Heritable forms of hypertension

Among the causes of secondary hypertension are a group of disorders with a Mendelian inheritance pattern. Recent advances in molecular biology have unveiled the pathogenesis of hypertension in many of these conditions. Remarkably, the mechanism in every case has proved to be upregulation of sodium (Na) reabsorption in the distal nephron, with accompanying expansion of extracellular volume. In one group, the mutations involve the Na-transport machinery in distal tubule cells themselves: the distal convoluted tubule (DCT) cell and the principal cell of the collecting duct. Examples include Liddle’s syndrome, with an activating mutation of epithelial Na channel (ENaC); two types of Gordon’s syndrome, with mutations in two regulatory kinases [with no lysine (K) serine/threonine protein kinases (WNK)1 or WNK4]; and apparent mineralocorticoid excess (AME), with an inactivating mutation in the glucocorticoid-metabolizing 11β-hydroxysteroid dehydrogenase type 2 enzyme (11HD2). In another group, abnormal adrenal steroid production leads to inappropriate stimulation of the mineralocorticoid receptor (MR) in the distal nephron. The pathophysiology may involve inappropriate production of aldosterone [in glucocorticoid-remediable aldosteronism (GRA) and familial hyperaldosteronism type II (FH II)], of cortisol (in familial glucocorticoid resistance), or of other steroid metabolites (in congenital adrenal hyperplasia and GRA). In contrast to earlier beliefs, hypertension in many of the inherited disorders may be mild, and electrolyte and acid-base abnormalities are often not present. Monogenic hypertension should therefore enter the differential diagnosis of any child or adolescent with hypertension. Plasma renin activity (PRA) is the appropriate screening tool for all types of inherited hypertension.     

Heritable disorders predisposing to aortic dissection

Heritable disorders of connective tissue often predispose patients to aortic pathology and in particular aortic dissection. The Marfan syndrome, vascular Ehlers-Danlos syndrome, familial forms of thoracic aortic aneurysms or aortic dissection, and bicuspid aortic valve are all examples of heritable disorders that have associated defects affecting the integrity of the aortic wall, posing a risk of both aneurysmal dilation and dissection. The purpose of this review was to outline the phenotypes of the heritable syndromes that predispose to aortic dissection, present a guideline to their management and surveillance, and to offer insight into some of the surgical pitfalls that occur when repairing ascending aortic dissections in these types of patients.     

Tumors of the nail and nail bed

This article reviews the tumors that most frequently affect the nail and nail bed. Clinical appearance, histopathology, differential diagnosis, and treatment are discussed.     

Half-and-half nail

Clinical and Experimental Nephrology -     

Vascularized nail flap vs. free nail graft

Summary With recent improvements in microvascular surgery, the vascularized nail flap procedure has had considerable success. On the other hand, free nail graft without microvascular anastomoses is still used but little has been published to make a comparison between these two procedures. Thus, it is not known which is the better procedure. In the past, hand nail defects in 12 patients have been reconstructed by the free nail graft procedure and in four patients by vascularized nail flap procedure. In this article, the free nail graft is compared with the vascularized nail flap and the merits and demerits of both techniques are presented. Requests for reprints: T. Endo, M.D.     

Heritable Thrombophilia-Hypofibrinolysis and Osteonecrosis of the Femoral Head

We hypothesized that inherited thrombophilia and hypofibrinolysis were risk factors for osteonecrosis of the femoral head. We compared measures of thrombophilia and hypofibrinolysis in referred new adult patients with idiopathic osteonecrosis (n = 71) or secondary osteonecrosis (n = 62) with the same measures in sex- and race-matched healthy control subjects. Heritable thrombophilic Factor VIII and hypofibrinolytic Lp(a) were more frequently high in the 71 patients with idiopathic osteonecrosis than in control subjects. High Factor VIII, Factor V Leiden heterozygosity, and resistance to activated protein C, all heritable thrombophilias, were more frequently present in the 62 patients with secondary osteonecrosis than in control subjects. Our data suggest inherited thrombophilia and hypofibrinolysis are risk factors for both idiopathic and secondary osteonecrosis of the head of the femur.     

Similarities between a conjoined nail and the palmar nail syndrome

The congenital palmar nail syndrome consists of a triad of palmar nail, absent finger flexion and abnormalities of the distal phalanx. There are two main theories about the pathogenesis of this syndrome: the ancestral reversion theory and the duplication theory. In this paper, similarities between a conjoined nail in conjoined twins and the palmar nail syndrome are described to support the duplication theory.     

Common nail disorders

The toenails and the rest of the human foot are constantly sandwiched in shoes, traumatized, and poorly supplied with blood that is necessary for normal morphology and function, resulting in more abnormal changes of the toenails (onychopathies). This article discusses briefly the following: (1) the conditions that are commonly seen in feet by podiatric practitioners; (2) clinical signs, symptoms, and etiology; and (3) differential diagnosis and care of the conditions.     

Pediatric nail disorders

This article lists common pediatric nail disorders seen in infancy and adolescence. The diagnosis of pediatric nail disorders can be a sign of systemic disorders and diseases. The surgical treatment of young children and the treatment of pediatric patients are presented for those who do not frequently treat pediatric patients. The analysis of pediatric onychomycosis is presented, and the incidence and prevalence in the population is discussed.     

Microvascular nail transfer

A composite of nail and its skin appendages can be transferred for the foot to the hand by microvascular anastomosis. For technical reasons, the most suitable donor nail is from the big toe, and this most closely approximates the thumb nail. A finite portion of hemipulp must be included with the transfer to ensure adequate vascularization. Nail size can be reduced by resection of the edges of the germinal matrix so as to match the donor defects. For finger nail reconstruction, it is usually more practical to transfer the whole of the tip of the second or third toe to replace the whole of the tip of the finger. The indications of nail reconstruction by this technique are relatively rare and are predominantly cosmetic.     

Surgical nail procedures

As the so-called "non-surgical" nail procedures grow more and more aggressive and invasive in nature, the cold steel matrixectomy becomes an increasingly viable alternative. Many chemical and thermal matrixectomies are performed under poor aseptic conditions, increasing the risk of wound infection. With chemical matrixectomy, regulation of the level of tissue destruction is uncontrolled and often results in bone injury. The combination of these two elements can result in delayed diagnosis and recognition of osteomyelitis. When a practitioner is faced with a challenging ingrown, dystrophic, or mycotic nail, surgical nail removal should be considered the preferred technique. Etiologic variants of nail deformity, such as hypertrophied ungual labia, subungual exostosis, traumatized nail, and prominent underlying bony condyles, are well managed by the two procedure modifications presented. Advantages in asepsis, quicker wound healing, low reoccurrence rates, and good postoperative cosmesis make surgical nail removal a good choice. The difficulty of the technique and the danger of bone infection have frightened many practitioners away from the cold steel nail procedure. The preferred phenol technique or "p and a" may be simpler to perform, but it yields an unpredictable result. The constant draining and erythema of a phenolized nail may mask an underlying infection. This is one reason why cold steel nails are the preferred technique for nail removal in a diabetic patient. Complications makes cold steel a necessary addition to the surgeons armamentarium. We have presented a brief clarification and historical overview of the four most important contributors to surgical nail removal. These four techniques (Winograd, Frost, Zadik, and Kaplan) have been interwined into the two modifications commonly used today. By following the step-by-step surgical method presented and adding the reader's own successful techniques, a good surgical result can be easily achieved.