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Intrinsic Renal Failure Diagnosis

During acute intrinsic renal failure, three clinical phases can be distinguished. The initial phase of injury is the period between the onset of insult and established renal failure. This phase can last several hours or, rarely, days. The second phase is that of established renal failure or the maintenance phase, characterized by reduction of the GFR and azotemia. This phase usually lasts several days to weeks. Oliguria that lasts more than 90 days often indicates the possibility of residual structural impairment.

The third or recovery phase results in a gradual increase in GFR and diuresis. An increase in urine output will improve the fluid and electrolyte imbalance. Glomerular filtration recovers more rapidly than tubular function, and the patient may demonstrate a lengthy period of tubular dysfunction, such as an inability to concentrate urine and increased salt losses. Recovery may extend over several weeks to months; the usual time of renal recovery is about 30 days.

A history may help in establishing the etiology of intrinsic renal failure. Edema, skin infection, or smoky urine suggests postinfection glomerulonephritis; purpuric rash, abdominal pain, and diarrhea suggest vasculitis; and urticarial rash, use of drugs, fever, and arthralgia may indicate acute interstitial nephritis. Once the kidney has developed intrinsic renal failure, the signs and symptoms usually are independent of the etiology. Nonspecific generalized symptoms (lethargy, anorexia, vomiting, abdominal pain) can be present. Signs of fluid retention (peripheral and pulmonary edema, hypertension) and changes in urine pattern (oliguria, anuria, or polyuria) are prominent. The hallmark of intrinsic renal failure is the worsening of azotemia, with a daily rise in serum creatinine (0.5 to 1.5 mg/dL) and in BUN (10 to 20 mg/dL).

Hyponatremia frequently is dilutional, secondary to fluid retention and/or to the administration of hypotonic solutions. Hyperkalemia develops primarily as the result of decreased GFR and cellular catabolism. Metabolic acidosis results from the reduced capacity of the kidneys to regulate acid base homeostasis and lactic acid accumulation. Hyperphosphatemia develop secondary to decreased filtration as well as cell destruction. Low serum calcium is secondary to hyperphosphatemia, resistance to parathyroid hormone, and abnormalities in vitamin D metabolism. Usually, hypocalcemia is asymptomatic, but can lead to tetany, convulsions, or hypotension. The uric acid level may become markedly elevated during the oliguric phase.

Anemia is a result of the dilution, decreased erythropoiesis, hemolysis, and blood loss. Leukopenia or leukocytosis can be evident. Microangiopathic hemolytic anemia (Coombs negative) with fragmented erythrocytes on the peripheral smear and thrombocytopenia are characteristics of hemolytic-uremic syndrome. Coagulation abnormalities accompanied by an increase in bleeding time secondary to the platelet dysfunction are found in severe uremia.

Proteinuria of more than 1 g/d, numerous dysmorphic red blood cells, and red blood cell and granular casts are seen in glomerulonephritis and vasculitis. In the case of acute interstitial nephritis, pyuria, eosinophiluria, scant casts (mainly white blood cell casts), and tubular cells are present. Myoglobinuria or hemoglobinuria should be suspected whenever there exists a urine sample that has blood on the dipstick and only 1 to 2 red blood cells in the sediment. Urinary sediment with numerous coarse granular or pigmented casts and/or tubular cells are characteristic of ATN. Urinary indices will reflect tubular dysfunction and injury and will document the inability of the kidney to concentrate urine and conserve sodium (a urine osmolality <350 mOsm/kg H2O, urine Na >40 mEq/L, FENa >2.5%).

Renal ultrasonography usually shows enlarged kidneys with a uniform increased cortical echogenicity; a renal scan shows poor uptake and excretion of radioisotope.

image source: http://en.wikipedia.org/wiki/Acute_kidney_injury

Postrenal Failure Diagnosis

The pediatrician must be alert to the possibility of renal obstruction. When a child presents with the signs of azotemia and a sudden decrease in urine output, the history and physical examination can help determine the location and cause of obstruction. The patient may have had frequent urinary tract infections, hematuria, trauma, underlying lesions, an alteration in the urinary pattern (decrease in urine stream, dribbling), and presence of lower abdominal or flank pain secondary to renal enlargement and dilatation of the collecting system. The physical examination may reveal a palpable suprapubic mass, such as in male newborns who have posterior urethral valves. This is the most common cause of postrenal failure in boys.

Rectal and gynecologic examinations should be done to exclude extrinsic causes of renal obstruction. The patency of the urinary tract must be established first in every patient who has Acute Renal Failure (ARF). Thus, in patients who have ARF, assessment by renal ultrasonography must include evaluation of the lower urinary tract and bladder.

Urinalysis can reveal microscopic or macroscopic hematuria with eumorphic (normal-appearing) red blood cells, pyuria in case of infection, crystals such as calcium oxalate in nephrolithiasis, or ethylene glycol intoxication. A plain abdominal radiograph can demonstrate radiopaque stones or an ileus secondary to colic, suggest abdominal masses, and provide data about bony structures. Renal ultrasonography can detect the pattern of hydronephrosis and sometimes the site of obstruction.

image source: http://www.studyblue.com/notes/note/n/chapter-11-pathophysiology-review-terms/deck/5670061

Prerenal Failure Diagnosis

The patient who has prerenal failure will evidence the signs and symptoms of decreased effective blood volume or perfusion. There may be a history of vomiting, diarrhea, recent febrile illness, surgery, imbalance between input and output, heart problems, thirst, weight loss, or decrease in urine output. Signs of moderate or severe dehydration (hypotension, tachycardia, decreased skin turgor, dry mucous membrane, oliguria/ anuria) or of congestive heart failure (hepatomegaly, pulmonary edema, peripheral edema, gallop) may be present.

