METABOLIC ACIDOSIS : DEFINITION , CAUSES, MECHANISM AND SYMPTOMS :

METABOLIC ACIDOSIS : DEFINITION , CAUSES, MECHANISM AND SYMPTOMS :

 

METABOLIC ACIDOSIS

 

Metabolic acidosis is a sinister acid base disorder in which there is accumulation of excessive acid in the blood and body tissues.It is a serious and life threatening condition

 

PATHOPHYSIOLOGY OF METABOLIC ACIDOSIS

 

OCCURS DUE TO THREE MAIN MECHANISMS:

 

1. EXCESSIVE PRODUCTION OF ACID IN THE BODY

 

2. LOSS OF ACID BUFFERING SYSTEM WHICH IS LACK OF BICARBONATE IN THE BODY

 

3 . INABILITY OF KIDNEYS TO GET RID OF EXCESSIVE ACID FROM THE BODY

 

PATHOPHYSIOLOGY

 

Metabolic acidosis can lead to acidemia, which is defined as arterial blood pH that is lower than 7.35

 

Acute metabolic acidosis, lasting from minutes to several days, often occurs during serious illnesses or hospitalizations, and is generally caused when the body produces an excess amount of organic acids (ketoacids or lactic acid).

 

Chronic metabolic acidosis, lasting several weeks to years, can be the result of impaired kidney function (Chronic Kidney Disease) and/or bicarbonate wasting.

 

CAUSES OF METABOLIC ACIDOSIS

 

There are several types of metabolic acidosis:

 

Diabetic acidosis (also called diabetic ketoacidosis and DKA) develops when substances called ketone bodies (which are acidic) build up during uncontrolled diabetes.

 

Hyperchloremic acidosis is caused by the loss of too much sodium bicarbonate from the body, which can happen with severe diarrhea.

 

Kidney disease (uremia, distal renal tubular acidosis or proximal renal tubular acidosis).

 

Lactic acidosis.

 

Poisoning by aspirin, ethylene glycol (found in antifreeze), or methanol.

 

Severe dehydration.

 

 

 

MECHANISM OF METABOLIC ACIDOSIS

 

Metabolic acidosis is characterized by a low concentration of bicarbonate (HCO−3), which can happen with increased generation of acids (such as ketoacids or lactic acid), excess loss of HCO-3 by the kidneys or gastrointestinal tract, or an inability to generate sufficient HCO−3.

 

The body regulates the acidity of the blood by four buffering mechanisms.

 

Bicarbonate buffering system.

 

Intracellular buffering by absorption of hydrogen atoms by various molecules, including proteins, phosphates and carbonate in bone.

 

Respiratory compensation. Hyperventilation will cause more carbon dioxide to be removed from the body and thereby decrease pH.

 

Kidney compensation

 

SYMPTOMS OF METABOLIC ACIDOSIS

 

Symptoms

 

Most symptoms are caused by the underlying disease or condition that is causing the metabolic acidosis.

 

Metabolic acidosis itself most often causes rapid breathing.

 

Acting confused or very tired may also occur.

 

Severe metabolic acidosis can lead to shock or death.

 

In some situations, metabolic acidosis can be a mild, ongoing (chronic) condition.

Confusion : Definition , Causes , Clinical Features & Management : You tube Link

 

Confusion : Definition , Causes , clinical features and Management:

Click on you tube link below :

https://www.youtube.com/watch?v=4x30KGWaEw4

Acute Emergencies : Anaphylaxis

 

ANAPHYLAXIS

Anaphylaxis means a  severe allergic reaction to an allergen to which an individual has previously been exposed to.

It occurs due to antigen specific cross linking of IgE on surface of tissue mast cells and peripheral basophils.

History Taking

Usually there is a clearly identifiable allergen / precipitant which has caused anaphylaxis.

If the allergen is not identifiable  we have to ask the following points in History :

Any past history of similar allergic reaction

Any known allergies.

Did this reaction occur after eating a particular food ?

