety, agitation, daytime sleepiness, and increasing disorientation, was associated with acute psychomotor abnormalities, including backward disequilibrium, reactional hypertonia, alteration of postural reactions, and fear of falling. She had no focal neurologic deficits. It was impossible for her to remain standing. An electrocardiogram showed a sinus rhythm at 90 beats per minute and first-degree atrioventricular block with no other conduction or repolarization abnormalities. Chest radiography revealed no parenchymal or mediastinal disorders.
Results of a complete blood count and a basic metabolic panel were within normal limits, as were thyroid, renal, and hepatic assays. No inflammatory syndrome was revealed. The initial arterial blood gas analysis showed a severe shunt effect; partial pressure of oxygen was 47.6 mm Hg, partial pressure of carbon dioxide was 25.5 mm Hg, pH was 7.48, and bicarbonate was 22 mmol/L. Because the patient’s unexplained desaturation and confusion led us to suspect pulmonary embolism, emergency contrast-enhanced thoracic and cerebral computed tomography scans were performed.
Owing to our concern for thromboembolic disease, she was strictly maintained in the dorsal decubitus position until the imaging results were available. No abnormalities, apart from the sequelae of a left cerebellar lacunar stroke, were found on the computed tomography scan. Her delirium, cyanosis, and oxygen saturation, obtained via transcutaneous oximetry, improved while she was lying on her back (Table).
Diagnosis
We believed the patient had platypnea-orthodeoxia syndrome, on the basis of her positional hypoxemia, which occurred when she was upright and resolved when she was recumbent. These findings contrasted sharply with what we expected to discover, because her distended jugular vein first suggested congestive heart failure.
Transthoracic echocardiography was performed in an effort to find a source for the patient’s signs and symptoms. Her left and right ventricular ejection fractions were within normal limits, as were her pulmonary arterial pressure and cardiac output. Both atria were clear. A bubble study followed, and transthoracic echocardiography then disclosed an intracardiac right-to-left shunt caused by a patent foramen ovale and multiple defects in the interatrial septum, including an aneurysm (Figure).
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-Alain Putot, MD, Caroline Laborde, MD, Marie Fichot, MD, Philippe Brunel, MD, Martha Deidda, MD, Hélène Guepet, MD, Patrick Manckoundia, MD, PhD
This article originally appeared in the March issue of The American Journal of Medicine.