Laboratory studies will demonstrate hemoconcentration with an increase in hematocrit, uric acid, and total protein and a markedly elevated BUN. The BUN/SCr ratio usually is more than 20. Urinalysis will show a trace to + 1 protein, and sediment usually is normal, but hyaline and fine granular casts may be present as well. Urinary indices will reflect a maximally concentrated urine (specific gravity >1.016 to 1.030, urine osmolality >400 mOsm per kg H2O), preserved tubular integrity (urine/ plasma osmolality ratio > 1.5, urine/ plasma creatinine ratio >40, urine/ plasma urea ratio >20), and salt conservation (urine sodium <720 mEq/L, FENA <1%). In the case of metabolic alkalosis, a spot urine chloride of less than 20 mEq/L usually indicates perserved tubular function.

The chest radiograph may evidence signs of heart failure. Findings on renal ultrasonography usually are non specific, and kidney size is normal.

image source: http://www.buzzle.com/articles/prerenal-failure.html

Acute Renal Failure (ARF) in Children

Acute Renal Failure in Children

Acute Renal Failure (ARF) is relatively uncommon, its mortality rate is potentially so high that it is important to recognize this condition in children. Rapid deterioration of renal function is caused by numerous insults and results in typical findings, including extracellular volume expansion, hyperkalemia, hypertension, metabolic acidosis, and azotemia. It usually is reversible, with the majority of patients recovering completely. However, ARF can lead to residual impairment of renal function and progress to end-stage renal disease and death. Conservative medical treatment often is life-saving.

Definition

Acute Renal Failure (ARF) represents the rapidly progressive (within several hours or days) cessation of renal function, which results in the inability of the kidney to control body homeostasis, manifesting in retention of nitrogenous waste products (azotemia) and fluid and electrolyte imbalance. On the basis of pathophysiologic process, ARF has been divided broadly into three diagnostic categories: prerenal, intrarenal (organic-intrinsic), and postrenal failure. Prerenal and early postrenal failures are renal functional disorders and responses of a structurally intact kidney to extrarenal processes. These forms of renal dysfunction recover rapidly as soon as the cause is reversed. However, if these two disorders are not recognized in time, persist too long, or are treated inadequately, they can result in intrinsic renal failure. Intrinsic or organic renal failure is caused by structural changes within the kidney. It is potentially reversible but requires an extended period of recovery.

Etimology
Prerenal failure is the most common form of Acute Renal Failure (ARF) in children. The main process in the development of prerenal failure is hypoperfusion of the kidney, secondary to reduced effective plasma volume or heart failure. Numerous underlying conditions can lead to prerenal failure. In children, the most common causes are hypovolemia secondary to gastrointestinal losses, the state of shock, and postoperative conditions. For example, ARF may occur after heart surgery when the aorta is cross-clamped or following prolonged cardiopulmonary bypass time.
A variety of renal disorders and insulting events can contribute to the development of intrinsic renal failure. Among these are acute glomerulonephritis and vasculitis of childhood, acute tubular necrosis, and acute interstitial nephritis.
Acute tubular necrosis (ATN) is the most common cause of intrinsic renal failure. It is associated with necrosis of the tubular epithelium following hypoxic or nephrotoxic injury. Various substances, including ethylene glycol, heavy metals, hydrocarbons, and certain antibiotics, including cephalosporins, aminoglycosides, sulfonamides, methicillin, and colistin, are potent nephrotoxins. Aminoglycoside-induced acute renal failure occurs typically 5 days after drug administration and represents a dose-dependent phenomenon.
Radiologic contrast material of the ionic type can cause ARF, usually within 24 hours after exposure, especially in individuals who are dehydrated, have diabetes mellitus, or have preexisting renal insufficiency. Primary diseases of the glomeruli and small blood vessels of the kidney may present with rapidly progressive ARF. Large vessel diseases (renal artery thrombosis or embolism, renal vein thrombosis) are uncommon. Acute interstitial nephritis usually results from immune-mediated drug sensitivity or infection.
Postrenal failure is a less frequent cause of ARF in children. It presents as an abrupt decline in glomerular filtration rate (GFR) secondary to lower tract obstruction or bilateral upper tract obstructions, unless the patient has a single kidney. Obstruction can be secondary to structural, congenital, or acquired anomalies of the urinary tract, including posterior urethral valve, ectopic ureter, aberrant vessels, or stones, or may result from functional abnormalities such as neurogenic bladder. Uric acid, the end product of purine metabolism, is insoluble at high concentrations in an acidic medium; during rapid cellular lysis before or after chemotherapy it often will precipitate in a distal nephron and cause renal obstruction. Depending on localization, obstruction can be extrinsic or intrinsic, at the level of the collecting duct, pelvis, ureter, bladder, urethra, or meatus.

Pathophysiology
Prerenal dysfunction can lead to development of renal failure and is characterized by a decline in renal blood flow (RBF), GFR, and urine flow. After an acute reduction in effective intravascular volume, compensatory mechanisms of both the organism and the kidney will operate to counteract the volume loss and restore renal perfusion. Central activation of several neural and humoral responses occurs, including increased activity of the sympathetic system and the renin-angiotensin II-aldosterone system and enhanced release of antidiuretic hormone.
Hemodynamic alterations within the kidney develop. An initial, short response of maximum dilatation of afferent arteriole is replaced by vasoconstriction. Blood flow is redistributed away from the renal cortex to juxtamedullary nephrons, which results in extensive tubular reabsorption of sodium, water, and urea.
With intense vasoconstriction, the kidney, acting as a blood reservoir, will shunt additional volumes of blood to the most vital organs (brain and heart); this response actually may be lifesaving in states of shock, blood loss, or severe dehydration. When the kidney has used these compensatory mechanisms fully, and the delivery of oxygen to the kidney remains critically impaired, acute necrosis of tubular cells occurs.
Injury due to ischemia or toxins is manifested by alterations in cellular metabolism. Cell detachment, desquamation, necrosis, and generation of intratubular debris and cast formations develop. The backward leak of tubular fluid across the injured tubular membrane and tubular obstruction results in further hemodynamic changes. Finally, decreased filtration rate leads to oliguria or anuria, defined as follows:

