Hypertrophic Pulmonary Osteoarthropathy
Hypertrophic pulmonary osteoarthropathy is a paraneoplastic syndrome characterised by
1.grade 4 clubbing of fingers or toes,
2.symmetrical periostitis of long bones distally
3.arthropathy of wrists, ankles, knees
Swelling and extreme pain of the affected limbs (wrists, ankles, knees and elbows, fingers and toes, long bones distally)
Stiffness of the joints may occur
Edema of the hand and foot can occur
Fever can occur
Gynaecomastia may be present in some cases
Joint (Knee) effusions may occur
Rarely thickening and swelling of the end of the nose
Lovibond’s angle – The angle of the nail with the proximal nail fold is greater than 180 degree
Schamroth sign – The normal diamond shaped window created by placing the dorsal surfaces of opposite terminal phalanges is obliterated in clubbing.
Tenderness may be present in the wrist and the distal long bones.
Mesothelioma and pleural malignancies
Congenital cyanotic heart disease
Inflammatory bowel disease
Cirrhosis of liver
Clubbing due to any cause can also progress to HPOA
Males are more commonly affected than females. In bronchogenic carcinoma it is rare with the oat cell type.
The pathogenesis is unclear and various theories have been postulated.
1) Shunt theory In diseases with significant arterio-venous shunting, the megakaryocytes bypass the pulmonary circulation,where they usually get fragmented. These unfragmented megakaryocytes gets deposited in the finger tips stimulate the secretion of platelet derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). This results in angiogenesis and endothelial hyperplasia which manifests as clubbing.
2) Hormonal theory Humoral mechanism – the tumours may secrete substances that may act on the nail bed. Raised growth hormone and oestrogen are suggested by some researchers
3) Neurogenic theory - Reflex vasodilatation of the nail bed mediated through the intercostal nerves or vagus has also been hypothesized. The resolution of the symptoms after vagotomy is claimed as a support of this hypothesis.
X rays of the lone bones – subperiosteal new bone formation
Bone Scintigraphy can be done to confirm the diagnosis.It shows increased tracer uptake along the cortical margins.
HPOA can be very disabling and should be treated even if the primary tumour is inoperable.
Treatment of the primary cause, such us resection of lung tumour usually leads to the resolution of pulmonary osteoarthropathy.
If the tumor is inoperable, chemotherapy and radiotherapy may be given
Non-steroidal anti-inflammatory drugs especially indomethacin can reduce pain
Vagotomy has shown to reduce the symptoms of HPOA
SLE with polyarthritis