Tuesday, December 27, 2016

Endomysium, Perimysium and epimysium - definition, histology

Each muscle fibre is closely surrounded by connective tissue.
This acts as a support for the muscle fibres and unites them to each other.

1) Each muscle fibres is surrounded by delicate connective tissue that is called the endomysium.
2) Individual fasciculi are enclosed by a stronger sheath of connective tissue called the perimysium.
3) The entire muscle is surrounded by connective tissue called the epimysium.

This is illustrated by the schematic diagram below.

1= perimysium, 2= endomysium, 3= fasciculus.

At the junction of a muscle with a tendon, the fibres of the endomysium, the perimysium and the epimysium become continuous with the fibres of the tendon.

First published on: 27 December 2016

Sunday, July 24, 2016

Chronic sinusitis - Steam inhalation not effective, nasal irrigation may help

Chronic sinusitis refers to inflammation the paranasal sinuses for a period of at least 12 weeks. The most important cause of chronic sinusitis is failure of acute infections to resolve.

Acute infection destroys the normal ciliated epithelium, thus impairing drainage from the sinuses. There is pooling and stagnation of secretions in the sinuses which favours infections. Persistence of infection causes mucosal changes, such as loss of cilia, edema and polyp formation. We eventually have a vicious cycle.

Patients may complain of blocked nose, runny nose, headache and a reduced sense of smell (hyposmia). Foul-smelling discharge suggests anaerobic infection. Some people will also have nasal polyps.

1) We should always search for underlying aetiological factors which obstruct sinus drainage and ventilation.
2) A work-up for nasal allergy may be required.
3) Culture and sensitivity of sinus discharge helps in the proper selection of an antibiotic.

Initial treatment of chronic sinusitis is conservative, including antibiotics, decongestants, antihistaminics and sinus/nasal irrigations.

Nasal irrigation is a procedure that rinses the nasal cavity with isotonic or hypertonic saline solutions. The patient instils saline into one nostril and allows it to drain out of the other nostril, bathing the nasal cavity.

In this Cochrane review, even though the level of evidence was low, the authors concluded that:

There is some benefit of daily, large-volume (150 ml) saline irrigation with a hypertonic solution when compared with placebo. 

A recent article published in the Canadian Medical Association Journal, concluded that steam inhalation was not effective but nasal irrigation may provide some symptomatic relief especially with regard to headaches.

First published on: 24 July 2016

Friday, June 10, 2016

The common cold - definition, diagnosis and treatment

It is an upper respiratory tract illness that comprises of rhinorrhea and nasal obstruction as the main symptoms.

5- 7 times/ year in children and 2-3 times/ year in adults.
most commonly seen between the early fall and late spring in temperate climates.
Transmission of the virus may occur via direct contact, large-particle aerosol, or small-particle aerosol.

The rhinoviruses are usually responsible for the majority of cases. Coronavirus, respiratory syncytial virus and metapneumovirus may also be associated with the common cold syndrome.

The diagnosis of the common cold is a clinical diagnosis. Polymerase chain reaction assay can determine the responsible pathogen but this is rarely useful in the management of the patient.

Management is mainly directed towards the bothersome symptoms as no specific antiviral agents are useful in the treatment.

First published on: 10 June 2016

Saturday, January 2, 2016


Reading chest radiograph - Penetration


Penetration is one of the five technical factors that help you in determining whether a radiograph is technically adequate.


If a frontal chest radiograph is adequately penetrated, you should be able to see the thoracic spine through the heart shadow.

In the radiograph above, we can see the thoracic spine through the heart shadow (solid white line).

It means that the penetration is inadequate. The radiograph will appear as too white. We will not be able to see the thoracic spine through the heart. This can lead us into making interpretation errors.
1) The pulmonary markings may appear more prominent and these can be mistaken for being due to a congestive heart failure or pulmonary fibrosis.
2) The left lung base will appear opaque thus obscuring the left hemidiaphragm. This can mimic or hide a true disease in the left lower lung field e.g. left lower lobe pneumonia or left pleural effusion.