· Oliguria-urine output less than 0.5 mL/kg per hour in infants or less than 500 mL/1.73 m² per day) in older children
· Anuria-total cessation of urinary output

Although intrinsic renal failures generally present as oliguria or anuria, the entity of nonoliguric ARF (sometimes called nonoliguric vasomotor nephropathy) is being increasingly recognized. Nonoliguric renal failure typically consists of azotemia in the face of a normal urine output (> 1 mL/kg per hour). It occurs primarily as a result of exposure to a nephrotoxic drug, especially an aminoglycoside.
Postrenal failure is a result of a total or partial obstruction of the urinary tract that affects the flow of normally produced urine. In the case of partial obstruction, the patient usually is nonoliguric and may even be polyuric. With the development of an obstruction, pressure proximal to the site of obstruction rises, which results in increased intratubular pressure and dilatation of the collecting system (hydronephrosis). Vasodilatation occurs only in the first 1 to 3 hours after obstruction and is followed by a period of intense vasoconstriction that leads to the ultimate damage of the tubular cells.

image source: http://topnews.net.nz/content/22630-fatal-kidney-disease-affects-many-indian-kids

Carpal Tunnel Syndrome: Clinical Findings and Treatment

What is Carpal Tunnel Syndrome?

Here's Carpal Tunnel Syndrome definition:
Carpal tunnel syndrome is a common disorder characterized by pain, burning , and tingling of the palmar surface of the hand, resulting from compression of the median nerve between the carpal ligament and other structures within the carpal tunnel (entrapment neuropathy). The volume of the contents of the tunnel can be increased by organic lesions such as synovitis of the tendon sheaths or carpal joints, recent or malhealed fractures, tumors, and occasionally congenital anomalies. Even though no anatomic lesion is apparent, flattening or even circumferential constriction of the median nerve may be observed during operative section of the ligament. The disorder may occur in pregnancy, is seen in individuals with a history of repetitive use of the hands, and may follow injuries of the wrists. A familial type of carpal tunnel syndrome has been reported in which no etiologic factor can be identified.
Carpal tunnel syndrome can also be a feature of many systemic diseases: rheumatoid arthritis and other rheumatic disorders (inflammatory tenosynovitis); myxedema, amyloidosis, sarcoidosis, and leukemia (tissue infiltration); acromegaly; hyperparathyroidism, hypocalcemia, and diabetes mellitus.

Clinical Findings of Carpal Tunnel Syndrome

Pain in the distribution of the median nerve, which may be burning and tingling (acroparesthesia), is the initial symptom. Aching pain may radiate proximally into the forearm and occasionally proximally to the shoulder, neck, and chest. Pain is exacerbated by manual activity, particularly by extremes of volar flexion or dorsiflexion of the wrist. It may be most bothersome at night. Impairment of sensation in the median nerve distribution may not be apparent. Subtle disparity between the affected and opposite sides can be demonstrated by testing for two-point discrimination or by requiring the patient to identify different textures of cloth by rubbing them between the tips of the thumb and the index finger. Tinel's or Phalen's sign may be positive. (Tinel's sign is tingling or shock-like pain on volar wrist percussion; Phalen's sign, pain or paresthesia in the distribution of the median nerve when the patient flexes both wrists to 90 degrees with the dorsal aspects of the hands held in apposition for 60 seconds.) The carpal compression test, performed by applying direct pressure on the carpal tunnel, may be more sensitive and specific than the Tinel and Phalen tests. Muscle weakness or atrophy, especially of the abductor pollicis brevis, appears later than sensory disturbances. Useful special examinations include electromyography and determinations of segmental sensory and motor conduction delay. Distal median sensory conduction delay may be evident before motor delay.

Differential Diagnosis of Carpal Tunnel Syndrome

This syndrome should be differentiated from other cervicobrachial pain syndromes, from compression syndromes of the median nerve in the forearm or arm, and from mononeuritis multiplex. When left-sided, it may be confused with angina pectoris.

Carpal Tunnel Syndrome Treatment

Treatment is directed toward relief of pressure on the median nerve. When a primary lesion is discovered, specific treatment should be given. When soft tissue swelling is a cause, elevation of the extremity may relieve symptoms. Splinting of the hand and forearm at night may be beneficial. Injection of corticosteroid into the carpal tunnel can alleviate symptoms in some patients, particularly those with synovitis of the wrist. To reduce the chance of nerve injury, this injection should be performed by a physician thoroughly familiar with the anatomy of the carpal tunnel. Operative division of the volar carpal ligament gives lasting relief from pain, which usually subsides within a few days. Muscle strength returns gradually, but complete recovery cannot be expected when atrophy is pronounced.

image Source:http://injuryfix.com/archives/carpal-tunnel-syndrome.php

BreastFeeding Benefits

Breast milk is universally recognized as the preferred source of infant nutrition, and the nutritional advantages of breast milk have been well documented. Colos-trum, the first milk produced after delivery, provides an initial dose of enzymes that promote gut maturation, facilitate digestion and stimulate passage of meco-nium. Colostrum is also high in protein, primarily because of high levels of im-munoglobulins and secretory IgA. The protein in human milk is ideal not only for absorption, but also for utilization, especially by the rapidly developing infant brain. Human milk also contains predominantly polyunsaturated fats with stable amounts of cholesterol, an important constituent of brain and nerve tissue.

