Hepatic Zonal Necrosis

TYPES OF HEPATIC ZONAL NECROSIS

I) Centilobular / Centrizonal Necrosis -

    a) Cardiac failure / Shock.

    b) CCl4 - Carbon Tetra Chloride.

    c) Chloroform Toxicity.

    d) Viral Hepatitis.

    e) Halothane Hepatitis (~1/35,000)

II) Peripheral Zonal Necrosis --> Necrosis around portal tracts.

     a) Eclampsia.(PIH)

     b) Phosphorus Poisoning.

III) Mid-zonal Necrosis --- RARE

       Seen in Yellow Fever.

STAINS Continued - Part 2

VARIOUS STAINS USED IN PATHOLOGY

8. Lactol Phenol Cotton Blue Stain       -- - (Spiked Spherical conidia)

                 and                                               ------> both Used for Histoplasma capsulatum

9. Grocott's Methenamine Silver Stain   -- -

(Ref: Harrison's 17th)

10. Calcium - VON KOSSA , Alizarin Red.

11. Iron - Pearl's Stain, Prussian Blue.

12. For detecting Eosinophiluria in Urinary Sediment - Hansten's Stain.

13. Dermataceous Fungi - Mason-Fontana Silver Stain. 

14. Heinz Bodies - Supravital staining with Methyl Violet.

to continue.

Don't forget to send your valuable suggestions to pgmeedoubts@gmail.com

pgmee notes by dv

Staining : Various Stains Used

VARIOUS STAINS USED IN PATHOLOGY

1. Nemalin Rods - Modified Gomori Stain.

2. H.Pylori - Warthin Starry Stain ( A silver stain).

3. Ragged Red Fibres of OXPHOS Diseases - Modified Gomori Trichrome Stain.

4. Cytoplasmic cores of 'Central Core Disease' - NADH Stain.

5. Fat / Adipose Tissue - 1. Oil Red O, 2. Sudan Black, 3. Sudan III.

6. Glycogen : PAS +ve , Diastase Sensitive.

7. Alpha-1-Antitrypsin - PAS +ve, Diastase Resistant.

Lot more to come..follow on.

dv.

Most Commons Medicine

Most common finding in histopathological examination of kidney in Denys-Drash Syndrome - Diffuse Mesangial Sclerosis

MC ECG manifestation of PTE / Pulm.ThromboEmbolism : Sinus Tachcardia >> Irregular ST-T changes

MCC for Drug induced SLE : Procainamide > Hydrallazine

Most Commons : Renal lesion in HIV infection

** The most common renal lesion in HIV infected individuals is  : 

                              OR 

** The most common HIV Associated Nephropathy is                :

ANSWER : FSGS- Collapsing Variant.

Reference : Robbins 7/e, p.n. 984 : pgmeenotes by dv.

VIRCHOW'S TRIAD

Virchow's Triad of Thrombosis

1. Altered Blood Flow ---> STASIS

2. Hypercoagulabillity.

3. Endothelial Injury.

Contents of Neutrophil Granules

Toll-Like Receptor 7 Triggers Immune Response to West Nile Virus

NEW YORK (Reuters Health) Feb 09 - Toll-like receptor 7 -- the mammalian host's first line of defense against West Nile virus infection - may represent a therapeutic target in the treatment of viral encephalitis, scientists report in the February 20 issue of Immunity, posted online on February 5.

Toll-like receptors (TLRs) are responsible for initiating innate immunity, lead author Dr. Terrence Town, from Cedars Sinai Medical Center in Los Angeles, explained in an interview with Reuters Health. Up to a dozen TLRs have been identified in mammals, each of which recognizes specific pathogens, such as bacteria, flagellated protozoans, and fungi. TLR3 mediates host recognition of viral components and intact West Nile virus.

"When we infected TLR3 knockout mice with West Nile virus, we expected the mice to do worse, and were surprised to see that they became more resistant," Dr. Town said.

They discovered that TLR3 activation elicits systemic TNF-alpha production, which increases permeability of the blood-brain barrier to the virus.

"Most individuals that receive a West Nile virus challenge by mosquito bite remain asymptomatic, and the body clears the virus, so we knew that other mechanisms must be in place that serve to clear this virus," the scientist continued.

