Clubbing of the digits

Comparison of bone microstructure and strength in the distal radius and tibia between the different types of primary hypertrophic osteoarthropathy: an HR-pQCT study

Primary hypertrophic osteoarthropathy (PHO) is a hereditary bone disease that is grouped into PHO autosomal recessive 1 (PHOAR1) and PHO autosomal recessive 2 (PHOAR2) due to different causative genes. Data comparing bone microstructure between the two subtypes are scarce. This is the first study to find that PHOAR1 patients had inferior bone microstructure compared with PHOAR2 patients.

PURPOSE

The primary goal of this study was to assess bone microarchitecture and strength in PHOAR1 and PHOAR2 patients and to compare them with age- and sex-matched healthy controls (HCs). The secondary goal was to assess the differences between PHOAR1 and PHOAR2 patients.

METHODS

Twenty-seven male Chinese PHO patients (PHOAR1 = 7; PHOAR2 = 20) were recruited from Peking Union Medical College Hospital. The areal bone mineral density (aBMD) was assessed by dual-energy X-ray absorptiometry (DXA). Peripheral bone microarchitecture at the distal radius and tibia were evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT). Biochemical markers of PGE2, bone turnover, and Dickkopf-1 (DKK1) were investigated.

RESULTS

Compared with HCs, PHOAR1 and PHOAR2 patients had distinctively larger bone geometry, substantially lower vBMD at the radius and tibia, and compromised cortical microstructure at the radius. For trabecular bone, PHOAR1 and PHOAR2 patients showed different changes at the tibia. PHOAR1 patients had significant deficits in the trabecular compartment, resulting in lower estimated bone strength. Conversely, PHOAR2 patients showed a higher trabecular number, narrower trabecular separation, and lower trabecular network inhomogeneity than HCs, translating into preserved or slightly high estimated bone strength.

CONCLUSION

PHOAR1 patients had inferior bone microstructure and strength compared with PHOAR2 patients and HCs. Additionally, this study was the first to find differences in the bone microstructure between PHOAR1 and PHOAR2 patients.

Hipocratismo digital: conociendo sus causas. Reporte de caso

Introducción. El hipocratismo digital es un signo clínico que afecta principalmente los dedos de las manos y se caracteriza por deformidad en uñas con abombamiento en vidrio de reloj. Puede presentarse en pacientes con cáncer diseminado, enfermedad pulmonar preexistente y dolor óseo, por lo cual es importante considerar esta entidad para un diagnóstico y un tratamiento oportunos.Presentación del caso. Paciente masculino de 86 años con hipocratismo digital, tabaquista en abstinencia, quien ingresa a urgencias por cuadro clínico de 2 meses de evolución consistente en fiebre y pérdida de 19kg de peso. Al examen físico presentaba disminución de ruidos respiratorios en base pulmonar derecha, dedos en palillo de tambor y deformidad ungüeal en manos. La radiografía de tórax mostró opacidad a nivel parahiliar derecho bien definida de 5cm. La tomografía computarizada de tórax mostró masas de bordes irregulares a nivel parahiliar derecho y en segmento apical del lóbulo inferior del pulmón derecho, y derrame pleural ipsilateral. La biopsia guiada por tomografía documentó adenocarcinoma pulmonar bien diferenciado.Conclusiones. El hipocratismo digital plantea un desafío en medicina debido a que puede ser difícil llegar a un diagnóstico etiológico y se pueden requerir muchos estudios para su confirmación.

A Common Mutation and a Novel Mutation in the HPGD Gene in Nine Patients with Primary Hypertrophic Osteoarthropathy

Primary hypertrophic osteoarthropathy (PHO) is a hereditary bone disease characterized by digital clubbing, periostosis, and pachydermia. The HPGD gene encoding 15-prostaglandin dehydrogenase and SLCO2A1 encoding one type of prostaglandin transporter were found to be responsible for PHO. Mutations of either gene would lead to increased level of prostaglandin E2 (PGE2), which might contribute to the constellation of the symptoms. The aim of the study was to analyze the HPGD gene and the clinical characteristics in nine patients with the diagnosis of PHO. Nine patients, (eight males and one female) including two siblings and seven sporadic cases, were enrolled in the study. Clinical features were summarized, and blood and urine samples were collected. Sanger method was used to sequence the HPGD gene to detect mutations. Urinary PGE2 and prostaglandin metabolite (PGE-M) levels for each patient were measured and compared to the healthy controls. A recurrent c.310_311delCT mutation was identified in all patients, of which six were homozygous, two were heterozygous, and one was compound heterozygous with this mutation and a novel heterozygous missense mutation c.488G>A (p.R163H). The levels of PGE2 in urine were much higher than normal in all patients, along with lower PGE-M levels. In conclusion, nine PHO patients were characterized by typical clinical manifestations including digital clubbing, periostosis, and pachydermia. A common mutation and a novel mutation in HPGD gene were identified to be responsible for the disease, and c.310_311delCT mutation is likely to be a hot-spot mutation site for Asian PHO patients.

Idiopathic clubbing confined to lower limb digits and idiopathic pulmonary fibrosis: an unusual association

A 62-year-old housewife presented to the chest outpatient department with a history of exertional breathlessness of four-month duration. On general physical examination, clubbing of toes was present with sparing of fingers. Chest examination revealed bilateral basal end inspiratory fine crepitations. A diagnosis of idiopathic pulmonary fibrosis was made on the basis of clinical, spirometric, and high-resolution computed tomography findings. Extensive evaluation could not reveal any cause for the differential clubbing. The unusual distribution of clubbing in a clinical condition, such as idiopathic pulmonary fibrosis, where generalized clubbing is expected can lead to a diagnostic confusion. This can lead to a further burden of investigations on the patient as clubbing being a significant finding cannot be ignored.