Pathophysiology of Diseases of Abdominal Wall, Inguinal Region, and Suprarenal Glands PDF

Pathophysiology of diseases of (Abdominal wall, Inguinal Region, and Suprarenal glands) Prepared by Dr Ibrahim Mousa Maaroof Higher Diploma student M.B.Ch.B. Dr Sarmad Nadhem Ismael Higher Diploma student M.B.Ch.B. Supervised by Assist. Prof. Dr Baderkhan Saeed Ahmed Assist. Prof. Dr Azhy Muhammed D...

Pathophysiology of diseases of (Abdominal wall, Inguinal Region, and Suprarenal glands) Prepared by Dr Ibrahim Mousa Maaroof Higher Diploma student M.B.Ch.B. Dr Sarmad Nadhem Ismael Higher Diploma student M.B.Ch.B. Supervised by Assist. Prof. Dr Baderkhan Saeed Ahmed Assist. Prof. Dr Azhy Muhammed Dewana 16 January 2024 1 ABDOMINAL WALL AND INGUINAL REGION 16 January 2024 2 TERMINOLOGY A. HERNIA Protrusion of a part or structure through the tissues normally containing it; from the Latin for “rupture” B. REDUCIBILITY 1. Contents of the hernia sac can be returned to their normal location. C. INCARCERATION Nonreducible hernia sac contents that, in the acute setting, may present with obstructive symptoms and pain, among other symptoms. This may also occur chronically and be essentially asymptomatic. D. STRANGULATION Incarcerated hernia with vascular compromise of contents of the sac leading to gangrene and perforation of hollow viscus if left untreated. This is a surgical emergency and is often accompanied by obstructive symptoms (exception is Richter hernia), pain (potentially focal peritonitis), leukocytosis, fever, and skin changes (e.g., warmth, erythema). 16 January 2024 3 INCIDENCE 1. Approximately 5% of all people will develop a hernia in their lifetime. a. Lifetime risk reported variably in the literature: males 5%–24%; females 1%–2% 2. Likelihood of strangulation increases with age. a. Only 1%–3% of all hernias will strangulate. b. Femoral hernias have a significantly greater rate of strangulation at 15%– 20%. 16 January 2024 4 3. Inguinal hernias make up 75% of all abdominal wall hernias. a. Indirect hernias are the most common type of hernia regardless of sex and outnumber direct hernias 2:1 in men. b. Right-sided hernias are more common than left because of the slower descent of the right testicle and the delay in atrophy of the processus vaginalis. 4. Femoral hernias account for 10% of abdominal wall hernias, yet upward of 40% will present as surgical urgency or emergency in the form of an incarcerated or strangulated hernia. a. Predominance of right-sided femoral hernias is thought to be due to the occluding effect of the sigmoid colon on the left femoral canal. 16 January 2024 5 CLASSIFICATION OF HERNIAS A. GROIN HERNIAS 1. Indirect inguinal hernia—the sac exits through internal ring, lateral to the inferior epigastric vessels. Hernia sac is found anteromedial to the spermatic cord in males and the round ligament in female individuals. 2. Direct inguinal hernia—the sac exits through Hesselbach triangle, medial to the inferior epigastric vessels. 3. Pantaloon hernia—inguinal hernia that involves both indirect and direct components straddling the inferior epigastric vessels 4. Femoral hernia—the sac exits through the femoral canal, medial to the femoral vein. 16 January 2024 6 16 January 2024 7 B. VENTRAL HERNIAS 1. Umbilical hernia—This may be congenital or acquired. 2. Epigastric hernia—the sac exits in the midline through the linea alba, above the umbilicus. 3. Incisional hernia—defect of the fascia resulting at the site of a previous fascial closure, most commonly after a midline laparotomy; however, it may develop in the setting of any fascial repair, including those from laparoscopic surgical procedures. 4. Rectus diastasis—not a true hernia but is often mistaken for one. Represents a weakening of the linea alba and stretching of the rectus abdominis muscles away from each other. There is no sac and no true herniation of abdominal contents through this weakened layer. 16 January 2024 8 C. MISCELLANEOUS HERNIAS 1. Amyand hernia—is a rare form of an inguinal hernia (less than 1% of inguinal hernias) which occurs when the appendix is included in the hernial sac and becomes incarcerated. The condition is an eponymous disease named after a French surgeon, Claudius Amyand (1660– 1740), who performed the first successful appendectomy in 1735. 2. Grynfeltt hernia—the sac exits through the superior lumbar triangle. 3. Littre hernia—Inguinal hernia contents include Meckel diverticulum. 4. Obturator hernia—the sac exits through the obturator foramen and compresses the obturator nerve and vessels. 