Mindmap for Appendicitis

Revise appendicitis faster with this mindmap!

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Synthesis and metabolism of vitamin D in the regulation of calcium, phosphorus, and bone metabolism.

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During exposure to solar UVB radiation, 7-dehydrocholesterol in the skin is converted to previtamin D3, which is immediately converted to vitamin D3 in a heat-dependent process. Excessive exposure to sunlight degrades previtamin D3 and vitamin D3 into inactive photoproducts. Vitamin D2 and vitamin D3 from dietary sources are incorporated into chylomicrons and transported by the lymphatic system into the venous circulation. Vitamin D (hereafter, “D” represents D2 or D3) made in the skin or ingested in the diet can be stored in and then released from fat cells.
Vitamin D in the circulation is bound to the vitamin D–binding protein, which transports it to the liver, where vitamin D is converted by vitamin D-25-hydroxylase to 25(OH)D. This is the major circulating form of vitamin D that is used by clinicians to determine vitamin D status. (Although most laboratories report the normal range to be 20 to 100 ng/mL [50 to 250 nmol/L], the preferred range is 30 to 60 ng/mL [75 to 150 nmol/L].) This form of vitamin D is biologically inactive and must be converted in the kidneys by 25-hydroxyvitamin D-1α-hydroxylase (1-OHase) to the biologically active form 1,25(OH)2D.
 Serum phosphorus, calcium, fibroblast growth factor 23 (FGF-23), and other factors can either increase (+) or decrease (−) the renal production of 1,25(OH)2D. 1,25(OH)2D decreases its own synthesis through negative feedback and decreases the synthesis and secretion of PTH by the parathyroid glands. 1,25(OH)2D increases the expression of 25-hydroxyvitamin D-24-hydroxylase (24-OHase) to catabolize 1,25(OH)2D to the water-solubl biologically inactive calcitroic acid, which is excreted in the bile.

1,25(OH)2D enhances intestinal calcium absorption in the small intestine by interacting with the vitamin D receptor–retinoic acid x-receptor complex (VDR-RXR) to enhance the expression of the epithelial calcium channel (transient receptor potential cation channel, subfamily V, member 6 [TRPV6]) and calbindin 9K, a calcium-binding protein (CaBP). 1,25(OH)2D is recognized by its receptor in osteoblasts, causing an increase in the expression of the receptor activator of RANKL.
RANK, the receptor for RANKL on preosteoclasts, binds RANKL, which induces preosteoclasts to become mature osteoclasts. Mature osteoclasts remove calcium and phosphorus from the bone, maintaining calcium and phosphorus levels in the blood. Adequate Ca2+ and phosphorus (HPO42−) levels promote the mineralization of the skeleton.

Prostate diseases in relation to Prostate zones

Most cancer lesions occur in the peripheral zone of the gland, fewer occur in the transition zone and almost none arise in the central zone. Most benign prostate hyperplasia (BPH) lesions develop in the transition zone, which might enlarge considerably beyond what is shown.

The inflammation found in the transition zone is associated with BPH nodules and atrophy, and the latter is often present in and around the BPH nodules. Acute inflammation can be prominent in both the peripheral and transition zones, but is quite variable.
The inflammation in the peripheral zone occurs in association with atrophy in most cases.

Although carcinoma might involve the central zone, small carcinoma lesions are virtually never found here in isolation, strongly suggesting that prostatic intraepithelial neoplasia (PIN) lesions do not readily progress to carcinoma in this zone. Both small and large carcinomas in the peripheral zone are often found in association with high-grade PIN, whereas carcinoma in the transition zone tends to be of lower grade and is more often associated with atypical adenomatous hyperplasia or adenosis, and less often associated with high-grade PIN. The various patterns of prostate atrophy, some of which frequently merge directly with PIN and at times with small carcinoma lesions, are also much more prevalent in the peripheral zone, with fewer occurring in the transition zone and very few occurring in the central zone.

