Nausea: Clinical Meaning

Ear Infection (Otitis Media)

Ear infections occur when bacteria or viruses infect the middle ear, causing pain, fluid buildup, and temporary hearing loss. They are especially common in children but can affect adults as well.

Gastritis

Gastritis is inflammation of the stomach lining, commonly caused by H. pylori infection, prolonged NSAID use, or excessive alcohol. It can be acute (sudden) or chronic (long-term) and may lead to peptic ulcers if untreated.

Peptic Ulcer

Peptic ulcers are open sores that develop on the inner lining of the stomach or the upper part of the small intestine. H. pylori infection and long-term NSAID use are the most common causes. They cause burning stomach pain, especially when the stomach is empty.

GERD (Acid Reflux)

Gastroesophageal reflux disease (GERD) is a chronic condition where stomach acid flows back into the esophagus, causing heartburn, regurgitation, and chest discomfort. Long-term untreated GERD can lead to esophageal damage.

Migraine

Migraine is a neurological disorder characterized by recurrent, severe headaches often accompanied by nausea, vomiting, and sensitivity to light and sound. Attacks can last 4–72 hours and significantly impair daily functioning.

Heart Attack (Myocardial Infarction)

A heart attack occurs when blood flow to part of the heart muscle is blocked, usually by a blood clot in a coronary artery. Immediate treatment is critical. Symptoms include chest pain, pressure radiating to the arm or jaw, sweating, and nausea.

Hepatitis

Hepatitis is inflammation of the liver, most commonly caused by viral infections (Hepatitis A, B, C, D, E). It can also result from alcohol use, toxins, or autoimmune conditions. Symptoms include jaundice, fatigue, abdominal pain, and dark urine.

Liver Cirrhosis

Liver cirrhosis is advanced scarring (fibrosis) of the liver caused by long-term damage from hepatitis, alcohol abuse, or fatty liver disease. As scar tissue replaces healthy tissue, the liver loses its ability to function properly.

Pancreatitis

Pancreatitis is inflammation of the pancreas, which can be acute (sudden) or chronic (long-term). Gallstones and heavy alcohol use are the most common causes. It causes severe upper abdominal pain that may radiate to the back, nausea, and vomiting.

Cholecystitis

Cholecystitis is inflammation of the gallbladder, usually caused by gallstones blocking the bile duct. It causes severe pain in the upper right abdomen, nausea, vomiting, and fever. Acute cholecystitis often requires surgery.

Gallstones

Gallstones are hardened deposits of digestive fluid that form in the gallbladder. They can range from sand-grain size to golf-ball size. Many are asymptomatic, but when they block a duct they cause severe 'biliary colic' pain in the upper right abdomen.

Kidney Stones

Kidney stones are hard mineral deposits that form in the kidneys and can cause severe pain when passing through the urinary tract. The pain typically starts in the back or side and radiates to the lower abdomen. Increased fluid intake is key to prevention.

Endometriosis

Endometriosis is a condition where tissue similar to the uterine lining grows outside the uterus. It causes chronic pelvic pain, especially during menstruation, and can lead to infertility. It affects approximately 10% of reproductive-age women.

Multiple Myeloma

Multiple myeloma is a cancer of plasma cells in the bone marrow, causing bone pain, anemia, kidney damage, and recurrent infections. Symptoms arise from the accumulation of abnormal plasma cells.

Liver Cancer (Hepatocellular Carcinoma)

Hepatocellular carcinoma typically develops in the setting of chronic liver disease or cirrhosis due to hepatitis B, hepatitis C, or alcohol. It is a leading cause of cancer death globally.

Pancreatic Cancer

Pancreatic cancer has one of the lowest survival rates of all cancers, largely due to late-stage diagnosis. Symptoms include jaundice, weight loss, abdominal pain, and new-onset diabetes; most cases are adenocarcinomas.

Stomach Cancer (Gastric Cancer)

Gastric cancer is more common in East Asia and is strongly associated with H. pylori infection, smoking, and salt-preserved foods. It often presents late with weight loss, early satiety, and abdominal pain.