Human milk also protects against infection by providing cellular immunity through macrophages and humoral factors, such as antibodies. Numerous studies have verified that breast-fed infants have a lower incidence of bacterial and viral illnesses than bottle-fed infants. This low incidence is of particular clinical significance in developing nations? Ongoing research suggests that breast feeding may provide immuno-logic protection against diabetes mellitus, cancer and lymphoma. Finally, breast feeding has been found to provide protection from allergic diseases, including eczema, asthma and allergic rhinitis. This protection is most likely the result of breast milk decreasing intestinal permeability to large, allergenic molecules.

Recognizing these as well as other advantages, the American Academy of Family Physicians (AAFP) and the American Academy of Pediatrics (AAP) have identified breast milk as the preferred source of infant nutrition. In addition, the U.S. Public Health Service (USPHS) has established a national goal that, by the turn of the century, 75 percent of new mothers will be breast-feeding at the time of hospital discharge. Despite an emphasis on breast feeding by both private and government organizations, only 54 percent of U.S. mothers initiate breast feeding, and fewer than half of these mothers continue nursing for at least six months. Clearly, all health care providers should actively promote breast feeding if the goal set by the USPHS is to be accomplished.

To successfully promote breast feeding, family physicians should consider the influence of marketing campaigns aimed at expectant and new mothers by the manufacturers of infant formulas. Historically, their dogged marketing efforts have included the distribution of free cases of infant formula to expectant mothers, as well as the inclusion of formula samples in commercial hospital discharge packs designed for breast-fed infants. Physicians must work proactively to weigh the risks and benefits of promotional materials and develop appropriate policies governing their distribution in their hospitals or academic institutions.

image source: http://healthynaturalbaby.org/breastfeeding-shown-to-reduce-crib-death-in-infants-by-50/

Heart disease: Problem diseases in pregnancy

Most heart disease in women of childbearing age is rheumatic in origin despite the recent great reduction in the prevalence of rheumatic fever. Better living conditions in the UK and the more prompt treatment of streptococcal sore throats with antibiotics in childhood have reduced rheumatic damage to the heart valves and myocardium. An increasing proportion of pregnant women have congenital heart lesions that have been treated previously.
Pregnancy puts an increased load on the cardiovascular system. More blood has to be circulated so that cardiac output increases by up to 40% by mid-pregnancy, staying steady until labour, when it increases further. This increased cardiac work cannot be done as effectively by a damaged heart; if the heart is compromised a woman would be wise to avoid other increased loads that might precipitate cardiac failure. The most frequently encountered are:

Household work
Recrudescence of rheumatic fever
Paid work outside the home
Care of other family members
Respiratory infection
Pre-eclampsia
Urinary infection
AnaemiaBacterial endocarditis

Care should be taken just after delivery: with the uterine retraction up to a litre of blood can be swiftly shunted from the uterine veins into the general venous system.

References:
Geoffrey Chamberlain. 2002. ABC of Antenatal Care. London: BMJ Books.
Image Source: http://www.nhs.uk/Conditions/Congenital-heart-disease/Pages/Complications.aspx

Take Care of Newborn Baby Skin

Picture: Strawberry Birth Mark

Diffuse capillary naevi on the face, eyelids, or occiput are common and resolve within a few months.
The “strawberry mark” (Strawberry Angioma) starts as a tiny red spot and grows rapidly for several weeks until it has a raised red appearance with small white areas, suggesting the seeds of a strawberry. Such marks are common in preterm babies. They may occur anywhere on the body but cause no symptoms, except on the eyelids, where they may prevent easy opening of the eyes and need treatment. Strawberry naevi grow, often rapidly, for 3–9 months, but at least 90% resolve spontaneously, either completely or partially. Resolution usually begins at 6–12 months and is complete in half the children by the age of five and in 70% by the age of seven years. In 80% of cases these naevi resolve completely without trace.

The port wine stain is not raised and may be extensive. It does not resolve, but the skin texture remains normal. When the naevus occurs in the distribution of the trigeminal nerve, there may be an associated intracranial vascular anomaly.

Neonatal erythema (erythema “toxicum”) consists of blotchy ill defined areas of bright erythema surrounding white or yellow wheals which may resemble septic spots. It usually appears on the second day of life and in most infants clears within 48 hours. The lesions contain many eosinophils and have no pathological importance. Neonatal erythema is more common in full term infants. By ringing individual lesions with a skin pencil they can be shown to disappear in a few hours, to be replaced by others elsewhere. This contrasts with septic lesions, which appear later and do not resolve so quickly.

Mongolian blue spots are patchy accumulations of pigment, especially over the buttocks and lower back in infants of races with pigmented skins. They are common in babies of African or Mongolian descent, but also occur in Italian and Greek babies. They may be mistaken for bruises and a wrong diagnosis of non-accidental injury made. They become less obvious as the skin darkens.

A midline pit over the spine is most commonly found over the coccyx, where it does not usually communicate with the spinal canal. A midline pit anywhere else along the spine may be connected with an underlying sinus, which may communicate with the spinal canal and requires excision to prevent the entry of bacteria and meningitis.