Was the patient bitten by an insect eg bee, wasp, ant etc?

Did he wear any new jewelry or used any new cosmetic product ,hair dye etc.

Any latex / rubber allergy?

Any history of allergy in the family?

Investigations

Full blood count including Eosinophils

Skin prick testing

Serum mast cell tryptase : Elevated after anaphylaxis

C1 inhibitor deficiency

Clinical features

Patient develops symptoms within seconds to minutes.

These occur due to development of tissue oedema as a result of release of inflammatory mediators.

The common Signs and Symptoms include :

Difficulty breathing

Facial and tissues swelling

Rash over body

Itching of eyes

Sneezing and conjunctivitis to name a few.

Sometimes if the reaction is severe, it will prove to be life threatening.

Management :

Assessemnt of ABC : Airway , Breathing , Circulation

Administer High Flow Oxygen

Monitor Oxygen Saturations

Establish iv access / cannulation

In case of respiratory distress or wheeze / stridor, give adrenaline /epinephrine  0.5 ml of 1:1000 solution intramuscularly.

This can be repeated in 5 minutes if no improvement.

Administer iv hydrocortisone from 100 mg upto 500 mg depending on the severity of anaphylaxis.

Administer Chlorpheniramine 10 mg iv .

In case of  wheeze / bronchospasm , give nebulization by salbutamol / ipratropium or Clenil .

If patient is hypotensive give iv fluids eg Normal saline 0.9 % 1 litre straight away.

 

 

RESPIRATORY MEDICINE MADE SIMPLE : RESPIRATORY ACIDOSIS : INTRODUCTION , CLINICAL FEATURES AND CAUSES

 RESPIRATORY ACIDOSIS

Respiratory acidosis is a pathological state of the body in which there is excessive accumulation of Carbon dioxide in the blood due to inability of the lungs / failure of respiratory system to exhale the required carbon di oxide from the body necessary for maintaining a normal Acid Base balance.

pH is the parameter used to detect acid base balance in the body.

Normal Blood pH is between 7.35 – 7.45. Acidosis occurs when blood pH becomes lower than 7.35 and if it is due to respiratory pathology resulting in accumulation of Carbondioxide that combines with water to form Carbonic acid, this is called as Respiratory Acidosis

Respiratory acidosis is typically caused by an underlying disease or condition. This is also called respiratory failure or ventilatory failure.

Normally, the lungs take in oxygen and exhale CO2. Oxygen passes from the lungs into the blood. CO2 passes from the blood into the lungs. However, sometimes the lungs can’t remove enough CO2. This may be due to a decrease in respiratory rate or decrease in air movement due to an underlying condition such as:

Asthma

COPD

Pneumonia

Sleep apnea

Forms of respiratory acidosis

There are two forms of respiratory acidosis: acute and chronic.

Acute respiratory acidosis occurs quickly. It’s a medical emergency. Left untreated, symptoms will get progressively worse. It can become life-threatening.

Chronic respiratory acidosis develops over time. It doesn’t cause symptoms. Instead, the body adapts to the increased acidity. For example, the kidneys produce more bicarbonate to help maintain balance.

Chronic respiratory acidosis may not cause symptoms. Developing another illness may cause chronic respiratory acidosis to worsen and become acute respiratory acidosis.

Symptoms of respiratory acidosis

Initial signs of acute respiratory acidosis include:

Headache

Anxiety

Blurred vision

Restlessness

Confusion

Without treatment, other symptoms may occur. These include:

Sleepiness or fatigue

Lethargy

delirium or confusion

Shortness of breath

Coma

The chronic form of respiratory acidosis doesn’t typically cause any noticeable symptoms. Signs are subtle and nonspecific and may include:

Memory loss

Sleep disturbances

Personality changes

Common causes of respiratory acidosis

The lungs and the kidneys are the major organs that help regulate your blood’s pH. The lungs remove acid by exhaling CO2, and the kidneys excrete acids through the urine. The kidneys also regulate your blood’s concentration of bicarbonate (a base).