Further work revealed that TLR7 also recognizes West Nile virus. TLR7 knockout mice were susceptible to lethal West Nile virus encephalitis, despite the upregulation of many proinflammatory cytokines in the peripheral circulation. However, levels of interleukin-23 were reduced, and homing of leukocytes, microglia, and macrophages to virus-infected cells in the brain was impaired.

MOST COMMONS - IN THORAX / LUNGS

Most Common Type of Carcinoma to cavitate  --Squamous cell carcinoma

Most Common Location of bullae in Alpha-1 Antitrypsin Deficiency-- Lower lobes

Most Common-Benign extrapleural mass---Lipoma of chest wall

Most Common- Location of cysts in Eosinophilic Granuloma---Upper lobes

Most Common- Histology of mediastinal Hodgkin's----Nodular sclerosing

Most Common- Segment of lower lobe most often affected by bronchiectasis----Posterior

ANGIOD STREAKS

Angioid Streaks (Syn : KNAPP's STRIAE)

The causes for angiod streaks can be remembered by the Mnemonic - "PEPSI"

P - Pseudoxanthoma Elasticum
E - Ehlers-Danlos Disease
P - Paget's Disease
Si - Sickle Cell Anemia
I - Idiopathic (50% - Most Common)

Rare etiologies include patients with peptic ulcer, diabetes, hypertension, arthritis, breast cancer, metastatic cancer, rheumatoid spondylitis, and heart disease.

More Info on Angioid Streaks.

CEROID Bodies

Q) Ceroid Bodies are :

a) Lipid Inclusions in pancreatic beta cells.
b) Beta cell calcifications in FCPD.
c) Amylin Depostions in Beta cells.
d) None of the above.

Ans: (A) Lipid Inclusions in pancreatic beta cells.

Carcinoma Lung / Bronchogenic Carcinoma : Few important facts

1. Most common histological type of lung cancer associated with Para Neoplastic (PNP) syndromes ?

2. Most common histological type associated with Hypokalemia ?

3. Type of Lung cancer with good reponse to chemotherapy and radiation ?


Answer : SMALL CELL LUNG Carcinoma.

Note: Although SCLC shows good response to chemo-radiation, overall the prognosis is poor due to it's late detection.

Carcinoma Lung / Bronchogenic Carcinoma : Few important facts

1. Most common histological type of lung cancer in India.

2. Lung cancer which is mostly central in location and in which cavities are seen

3. Histological type with best prognosis

4. Most common histological type with hypercalcemia as a paraneoplastic manifestation.


is SQUAMOUS CELL CARCINOMA Lung..


Note : Pancoast tumor although peripheral in location (Apex of Lung) is of Squamous Cell variety.

Carcinoma Lung : Few important facts

1. Most common histological type worldwide
2. Most common histological type in 'lifetime non-smokers' / women / young patients
3. Most common lung cancer which metastasizes to opposite lung
4. Lung cancer which is usually peripheral in location



is ADENOCARCINOMA Lung.

Characteristic Appearances

Characteristic Appearances in Histopathology/Microscopy

"Appearances can be deceiving"

1. Tree Bark appearance of intima - is seen in Syphilitic Aneurysm.

2. Koilocytic Atypia - is seen in HPV Infection

3. Gullwing shaped rod (bacteria) - Campylobacter jejuni

4. Rosenthal Fibres - Alexander's Disease(Rare Sporadic Leukodystrophy d/t mutation of GFAP).

pgmeenotes by dv

CATCH 22 - DiGeorge Syndrome / Velo-cardio-facial syndrome

CATCH 22 is an acronym for

C - Cardiac defects *
A - Abnormal Facies
T - Thymic (and parathyroid) hypoplasia
C - Cleft Palate
H - Hypocalcemia due to parathyroid hypoplasia

22 - It's the most common microdeletion syndrome and it affects Chr.22q11**

Further :

* " In a series of 545 patients with 22q11 deletions, 20% had no cardiac defects (ie, based on clinical examination and echocardiography findings). The most common cardiac anomalies included tetralogy of Fallot (17%), ventricular septal defect and interrupted aortic arch (14% each), pulmonary atresia/ventricular septal defect (10%), and truncus arteriosus (9%). Other anomalies included pulmonic stenosis, atrial septal defect, atrioventricular septal defect, and transposition of great arteries".

http://emedicine.medscape.com/article/135711-overview

** "DiGeorge anomaly is the most frequent contiguous gene deletion syndrome in humans. Microdeletion of chromosome 22 accounts for more than 90% of cases of DiGeorge anomaly. Deletions of chromosome 22q11.2 are found in the vast majority of patients with DiGeorge anomaly and VCFS."