References:
Bernard Valman. 2002. ABC of the First Year. London: BMJ Books.
Image Source: http://doctorv.ca/cosmetic-services/telangiectasia-broken-facial-blood-vessels/strawberry-hemangioma-strawberry-angioma/ (downloaded Januari 2, 2014 at 22:16 GMT+07)

Umbilical Hernia Symptoms, Causes, Treatment

An umbilical hernia, usually containing omentum and gut. About 30% of preterm infants who have received mechanical ventilation have an umbilical hernia. No treatment is needed, as the hernia usually disappears spontaneously by the age of three years, although in West Indian infants it may take a further three years.
In contrast to an umbilical hernia the sac of an omphalocoele is covered by peritoneum but incompletely by skin. An omphalocoele is a hernia into the base of the umbilical cord and contains gut and sometimes solid organs like the liver. Immediate transfer to a surgical unit is needed.

Umbilical Hernia Symptoms

Umbilical hernias can usually be seen when your baby is crying, laughing, or straining to use the bathroom. The telltale symptom is a swelling or bulge near the naval area—a symptom not present when your baby is relaxed.
Adults can get umbilical hernias as well. The symptoms will be the same—a swelling or bulge near the navel area. These can be very painful and treatment is usually required.
Symptoms that indicate a more serious situation requiring medical treatment include:
    the baby is in obvious pain
    the baby is vomiting
    the bulge (in both children and adults) is tender, swollen, or discolored

Umbilical Hernia Causes

In a majority of cases, umbilical hernias occur in babies. Babies who are African-American, premature, and of low birth weight are at even higher risk of developing an umbilical hernia. There is no noted difference in occurrence between boys and girls.
An umbilical hernia in adults usually occurs when too much pressure is put on a weak section of the stomach muscles due to:
    being overweight
    frequent pregnancies
    fluid in the abdominal cavity
    stomach surgery

References:
Bernard Valman. 2002. ABC of the First Year. London: BMJ Books.
Shannon Johnson. 2012. Umbilical Hernia. http://www.healthline.com/health/umbilical-hernia (viewed Januari 2, 2014 at 22:16 GMT+07)
Image Source: http://en.wikipedia.org/wiki/File:Umbilical_Hernia.JPG

Beware of Myelomeningocele (Spina Bifida) in infants

Myelomeningocele (Spina Bifida)

A myelomeningocele is a flat or raised neural plaque partly devoid of skin in the midline over the spine due to abnormal development of the spinal cord and associated deficiency of the dorsal laminae and spines of the vertebrae. It is usually found in the lumbar region. The absence of the various coverings that normally protect the cord allows meningitis to occur easily. If there are no active movements in the legs and the anus is patulous, the infant will probably be incontinent of urine and faeces for life and never be able to walk unaided. Thoracic lesions and kyphosis are signs of poor prognosis.
Infants with a good prognosis need urgent treatment, so all affected infants should either be seen by a consultant paediatrician without delay or sent to a special centre, where selection for surgery can be made. About 30% of the infants have surgery as a result of this policy. During the first operation the lesion on the back is covered by skin.
Most of these infants develop progressive hydrocephalus later and those considered suitable for surgery require insertion of a catheter with a valve from a cerebral ventricle to the peritoneal cavity to reduce the cerebrospinal fluid pressure.
Hydrocephalus can be detected by ultrasound examination of the brain. Serial measurements show whether ventricular size is increasing rapidly. In addition, progressive hydrocephalus is confirmed by measuring the circumference of the head at its largest circumference (occipitofrontal) every three days with a disposable paper tape measure, plotting these values on a growth chart, and showing that the head is growing faster than normal.
Raised concentrations of a-fetoprotein are found in the amniotic fluid when the fetus has an open myelomeningocele or anencephaly. In anencephaly there is absence of the cranial vault and most of the brain.
A routine anomaly scan at 18–24 weeks of gestation will detect most neural tube defects and the parents may decide that the pregnancy should be terminated in view of the poor prognosis. Anencephaly is a lethal condition but some infants survive for a few hours or days after birth.

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References: Bernard Valman. 2002. ABC of the First Year. London: BMJ Books. Image source: http://www.flickr.com/photos/laaradj_saadaoui/3461465263/

Psychiatric and social factors of failure to thrive

A physical cause for failure to thrive may be present in a family with psychiatric and social problems and therefore a physical cause must be excluded for all infants. The exclusion of a physical cause is often helpful in persuading the parents to accept that psychiatric or social factors are the main reason for the problem. Features in the history that may suggest this possibility include maternal depression, marital discord, or a disorganised household. Maternal food preferences may result in the exclusion of certain foods, such as cow’s milk, from the diet without reason and without adequate supervision, and may result in a deficient energy intake.

There are more subtle ways in which maternal emotional factors may affect the infant. The mother may be depressed and tense, and this anxiety is transmitted to the child, who does not feed. The mother then reacts by removing the food. In other families the child may be intrinsically less responsive than the average child to food and this may affect the mother’s response to the child at mealtimes. In both these examples the amount of food taken by the child falls to a plateau where the infant appears to be satisfied with the amount given. Another possibility is that the mother keeps to a diet herself as she perceives that she is overweight and also gives a diet to the infant in a similar way.
Some infants are deliberately underfed as part of child abuse. Normal weight gain occurs when fostering has been carried out.

Effective management of infants with this diagnosis requires a team approach involving a health visitor, the family doctor, a child psychiatrist, and paediatrician. Regular advice from a health visitor or dietitian often improves the rate of weight gain.

References:
Bernard Valman. 2002. ABC of the First Year. London: BMJ Books.
Image source: http://emedicine.medscape.com/article/915575-overview

Helicobacter pylori Infection Diagnosis

Invasive tests

H pylori can be detected at endoscopy by histology, culture, or urease tests, each with inherent advantages and disadvantages. All these biopsy based methods for detecting H pylori are lible to sampling error because infection is patchy. Up to 14% of infected patients do not have antral infection but have H pylori elsewhere in the stomach, especially if they have gastric atrophy, intestinal metaplasia, or bile reflux. In addition, after partially effective eradication treatment, low levels of infection can easily be missed by endoscopic biopsy, leading to overestimates of the efficacy of eradication treatment and reinfection rates. Proton pump inhibitors affect the pattern of H pylori colonisation of the stomach and compromise the accuracy of antral biopsy. Consensus guidelines therefore recommend that multiple biopsies are taken from the antrum and corpus for histology and for one other method (either culture or urease testing).