To avoid these misinterpretations always correlate clinically. Also if you are suspecting a congestive heart failure, look for other signs apart from increased pulmonary markings e.g. effusions, Kerley lines etc. A lateral radiograph will also help us when faced with these dilemmas.

In this frontal chest radiograph we can see that there is under penetration.

The solid black line shows that the thoracic spine cannot be seen through the heart shadow.

The broken black lines show that the left hemidiaphragm is not clearly visible.

In this case, the lung markings will appear decreased or absent. The patient may be mistaken of having a pneumothorax or emphysema. We may also miss a pulmonary nodule if the radiograph is too dark.

This is an example of an over penetrated chest radiograph.

At first glance we may suspect emphysema in this patient because of the increased lucency at the apices but when we look at the diaphragm we find that it is not flattened, which means there is no hyperinflation as expected for a case of emphysema.

First published on: 01 January 2016

Monday, November 30, 2015


BMI versus waist to hip ratio

Obesity is a state of excess adipose tissue mass. It is often viewed as equivalent to an increased body weight. This is not true because muscular individuals may have increased body weight but are not obese.

Weight follows a continuous distribution pattern in human population. The point at which mortality and morbidity becomes statistically significant is the cut-off to call a patient obese.

Various methods have been used to measure obesity. These include:
1) Anthropometry (skin-fold thickness)
2) Densitometry (underwater weighing)
4) Electrical impedance.

Still the most common techniques used in clinical practice are:
1) BMI measurement
2) Waist-to-hip ratio measurement.

It is not an accurate measure of obesity but since it is simple to calculate, it is the most frequently measured parameter.

At similar BMI, women usually have more fat than men. When the BMI > 25 Kg/m2, morbidity starts to increase and if associated with risk factors then therapeutic interventions should be considered.

Intra-abdominal or abdominal subcutaneous tissue fat has more significant implications on morbidity than fat present in the buttocks and lower extremities. A WHR > 0.9 for women and > 1.0 for men is considered abnormal. (0.85 and 0.90 respectively according to WHO)

Insulin resitance, hypertension, dyslipidemia and diabetes mellitus are more strongly associated with intra-abdominal / abdominal subcutaneous tissue fat than to overall adiposity.

The probable explanation of this issue is that intra-abdominal adipocytes may be lipolytically more active than those from other depots. There is also release of free fatty acids into the portal circulation and this has adverse metabolic effects, especially on the liver.

A recent article published in the Annals of Internal Medicine concluded that
" normal-weight U.S. adults with central obesity have the worst long-term survival compared with participants with normal fat distribution, regardless of BMI category, even after adjustment for potential mediators. "

First published on: 30 November 2015

Tuesday, September 22, 2015

, , ,

Alcoholic liver disease

Chronic and excessive use of alcohol is one of the major causes of liver disease.

90% of daily heavy drinkers (>60 g alcohol/day) as well as binge drinkers have fatty liver but a smaller percentage (10-35%) of drinkers progress to alcoholic hepatitis which is a precursor for cirrhosis.

The long-term risk is 9 times higher in patients with alcoholic hepatitis compared to those with fatty liver alone.

Some population-based surveys have documented that men must drink 40 to 80 g of alcohol daily and women must drink 20 to 40 g daily for 10 to 12 years to achieve a significant risk of liver disease.

Liver pathology consists of 3 major lesions that are progressive and rarely exist in a pure form:
1) fatty liver (usually reverses quickly with abstinence),
2) alcoholic hepatitis and
3) cirrhosis.

histologic staging alcoholic liver disease

Prognosis of severe alcoholic liver disease (ALD) is bad. Mortality of patients with alcoholic hepatitis concurrent with cirrhosis id nearly 60% at 4 years.

Although alcohol is a direct hepatotoxin, it is unclear why only 10-20% of alcoholics will develop alcoholic hepatitis. It appears to involve a complex interaction of facilitating factors like drinking patterns, diet, obesity and gender.