16 January 2024 9 Surgical Pearl: Howship-Romberg sign is pain along medial thigh exacerbated by abduction, extension, and medial rotation of the thigh. This is secondary to compression on the obturator nerve whose anterior branch supplies sensory fibers to the distal medial thigh. This finding is present in only 50% of patients. 5. Parastomal hernia—This hernia is at an ostomy site, more commonly occurring at colostomy sites, in particular, those stomas through the semilunar line. 6. Petit hernia—the sac exits through the inferior lumbar triangle 16 January 2024 10 7. Richter hernia—condition in which one sidewall of a viscus is incorporated into hernia sac, thus the hernia contents may incarcerate and strangulate without causing bowel obstruction symptoms. Bowel may also reduce after incarceration, leading to intraabdominal perforation with peritonitis. 16 January 2024 11 8. Sciatic hernia—the sac exits through the greater or lesser sciatic foramen. 9. Sliding hernia—the wall of the hernia sac is composed of a viscus (commonly sigmoid colon, cecum, or bladder) 10. Spigelian hernia—This abdominal hernia is through the semilunar line of Spigelius (lateral to the rectus abdominis), most commonly at the junction of the semilunar line and the semicircular line of Douglas (the point at which the posterior rectus sheath terminates). 16 January 2024 12 CAUSATIVE FACTORS A. INDIRECT INGUINAL HERNIA Persistence of a patent processus vaginalis is the primary causative factor in pediatric population; in adults, the cause is likely multifactorial. B. DIRECT INGUINAL HERNIA Considered to be an acquired phenomenon related to chronic increases in intraabdominal pressure, placing stress in the area of Hesselbach triangle, as well as inguinal floor weakness 16 January 2024 13 C. FEMORAL HERNIA Similar to the causes of direct inguinal hernias involving chronic increases in abdominal pressure together with anatomic variability. Femoral hernias are particularly at risk for incarceration and subsequent strangulation, given the relative rigidity of the structures that make up the femoral canal. D. CONTRIBUTING FACTORS Contributing factors include obesity, smoking, chronic cough, connective tissue disorders, chronic straining from constipation/obstipation, prostatism, pregnancy, and ascites. 16 January 2024 14 ACUTE GROIN SWELLING Causes and features • Incarcerated groin hernia (inguinal or femoral). May be associated with bowel obstruction; often red, hot, and tender. • Acute epididymo- orchitis (in ). Tenderness is particularly over the spermatic cord and the epididymis. • Torsion of the testis. May present with pain radiating into the groin; however, tenderness is primarily over the scrotum (and affected testis). Testicle is tender, swollen, and high- riding. Elevation of the scrotum, unlike epididymitis, makes the pain worse. 16 January 2024 15 Iliopsoas abscess. Tenderness is primarily below the inguinal ligament; swelling can be fluctuant, associated with RIF or left iliac fossa (LIF) tenderness. • Acute iliofemoral lymphadenopathy (e.g. from infected toenail). Tender diffuse swelling; often multiple palpable lumps (nodes). • Acute saphena varix. Compressible, cough thrill. • Acute complications of femoral artery aneurysm commonly pseudoaneurysm 2° to IV drug abuse or angiography via the groin. 16 January 2024 16 SUPRARENAL GLANDS 16 January 2024 17 ZONA GLOMERULOSA—MINERALOCORTICOIDS A. PHYSIOLOGY 1. Aldosterone secretion is regulated by renin-angiotensin system. a. Juxtaglomerular cells in kidney stimulate renin release with decreased renal blood flow, decreased plasma Na+, and increased sympathetic tone. b. Renin induces conversion of angiotensinogen to angiotensin I. c. Angiotensin I is cleaved by angiotensin-converting enzyme (ACE) in lungs to angiotensin II. d. Angiotensin II is a potent vasoconstrictor and increases aldosterone synthesis/release. e. Aldosterone acts on distal convoluted tubule to increase Na+ reabsorption and H+/K+ excretion. B. PRIMARY ALDOSTERONISM/CONN SYNDROME Pathophysiology: 70% single functional adrenal adenoma, 30% bilateral adrenal hyperplasia (BAH), differential includes renal artery stenosis, cirrhosis, congestive heart failure (CHF), and adrenocortical carcinoma 16 January 2024 18 ZONA FASICULATA—GLUCOCORTICOIDS A. PHYSIOLOGY Cortisol release regulated by hypothalamic-pituitary-adrenal axis a. Hypothalamus secretes corticotropin-releasing hormone (CRH). b. CRH induces the anterior pituitary to secrete ACTH (derived from proopiomelanocortin hormone [POMC]). c. ACTH stimulates