Diverticulitis

 

Diverticulitis is a frequent, acute disease, especially but not exclusively in older adults.

The colon wall is  multi-layered. During life, especially when the pressure in the colon is increased, such as with straining, the inner layer tends to protrude through weaker spots of the outer layer. This forms small pouches, which are diverticula. When one, or sometimes more of these diverticula becomes inflamed or infected, diverticulitis ensues.

Diverticula tend to be more frequent in the sigmoid colon, which is the last part, before the rectum. It is on the left side of the abdomen, thus diverticulitis presents most commonly as left sided pain. However, all parts of the colon can form diverticula. In patients with Asian ancestry, right sided diverticulosis is more common. This can be mistaken for appendicitis.

Diverticulitis is almost always an acute disease. It presents with sometimes severe abdominal pain, tenderness. Frequently it is accompanied by fever, chills, bloating, a feeling of fullness, nausea, vomiting, general malaise. In the majority of cases it progresses rapidly but there are patients, in whom the onset is more insidious, the symptoms wax and wane over several days or even weeks.

Diverticulitis may cause diarrhea but constipation is more common. Although we don’t quite understand the factors leading to the development of diverticulitis, constipation is probably one of them.

It is also not clear, if uncomplicated diverticulitis is just an inflammation of the diverticulum or also an infection. However, when the disease progresses, not infrequently there is a micro-perforation of the involved diverticulum, leading to a localized, small abscess formation in the colon wall. This can progress to larger, bone fide abdominal abscesses, which may rupture, leading to infectious peritonitis. This is a potentially very serious condition, the infection of the peritoneum, the lining of the abdominal wall and the covering layer of most intraabdominal organs.

The usual treatment of diverticulitis is going on a liquid diet and antibiotics, for 7-10 days. Recently it has been shown, that uncomplicated diverticulitis probably does not require antibiotics. Once the pain resolves, diet can be gradually advanced. It is important, that patients drink plenty of liquids.

 

Diverticulitis tends to recur and we don’t have a good handle on when and why this happens. It is thought that regulating bowel movements, avoiding constipation, may help prevent recurrent attacks.

 

When it recurs, especially several times, surgery can be considered. The operation will remove the sigmoid colon. If the diverticula are present only in the sigmoid, this will indeed prevent recurrence. There is no clear agreement, after how many episodes would surgery be indicated, but generally after three or four, the benefits of surgery outweigh its risks, which are minimal, given that it is done laparoscopically most of the time.

If an abscess is present, surgery is more likely needed. In the acute situation, when surgical risks are higher, the abscess can be drained under X-ray guidance.

Infectious Diarrhea

 

Diarrhea is a very frequent complaint; at one point in life everybody will have it. Most of these episodes are due to an acute environmental injury: a bacterial or viral infection, such as salmonella or norovirus, or some irritating food.

There are several ways to categorize diarrhea: acute or chronic, bloody or not bloody, profuse or just loose stools, accompanied by abdominal pain or not. Looking at the underlying mechanism of disease, it can also be divided into secretory diarrhea, when the lining of the gut secretes too much fluid or osmotic diarrhea, when the contents of the gut are too concentrated and pull in water from the gut tissue.

The most frequent cause of diarrhea is infection. These come in many forms: viral, bacterial or parasitic, which can be small, single cell organisms (protozoa) or worms.

Infectious agents can act on the small bowel , causing high volume, mostly non bloody diarrhea, or the colon, which results in frequent, sometimes painful bowel movement, which can be bloody, if there is invasion of the colon wall, but not as high volume as small bowel diarrhea.

Norovirus is the most prevalent agent. It is very infectious and usually causes clusters of cases, such as abord cruise ships. It may present with vomiting and profuse diarrhea and, in an otherwise healthy person, is self limited. As with all, especially high volume diarrheal cases, dehydration is the main cause to worry. Drinking plenty of fluids, especially oral rehydration solutions, is essential, but sometimes intravenous fluids are needed. Rotavirus is the most common cause of diarrhea in children and there is an effective vaccine against it.

The most common bacterial pathogens are Salmonella, Campylobacter, Shigella and E. coli. These can be invasive, causing fever, chills, sometimes bloody diarrhea, weight loss. Treatment is usually symptomatic but, if there are symptoms of invasion, antibiotics might be required.

There are bacteria, which cause diarrhea nit by directly attacking the gut but through toxin production. These range from the relatively minor problems of self limited diarrhea caused by toxins produced by Staphylococcus or B. cereus ( Chinese rice syndrome) in improperly handled food to severe diseases such as cholera (which can be rapidly fatal due to profound dehydration) od C. difficile, which is an increasingly common cause of bloody diarrhea in hospitalized patient or patients after antibiotic treatment. These most be treated quickly to avoid complications.