Indication and Technique of Buried Intradermal Sutures

Indication:

Buried Intradermal Sutures technique is useful for wide, gaping wounds and when it is difficult to evert the skin edges. When buried intradermal sutures are placed properly, they make skin closure much easier. The purpose of this stitch is to line up the dermis and thus enhance healing.
It is termed buried as the knot needs to be as deep into the tissues as possible so that it does not come up through the epidermis and cause irritation and pain.

Technique:

-By using a cutting needle and absorbable material Start just under the dermal layer and come out below the epidermis.
You are going from deep to more superficial tissues.

-Now the technique becomes a bit challenging. You need to enter the skin on the opposite side at a depth similar to where you exited the skin on the first side, just below the epidermis. To do so, you should position the needle with the tip pointing down and pronate your wrist to get the correct angle. It will help to use the forceps (in the other hand) to hold up the skin. The needle should come out of the tissues below the dermis. Try to get as little fat in the stitch as possible; it does not contribute to the suture.

-Finnaly Tie the suture.

How to differentiate between transmitted and expansile pulsations

If you are palpating a swelling like an abdominal swelling infront of the aorta, You have to decide whether the mass you feel is pulsatile/expansile in itself (in which case your fingers will move outwards A ) or whether the pulsation is transmitted through other tissue (in which case your fingers will move upwards B ).See diagram below

Also in transmitted pulsation you can make this pulsation disappear if you can move the swelling away from the aorta ( if you put the patient in the knee-elbow position, an enlarged intra-abdominal swelling which was transmitting aortic pulsation will get away from the aorta and the pulsations will disappear)

Blood and nerve supply of a Synovial joint

The blood supply of a synovial joint is derived from the arteries sharing in the anastomosis around the joint.And the nerve supply of a synovial joint is derived from the muscles which act on the joint ,best expressed by Hilton in 1863:
"The same trunks of nerves, whose branches supply the groups of muscles moving a joint, furnish also a distribution of nerves to the skin over the insertions of the same muscles; and what at this moment more especially merits our attention-the interior of the joint receives its nerves from the same source."

proprioceptive fibers endings in the capsule and ligaments are very sensitive to position and movement. Their central connections are such that they are concerned with the reflex control of posture and locomotion and the detection of position and movement.

The blood and nerve supply of a synovial joint. This diagram shows the artery supplying the epiphysis, joint capsule, and synovial membrane. The nerve that contains (1) sensory (mostly pain) fibers from the capsule and synovial membrane, (2) autonomic (postganglionic sympathetic) fibers to blood vessels, (3) sensory (pain) fibers from the adventitia of blood vessels, and (4) proprioceptive fibers. 

N.B.Arrowheads indicate direction of conduction.

Diagram shows pathway of the pupillary light reflex

This is a schematic diagram of the pupillary light reflex. The afferent limb originates in the retinal photoreceptors, which convert light energy to a neural signal. Pupillary information is conveyed from the eye to the brain by the melanopsin-expressing retinal ganglion cells, and their axons project to the dorsal midbrain, synapsing in the pretectal olivary nucleus. Each pretectal olivary nucleus distributes the afferent pupillary impulses to the ipsilateral and contralateral Edinger-Westphal subnucleus of the oculomotor nuclear complex.
The neurons of the Edinger-Westphal subnucleus initiate the efferent limb of the pupillary light reflex, that is, pupilloconstriction. Efferent pupillomotor impulses travel in the parasympathetic fibers of the oculomotor nerve, synapse in the ciliary ganglion of the orbit, and then pass via the short ciliary nerves to innervate the iris sphincter muscle.

Common recommended sites for insulin injection

At first insulin recommended to be injected into some sites where a less-sensitive layer of fatty tissue just below the skin to absorb the insulin with no many nerves ,so that insulin injection will be more comfortable in these sites more than others the  just under the skin.
Also these sites make it easier to inject into the subcutaneous tissue, where insulin injection is recommended. 

Common sites for insulin injection are :

A-Abdomen :the most common insulin injection site because it has easily accessible fatty areas and Insulin is absorbed faster when it is injected into the abdomen " So:you should inject the insulin into the abdomen just before meals",Also This area allows for greater access if injecting individually.

