Acute Acalculous Cholecystitis

Acute acalculous cholecystitis is acute gallbladder inflammation and necroinflammatory injury occurring without gallstones.

It predominantly affects critically ill patients and is associated with major trauma, burns, sepsis, prolonged ventilation, vasopressor exposure, major surgery and prolonged fasting or parenteral nutrition.

Pathogenesis involves gallbladder stasis, impaired perfusion, ischaemic injury and secondary infection.

Acalculous disease has a greater tendency toward gangrene and perforation than routine calculous cholecystitis and may be difficult to recognise because the patient is often already critically ill.

A conscious patient may develop right upper quadrant pain, fever and tenderness.

In an intubated or critically ill patient, presentation may consist only of:

Unexplained fever
Increasing inflammatory markers
New sepsis
Haemodynamic deterioration
Failure to improve despite treatment of another presumed infection

The abdominal examination may be minimally informative.

Progression to gangrene or perforation may occur before classical local signs become obvious.

Right upper quadrant ultrasound: first line investigation; look for gallbladder distension and inflammatory wall changes in the absence of stones.

CT is useful when ultrasound is equivocal or when another intra abdominal septic source must be excluded.

Because critically ill patients can develop nonspecific gallbladder wall thickening from hypoalbuminaemia, heart failure or systemic oedema, imaging must be interpreted alongside the clinical trajectory.

Treat this as a potential source control problem rather than relying on antibiotics alone.

Correct haemodynamic instability and optimise tissue perfusion.

Start broad antimicrobial therapy.

A practical regimen is:

Piperacillin tazobactam 4.5 g IV every 8 hours by extended infusion, adjusted for renal function.

In a stable operative candidate, laparoscopic cholecystectomy provides definitive treatment.

In the typical critically ill or physiologically unstable patient, percutaneous cholecystostomy is preferred initial source control because it can decompress and drain the infected or ischaemic gallbladder without major general anaesthesia.

A transhepatic catheter route is often preferred because it provides greater catheter stability and limits bile leakage.

Clinical improvement should follow drainage. Persistent fever, shock or organ dysfunction requires reassessment for:

Malpositioned or obstructed drain
Gangrenous gallbladder
Gallbladder perforation
Another septic source

Gangrene, free perforation, biliary peritonitis or failure of percutaneous source control requires operative treatment despite high surgical risk.

Patients who recover and become acceptable operative candidates should be reassessed for definitive laparoscopic cholecystectomy.

Pancreatic Cancer

Predominantly pancreatic ductal adenocarcinoma (over 90% of cases), most often arising in the head of the pancreas.

Risk factors include smoking, chronic pancreatitis, long-standing diabetes, obesity, and hereditary syndromes (BRCA1/2, Peutz-Jeghers, hereditary pancreatitis, Lynch syndrome).

Carries a poor prognosis overall, reflecting typically late presentation and early micrometastatic spread even in apparently localized disease.

Symptoms are often vague and nonspecific until the tumor is locally advanced.

Painless progressive jaundice is classic for head of pancreas tumors, from biliary obstruction; a palpable, nontender, distended gallbladder (Courvoisier's sign) supports malignant rather than gallstone related obstruction.

Other features include epigastric or back pain (suggesting retroperitoneal or neural invasion, generally a marker of advanced disease), unintentional weight loss, new onset diabetes or sudden worsening of previously stable diabetes in an older adult, anorexia, and, less commonly, migratory thrombophlebitis (Trousseau's sign of malignancy).

Body and tail tumors present later, typically with pain and weight loss rather than jaundice, since biliary obstruction is absent.

Contrast enhanced CT pancreas protocol is the primary staging investigation, assessing resectability by evaluating relationships to the superior mesenteric artery, superior mesenteric vein, portal vein, and celiac axis.

CA19-9 is used for monitoring response to treatment rather than diagnosis (it lacks sufficient sensitivity and specificity to screen or diagnose, and can be falsely elevated by biliary obstruction alone).

Endoscopic ultrasound with fine needle aspiration provides tissue diagnosis and assesses vascular invasion with high accuracy. MRCP or ERCP characterizes biliary anatomy and allows stenting for symptomatic jaundice.

PET CT and staging laparoscopy assess for occult metastatic or peritoneal disease before committing to major resection.

Differentials include chronic pancreatitis (particularly autoimmune pancreatitis, which can closely mimic pancreatic cancer radiologically), other periampullary tumors (ampullary, distal cholangiocarcinoma, duodenal), and pancreatic neuroendocrine tumors (distinct biology and management).

Resectable disease (roughly 15 to 20% of cases at diagnosis) is treated with pancreaticoduodenectomy (Whipple procedure) for head of pancreas tumors, or distal pancreatectomy with splenectomy for body and tail tumors, followed by adjuvant chemotherapy (commonly modified FOLFIRINOX or gemcitabine based regimens).

Borderline resectable disease receives neoadjuvant chemotherapy, sometimes with radiotherapy, to downstage before surgery is reconsidered. Locally advanced unresectable disease is treated with systemic chemotherapy, with radiotherapy considered for local control in selected patients.

Metastatic disease is managed with palliative chemotherapy (FOLFIRINOX in fit patients, gemcitabine with nab-paclitaxel as an alternative, or gemcitabine alone in frailer patients), guided by performance status.

Palliative measures address the dominant symptom burden: biliary stenting (endoscopic or percutaneous) for jaundice, duodenal stenting or surgical bypass for gastric outlet obstruction, and aggressive pain control including celiac plexus block for refractory pain.

Pancreatic enzyme replacement is given for associated exocrine insufficiency, and nutritional support is prioritized throughout given the profound catabolic burden of this disease.

Referral: hepatobiliary and pancreatic surgery and oncology multidisciplinary team for all suspected cases at the point of diagnosis, given the narrow and time sensitive resectability window.

Acute Acalculous Cholecystitis

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management