Some common causes of the acute form are:

Conditions that affect the rate of breathing

Muscle weakness that affects breathing or taking a deep breath

Obstructed airways (due to choking or other causes)

Sedative overdose

Cardiac arrest

Some common causes of the chronic form are:

Asthma

Chronic obstructive pulmonary disease (COPD)

Acute pulmonary edema

Severe obesity (which can interfere with expansion of the lungs)

Neuromuscular disorders (such as multiple sclerosis or muscular dystrophy)

Scoliosis

Rheumatology Made Simple : Proximal Myopathy

 PROXIMAL MYOPATHY

Muscle weakness can also be classified as either "proximal" or "distal" based on the location of the muscles that it affects. Proximal muscle weakness affects muscles closest to the body's midline, while distal muscle weakness affects muscles further out on the limbs.

Proximal myopathy presents as symmetrical weakness of proximal upper and/or lower limbs.

Patient usually finds it difficult to climb stairs.

They may also present with  falls.

Also patient will be unable to get up / stand up from sitting position without support or aid.

CAUSUES

There is a broad range of underlying causes including

Drugs

Excessive steroids in Rheumatoid Arthritis , SLE or Asthma)  

Statins

Alcohol

Endocrinological diseases

Thyroid disease and

Cushings Syndrome,

Addisons Disease ,

Acromegaly,

Diabetes

Osteomalacia

Idiopathic inflammatory myopathies (IIM)

Hereditary myopathies

Malignancy /Cancer  and paraneoplastc syndromes

Inflammatory:

Polymyositis &dermatomyositis.

Mixed connective tissue disease

Other connective tissue disease eg.

SLE

Vasculitis

Rheumatoid Arthritis

Systemic sclerosis.

Infections

Bacterial infections,

HIV

Cytomegalovirus  

Ebstein Barr Virus  

Hepatitis

Metabolic disorders and pathologies

Renal failure

Hepatic failure

Electrolyte disturbance

Miscellaneous causes

Inclusion body myositis,

Rhabdomyolysis,

Sarcoidosis

Mitochondrial myopathies

Muscular dystrophies

CLINICAL EXAMINATION

Inspection

Look for any wasting of muscles and any fasciculations

Is the wasting symmetrical or asymmetrical

Look for any walking aid

Palpation

Palpate muscles for bulk and tenderness

Ask patient to rise from sitting with arms crossed.

Ask them to raise arms above head and note if the weakness proximal or distal or both?

Examine tone of muscles

Usually normal in Proximal myopathy

Examine and Grade power in upper and lower limbs according to MRC Scale.

Power (MRC grade) and.

Reflexes (normal)

Sensation (normal unless peripheral neuropathy too)

Coordination (normal  or in proportion to weakness)

Does the patient appear Cushingoid from steroid use?

Any signs of Myasthenia gravis eg ptosis and fatiguability on repetition of movements.

Any fasciculations eg in Motor Neuron Disease.

Investigations

Bloods

Routine (FBC, U+E, LFT, Ca, P, Mg)

CK, AST, ALT, LDH

HBa1C, fasting glucose, cortisol, HIV, Hepatitis screen, CMV/EBV/adenovirus, serum ACE

Rheumatological screen:

ESR 

CRP 

ANA

ANCA

Rheumatoid factor

Anti-CCP

MRI muscle eg. thigh (inflamed muscle)

Cancer screen if dermato/polymyositis: FOB, CXR, mammogram, CT, tumour markers (PSA, CEA, CA125, CA19-9, CA15-3)

Keep common causes in mind eg

Vitamin D levels and bone profile

Thyroid function Tests

Creatine Kinase

Routine blood tests eg Full blood count

Renal function tests

Random blood sugar and HbA1c

To exclude other causes , we may need to opt for Neurophysiological studies and muscle investigations eg Muscle imaging and muscle biopsy after decision and evaluation by a specialist doctor.

