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Sunday, November 20, 2022

Neurogenic Disorders of Mouth and Pharynx

Neurogenic Disorders of Mouth and Pharynx


Neurogenic Disorders of Mouth and Pharynx
Neurogenic Disorders of Mouth and Pharynx

The motor innervation to the pharynx and almost all of the sensory supply is through the pharyngeal plexus, which is formed by branches of cranial nerves IX and X. Disturbances to the neural conduction of both of these cranial nerves will be reviewed together because anatomically and functionally there is considerable overlap in their conductive patterns.
Renin-Angiotensin-Aldosterone System

Renin-Angiotensin-Aldosterone System


Renin – Angiotensin – Aldosterone System
Oxytocin, Biosynthesis, Parturition, Milk ejection
Clinical background
Activation of the renin – angiotensin – aldosterone system is an important mechanism in the pathophysiology of heart failure as part of the counter-regulatory neurohormonal response to impaired cardiac output. In conjunction with sympathetic drive, there is an increase in peripheral vasoconstriction mediated by increased sympathetic tone and angiotensin II coupled with the salt and water retention induced by elevated aldosterone concentrations. Together, these increase preload and afterload on the heart, further compromising impaired ventricular function and setting up a vicious circle of heart failure.
Pulmonary Hypertension

Pulmonary Hypertension


Pulmonary Hypertension
Pulmonary Hypertension, Types of pulmonary hypertension, Pulmonary arterial hypertension,

The mean pressure in the pulmonary artery (mPAP) in a normal resting adult is 16 mmHg. Pulmonary hypertension (PH) is defined as a mPAP exceeding 25 mmHg at rest. The increased PAP can be due to a rise in pulmonary vascular resistance (PVR), increased pulmonary blood flow due to a systemic to pulmonary shunt (Eisenmenger’s syndrome; see Chapter 55) or back pressure from the left heart. PH increases right ventricular afterload, eventually leading to right heart failure.
Blood Supply of Mouth and Pharynx

Blood Supply of Mouth and Pharynx


Blood Supply of Mouth and Pharynx

Blood Supply of Mouth and Pharynx
The external carotid artery and its branches are responsible for essentially the total arterial supply of the mouth and pharynx. The common carotid artery, arising from the brachiocephalic trunk on the right and the arch of the aorta on the left, bifurcates at the level of the superior border of the thyroid cartilage into external and internal carotid arteries. From here the external carotid artery courses superiorly to a point posterior to the neck of the mandible, dividing in the substance of the parotid gland into the maxillary and superficial temporal arteries. The parotid gland surrounds part of the external carotid artery and the beginnings of its terminal branches. The gland gets many small branches from these vessels in its substance.
Masseter, Temporalis and Infratemporal Fossa

Masseter, Temporalis and Infratemporal Fossa


Masseter, Temporalis and Infratemporal Fossa

Masseter, showing its attachment to the zygomatic arch and the angle of the mandible, after removal of the parotid gland.
Masseter
Masseter (Fig. 7.29) attaches along the length of the zygomatic arch and its fibres slope downwards and backwards to the lateral surface of the ramus of the mandible adjacent to the angle (Fig. 7.31). This muscle is a powerful elevator of the mandible and is easily palpated when the teeth are clenched. It is supplied by the masseteric branch of the mandibular (V3) division of the trigeminal nerve.
Muscles Involved in Mastication

Muscles Involved in Mastication


Muscles Involved in Mastication
Muscles Involved in Mastication, superficial part, deep portion, temporal fascia,  temporalis muscle, lateral pterygoid muscle, medial pterygoid muscle, orbicularis oris muscle
Chewing, or mastication, is one of the important functions carried on in the mouth, and a number of muscles are involved either directly or indirectly in this activity. However, the four muscles that are primarily responsible for the forceful chewing movements of the mandible are classified by most authors as the “muscles of mastication.” These are the masseter, temporalis, lateral pterygoid, and medial pterygoid muscles.

Thursday, November 10, 2022

PULMONARY METASTASES

PULMONARY METASTASES

PULMONARY METASTASES

PULMONARY METASTASES

Lung metastasis occurs in one-third to one-half of all patients with a non-lung primary malignancy at the time of death based on autopsy data. Primary malignancies with the greatest tendency to metastasize to the lung are breast, lung, melanoma, osteosarcoma, choriocarcinoma, and germ cell tumors. Most pulmonary metastases are caused by common malignancies that include breast, colorectal, prostate, and renal cell carcinomas. Recent studies have demonstrated a high number of circulatory tumor cells in many different primary cancers. These are believed to lodge in the small pulmonary vessels, proliferate, and ultimately form nodules. Multiple pulmonary nodules are the most common manifestations of pulmonary metastasis. They are frequently spherical and variable in size. Multiple nodules larger than 1 cm in diameter are more likely to be malignant than benign. Larger lesions or “cannonballs” are a classic manifestation. Approximately 90% of individuals with pulmonary metastasis have or had a known primary malignancy. Solitary pulmonary metastasis may occur and in general should be treated as a possible new primary lung cancer if no other metastatic sites are identified and benign disease cannot be confirmed. Surgical resection is the treatment of choice in medically fit individuals.