Harmful use of alcohol results in 2.5 million deaths each yr. Most of the mortality is due to cirrhosis. The mortality is declining now because of decreased consumption of alcohol in the Western countries except in the U.K, Romania, Russia and Hungary.

a) Quantity and duration of alcohol intake - are the most important risk factors. Time taken to develop liver disease is directly related to the amount of alcohol consumed.
b) There is no clear role of the type of beverage and the pattern of drinking.
c) Genetic - some people are genetically predisposed  for alcoholism and subsequently to the ill effects of alcohol on the liver.
d) Gender - It is a strong determinant for ALD. Women are more susceptible to alcoholic liver injury. They develop advanced liver disease with substantially less alcohol intake. Gender-dependent differences may be due to the effects of estrogen, proportion of body fat and gastric metabolism of alcohol.
e) Chronic infection with Hepatitis C virus - It is an important comorbidity in the progression of ALD to cirrhosis in chronic and excessive drinkers. Even moderate alcohol intake of 20-50 g/day increases the risk of cirrhosis and hepatocellular cancer. Intake of more than 50 g/day decreases the efficacy of interferon-based antiviral therapy.

It is unclear but what is known is that alcohol can act as a direct hepatotxin and malnutrition does not play a major role.
- Alcohol is metabolised to acetyldehyde which in turn initiates an inflammatory cascade that results in a variety of metabolic responses.
- Steatosis from lipogenesis, fatty acid synthesis and depression of fatty acid oxidation occur secondary to effects on sterol regulatory transcription factor (SRTF) and peroxisome proliferator-activated receptor alpha (PPAR-alpha).
- Intestinal derived endotoxin initiates a pathogenic process through toll-like receptor-4 and TNF-alpha. This facilitates hepatocyte apoptosis and necrosis.
- Cell-injury endotoxin also activates innate and adaptive immunity pathways. There is release of pro-inflammatory cytokines (TNF-alpha) and proliferation of T/B cells.
- Production of toxic protein-aldehyde adducts, generation of reducing equivalents and oxidative stress also contribute to liver injury.

Finally hepatocyte injury and impaired regeneration are associated with stellate cell activation and collagen production which are key events in fibrogenesis. The resulting fibrosis causes architectural derangement of the liver and the associated pathophysiology.

Fatty liver is the initial and most common histologic response to hepatotoxic stimuli, including excess alcohol ingestion. Accumulation of fat within the perivenular hepatocytes coincides with the location of alcohol dehydrogenase. Continuing alcohol ingestion results in deposition of fat throughout the entire hepatic lobule.

Alcoholic fatty liver - traditionally regarded as benign but appearance of steatohepatitis and certain features like giant mitochondria, perivenular fibrosis and microvesicular fat are associated with progressive liver injury.

Hallmarks of alcoholic hepatitis include: (hepatocyte injury)
a) ballooning degeneration,
b) spotty necrosis,
c) polymorphonuclear infiltrate and
d) fibrosis in the perivenular and perisinusoidal space of Disse.

Mallory-Denk bodies are often present in florid cases but these are neither specific nor necessary to establish the diagnosis.

Usually the patients are asymptomatic.
Hepatomegaly is often the only clinical finding.
It is very important to assess the drinking history and estimate how much alcohol is consumed per day and for how long.
1 beer, 4-5 ounces of wine, 1.5 oz of 40% liquor and 1 ounce (approximately 30 mL) of 80% spirits all have around 12 g of alcohol.

Alcohol content of various beverages

- Patients with fatty liver may have:
1) right upper quadrant discomfort,
2) nausea and
3) rarely jaundice.

- Patients with alcoholic hepatitis may have:
1) fever
2) spider nevi
3) jaundice
4) abdominal pain.
We can also see portal hypertension, ascites and variceal bleeding even in the absence of cirrhosis.

These are most identified through routine screening tests.