secretion of glucocorticoids, mineralocorticoids, and androgens. d. ACTH secretion is stimulated by stress, pain, hypoxia, hypothermia, trauma, and hypoglycemia; basal levels at peak in morning and at nadir in late afternoon. e. Cortisol binds to receptors in cytosol of target cells to stimulate gene transcription. f. Axis is controlled by a negative feedback loop. 16 January 2024 19 CUSHING SYNDROME 1. female predominance (1:8) 2. Pathophysiology: hypercortisolism; can be ACTH independent or dependent a. ACTH independent usually secondary to exogenous steroid use, adrenal adenoma/carcinoma, or BAH b. ACTH dependent: 70% are Cushing disease (pituitary adenoma) that causes BAH; can also have ectopic ACTH hypersecretion from carcinoid, bronchial tumors, primary adrenal neoplasm, or ectopic CRH production 16 January 2024 20 ZONA RETICULARIS—ANDROGENS A. PHYSIOLOGY 1. ACTH stimulates production of androgens (dihydroepiandrosterone [DHEA], androstenedione, testosterone, and estrogen) from 17- hydroxypregnenolone; during development adrenal androgens promote male genitalia formation. B. ANDROGEN-BASED TUMORS 1. Virilizing tumors a. Present in children with early growth spurts, premature development of facial and pubic hair, acne, and enlarged genitals b. Present in females with hirsutism, amenorrhea, infertility, masculine features c. Can be hard to diagnose in males d. Diagnosed with elevated plasma or urine DHEA/17-ketosteroids 2. Feminizing tumors a. Males present at 30–50 years of age with gynecomastia, impotence, and testicular atrophy. b. Women present with irregular menses and uterine bleeding. c. Female children present with breast enlargement and early menarche. d. Elevated urine 17-ketosteroids and estrogens are diagnostic. 16 January 2024 21 ADRENOCORTICAL CANCER 1. Presentation: rare; bimodal age distribution in childhood and 30–40 years of age; 50% have nonfunctioning tumors; if functioning tumors, present with Cushing syndrome and virilizing factors 2. Metastatic disease to the adrenals includes lung cancer (small cell carcinoma), renal cell carcinoma, melanoma, gastric adenocarcinoma, hepatocellular adenocarcinoma, esophageal adenocarcinoma, and breast cancer. 16 January 2024 22 ADRENAL MEDULLA A. PHYSIOLOGY 1. It produces and releases catecholamine hormones—epinephrine, norepinephrine, and dopamine. 2. Metabolism in liver and kidneys forms metabolites metanephrines, normetanephrines, and vanillylmandelic acid. B. PHEOCHROMOCYTOMA—CATECHOLAMINE-SECRETING TUMOR a. Located in adrenals or along sympathetic ganglia, including organ of Zuckerkandl, neck, mediastinum, abdomen, and pelvis b. Follows “rule of 10s”—10% bilateral, familial, malignant, extraadrenal, and present in children c. Associated with multiple endocrine neoplasia (MEN) IIa and IIb, von Hippel-Lindau disease, Sturge-Weber syndrome; hereditary tumors tend to be multiple and bilateral Pathophysiology: Adrenal tumors secrete epinephrine; extraadrenal sites secrete norepinephrine because they lack phenylethanolamine-Nmethyltransferase (converts norepinephrine to epinephrine). 16 January 2024 23 INCIDENTALOMA EPIDEMIOLOGY 1. Adrenal lesion found during routine imaging; excludes tumors discovered for evaluation of hormone hypersecretion or staging of known cancers 2. Incidence 0.4%–4% 3. Differential includes: a. Benign functioning lesion—aldosteronoma, cortisol- or sex steroid–producing adenoma, pheochromocytoma b. Malignant functioning lesion—adrenocortical cancer, malignant pheochromocytoma c. Benign nonfunctioning lesion—cortical adenoma, myelolipoma, cyst, ganglioneuroma, hemorrhage d. Malignant nonfunctioning lesion—metastasis 16 January 2024 24 ADRENAL INSUFFICIENCY PATHOPHYSIOLOGY AND CLINICAL PRESENTATION 1. Primary (adrenal source) or secondary (ACTH deficiency) 2. It can be caused by autoimmune disease, infections, metastatic deposits, hemorrhage (Waterhouse-Friderichsen syndrome from fulminant meningococcemia), trauma, severe stress, or exogenous steroid discontinuation. 3. Patients often present with symptoms that mimic sepsis—fever, nausea, vomiting, lethargy, abdominal pain, hypotension—after recent steroid withdrawal or significant clinical stress. 16 January 2024 25 REFERENCES • O'Connell, P.R., McCaskie, A.W., & Sayers, R.D. (Eds.). (2023). Bailey & Love's Short Practice of Surgery - 28th Edition • Brunicardi F, & Andersen D.K., & Billiar T.R., & Dunn D.L., & Kao L.S., & Hunter J.G., & Matthews J.B., & Pollock R.E.(Eds.), (2019). Schwartz's Principles of Surgery, 11e. 16 January 2024 26 Thank You 16 January 2024 27