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Muscular Dystrophies

These inherited myopathic disorders are characterized by progressive muscle weakness and wasting. They are subdivided by mode of inheritance, age at onset, and clinical features, as shown in Table 24-6. In the Duchenne type, pseudohypertrophy of muscles frequently occurs at some stage; intellectual retardation is common; and there may be skeletal deformities, muscle contractures, and cardiac involvement. The serum creatine kinase level is increased, especially in the Duchenne and Becker varieties, and mildly increased also in limb-girdle dystrophy. Electromyography may help to confirm that weakness is myopathic rather than neurogenic. Similarly, histopathologic examination of a muscle biopsy specimen may help to confirm that weakness is due to a primary disorder of muscle and to distinguish between various muscle diseases.

A genetic defect on the short arm of the X chromosome has been identified in Duchenne dystrophy. The affected gene codes for the protein dystrophin, which is markedly reduced or absent from the muscle of patients with the disease. Dystrophin levels are generally normal in the Becker variety, but the protein is qualitatively altered.

Duchenne muscular dystrophy can now be recognized early in pregnancy in about 95% of women .

Terminal Ileal Resection

Resection of the terminal ileum results in malabsorption of bile salts and vitamin B 12' which are normally absorbed in this region. Patients with low Serum vitamin B12 levels, an abnormal Schilling test, resection of over 50 cm of ileum require monthly intramuscular vitamin Bl1 injections. In patients with less than 100 cm of ileal resection, bile salt malabsorption stimulates fluid secretion from the colon, resulting in watery diarrhea. This may be treated with bile salt binding resins (cholestyrarnine, 2-4 g three times daily with meals). Resection of over 100 cm of ileum leads to a reduction in the bile salt pool results in steatorrhea and malabsorption of fat-soluble vitamins. Treatment is with a low-fat diet and vitamins supplemented with medium-chain triglycerides, which do not-require micellar solubilization. Unabsorbed fatty acids bind with calcium, reducing its absorption and enhancing the absorption of oxalate. Oxalate kidney stones may develop. Calcium supplements should be administered to bind oxalate and increase serum calcium. Cholesterol gallstones due to decreased bile salts are common also. In patients With resection of the ileo-colonic valve, bacterial overgrowth may occur in the small intestine, further complicating malabsorption (as. outlined above).

Presinusoidal

# Extra-hepatic - e.g. portal vein thrombosis

# Intra-hepatic - e.g. schistosomiasis

Sinusoidal- e.g. cirrhosis

Postsinusoidal .

. Extra-hepatic - e.g. Budd-Chiari syndrome

Intra-hepatic - e.g. veno-occlusive disease affecting

central hepatic venules

Obstruction to the hepatic venous outflow can occur at the following levels.

* Central hepatic veins.

* Large hepatic veins.

* Inferior vena cava.

* Heart.

Budd-Chiari syndrome is characterized by obstruction in the larger hepatic veins and occasionally in inferior vena cava.

Prognosis -. .

This is a serious disease and often leads to chronic disability. The prognosis is best in patients with recurrent acute pancreatitis caused by a remediable condition such as cholelithiasis, choledocholithiasis, stenosis of the sphincter of Oddi, or hyperparathyroidism. Medical management of the hyperlipidemia frequently associated with the condition may also prevent recurrent attacks of pancreatitis. In alcoholic pancreatitis, pain relief is most likely when a dilated pancreatic duct can be decompressed. In patients with disease not amenable to decompressive surgery, addiction to narcotics is a frequent outcome of treatment.

11] . A 45-year old woman visited her physician with complaints of increased appetite and thirst with increased frequency of urination.She also had the symptoms of diminished or Inpalpable pulses in the feet, besides gangrene of the feet. Her laboratory findings on the oral glucose tolerance test are as follows:

Parameters	Fasting	1 hr	2hr
Blood glucose	155	270	205
[mg/dl]
Urine glucose	-ve	+++	++
Ketone bodies	-ve	-ve	-ve

Which of the following statements is not correct for the above mentioned case?

1. She was suffering from insulin dependent diabetes mellitus.

2. She was suffering from non-insulin dependent diabetes mellitus.

3. She was treated with oral hypoglycemic drugs only when diet control and exercise could not control the pathological situation.