Notes:

Do not inject within 1-2 inches around the navel "tissue is tough" ,surgical, other scar tissue, moles.

B-Thighs :The middle and outer thigh area is another one of the common insulin injection sites that are suitable for injecting long-acting insulin.Don't inject too close to the area just above knee because the tissue is very tough.


C-Arms :The back of the upper arm

Diagram of Anterior anatomical relations of both kidneys

The kidneys are retroperitoneal organs that are located in the perirenal retroperitoneal space with a longitudinal diameter of 10–12 cm and a latero-lateral diameter of 3–5 cm and a weight of 250–270 g.
In the supine position, the medial border of the normal kidney is much more anterior than the lateral border, The upper pole of each kidney is situated more posteriorly than the lower pole.

The right kidney,  anteriorly :
has a relation with the inferior surface of the liver with peritoneal interposition,and with the second portion of the duodenum without any peritoneal interposition since the second portion of the duodenum is retroperitoneal .
The left kidney, anteriorly :
has a relation with the pancreatic tail, the spleen, the stomach, the ligament of Treitz and small bowel, and with the left colic lexure and left colon . Over the left kidney, there are two important peritoneal relections, one vertical corresponding to the spleno-renal ligament (connected to
the gastro-diaphragmatic and gastrosplenic ligaments) and one horizontal corresponding to the transverse mesocolon.

Simple illustrations of Carotid Endarterectomy Procedure

Carotid Endarterectomy or may be called Stroke Prevention Surgery is indicated to prevent a stroke in patients with narrowed carotid arteries(Endarterectomy is the removal of material on the inside "end-" of an artery).

Procedure: The carotid artery is exposed through an incision on the side of the neck. The artery is clamped above and below where the narrowing is located. The flow of blood to the brain is maintained with the use of a specialized shunt (tube) that carries fresh blood to the brain during the procedure. The diseased material narrowing the artery is removed. The artery is then closed.

Diagram for possible long-term effects of ethanol

This diagram shows most significant possible long-term effects of ethanol.

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Preferred method for chest compressions in neonatal resuscitations

In the most of neonatal resuscitations, if adequate ventilation is achieved, no need for chest compressions . However, in certain cases of advanced asphyxia and myocardial depression or severe pulmonary dysfunction in which adequate ventilation cannot be readily achieved, chest compressions are necessary to support the circulation during more extensive resuscitation.

Thus, the indication for chest compressions in the newly born differs significantly from that in older children and adults. The mechanics of the thoracic cage and the physical forces of the circulation of blood also differ, especially in preterm infants. The predominance of pulmonary dysfunction, necessitates a relatively lower ratio of compressions to ventilations. The 3:1 ratio of compressions to ventilations is performed with 90 compressions and 30 interposed breaths per minute (or one cycle of 4 events every 2 seconds).

The preferred method for chest compressions is the two-thumb-encircling-hands method , which provides firm support for the back and generates higher systemic arterial pressure and better coronary perfusion pressure than the two-finger method.

Clinical symptoms of Haemophilus influenzae Vs Haemophilus ducreyi Vs Haemophilus aegyptius

Haemophilus influenzae

H. influenzae has a variety of symptoms some of which may depend on the presence of the bacterial capsule. Until the availability of the Hib vaccine, the type-b H. influenzae was the main cause of meningitis in children between 6 months and 5 years, although older children, adolescents and adults can also be infected.

At first the infection causes a runny nose, low grade fever and headache (1-3 days). Due to the invasive nature of the organism ,it enters the circulation and crosses the blood-brain barrier, resulting in a rapidly progressing meningitis (stiff neck), convulsions, coma and death. Timely treatment may prevent coma and death, but the patient may still suffer from deafness and mental retardation.
Type-b H. influenzae may also cause septic arthritis conjunctivitis, cellulitis, and epiglottitis, the latter results in the obstruction of the upper airway and suffocation. H. influenzae of other types may rarely cause some of the symptoms listed above.