Histology—Although H pylori may be recognised on sections stained with haematoxylin and eosin alone, supplementary stains (such as Giemsa, Genta, Gimenez, Warthin-Starry silver, Creosyl violet) are needed to detect low levels of infection and to show the characteristic morphology of H pylori. An important advantage of histology is that, in addition to the historical record provided, sections from biopsies (or even additional sections) can be examined at any time, and that gastritis, atrophy, or intestinal metaplasia can also be assessed. Biopsy specimens from other parts of the stomach can be retained in formalin to be processed only if antral histology is inconclusive.

Culture—Microbiological isolation is the theoretical gold standard for identifying any bacterial infection, but culture of H pylori can be unreliable. Risks of overgrowth or contamination make it the least sensitive method of detection, and it is the least readily available test for use with endoscopy. Although only a few centres routinely offer microbiological isolation of H pylori, the prevalence of multiresistant strains makes it increasing likely that culture and antibiotic sensitivity testing may become a prerequisite for patients with persistent infection after initial or repeated treatment failure.

Urease tests are quick and simple tests for detecting H pylori infection but indicate only the presence or absence of infection. The CLO test and cheaper “home made” urease tests are of similar sensitivity and specificity. However, the sensitivity of urease tests is often higher than that of other biopsy based methods because the entire biopsy specimen is placed in the media, thereby avoiding the additional sampling or processing error associated with histology or culture. The sensitivity of biopsy urease tests seems to be much lower (~60%) in patients with upper gastrointestinal bleeding, but this can be improved by placing multiple biopsy samples into the same test vial.

Non-invasive tests

Serology
H pylori infection elicits a local mucosal and a systemic antibody response. Circulating IgG antibodies to H pylori can be detected by enzyme linked immunosorbent assay (ELISA) antibody or latexagglutination tests. These tests are generally simple, reproducible, inexpensive, and can be done on stored samples. They have been used widely in epidemiological studies, including retrospective studies to determine the prevalence or incidence of infection.

Individuals vary considerably in their antibody responses to H pylori antigens, and no single antigen is recognised by sera from all subjects. The accuracy of serological tests therefore depends on the antigens used in the test, making it essential that H pylori ELISA is locally validated. In elderly people with lifelong infection, underlying atrophic gastritis has been associated with false negative results. Consumption of non-steroidal anti-inflammatory drugs has also been reported to affect the accuracy of ELISAs.

Antibody titres fall only slowly after successful eradication, so serology cannot be used to determine H pylori eradication or to measure reinfection rates. Although titres of IgM antibodies to H pylori fall with age, there are no reliable IgM assays to indicate recent acquisition, which, since this is usually asymptomatic, makes it difficult to identify cases of primary infection and thus establish possible routes of transmission.

An important advantage of serological methods over other tests for H pylori infection has been the development of simple finger prick tests that use a fixed, solid phase assay to detect the presence of H pylori immunoglobulins. These “near patient tests” (NPT) can be performed in primary care and are much simpler than the C-urea breath test, which is the only other test for H pylori that is currently used as a NPT. However, the accuracy of the serological NPT is lower than that reported for standard ELISA tests using the same antigen preparations. These tests are often used to reassure patients, but to date no studies have compared the accuracy, cost effectiveness, and reassurance value of the C-urea breath test with the serological NPT in primary care.

Urea breath test
Non-invasive detection of H pylori by the C-urea breath test is based on the principle that a solution of urea labelled with carbon- will be rapidly hydrolysed by the urease enzyme of H pylori. The resulting CO2 is absorbed across the gastric mucosa and hence, via the systemic circulation, excreted as CO2 in the expired breath. The C-urea breath test detects current infection and is not radioactive. It can be used as a screening test for H pylori, to assess eradication and to detect infection in children. The similar but radioactive C-urea breath test cannot be performed in primary care.

Faecal antigen test
In the stool antigen test a simple sandwich ELISA is used to detect the presence of H pylori antigens shed in the faeces. Studies have reported sensitivities and specificities similar to those of the C-urea breath test ( > 90%), and the technique has the potential to be developed as a near patient test. The main advantage of the test, however, is in large scale epidemiological studies of acquisition of H pylori in children.

References:
- Robert PH Logan. 2002. ABC OF THE UPPER GASTROINTESTINAL TRACT. London: BMJ Books

Helicobacter pylori infection - Definition and Epidemiology

Helicobacter pylori is a small, curved, highly motile, Gram negative bacillus that colonises only the mucus layer of the human stomach. Since its discovery in 1984, it has been recognised as the principal cause of peptic ulcer disease and as the main risk factor for the development of gastric cancer. However, most infected people ( > 70%) are asymptomatic. We therefore need to discover how infection is acquired, why ulcers or cancer occur in so few of those infected, and how this subgroup can be identified and treated.

Epidemiology of H pylori infection

H pylori is one of the commonest bacterial pathogens in humans. The prevalence of infection varies but is falling in most developed countries. Seropositivity increases with age and low socioeconomic status. Retrospective seroepidemiological studies have shown a cohort effect consistent with the hypothesis that infection is mainly acquired in early childhood. Until recently, however, it has been difficult to assess accurately the incidence (or route) of infection because of the inaccuracy and cost of detecting (non-invasively) H pylori in young children. Primary acquisition in adults, or reinfection after successful eradication, does occur but is less common, with an annual incidence of 0.3-0.7% in developed countries and 6-14% in developing countries.