4. Knowledge of family history of diabetes mellitus is useful in predicting the nature of the diabetes.

Ans : 1 ( The Question is self explanatory )

12] Which of the following elements is known to influence the body's ability to handle oxidative stress?

1. Calcium..

2. Iron.

3. Potassium.

4. Selenium.

Ans : 4

13] In which of the following conditions the level of creatinine kinase-l increases?

1. Myocardial Ischemia.

2. Brain Ischemia.

3. Kidney damage.

4. Electrical cardio version.

Ans : 1

14] A 20-year-old woman presents with bilateral conductive deafness, palpable purpura on the legs and hemoptysis. Radiograph of the chest shows a thin-walled cavity in left lower zone. Investigations reveal total leukocyte count 12000/mm red cell casts in the urine and 12,000/mm serum creatinine 3 ing/dL. What is the most probable diagnosis?

1. Henoch - Schonlein purpura.

2. Polyarteritis nodosa.

3. Wegener’s granulornatosis.

4. Disseminated tuberculosis.

[Ans : 3 / Harrison Pg 1961/ 15th edition--given below]

CLINICAL AND LABORATORY MANIFESTATIONS OF Wegener’s granulornatosis: A typical patient presents with severe upper respiratory tract findings such as Para nasal sinus pain and drainage and purulent or bloody nasal discharge with or without nasal mucosal ulceration (Table 317-4). Nasal septal perforation may follow, leading to saddle nose deformity. Serous otitis media may occur as a result of Eustachian tube blockage. Hearing loss is also seen in some .

Pulmonary involvement may be manifested as asymptomatic infiltrates or may be clinically expressed as cough, hemoptysis, dyspnoea, and chest discomfort. It is present in 85 to 90% of patients. Subglottic stenosis resulting from active disease or scarring occurs in approximately 16% of patients and may result in, severe airway obstruction.

Eye involvement (52% of patients) may range from a mild conjunctivitis to dacryocystitis, episcleritis, scleritis, granulomatous sclerouveitis, ciliary vessel vasculitis, and retro orbital mass lesions leading to proptosis.

Skin lesions (46% of patients) appear as papules, vesicles, palpable purpura, ulcers, or subcutaneous nodules; biopsy reveals vasculitis, granuloma, or both. Cardiac involvement (8% of patients) manifests as pericarditis, coronary vasculitis, or, rarely, cardiomyopathy. Nervous system manifestations (23 % of patients) include cranial neuritis, mononeuritis multiplex, or, rarely, cerebral vasculitis and/or granuloma. /

Renal disease (77% of patients) generally dominates the clinical picture and, if left untreated, accounts directly or indirectly for most of the mortality in this disease. Although it may smolder in some cases as a mild glomerulitis with proteinuria, hematuria, and red blood cell casts, it is clear that once clinically detectable renal functional impairment occurs, rapidly progressive renal failure usually ensues unless appropriate treatment is instituted.

While the disease is active, most patients have nonspecific symptoms and signs such as malaise, weakness, arthralgias, anorexia, and weight loss. Fever may indicate activity of the underlying disease but more often reflects secondary infection, usually of the upper airway.

Characteristic laboratory findings include a markedly elevated ESR, mild anemia and leukocytosis, mild hypergammaglobulinemia (particularly of the IgA class), and mildly elevated rheumatoid factor. Thrombocytosis may be seen as an acute-phase reactant. In typical Wegener's granulomatosis with granulomatous vasculitis of the respiratory tract and glomerulonephritis, approximately 90% of patients have a positive c-ANCA.

15] A woman is admitted with complaints of low-grade fever of 6 weeks duration. Chest radiograph reveals bihilar adenopathy with clear lung fields. All of the following investigations will be useful in differential diagnosis except:

1. CD4/CD8 counts in the blood.

2. Serum ACE levels.

3. CECT of chest.

4. Gallium scan.

Ans : 3 ( Harrison 15th edition /Pg 1973 )