Non-typable strains of H. influenzae are the second commonest cause of otitis media in young children (second to Streptococcus pneumoniae). In adults, these organisms cause pneumonia, particularly in individuals with other underlying pulmonary infections. These organisms also cause acute or chronic sinusitis in individuals of all ages.

Clinical symptoms of infection by Haemophilus

Clinical symptoms of infection by HaemophilusClinical symptoms of infection by Haemophilus

Haemophilus ducreyi

A significant cause of genital ulcers (chancroid) in Asia and Africa but, is seen less commonly in the USA. The incidence is approximately 4000-5000 per year with clusters found in California, Florida, Georgia and New York.

The infection is asymptomatic in women but about a week following sexual transmission to a man, it causes appearance of a tender papule with erythematous base on the genitalia or the peripheral area. The lesion progresses to become a painful ulcer with inguinal lymphadenopathy. The H. ducreyi lesion (chancroid) is distinguished from a syphilitic lesion (chancre) in that it is a comparatively soft lesion.

Haemophilus influenzae aegyptius

This bacterium, previously known as H. aegyptius, causes an opportunistic organism which can result in a fulminant pediatric disease (Brazilian purpuric fever) characterized by an initial conjunctivitis, followed by an acute onset of fever, accompanied by vomiting and abdominal pain. Subsequently, the patient develops petechiae, purpura, shock and may face death. The pathogenesis of this infection is poorly understood. The growth conditions for this organism are the same as those for H. influenzae.

Terms of Position, Direction and the main Planes of human body anatomy

The Diagram below shows the chief terms of position and direction and the main planes of reference in the body.

*A convention whereby the body is erect, with the head, eyes, and toes directed forward and the upper limbs by the side and held so that the palms of the hands face forward "unlike the figure at left " . It is often necessary, however, to describe the position of the viscera also in the recumbent posture, because this is a posture in which patients are frequently examined clinically. 

*The median plane is an imaginary vertical plane of section that passes longitudinally through the body and divides it into right and left halves. The median plane intersects the surface of the front and back of the body at what are called the anterior and posterior median lines. It is a common error, however, to refer to the" midline" when the median plane is meant.

*Any vertical plane through the body that is parallel with the median plane is called a sagittal plane. The sagittal planes are named after the sagittal suture of the skull, to which they are parallel. The term "parasagittal" is redundant: anything parallel with a sagittal plane is still sagittal.

*The term horizontal plane refers to a plane at a right angle to both the median and coronal planes: it separates the body into superior and inferior parts. This is often termed an axial plane, particularly in radiology.

*The term transverse means at a right angle to the longitudinal axis of a structure. Thus, a transverse section through an artery is not necessarily horizontal. A transverse section through the hand is horizontal, whereas a transverse section through the foot is coronal !!

*The suffix "-ad" is sometimes added to a positional term to indicate the idea of motion. Thus, cephalad means proceeding toward the head. Such terms are useful occasionally in describing growth processes, but their application is best limited.

ECG changes in acute MI

The ECG changes are often  critical in the diagnosis of acute MI and guiding therapy.
There is a series of ECG changes reflect the evolution of the infarction (The Figure below).
1.The earliest changes are : tall, positive, hyper acute T waves in the ischemic vascular territory.
2.This is followed by elevation of the ST segments (myocardial “injury pattern”).
3.Over hours to days, T-wave inversion frequently develops.
4.And finally, diminished R-wave amplitude or Q waves occur, representing significant myocardial necrosis and replacement by scar tissue, and they are what one seeks to prevent in treating the acute MI .

 Temporal evolution of ECG changes in acute myocardial infarction.

Note the tall hyperacute T waves and loss of R-wave amplitude,followed by ST-segment elevation,T-wave inversion,and development of Q waves.Persistent ST-segment elevation suggests left ventricular aneurysm.

Le Fort Classification of facial fractures

In 1901 ;René Le Fort (1869-1951),French surgeon, reported his work on cadaver skulls that were subjected to blunt forces of various magnitudes and directions. He concluded that predictable patterns of fractures follow certain types of injuries. Three predominant types were described.