Hope it's of some help.

Alagille syndrome : An Overview

Alagille syndrome is an autosomal dominant disorder with variable expression. Associated abnormalities include those of the liver, heart, eye, skeleton, and kidneys and characteristic facial features. Mild-to-moderate mental retardation also may be present. The syndrome has recently been mapped to the 20p12-jagged-1 locus (JAG1), which encodes a ligand critical to the notch gene–signaling cascade that is important in fetal development. A minority (6-7%) of patients have complete deletion of JAG1, and approximately 15-50% of mutations are spontaneous.

Clinical

Physical

Presentation varies. Some patients are diagnosed after prolonged neonatal jaundice or when liver biopsy findings reveal paucity of intrahepatic bile ducts. Others may be diagnosed during evaluation for right-sided heart disease. Some individuals are diagnosed by careful examination after an index case is identified in the family.

• Nutrition and growth
  • Children often present with poor linear growth.
  • Altered longitudinal growth is attributed to wasting or inadequate intake, and an element of growth hormone resistance may also be present.⁶ Studies to assess the impact of higher doses of growth hormone on linear growth in patients with Alagille syndrome are currently underway.
• Head and neck
  • Commonly associated facial features include broadened forehead, pointed chin, and elongated nose with bulbous tip.
  • Characteristic facial features may not be obvious during infancy but may become more apparent as the child ages.
• Ophthalmologic
  • Ocular abnormalities are common.⁷ The most frequent ophthalmologic finding is a posterior embryotoxon, which was observed in more than 75% of patients in one large series conducted by Emerick et al.⁸
  • Some of these patients may also have the Axenfeld anomaly (ie, iris attachment to Descemet membrane).
  • Other findings reported include retinitis pigmentosa, pupillary abnormalities, and anomalies of the optic disc.
• Cardiovascular
  • Nearly all patients have cardiac murmurs.
  • The most common cardiac lesions are stenoses within the pulmonary tree (peripheral pulmonic stenosis) with or without other structural lesions.
  • Hemodynamically significant lesions include atrial septal defect (ASD), ventricular septal defect (VSD), tetralogy of Fallot, patent ductus arteriosus (PDA), and pulmonary atresia (PA). Significant intracardiac lesions place patients with Alagille syndrome at increased mortality risk.
• Hepatic
  • Hepatic disease is a key feature of Alagille syndrome.
  • Most infants present with cholestatic jaundice.
  • Hepatosplenomegaly is common.
  • Elevations in serum bile acids often result in severe pruritus and xanthomas (hypercholesterolemia).
  • Fat-soluble vitamin deficiencies, including coagulopathies and rickets, are frequent.
• Skeletal
  • Abnormalities of the vertebrae, ribs, and hands are frequently associated with Alagille syndrome.
  • Butterfly hemivertebrae were found in one half of the patients analyzed by Emerick et al in a large series of patients with Alagille syndrome.⁸
  • Other isolated anomalies include rib anomalies and shortening of the radius, ulna, and phalanges.
• Neurologic
  • Mild developmental delay and mental retardation are reported in some children with Alagille syndrome.
  • If noted during the physical examination, diminished deep tendon reflexes should direct the clinician to exclude vitamin E deficiency.
• Renal: Occult renal artery stenosis, lipoid nephrosis, or glomerulosclerosis may present with signs and symptoms of chronic hypertension.
• Vascular: Vascular lesions have been recently described in 6% of the patients with confirmed Alagille syndrome who were followed by Kamath et al.⁹ These lesions included basilar artery aneurysms, internal carotid artery anomalies, middle cerebral artery aneurysm, Moyamoya disease and aortic aneurysms,coarctation of the aorta, and renal artery stenosis.

Causes

• Alagille syndrome is an autosomal dominant mutation with variable expression localized to the JAG1 gene (20p12).
• The JAG1 gene product functions as a ligand for the notch-1 receptor. In animal models, interactions between JAG1 ligand and notch-1 receptor play an important role in the determination of ultimate cell fate. Few patients, generally those with more severe phenotypes, have complete deletion of the JAG1 gene.