Features of Sarcoidosis

Disabling symptoms Fever Arthralgias Cough Dyspnoea Chest

Discomfort

Exercise

Limitation

Organ dysfunction Lung

Eye

Heart

CNS

Liver

Organ Derangement Enlarged lymph

Nodes Enlarged spleen Parotid swelling Cutaneous

Lesions

Ancillary criteria

ELevated numbersOf lavage Cd4 lymphocytes

Increased serum angiotensinconverting enzyme

Abnormal

Gallium-67 scan

16] An 18-yr-old boy presents with digital gangrene in third and fourth fingers for last 2 weeks. On examination the blood pressure is 170/110 mm of Hg and all peripheral pulses were palpable. Blood and urine examinations were unremarkable. Antinuclear antibodies. antibody to double stranded DNA and antineutrophil cytoplasmic antibody were negative. The most likely diagnosis is:

1. Wegener’s granulomatosis.

2. Polyarteritis nodosa.

3. Takayasu’s arteritis.

4. Systemic lupus erythemazosus (SLE).

Ans : 2 ( Pg 921 Davidson 17th edition )

POLYARTERITIS NODOSA (PAN)

Classical PAN is a necrotizing vasculitis affecting medium sized arteries.

Epidemiology

PAN is a rare disorder with an annual incidence of only 5-10/million in most populations.

All age groups can be affected, with a peak incidence in the 4th and 5th decades and a male to female ratio of 2: 1. The incidence is ten times higher in the Inuit population of Alaska where hepatitis B infection is endemic.

Aetiology and pathogenesis

In most cases the aetiology of PAN is unknown. In 5-50%, however, depending on the population studied, PAN is associated with circulating immune complexes containing the hepatitis B surface antigen. Other viruses implicated include hepatitis A, cytomegalovirus, parvovirus and HIV. Immune complex deposition is associated with endothelial cell damage, intimal proliferation, panarteritis, fibrosis, organ infarction and aneurysm formation.

Clinical features

Clinical presentation is very variable. The major features are listed in Table 15.13. Some patients present with non-specific features of systemic illness such as fever, weight loss and profound fatigue. Myalgia, arthralgia and a non-erosive polyarthritis are common. In others there is evidence of obvious vasculitic damage with skin lesions such as ulcers, palpable purpura, Cutaneous infarcts or gangrene. Mononeuritis multiplex results from arthritic involvement of the vasa nervorum. In some patients the presentation is with severe hypertension and/or renal impairment and a significant number present as an acute surgical emergency with abdominal pain, peritonitis, pancreatitis, major gastrointestinal hemorrhage, gut or gall bladder infarction. Testicular pain, leg and jaw claudication can occur as a result of vascular occlusion and about a third of patients have some lung involvement with chest pain, consolidation or variable pulmonary infiltrates. The frequency of organ involvement is shown in Figure 15.36.

17] A 28-year old lady has put on weight (10 kg over a period of 3 years), and has oligomenorrhoea followed by amenorrhea for 8 months. The blood pressure is 160/100 mm of Hg. Which of the following is the most appropriate investigation ?

1. Serum electrolytes.

2. Plasma Cortisol.

3. Plasma testosterone and ultrasound evaluation of pelvis.

4. T3. T4 and TSH.

Ans : 4 ( Pg 723 / Davidson 17th edition)

Clinical features in secondary amenorrhea

These will depend on the condition. If there is weight loss then this may be primary as in anorexia nervosa or secondary to an underlying disease such as TB, malignancy or hyperthyroidism. Weight gain may suggest Cushing’s syndrome, hypothyroidism or, very rarely, a hypothalamic lesion. Hirsutism may indicate androgen excess. A very common cause of this is the polycystic Ovary syndrome.

18] A 10 year old boy has a fracture of femur. Biochemical evaluation revealed Hb 11.5 gm/dl and ESR 18 mm 1 hour, Serum calcium 12.8 mg/dl, serum phosphorus 2.3 mg/dl, alkaline phosphatase 28 KA units and Blood urea 32 mg/dl. Which of the following is the most probable diagnosis in his case?

1. Nutritional rickets.

2. Renal rickets.

3. Hyperparathyroidism.

4. Skeletal dysplasia.

Ans : 3 ( Davidson Pg 702)

The diagnosis of primary hyperparathyroidism depends upon the finding of a raised serum calcium and raised PTH (Fig. 12.16). The serum PTH concentrations in other causes of Hypercalcemia are shown in Table 12.9.