Brain Tumor

Brain tumors can be primary (arising in the brain) or metastatic (spreading from elsewhere). Glioblastoma is the most common malignant primary brain tumor, causing headaches, seizures, and progressive neurological deficits.

Bile Duct Cancer (Cholangiocarcinoma)

Cholangiocarcinoma arises from the bile duct epithelium and often presents with obstructive jaundice, weight loss, and abdominal pain. It is typically diagnosed at an advanced stage with limited treatment options.

Hypotension (Low Blood Pressure)

Hypotension is defined as blood pressure below 90/60 mmHg, causing dizziness, fainting, and fatigue. Causes include dehydration, prolonged standing (orthostatic hypotension), heart problems, and certain medications.

Meningitis

Meningitis is inflammation of the meninges (membranes surrounding the brain and spinal cord), caused by bacteria, viruses, or fungi. Bacterial meningitis is a medical emergency causing severe headache, neck stiffness, fever, and potentially fatal if untreated.

Encephalitis

Encephalitis is inflammation of the brain parenchyma, most commonly caused by viral infections (herpes simplex, enteroviruses). It presents with fever, altered consciousness, seizures, and focal neurological deficits; early antiviral treatment is crucial.

Malaria

Malaria is a life-threatening parasitic disease transmitted by Anopheles mosquitoes, causing cyclical fever, chills, and anemia. Plasmodium falciparum causes the most severe form; artemisinin-based combination therapy is the first-line treatment.

Dengue Fever

Dengue fever is a mosquito-borne viral infection causing high fever, severe headache, muscle and joint pain, and a characteristic skin rash. Dengue hemorrhagic fever is a severe form with bleeding and organ impairment.

Typhoid Fever

Typhoid fever is caused by Salmonella typhi, transmitted through contaminated food and water, causing sustained fever, abdominal pain, and rose spots. Antibiotic treatment is effective; vaccination is recommended for travellers to endemic areas.

Hepatitis C

Hepatitis C is a blood-borne viral infection causing chronic liver inflammation that can progress to cirrhosis and liver cancer over decades. Direct-acting antiviral therapy achieves cure rates above 95%.

Appendicitis

Appendicitis is inflammation of the appendix causing progressive right lower quadrant abdominal pain, nausea, fever, and rebound tenderness. Perforation risk increases with delayed treatment; surgical removal (appendectomy) is standard care.

Norovirus (Stomach Flu)

Norovirus is the leading cause of acute gastroenteritis worldwide, spreading through contaminated food, water, and surfaces. It causes sudden-onset vomiting, diarrhea, and stomach cramps lasting 1-3 days; hydration is the mainstay of treatment.

Salmonellosis

Salmonellosis is a foodborne illness caused by Salmonella bacteria, typically from contaminated poultry, eggs, or raw produce. Symptoms include diarrhea, fever, and abdominal cramps beginning 6-48 hours after exposure; most resolve within a week.

Celiac Disease

Celiac disease is an autoimmune reaction to gluten that damages the small intestine villi, impairing nutrient absorption. Symptoms include diarrhea, bloating, weight loss, and fatigue; strict gluten-free diet is the only treatment.

Diverticulitis

Diverticulitis occurs when diverticula (small pouches in the colon wall) become inflamed or infected, causing left lower quadrant pain, fever, and bowel changes. Uncomplicated cases are treated with antibiotics; perforation or abscess may require surgery.

Intestinal Obstruction

Intestinal obstruction is blockage of the small or large bowel, causing abdominal pain, distension, vomiting, and inability to pass gas or stool. Adhesions and hernias are the most common causes; emergency surgery may be required.

Non-Alcoholic Fatty Liver Disease (NAFLD)

NAFLD is the accumulation of fat in liver cells not caused by alcohol, affecting up to 25% of adults globally. It ranges from simple steatosis to NASH (non-alcoholic steatohepatitis), which can progress to cirrhosis; lifestyle modification is the primary treatment.