Cavitation of metastatic nodules occurs in 5% or fewer of cases and is most commonly associated with squamous cell carcinoma of the head and neck, esophagus, and cervix. Sarcomas, especially osteosarcoma, are well known to cavitate. Cavitation has also been observed with adenocarcinoma of colorectal origin and transitional cell carcinoma of the bladder. Pneumothorax occurs with cavitary pulmonary metastasis in the subpleural location because of rupture into the pleural space. Osteosarcoma is the most common metastatic malignancy to cause a spontaneous pneumothorax. A spontaneous pneumothorax in a patient with a history of a sarcoma should raise the question of occult pulmonary metastasis. Calcification of nodules, although generally a sign of benignity, has been observed in metastatic chondrosarcoma and osteosarcoma and very rarely from other primary sites.

Airspace consolidation is most often seen with metastatic adenocarcinoma for gastrointestinal sources. The adenocarcinoma may spread along intact alveolar structures (lepidic growth) and form consolidation with air bronchograms or extensive ground-glass opacities. Sometimes this pattern is confused with primary bronchioloalveolar cell lung cancer.

Lymphangitic pulmonary metastasis is most commonly associated with adenocarcinoma. It is believed to be caused by hematogenous spread of tumor to the periphery of the lung and subsequent lymphangitic spread centrally toward the hilum. By this mechanism, it is most commonly bilateral. Some cases may develop because of hilar tumor involvement with centrifugal spread and account for cases of unilateral lymphangitic spread. The primary malignancies that account for most lymphangitic metastases are the lung, breast, and gastrointestinal tract, especially the stomach. The chest radiograph may reveal increased interstitial markings or demonstrate a sunburst pattern radiating from the hilar area. High-resolution computed tomography is more sensitive at detecting lymphangitic disease than chest radiography. Characteristic findings are a thickened interlobular septum with beading with or without polygonal formations. A thickened subpleural interstitium is also a frequent occurrence.

Patients will usually present with dyspnea with or without cough. The chest radiograph may be normal. Bronchoscopy with bronchoalveolar lavage and transbronchoscopic biopsy will result in a high diagnostic yield. The prognosis of lymphangitic carcinoma is generally poor unless the patient has a chemoresponsive tumor such as breast cancer, lymphoma, or choriocarcinoma.


ADENOCARCINOMA OF ESOPHAGUS

ADENOCARCINOMA OF ESOPHAGUS

ADENOCARCINOMA OF ESOPHAGUS

ADENOCARCINOMA OF ESOPHAGUS
Adenocarcinoma of the esophagus generally, if not consistently, arises from Barrett esophagus, that is, metaplastic intestinal epithelium in the esophagus. It therefore has the same risk factors as Barrett esophagus, such as chronic gastroesophageal reflux, white race, male gender, central obesity, and cigarette smoking. It may arise anywhere within the region of the Barrett esophagus; its origin thereby determines its potential location within the esophagus. In other words, in patients with short­segment Barrett esophagus, cancer will develop in the distal esophagus, whereas in patients with long­segment Barrett esophagus, both the distal and middle thirds are susceptible to neoplastic transformation. Adenocarcinoma rarely develops in the proximal esophagus. The most common presenting symptom is dysphagia due to narrowing of the lumen either by the mass lesion itself or as a malignant stricture. Some patients may have iron deficiency anemia due to occult bleeding from tumor areas of friability and ulceration. Weight loss and early satiety are also common, the latter due to infiltration and fixation of the proximal stomach with loss of gastric accommodation function. Notably, these patients do not usually have reflux symptoms; if they do, symptoms are mild enough or far enough in the past that patients have not undergone screening endoscopy for Barrett esophagus. This may explain why less than 10% of patients found to develop esophageal adenocarcinoma are enrolled in a Barrett esophagus surveillance program.

EUKARYOTIC CELLS

EUKARYOTIC CELLS

EUKARYOTIC CELLS

Structures of animal and plant cells Both animal and plant cells are surrounded by a plasma membrane and contain a nucleus
Figure 1.6 Structures of animal and plant cells Both animal and plant cells are surrounded by a plasma membrane and contain a nucleus, a cytoskeleton, and many cytoplasmic organelles in common. Plant cells are also surrounded by a cell wall and contain chloroplasts and large vacuoles.

Like prokaryotic cells, all eukaryotic cells are surrounded by a plasma membrane and contain ribosomes. However, eukaryotic cells are much more complex and contain a nucleus and a variety of cytoplasmic organelles (Figure 1.6). The largest and most prominent organelle of eukaryotic cells is the nucleus, with a diameter of approximately 5 μm. The nucleus contains the genetic information of the cell, which in eukaryotes is organized as linear rather than circular DNA molecules. The nucleus is the site of DNA replication and of RNA synthesis; the translation of RNA into proteins takes place on ribosomes in the cytoplasm.

SARCOID

SARCOID

SARCOID

CUTANEOUS MANIFESTATIONS OF SARCOID
CUTANEOUS MANIFESTATIONS OF SARCOID

Sarcoid, or sarcoidosis, is a relatively common condition that can affect many organ systems. There is a wide spectrum of disease activity, from localized skin disease to widespread involvement of the integumentary, pulmonary, cardiac, renal, gastrointestinal, ophthalmic, endocrine, neurological, and lymphatic systems. However, most cases are mild in nature and can be controlled with proper care. Although an infectious etiology has often been theorized, no conclusive evidence has been established. This idiopathic condition can produce multiple skin findings. The skin findings should cause the attending physician to look for systemic involvement.

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