It is preferable to avoid artefactual increases in serum calcium by collecting blood under standardized conditions with the patient supine and avoiding the use of a tourniquet while withdrawing the sample. Although changes in serum calcium in response to dietary intake are small, specimens should be collected with the patient fasting. If serum albumin is low, the value for calcium should be adjusted upward by 0.1 mmol/I for each 6 g/I that the albumin is below the laboratory mean. Serum phosphate is usually low in hyperparathyroidism and chloride elevated. Serum alkaline phosphatase, an index of osteoblastic activity, may be raised depending on the degree of involvement of bone.

Idiopathic Edema This syndrome, which occurs almost exclusively in women, is characterized by periodic episodes of edema (unrelated to the menstrual cycle), frequently accompanied by abdominal distention. Diurnal alterations in weight occur with orthostatic retention of sodium and water, so that the patient may weigh several pounds more after having been in the upright posture for several hours. Such large diurnal weight changes suggest an increase in capillary permeability that appears to fluctuate in severity and to be aggravated by hot weather. There is some evidence that a reduction in plasma volume occurs in this condition with secondary activation of the RAA system & impaired suppression of A VP release. Idiopathic edema should be distinguished from cyclical or premenstrual edema, in which the sodium and water retention may be secondary to excessive estrogen stimulation. There are also some cases in which the edema appears to be 'diuretic-induced." It has been postulated that in these patients, chronic diuretic administration leads to mild blood volume depletion, which causes chronic hyperreninemia and juxtaglomerular hyperplasia. Salt-retaining mechanisms appear to overcompensate for the direct Effects of the diuretics. Acute withdrawal of diuretic can then leave the sodium-retaining forces unopposed, leading to flu edema. Decreased dopaminergic activity and reduce krein and kinin excretion have been reported in this CO) also be of pathogenetic importance.

Diagnostic Evaluation for Gynecomastia : The evaluation of patients with gynecomastia should include: (1) a careful drug history; (2) measurement and examination of the testes (if both are small, a chromosomal karyotype should be obtained; if the testes are asymmetric, a workup for testicular tumor should be instituted); (3) evaluation of liver function; and (4) endocrine workup to include measurement of serum androstenedione or 24-h urinary 17-ketosteroids (usually elevated in feminizing adrenal states), measurement of plasma Estradiol and hCG (helpful if elevated but usually normal), and measurement of plasma LH and testosterone. If LH is high and testosterone is low, the diagnosis is usually testicular failure; if LH and testosterone are both low, the diagnosis is most likely increased primary estrogen production (e.g., a Sertoli cell tumor of the testis), provided hypogonadotropic hypogonadism has been excluded; and if both LH and testosterone are elevated, the diagnosis is either an androgen-resistance state or a gonadotropin-secreting tumor.

Causes of Thyrotoxicosis

Primary hyperthyroidism

Graves' disease

Toxic multinodular goiter

Toxic adenoma

Functioning thyroid carcinoma metastases

Activating mutation of the TSH receptor (autosomal dominant)

Struma ovarii

Drugs: iodine excess (Jod-Basedow phenomenon)

Thyrotoxicosis without hyperthyroidism

Subacute thyroiditis

Silent thyroiditis

Other causes of thyroid destruction: amiodarone, radiation, infarction of

adenoma

Ingestion of excess thyroid hormone (thyrotoxicosis factitia) or thyroid

tissue

Secondary hyperthyroidism

TSH-secreting pituitary adenoma

Thyroid hormone resistance syndrome: occasional patients may have fea

tures of thyrotoxicosis

Chronic gonadotropin-secreting tumors"

Gestational Thyrotoxicosis"

Clinical features of cardiac tamponade:

Pulsus paradoxus--common

Jugular veins

Prominent y descent------absent

Prominent x descent----present

Kussmaul's sign ---absent

Third heart sound----absent

Pericardial knock---------absent

Electrocardiogram

Low ECG voltage --- may be present

Electrical alternans---may be present

Echocardiography

Thickened pericardium --absent

Pericardial calcification ---absent

Pericardial effusion---present

R V size----small

Myocardial thickness ----normal

Right atrial collapse and RVDC-----present

Increased early filling,---absent

i mitral flow velocity---present

Exaggerated respiratory---absent

variation in flow velocity-----present

REGULATION OF THE THYROID AXIS

TSH, secreted by the thyrotrope cells of the anterior pituitary plays a pivotal role in control of the thyroid axis and serves as the most useful physiologic marker of thyroid hormone action. TSH is a 31-kDa hormone composed of a and f3 subunits; the a subunit is common to the other glycoprotein hormones [Luteinising hormone, follicle-stimulating hormone, human chorionic gonadotropin (hCG)], whereas the TSH f3 subunit is unique to TSH. The extent and nature of carbohydrate modification are modulated by thyrotropin-releasing hormone (TRH) !Simulation and influence the biologic activity of the hormone. TSH has been produced recombinantly and is approved for use in the detection of residual thyroid cancer (see "Follow-up Whole-Body Scanning and Thyroglobulin Detenninations," below).

The thyroid axis is a classic example of an endocrine Deiodination feedback loop. Hypothalamic TRH stimulates pituitary hormone, rev, production of TSH, which, in turn, stimulates thyroid hor

mone synthesis and secretion. Thyroid hormones feed back negatively 10 inhibit TRH and TSH production (Fig. 330-2). The "set-point" in this axis is established by TSH, the level of which is a sensitive and, specific marker of thyroid function. TRH is the major positive regulator of TSH synthesis and secretion. TRH acts through seven-trans membrane G protein-coupled receptor (GPCR) that activates phospholipase C to generate phosphatidylinositol turnover and the release If intracellular calcium. Peak TSH secretion occurs ~ IS min after administration of exogenous TRH. Dopamine, glucocorticoids, and stomatostatin suppress TSH but are not of major physiologic importance except when these agents are administered in pharmacologic doses. Reduced levels of thyroid hormone increase basal TSH production and enhance TRH-mediated stimulation of TSH. High thyroid IODINE levels rapidly and directly suppress TSH and inhibit TRH, mediated stimulation of TSH, indicating that thyroid hormones are the imminent regulator of TSH production. Like other pituitary hormones, TSH is released in a pulsatile manner and exhibits a diurnal rhythm; highest levels occur at night. However, these TSH excursions are modest in comparison to those of other pituitary hormones, in part because TSH has a relatively long plasma half-life (50 min). Consequently single measurements of TSH are adequate for assessing its circulating level. TSH is measured using immuno-radiometric assays

are highly sensitive and specific. These assays are capable of distinguishing between normal and suppressed TSH values, thus allowing H to be used for the diagnosis of hyperthyroidism (low TSH) as well as hypothyroidism (high TSH).

D. Herpes Encephalitis: Herpes simplex encephalitis presents with nonspecific symptoms: a flu-like prodrome, followed by headache, fever, behavioral and speech disturbances, and seizures that may be focal or generalized. A distinguishing feature is a propensity to involve the temporal lobe, with mass effect on imaging studies and temporal lobe seizure foci on EEGs. Cerebrospinal fluid white cell pleocytosis is common, and roughly equal numbers of red cells are also found.

HSV DNA polymerase chain reaction (PCR) in the cerebrospinal fluid is a rapid and sensitive and specific test.

Absence Seizures (Petit Mal) Absence seizures are characterized by sudden, brief lapses of consciousness without loss of postural control. The seizure typically lasts for only seconds, consciousness returns as suddenly as it was lost, and there is no postictal confusion. Although the brief loss of consciousness may be clinically in apparent or the sole manifestation of the seizure discharge, absence seizures are usually accompanied by subtle, bilateral motor signs such as rapid blinking of the eyelids, chewing movements, or small-amplitude, clonic movements of the hands.

Absence seizures usually begin in childhood (ages 4 to 8) or early adolescence and are the main seizure type in 15 to 20% of children with epilepsy. The seizures can occur hundreds of times per day, but the child may be unaware of or unable to convey their existence. This can lead to a situation in which the patient is constantly struggling to…………..

Types of heart failure

Acute and chronic heart failure

* Acute heart failure develops suddenly. The sudden reduction in cardiac output results in systemic hypotension

without peripheral edema. Best examples are acute myocardial infarction and rupture of a cardiac valve.

* Chronic heart failure develops gradually. Here systemic arterial pressure is well maintained, but edema

accumulates . Best examples are...dilated cardiomyopathy and multi-valvular disease.

* Compensated heart failure implies that the compensatory changes have prevented the development of overt heart failure. A minor insult like an infection may precipitate severe heart failure.

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