Fatty liver - laboratory abnormalities are non-specific
Modest elevation of AST, ALT, GGTP are seen. Triglycerides and bilirubin may also be increased.

Alcoholic hepatitis
a) increased AST and ALT - by 2-7 fold but rarely greater than 400 IU.
b) AST/ALT ratio greater than 1.
c) hyperbilirubinemia
d) modest increase in alkaline phosphatase

If synthetic function is deranged then the condition is more serious. Hypoalbuminemia and coagulopathy are more common in advanced liver disease.

Ultrasonography is also a useful investigation as it can determine the size of the liver and detect any fatty infiltration. If it demonstrates portal vein flow reversal, ascites and intraabdominal venous collaterals then the condition has less potential for complete reversal.

Below is an ultrasonographic picture of hepatic steatosis. Fatty infiltration produces an increased reflectivity of hepatic parenchyma, known as ‘bright liver pattern’. This feature can be assessed by comparing liver parenchyma with the right kidney’s cortex, which normally presents an echogenicity equal to or slightly lower than that of the liver. Severe steatosis produces a strong attenuation in the deepest liver sections, resulting in poor explorability.

bright liver with posterior attenuation

Critically ill patients with alcoholic hepatatis have short term (30-day) mortality rates exceeding 50%.
A Discriminant Function (DF) above 32 and a Model for End-stage Liver Disease (MELD) greater than 21 is associated with poor prognosis.
Worse prognosis if there is associated:
a) ascites,
b) variceal hemorrhage,
c) deep encephalopathy and
d) hepatorenal syndrome.

mortality alcoholic liver disease

a) Complete abstinence from alcohol is the mainstay for treatment.
b) Patients with severe alcoholic hepatitis i.e. DF>32 and MELD>21 should be given Prednisone 40mg/day or Prednisolone 32mg/day for 4 weeks followed by tapering over 4 weeks.
c) Alternatively Pentoxifylline, a non-specific TNF inhibitor, can be used in a dosage of 400mg 3 times per day for 4 weeks.
d) Liver transplantation is an accepted indication for treatment in selected and motivated patients with end-stage cirrhosis.

Below is an algorithm showing how to manage alcoholic hepatitis:
algorithm alcoholic hepatitis

N.B Monoclonal antibodies that neutralize serum TNF-alpha should not be used as studies have reported an increase in the number of deaths secondary to infections and renal failure.

First published on: 23 September 2015

Wednesday, September 2, 2015

Voltaire - Medical quote no longer valid

Times have changed Monsieur Voltaire.

Your quote is no longer valid in our "Evidence Based Medicine" world.

The quote's accuracy is stunning though if applied to quacks.

Our advice to young practitioners : DO NOT BLINDLY FOLLOW WHAT A SENIOR DOCTOR IS DOING.
Try to  understand why he did something for that specific problem.

Always ask if you do not understand.

Article resources:
1) "Voltaire lisant L’année littéraire de Fréron", huile sur toile de Jacques Augustin Catherine Pajou, 1811

Last reviewed on: 2 September 2015

Sunday, July 19, 2015

Menopause - Definition, symptoms and hormone replacement therapy

 Menopause  refers to a point in time that follows 1 year after the permanent cessation of menstrual periods that occurs naturally or is induced by surgery, chemotherapy or radiation.

On average, natural menopause occurs between 50 and 51 years (range 45–59) and is part of the process of normal ageing. It has been noted that smoking advances the age of menopause by approximately 2 years.
The diagnosis can only be made retrospectively and it is usually preceded by months or years of irregular cycles, that is not associated with some other physiological or pathological causes.