Le Fort I fractures (horizontal) may result from a force of injury directed low on the maxillary alveolar rim in a downward direction. The fracture extends from the nasal septum to the lateral pyriform rims, travels horizontally above the teeth apices, crosses below the zygomaticomaxillary junction, and traverses the pterygomaxillary junction to interrupt the pterygoid plates.

Le Fort II fractures (pyramidal) may result from a blow to the lower or mid maxilla. Such a fracture has a pyramidal shape and extends from the nasal bridge at or below the nasofrontal suture through the frontal processes of the maxilla, inferolaterally through the lacrimal bones and inferior orbital floor and rim through or near the inferior orbital foramen, and inferiorly through the anterior wall of the maxillary sinus; it then travels under the zygoma, across the pterygomaxillary fissure, and through the pterygoid plates.

Le Fort III fractures (transverse), also termed craniofacial dysjunctions, may follow impact to the nasal bridge or upper maxilla. These fractures start at the nasofrontal and frontomaxillary sutures and extend posteriorly along the medial wall of the orbit through the nasolacrimal groove and ethmoid bones. The thicker sphenoid bone posteriorly usually prevents continuation of the fracture into the optic canal. Instead, the fracture continues along the floor of the orbit along the inferior orbital fissure and continues superolaterally through the lateral orbital wall, through the zygomaticofrontal junction and the zygomatic arch. Intranasally, a branch of the fracture extends through the base of the perpendicular plate of the ethmoid, through the vomer, and through the interface of the pterygoid plates to the base of the sphenoid.

The staging evaluation of Esophageal Cancer

After establishing a diagnosis of esophageal cancer, adequate staging is required, because staging is the most important step in choosing appropriate therapy. More than 50% of patients have unresectable or metastatic disease at the time of presentation. For the others, survival is closely related to the stage of the disease.
The staging evaluation allows patients to be assigned a clinical stage according to the American Joint Committee on Cancer tumor-node-metastasis (TNM) classification. Informed recommendations about therapy and appropriate information regarding prognosis depends on this clinical staging, an assessment that can, however, only approximate the true disease stage.

 Primary Tumor (T)

* TX: Primary tumor cannot be assessed
* T0: No evidence of primary tumor
* Tis: Carcinoma in situ
* T1: Tumor invades lamina propria (T1a) or submucosa (T1b)
* T2: Tumor invades muscularis propria
* T3: Tumor invades adventitia
* T4: Tumor invades adjacent structures

Regional Lymph Nodes (N)

* NX: Regional lymph nodes cannot be assessed
* N0: No regional lymph node metastasis
* N1: Regional lymph node metastasis
* N1a: One to three nodes involved
* N1b: Four to seven nodes involved
* N1c: More than seven nodes involved

Distant Metastasis (M)

* MX: Distant metastasis cannot be assessed
* M0: No distant metastasis
* M1: Distant metastasis
1. Tumors of the lower thoracic esophagus:
- M1a: Metastases in celiac lymph nodes
- M1b: Other distant metastases
2. Tumors of the midthoracic esophagus:
- M1a: Not applicable
- M1b: Nonregional lymph nodes and/or other distant metastases
3. Tumors of the upper thoracic esophagus:
- M1a: Metastases in cervical nodes
- M1b: Other distant metastases

Diagram for Effects of sickle cell anemia

Complications of Sickle cell disease

Medical mnemonic for the Sickle cell disease complications

SICKLE:

Strokes/ Swelling of hands and feet/ Spleen problems
Infections/ Infarctions
Crises (painful, sequestration, aplastic)/ Cholelithiasis/ Chest syndrome/ Chronic hemolysis/ Cardiac problems
Kidney disease
Liver disease/ Lung problems

 Erection (priapism)/ Eye problems (retinopathy)

Synthesis of eicosanoid autacoids

The eicosanoids are an important group of endogenous fatty acid derivatives that are produced from arachidonic acid, a 20-carbon fatty acid lipid in cell membranes. Major families of eicosanoids include the straight-chain derivatives (leukotrienes) and cyclic derivatives (prostacyclin, prostaglandins, and thromboxane). Inhibitors of the eicosanoids are shown in Figure below.