SIBO (Small Intestinal Bacterial Overgrowth)

SIBO occurs when excessive bacteria colonize the small intestine, causing bloating, abdominal pain, diarrhea, and malabsorption. It is diagnosed with breath testing and treated with antibiotics and dietary modification.

Gastroparesis

Gastroparesis is delayed gastric emptying without mechanical obstruction, causing early satiety, nausea, vomiting, and abdominal discomfort. Diabetes is the most common cause; prokinetic medications and dietary modifications are the mainstay of treatment.

Dumping Syndrome

Dumping syndrome occurs after gastric surgery when food moves too quickly from the stomach into the small intestine, causing nausea, diarrhea, sweating, and dizziness after meals. Dietary modifications and slower eating are primary management strategies.

Microscopic Colitis

Microscopic colitis causes chronic watery diarrhea with normal colonoscopy appearance but characteristic changes on biopsy (collagenous or lymphocytic colitis). NSAIDs, PPIs, and smoking are risk factors; budesonide is effective treatment.

Mesenteric Ischemia

Mesenteric ischemia is inadequate blood supply to the small intestine, causing severe abdominal pain out of proportion to physical findings. Acute mesenteric ischemia is a surgical emergency; chronic forms cause postprandial pain and weight loss.

Type 1 Diabetes

Type 1 diabetes is an autoimmune disease in which the immune system destroys insulin-producing beta cells in the pancreas, requiring lifelong insulin therapy. It typically develops in childhood or adolescence and accounts for 5-10% of all diabetes cases.

Addison's Disease

Addison's disease is primary adrenal insufficiency causing insufficient production of cortisol and aldosterone. Symptoms include fatigue, weight loss, hyperpigmentation, low blood pressure, and salt craving; lifelong hormone replacement is required.

Hyperparathyroidism

Primary hyperparathyroidism is caused by overactive parathyroid glands producing excess PTH, leading to hypercalcemia, bone loss, kidney stones, and GI symptoms. Most cases are caused by a benign parathyroid adenoma.

Chronic Kidney Disease (CKD)

CKD is progressive, irreversible loss of kidney function over months to years, classified in stages 1-5 based on GFR. Diabetes and hypertension are the leading causes; management focuses on slowing progression and managing complications.

Acute Kidney Injury (AKI)

AKI is a sudden decrease in kidney function over hours to days, causing accumulation of waste products and fluid and electrolyte imbalances. Pre-renal (dehydration), intrinsic renal, and post-renal (obstruction) causes must be distinguished.

Glomerulonephritis

Glomerulonephritis is inflammation of the glomeruli causing hematuria, proteinuria, hypertension, and impaired kidney function. It can be acute (post-streptococcal) or chronic; IgA nephropathy is the most common form worldwide.

Nephrotic Syndrome

Nephrotic syndrome is characterized by massive proteinuria (>3.5g/day), hypoalbuminemia, edema, and hyperlipidemia. Causes include minimal change disease (children), membranous nephropathy, and diabetic nephropathy; steroids and immunosuppressants are used.

Hydronephrosis

Hydronephrosis is dilation of the renal collecting system due to obstruction of urine flow (kidney stones, stricture, tumor). If bilateral or complete, it can cause acute kidney injury; treatment addresses the underlying obstruction.

Bulimia Nervosa

Bulimia nervosa involves recurrent episodes of binge eating followed by compensatory behaviors (purging, laxative use, excessive exercise). Dental erosion, electrolyte abnormalities, and esophageal damage are common complications; CBT is first-line treatment.

Glaucoma

Glaucoma is a group of eye diseases causing progressive optic nerve damage, usually related to elevated intraocular pressure, leading to irreversible vision loss starting with peripheral vision. Eye drops to lower IOP, laser, or surgery are treatments.

Menière's Disease

Menière's disease is a chronic inner ear disorder causing episodic vertigo, fluctuating hearing loss, tinnitus, and aural fullness. It results from abnormal fluid pressure in the inner ear; low-sodium diet, diuretics, and vestibular rehabilitation are treatments.