If the cessation of menses occurs before the age of 40, then it is referred to as the "Premature ovarian failure".
The older terms perimenopause or climacteric generally refer to the time period in the late reproductive years, usually late 40s to early 50s. Characteristically, it begins with menstrual cycle irregularity and extends to 1 year after permanent cessation of menses. The more correct terminology for this time is menopausal transition. This transition typically develops over a span of 4 to 7 years, and the average age at its onset is 47 years

Up to 75% of women will experience adverse symptoms related to menopausal transition while the others may not have any symptoms at all. Although symptoms associated with menopause occur as a result of oestrogen deficiency, replacing it is not always the treatment of choice.
The use of HT should be made on an individual basis, after careful consideration of quality of life and personal risk factors. In addition to any pharmacological treatments considered, lifestyle modifications are essential.

Below a few of the symptoms are discussed and whether hormone replacement may be helpful:

Hot flushes are characterised by a feeling of intense warmth, often accompanied by profuse sweating, anxiety, skin reddening and palpitations. They are sometimes followed by chills.
In most cases, they will resolve in around 1 year or less without any treatment.
1/3 rd of the patients will have symptoms for up to 5 years after natural menopause and in 20% they may persist for up to 15 years or more.
Menopause induced by surgery is associated with about a 90% probability of hot flushes during the first year. In these cases, symptoms are often more abrupt and severe and can last longer than those associated with a non-surgical menopause.

Hormone therapy is the most effective (80% efficacy) treatment for vasomotor symptoms associated with menopause at any age, but benefits are more likely to outweigh risks for symptomatic women before the age of 60 years or within 10 years after menopause.
Extra care must be taken in women with a history of hormone-dependent cancer, e.g. breast cancer.

Genitourinary symptoms due to menopause can affect up to 50% of women, however it is under diagnosed and under treated. The pathology here is that there is a loss of estrogen which results in urogenital ageing. The tissues of the vaginal walls becomes thinner since the amount of collagen and elastin is reduced. The walls become pale, thin and lose their elasticity. A reduction in vaginal secretions and decreased tissue elasticity also increases the susceptibility to trauma and pain or irritation during or after intercourse.

In addition to vulvo-vaginal symptoms, the less acid pH of the estrogen-deficient vagina increases the likelihood of urinary tract infections.

Vaginal symptoms become apparent 4–5 years after the menopause. 25–50% of all postmenopausal women have some objective changes as well as subjective complaints.
Symptoms may include vaginal dryness (75%), dyspareunia (38%), vaginal itching, burning and pain (15%).
Locally administered vaginal estrogens (creams, pessaries, tablets and vaginal rings) are equally effective in the treatment of menopause-related vulval and vaginal symptoms. Local estrogen therapy will lower vaginal pH, thicken the epithelium, increase blood flow and improve vaginal lubrication.

There are no evidence to support the use of hormone replacement for the urinary symptoms.

The decline in estrogen results in a decrease in the bone mineral density and a subsequent significant increase in the prevalence of osteoporosis.

General management includes:
1) assessment of the risk of falls and their prevention,
2) maintenance of mobility and
3) correction of nutritional deficiencies, particularly of calcium, vitamin D and protein.

Pharmacological interventions include bisphosphonates, denosumab, parathyroid hormone peptides, raloxifene and strontium ranelate. All have been shown to reduce the risk of vertebral fracture and some have been shown to reduce the risk of non-vertebral fractures. However, all are associated
with side effects and many women will fail to comply.
Hormone therapy reduces the risk of spine and hip, as well as other osteoporotic fractures even in women at low risk. It would appear that half of the traditional bone conserving doses are effective in conserving bone mass and are successful means of fracture prevention. However, hormone replacement is not the first line therapy in treating post menopausal osteoporosis.

The incidence of CVD increases with age and menopause may have an adverse effect. Hormone therapy was thought to confer CVD risk reduction but some studies demonstrated an increased number of coronary heart disease events and strokes and concluded that the risks outweighed the benefits. These studies were carried out on elderly women though and probably there was already an element of atherosclerosis that influenced the outcomes. Recent studies suggest that if hormone replacement is started soon after menopause, it may actually be beneficial.

Since the sex hormones are known to be thrombogenic there is an expected increase in the risk of deep vein thrombosis and stroke when using oral replacement therapy. The risk is further increase if the patient is a smoker.