How H pylori is usually acquired and its route of transmission are unknown. Since humans are the only known reservoir of infection, it is likely that in developed countries H pylori is picked up from siblings, other children, or parents, predominantly via the gastro-oral route. In developing countries faecal-oral transmission may also occur. Various risk factors are associated with H pylori infection, but the extent to which these are simply markers of childhood socioeconomic deprivation is unclear. H pylori infection is an occupational hazard for gastroenterologists and is associated with performing endoscopy.

References:
- Robert PH Logan. 2002. ABC OF THE UPPER GASTROINTESTINAL TRACT. London: BMJ Books

Heartburn / Gastro-oesophageal reflux disease (GORD) Medical Treatment Guidelines

Aims
For most patients, the aim is acceptable symptom control using the least treatment necessary to achieve this. Therefore, if symptom control is the aim, endoscopy to assess healing of oesophagitis is unnecessary. Indeed, it is now known that, at least for patients treated with proton pump inhibitors, absence of symptoms on treatment equates with healing of oesophagitis. For those with complications, such as stricture or bleeding from oesophagitis, the aim will be long term healing of oesophagitis.
Patients with Barrett’s oesophagus have a risk of between 1 in 50 and 1 in 200 of developing adenocarcinoma of the oesophagus. Many gastroenterologists therefore recommend yearly or biennial endoscopic screening with multiple biopsies to detect dysplasia. Patients with severe dysplasia often have an undetected early cancer and so are offered oesophagectomy. Surveillance of patients with Barrett’s oesophagus to detect severe dysplasia or early cancer is controversial, partly because its benefits have not been established by well designed randomised controlled trials. Clearly a surveillance policy is inappropriate in elderly patients who are unfit for surgery. Endoscopic ablation of the abnormal columnar mucosa in Barrett’s oesophagus by photodynamic laser or thermal methods looks promising and may become standard treatment. It must be combined with high doses of proton pump inhibitors or antirefluxsurgery to prevent continuing acid reflux.

General measures
Patients should be advised to lose weight if overweight. There is no formal evidence to support this assertion, but success (though rarely achieved) may result in improved symptom control. Raising the head of the bed on 15 cm wooden blocks has been shown in a controlled trial to improve symptoms and healing of oesophagitis. There is little evidence that avoidance of specific foods has much effect on the course of the disease, but many patients have already identified and stopped eating foods that produce symptoms before consulting their doctor. Other potentially damaging drug treatment should also be reviewed.
While the benefits associated with these general measures may be unproved, they allow patients to be involved with decision making and may help them avoid over-medicalising their condition.

Antacids and alginates
Antacids are effective for short term relief of symptoms. Although their efficacy is difficult to confirm in controlled trials, many sufferers, particularly those who do not consult a doctor, rely on self medication with antacids. Alginates work by forming a floating viscous raft on top of the gastric contents that provides a physical barrier to prevent reflux. To maximise this effect, they are therefore best taken after meals, otherwise they rapidly empty from the stomach and thus give only transient relief of symptoms by virtue of their antacid content.

Acid suppression therapy
The two major classes of agent available are the H2 receptor antagonists and the proton pump inhibitors. There is little doubt that proton pump inhibitors are more rapidly and completely effective for both relieving symptoms and healing oesophagitis, regardless of disease severity. Because of this, a cost effectiveness argument has been made in favour of proton pump inhibitors as first choice treatments in all cases. However, the data on which these calculations have been made have generally come from hospital based clinical trials and may not be applicable to general practice.
Many patients in primary care may achieve good and lasting symptom relief from short intermittent courses of H2 receptor antagonists at standard doses (such as ranitidine 150 mg twice daily or cimetidine 400 mg twice daily). For patients with severe or refractory oesophagitis, particularly those with complications such as stricture, proton pump inhibitors are the drugs of choice. The optimal daily dose for most patients is omeprazole 20 mg , lansoprazole 30 mg, pantoprazole 40 mg, or rabeprazole 20 mg, but higher doses may give additional clinical benefit in patients with resistant oesophagitis. For most patients, there is no clinical advantage in choosing one proton pump inhibitor over another.

Motility modifying drugs
These include metoclopramide and domperidone. Although both relieve symptoms of heartburn to a degree similar to H2 receptor antagonists, they do not heal oesophagitis. In addition, metoclopramide has a relatively high incidence of side effects on the central nervous system. However, these drugs may be useful, particularly in patients with other dyspeptic symptoms such as nausea or early satiety.

Maintenance treatment
Only proton pump inhibitors, at standard or half standard doses, have been shown to be effective agents for maintenance of remission in those who require it. Indications for maintenance treatment include

Severe oesophagitis, especially presenting with complications (such as stricture, bleeding, peptic ulcers)
Barrett’s oesophagus (although there is no evidence that continuous treatment prevents evolution to cancer)
Symptoms (typical or atypical) relapsing as soon as treatment is stopped.

Surgery
Laparoscopic anti-refluxsurgery seems to be as successful as conventional surgery in controlling refluxin the short term without the disadvantages of a long hospital stay or convalescence. It has become an increasingly popular option for patients requiring long term medical treatment. The results from a randomised controlled trial comparing surgery with maintenance drug treatment are awaited.

References:
- Robert PH Logan. 2002. ABC OF THE UPPER GASTROINTESTINAL TRACT. London: BMJ Books.
- Image Source: http://www.webmd.com/heartburn-gerd/guide/complications-untreated-gerd

Oesophagus: Heartburn / Gastro-oesophageal reflux disease (GORD) Investigation

GORD is a disease of different facets. No single investigation is capable of infallibly diagnosing the condition nor of assuring its relevance to symptoms in an individual case.