Labyrinthitis

Labyrinthitis is inflammation of the inner ear labyrinth, usually following viral infection, causing acute vertigo, nausea, and hearing loss. Most cases resolve within weeks; vestibular exercises accelerate recovery.

Ovarian Cysts

Ovarian cysts are fluid-filled sacs on or in the ovary, most of which are benign and resolve spontaneously. Symptomatic cysts cause pelvic pain, bloating, and pressure; large or persistent cysts may require surgical evaluation.

Preeclampsia

Preeclampsia is a pregnancy complication characterized by hypertension and proteinuria after 20 weeks gestation, potentially progressing to eclampsia (seizures) and multi-organ failure. Delivery is the definitive treatment; low-dose aspirin is preventive in high-risk women.

Giardiasis

Giardiasis is a common intestinal infection caused by the protozoan parasite Giardia lamblia, transmitted through contaminated water or food. It presents with chronic diarrhoea, bloating, and malabsorption, and is treated with metronidazole or tinidazole.

Enterobiasis (Pinworm Infection)

Enterobiasis is the most common helminthic infection in temperate countries, caused by Enterobius vermicularis. It predominantly affects children and presents with intense nocturnal perianal itching. Treatment is with mebendazole or albendazole.

Ascariasis

Ascariasis is the most prevalent human helminthic infection worldwide, caused by Ascaris lumbricoides. It can cause pulmonary symptoms during larval migration and intestinal obstruction in heavy infections. Albendazole is the drug of choice.

Trichinellosis

Trichinellosis is caused by Trichinella spiralis larvae encysted in muscle tissue, typically acquired from eating undercooked pork or wild game. It presents with fever, periorbital oedema, and severe myalgia. Treatment includes mebendazole and corticosteroids.

Echinococcosis (Hydatid Disease)

Echinococcosis is caused by larval stages of Echinococcus tapeworms, forming slowly growing cysts primarily in the liver and lungs. It is acquired from contact with infected dogs or contaminated food. Surgical removal and albendazole are the main treatments.

Taeniasis (Tapeworm Infection)

Taeniasis is intestinal infection by Taenia solium or Taenia saginata tapeworms, acquired by eating undercooked pork or beef. Symptoms include abdominal discomfort and weight loss. Neurocysticercosis (T. solium larvae in the CNS) is the most severe complication. Praziquantel is curative.

Food Poisoning

Food poisoning is an illness caused by consuming contaminated food or water. Symptoms typically begin within hours to days of exposure and range from mild discomfort to severe dehydration.

Lactose Intolerance

Lactose intolerance is the inability to fully digest lactose due to insufficient lactase enzyme production. It causes digestive symptoms after dairy consumption but is manageable.

Dehydration

Dehydration occurs when the body loses more fluid than it takes in. Even mild dehydration (1-2% body weight) can impair cognitive and physical performance.

Heat Exhaustion

Heat exhaustion is a heat-related illness after prolonged exposure to high temperatures with dehydration. It is a precursor to heat stroke and requires prompt cooling and rehydration.

Hypercalcemia

Hypercalcemia is elevated blood calcium, most commonly caused by overactive parathyroid glands or cancer. Symptoms follow the mnemonic 'bones, stones, groans, and psychic moans'.

Adrenal Insufficiency

Adrenal insufficiency occurs when adrenal glands fail to produce sufficient cortisol. Primary (Addison's disease) is from adrenal damage; secondary is from pituitary or hypothalamic dysfunction.

Epididymitis

Epididymitis is inflammation of the epididymis. In men under 35, STIs are the most common cause; in older men, urinary tract bacteria predominate. It requires prompt antibiotic treatment.

Kidney Infection (Pyelonephritis)

Pyelonephritis is bacterial infection of one or both kidneys, usually ascending from a bladder infection. It requires prompt antibiotics to prevent kidney damage and sepsis.