MANAGEMENT

Management depends on underlying cause, and includes measures such as

Removal of offending agent

Correction of endocrine or metabolic problem,

Immunosuppressive therapy for Inflammatory muscle disorders

Physical therapy

Rehabilitation

Genetic counselling for muscular dystrophies.

METABOLIC MEDICINE MADE SIMPLE : METABOLIC ACIDOSIS

METABOLIC ACIDOSIS

Metabolic acidosis is a sinister acid base disorder in which there is accumulation of excessive acid in the blood and body tissues.It is a serious and life threatening condition

PATHOPHYSIOLOGY OF METABOLIC ACIDOSIS

OCCURS DUE TO THREE MAIN MECHANISMS:

1. EXCESSIVE PRODUCTION OF ACID IN THE BODY

2. LOSS OF ACID BUFFERING SYSTEM WHICH IS LACK OF BICARBONATE IN THE BODY

3 . INABILITY OF KIDNEYS TO GET RID OF EXCESSIVE ACID FROM THE BODY

PATHOPHYSIOLOGY

Metabolic acidosis can lead to acidemia, which is defined as arterial blood pH that is lower than 7.35

Acute metabolic acidosis, lasting from minutes to several days, often occurs during serious illnesses or hospitalizations, and is generally caused when the body produces an excess amount of organic acids (ketoacids or lactic acid).

Chronic metabolic acidosis, lasting several weeks to years, can be the result of impaired kidney function (Chronic Kidney Disease) and/or bicarbonate wasting.

CAUSES OF METABOLIC ACIDOSIS

There are several types of metabolic acidosis:

Diabetic acidosis (also called diabetic ketoacidosis and DKA) develops when substances called ketone bodies (which are acidic) build up during uncontrolled diabetes.

Hyperchloremic acidosis is caused by the loss of too much sodium bicarbonate from the body, which can happen with severe diarrhea.

Kidney disease (uremia, distal renal tubular acidosis or proximal renal tubular acidosis).

Lactic acidosis.

Poisoning by aspirin, ethylene glycol (found in antifreeze), or methanol.

Severe dehydration.

MECHANISM OF METABOLIC ACIDOSIS

Metabolic acidosis is characterized by a low concentration of bicarbonate (HCO−3), which can happen with increased generation of acids (such as ketoacids or lactic acid), excess loss of HCO-3 by the kidneys or gastrointestinal tract, or an inability to generate sufficient HCO−3.

 

The body regulates the acidity of the blood by four buffering mechanisms.

Bicarbonate buffering system.

Intracellular buffering by absorption of hydrogen atoms by various molecules, including proteins, phosphates and carbonate in bone.

Respiratory compensation. Hyperventilation will cause more carbon dioxide to be removed from the body and thereby decrease pH.

Kidney compensation

SYMPTOMS OF METABOLIC ACIDOSIS

Symptoms

Most symptoms are caused by the underlying disease or condition that is causing the metabolic acidosis.

Metabolic acidosis itself most often causes rapid breathing.

Acting confused or very tired may also occur.

Severe metabolic acidosis can lead to shock or death.

In some situations, metabolic acidosis can be a mild, ongoing (chronic) condition.

INVESTIGATIONS

These tests can help diagnose acidosis. They can also determine whether the cause is a breathing problem or a metabolic problem. Tests may include:

 

Arterial blood gas

Basic metabolic panel, (a group of blood tests that measure your sodium and potassium levels, kidney function, and other chemicals and functions)

Blood ketones

Lactic acid test

Urine ketones

Urine pH

Other tests may be needed to determine the cause of the acidosis.

MANAGEMENT OF METABOLIC ACIDOSIS

Treatment of metabolic acidosis depends on the underlying cause, and should target reversing the main process.

 

When considering course of treatment, it is important to distinguish between acute versus chronic forms.

Bicarbonate therapy is generally administered In patients with severe acute acidemia (pH < 7.11), or with less severe acidemia (pH 7.1-7.2) who have severe acute kidney injury.