Choice of clinical investigation depends on presentation, the patient’s age, presence or absence of “alarm” symptoms (such as dysphagia or weight loss), and the question to be answered. Thus, if the question is to decide if mucosal injury is present, endoscopy or barium radiology is most appropriate, whereas an acid perfusion test or 24 hour oesophageal pH monitoring with observation of symptom-refluxassociation is the most useful test in deciding if symptoms are due to oesophageal acid exposure.

Despite these considerations, in practice endoscopy is the most commonly performed initial investigation, combining inspection of the oesophagus with that of the stomach and duodenum to exclude other causes of dyspepsia. In up to two thirds of patients, however, the results of endoscopy are normal, particularly if patients are taking proton pump inhibitors or H2 antagonists at the time of investigation.

Therefore, in young patients with longstanding typical symptoms (heartburn or pharyngeal acid regurgitation after meals and with postural changes) no investigation is necessary. Atypical symptoms, dysphagia, or presentation with short duration of symptoms in patients aged over 55 years usually require investigation. There are no a priori grounds for diagnosis or treatment of Helicobacter pylori infection in most patients, since there is no evidence at present of an association.

Indeed, there is some evidence that eradication of infection, if present, may actually make acid suppression with proton pump inhibitors more difficult in GORD.

References:
Robert PH Logan. 2002. ABC OF THE UPPER GASTROINTESTINAL TRACT. London: BMJ Books

Image Source: http://www.webmd.com/heartburn-gerd/guide/complications-untreated-gerd

Oesophagus: Heartburn / Gastro-oesophageal reflux disease (GORD) - medical definition, causes, and symtoms

Oesophagus: Heartburn / Gastro-oesophageal reflux disease (GORD) - medical definition, causes, symptoms

Gastro-oesophageal reflux disease (GORD) is defined as symptoms or mucosal damage (oesophagitis) resulting from the exposure of the distal oesophagus to refluxed gastric contents. However, the symptoms of reflux oesophagitis do not equate with mucosal damage, and patients with endoscopic evidence of oesophagitis do not necessarily have the worst symptoms.

In primary care GORD is therefore best thought of in terms of symptoms: symptom control is the aim of most management strategies, and indeed typical symptoms can guide doctors to the correct diagnosis. A variety of other tests are available to diagnose and assess the severity of disease if symptoms are atypical and results of endoscopy normal.

Terminology and aetiology

Oesophagitis refers to endoscopic or histological evidence of an acute inflammatory process in the oesophagus. Only about 60% of patients in whom GORD is eventually diagnosed have endoscopic evidence of oesophagitis. Some evidence suggests that among patients in the community or those with atypical presenting symptoms the proportion with oesophagitis may be even lower.

Hiatus hernia is present when gastric mucosal folds are observed more than 2-3 cm above the diaphragm by endoscopy or barium radiology and is found in about 30% of people aged over 50 years. However, most patients with an hiatus hernia do not have GORD, but about 90% of patients with marked oesophagitis have hiatus hernia. Thus, hiatus hernia may not result in GORD but can contribute to the disease. Hiatus hernia itself rarely gives rise to symptoms, although a large hernia may undergo torsion (volvulus) to cause acute epigastric or retrosternal pain with vomiting.

Both oesophageal and gastric factors affect the occurrence of reflux. The critical factor is lower oesophageal sphincter incompetence: most refluxoccurs during transient relaxation of the lower oesophageal sphincter resulting from failed swallows (swallows not followed by a normal oesophageal peristaltic wave) and gastric distension (mostly after meals). Recent evidence has indicated that the diaphragmatic crural fibres surrounding the oesophageal hiatus act as an external sphincter in concert with the intrinsic lower oesophageal sphincter. Failure of this crural mechanism may allow a hiatus hernia to occur. The hernial sac may additionally provide a sump of gastric contents available for refluxonce the lower oesophageal sphincter relaxes. Oesophageal acid clearance depends both on swallowed saliva and intact lower oesophageal peristalsis, which is impaired in about 30% of patients with GORD. Gastric acid production is usually normal in GORD, while delayed gastric emptying occurs in about 40%.

Duodenogastro-oesophageal reflux of bile may play a subsidiary role to that of gastric acid and pepsin in patients with an intact stomach and has been implicated in the pathogenesis of Barrett’s oesophagus and its sequelae.

Clinical features and presentation

There is a spectrum of clinical presentation, ranging from symptoms alone to complications resulting from mucosal damage. Up to 40% of patients seen in hospital in whom reflux is eventually diagnosed have symptoms other than classic heartburn or pharyngeal acid regurgitation, including a variety of respiratory and pharyngeal symptoms.

Natural course of GORD

The condition is characteristically chronic and relapsing: in follow up studies at least two thirds of patients continue to take drugs continuously or intermittently for refluxsymptoms for up to 10 years. Symptoms disappear in less than a fifth of those taking no drugs, and in the short term endoscopic evidence of oesophagitis may come and go independently of symptoms. There is no evidence that patients inevitably go on to develop severe erosive oesophagitis, Barrett’s oesophagus, or stricture. Symptomatic relapse after discontinuing treatment is common and is chiefly dependent on initial severity of oesophagitis. In studies with large proportions of patients having initial severe oesophagitis, relapse rates of up to 80% at sixmonths have been reported.

References:
- Robert PH Logan. 2002. ABC OF THE UPPER GASTROINTESTINAL TRACT. London: BMJ Books.

- Image Source: http://www.webmd.com/heartburn-gerd/guide/complications-untreated-gerd