BPPV (Benign Paroxysmal Positional Vertigo)

BPPV is the most common cause of vertigo, caused by displaced calcium crystals in the inner ear. It causes brief but intense vertigo triggered by head position changes, treatable with repositioning maneuvers.

Labyrinthitis

Labyrinthitis is inflammation of the inner ear labyrinth, typically following a viral infection. It causes sudden severe vertigo, hearing loss, and tinnitus, significantly impacting daily functioning.

Pelvic Inflammatory Disease (PID)

PID is an infection of the female reproductive organs, usually caused by sexually transmitted bacteria. Untreated, it can lead to infertility, ectopic pregnancy, and chronic pelvic pain.

Viral Meningitis

Viral meningitis is inflammation of the membranes surrounding the brain and spinal cord caused by viruses. Less severe than bacterial meningitis, most cases resolve without specific treatment.

Hepatitis A

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus, transmitted through contaminated food and water. Unlike hepatitis B and C, it does not cause chronic disease.

Salmonella Infection

Salmonellosis is a common bacterial food poisoning caused by Salmonella bacteria. It typically causes diarrhea, fever, and stomach cramps beginning 12-72 hours after infection.

Anaphylaxis

Anaphylaxis is a severe, life-threatening allergic reaction requiring immediate emergency treatment with epinephrine. Common triggers include foods, insect stings, medications, and latex.

Food Allergy

Food allergies are immune system reactions that occur after eating a specific food. Even trace amounts can trigger signs and symptoms, including digestive problems, hives, or swollen airways.

Chronic Vertigo

Chronic vertigo encompasses multiple conditions causing persistent or recurrent episodes of dizziness and spinning sensation. Common causes include BPPV, Meniere's disease, vestibular migraine, and labyrinthitis.

Post-Concussion Syndrome

Post-concussion syndrome occurs when concussion symptoms last beyond the expected recovery period. Symptoms can persist for months or even years and require multidisciplinary management.

Mast Cell Activation Syndrome

Mast cell activation syndrome causes recurring episodes of anaphylaxis-like symptoms due to inappropriate mast cell activation. Diagnosis requires demonstration of abnormal mediator release.

Autoimmune Hepatitis

Autoimmune hepatitis is chronic liver inflammation where the immune system attacks liver cells. It can lead to cirrhosis if untreated but generally responds well to immunosuppressive therapy.

Non-Alcoholic Fatty Liver Disease

NAFLD is excessive fat buildup in the liver of people who drink little or no alcohol. It ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) with inflammation and fibrosis.

Diverticulitis

Diverticulitis occurs when small pouches (diverticula) that form in the digestive tract become inflamed or infected. It causes abdominal pain and can lead to serious complications.

Ectopic Pregnancy

An ectopic pregnancy occurs when a fertilised egg implants outside the uterus, most commonly in a fallopian tube. It cannot develop normally and is a medical emergency — if the tube ruptures, life-threatening internal bleeding can occur.

Ovarian Torsion

Ovarian torsion is the twisting of an ovary around its supporting ligaments, cutting off its blood supply. It causes sudden, severe pelvic pain and is a gynaecological emergency requiring urgent surgical intervention to preserve the ovary.

Diabetic Ketoacidosis

Diabetic ketoacidosis (DKA) is a life-threatening complication of diabetes in which the body produces dangerously high levels of blood acids called ketones. It most commonly affects people with type 1 diabetes and requires emergency treatment.

Subarachnoid Hemorrhage

Subarachnoid hemorrhage is bleeding into the subarachnoid space surrounding the brain, most often caused by a ruptured cerebral aneurysm. It classically presents with a sudden, severe thunderclap headache described as the worst headache of life, accompanied by nausea, vomiting, and neck stiffness.

Hypertensive Emergency

A hypertensive emergency is a severe elevation in blood pressure (typically above 180/120 mmHg) with acute end-organ damage, including hypertensive encephalopathy, acute heart failure, acute coronary syndrome, or aortic dissection. It requires immediate blood pressure reduction in an intensive care setting.