Bicarbonate therapy is not recommended for people with less severe acidosis (pH ≥ 7.1), unless severe acute kidney injury is present.

In the BICAR-ICU trial,bicarbonate therapy for maintaining a pH >7.3 had no overall effect on the composite outcome of all-cause mortality and the presence of at least one organ failure at day 7.

However, amongst the sub-group of patients with severe acute kidney injury, bicarbonate therapy significantly decreased the primary composite outcome, and 28-day mortality, along with the need for dialysis.

Currently, the most commonly used treatment for chronic metabolic acidosis is oral bicarbonate.

The NKF/KDOQI guidelines recommend starting treatment when serum bicarbonate levels are <22 mEq/L, in order to maintain levels ≥ 22 mEq/L.

 Studies investigating the effects of oral alkali therapy demonstrated improvements in serum bicarbonate levels, resulting in a slower decline in kidney function, and reduction in proteinuria – leading to a reduction in the risk of progressing to kidney failure.

However, side effects of oral alkali therapy include gastrointestinal intolerance, worsening edema, and worsening hypertension.

 Furthermore, large doses of oral alkali are required to treat chronic metabolic acidosis, and the pill burden can limit adherence.

Veverimer (TRC 101) is a promising investigational drug designed to treat metabolic acidosis by binding with the acid in the gastrointestinal tract and removing it from the body through excretion in the feces, in turn decreasing the amount of acid in the body, and increasing the level of bicarbonate in the blood

 

Rheumatology Made Simple : backache

BACKACHE

Back pain is a common complaint that we come across in our daily practice.

Most of the causes are not sinister but rather due to simple muscle strain that respond well to postural correction and analgesics.

However ,it is important to rule out serious causes by giving particular importance to presence of red flags in the history and investigate thoroughly if these are present.

MAIN CAUSES

SIMPLE MECHANICAL BACK PAIN

Usually affects the lower back and may be localized to  buttocks and thighs.

It can vary with posture and activity and can change in response to changes in posture and treatment.

It is dull and poorly localized

 

NERVE ROOT / RADICULAR PAIN

It is sharp and well localized

Usually affects a dermatome.

It is often accompanied by numbness and tingling.

Sciatica is an example of nerve root pain.

SINISTER CAUSES / RED FLAGS IN HISTORY

The presence of the following red flags indicate a sinister underlying pathology and demands further investigation of cause of Backpain

History of malignancy

History of excessive steroids  use.

Presence of systemic symptoms such as fever and weight loss.

Structural deformity

Persistent night pain

Progressive neurological defect and sensory or motor defecits.

 

CAUDA EQUINA SYNDROME

This is characterized by Saddle anesthesia , bladder disturbance , faecal incontinence and bilateral numbness or weakness in lower limbs.

EXAMINATION

A general examination should be undertaken

Particular focus should be on examination of the back and neurological examination of the legs.

BACK EXAMINATION:

Look for any deformity of the back and tenderness , signs of injury or wounds.

Perfom SLR Test : Passive Straight Leg raising test for diagnosing nerve root pain due to disc pathology.

INVESTIGATIONS

MRI is the best investigation for diagnosing Nerve Root Compression , Discitis and Neoplasms.

Other investigations to exclude underlying cause of back pain include:

Infection : Full Blood Count , CRP , Blood cultures , other inflammatory markers and Diagnostic biopsy

Malignancy : Liver and bone profile , PSA , Urinary Bence Jones proteins . Bone scana dn Protein Electrophoresis.

MANAGEMENT

Patients with simple mechanical back pain requires postural advice and comfortable sitting p osition and Adequate analgesia and muscle relaxants .

Analgesic ladder should be followed while prescribing analgesics. These include going from non-opiods eg paracetamol to opioids  such as co-codamol or oramorph.

Simple Mechanical pain has a good prognosis , 90 % recover at 6 weeks.

For other patients who don’t have simple mechanical back pain, management depends on treating underlying cause.

Any patient with symptoms suggestive of Cauda Equina requires immediate Neurosurgical  referral and management.