Toxins can cause diseases, where diarrhea is a minor factor, such as scombroid fish poisoning, where bacteria growing on improperly stored fish produce histamine and histamine-like substances or Ciguatera fish poisoning, where large, predatory fish, like barracuda, eat tiny organisms, which produce a neurotoxin. This is a potentially life threatening illness.

Protozoa, such as Giardia (frequent in non-tropical climates and usually found in contaminated water), which is a non-invasive organism, cause non bloody diarrhea, bloating and weight loss and can be treated fairly easily. Amebae are invasive, cause bloody diarrhea, can live in the liver (and other organs) as well as the gut, and both forms need to be treated in order to get rid of the infection.

Worms come in many forms, depending on the general hygiene in the region. Diarrhea is frequently part of these infestations but usually not the leading symptom. Most worms, especially when diagnosed promptly, can be treated effectively.

A special category of infectious diarrhea is Traveler’s Diarrhea. This is an acute, most likely self limited diarrhea, occurring in tourists coming into a tropical or subtropical country from more moderate climates, where the usually food or water borne pathogens are less frequent. Diarrhea can be quite debilitating but is usually over in 2-3 days. It can be treated with various antibiotics and prevented by taking PeptoBismol or Xifaxan

Hepatitis B

 Hepatitis B is a chronic liver infection, caused by the hepatitis B virus. This is prevalent in Asia and the Eastern Mediterranean region as in West Africa and the South Pacific but can be found in Europe and the Americas, too. It has been markedly decreased since vaccination was introduced thirty years ago but not all areas of the world are evenly vaccinated.

Hepatitis B can be transmitted with bodily fluids. Transfusion used to be a significant way but donor screening has been universal, especially in developed countries. It is easily transmitted sexually and with shared needles. A special form is mother-to-fetus transmission at the time of birth. There is mandatory testing and perinatal vaccination in the US and this form of transmission is exceedingly rare. Unfortunately, it is not so in many Asian countries.

Acute hepatitis B is mostly asymptomatic and is missed. Chronic disease is also rarely diagnosed because of symptoms but mostly on routine blood tests.

There are different phases of chronic hepatitis B, ranging from decades long immune tolerance, when the virus replicates but the body does not attack the infected liver cells (hence no hepatitis) to different immune active and inactive (carrier) phases. Infection may resolve spontaneously, more so in Caucasian than Asian patients.

In contrast to hepatitis C, the genetic material of the hepatitis B virus can be integrated into the liver cell’s DNA and this can cause liver cancer, even in patients, whose disease resolved, albeit to a much lesser extent.

 

Hepatitis B may also cause disease outside of the liver, the so-called extrahepatic manifestations: kidney disease, polyarteritis nodosa and aplastic anemia.

 

Vaccination is the most important way to fight hepatitis B. The newer, recombinant vaccines are well tolerated and very effective. In many places, vaccination is mandatory before age 14 and this strategy has been remarkably effective.

Treatment is effective mostly in suppressing the virus but is not curative in many patients. There are several oral medications, which are safe and effective and have been shown to prevent progression of the disease, stabilize even advanced disease and reduce the recurrence of liver cancer after its eradication by other means. They can also reduce the rate of transmission from mother to fetus and are used safely during pregnancy. These medications are used for very long times, frequently indefinitely. Interferon, an injectable drug, is used for about a year, alone or in combination with oral antivirals, but is also rarely curative and has many more side effects.

New therapeutics are being actively researched, aimed not only at viral suppression but also at elimination of the disease, by priming the body’s own immune cells to preferentially attack infected liver cells.

New Oral Treatments for Inflammatory Bowel Disease

 Biologics have been mainstay of treatment for moderate-to-severe IBD for the last two decades, gaining prominence and wide acceptance since the introduction of Remicade in the late 1990s. They have revolutionized IBD therapy and are still growing in numbers. There are three main groups : anti-TNFs ( Remicade, Humira, Simponi, Cimzia), anti-Integrins (Entyvio, Tysabri) and anti- IL 12/23 ( Stelara). They are all so-called monoclonal antibodies and need to be given as injection, some intravenously, some subcutaneously. They work, but not universally and all can provoke an immune reaction against themselves in the human body. They are also expensive and cumbersome to administer. I have been closely involved with their development as a clinical researcher.

The last few years brought oral medications for IBD to supplement, and maybe one day to supplant, the current biologics. First came Xeljanz ( Tofacitinib) and more recently Zeposia  (Ozanimod).

Xeljanz is a JAK inhibitor. This mechanism of action is similar to that of biologics: it disrupts one step of the cellular inflammatory response. It is rapidly effective in many patients. While it is generally safe, there have been serious side effects, such as the development of shingles and pulmonary embolism. Also, Xeljanz  is not active for Crohn’s Disease, although second generation JAK inhibitors show promise. Rinvoq, a selective JAK inhibitor, has just been approved for Ulcerative Colitis patients, who failed treatment with an anti-TNF agent.

Zeposia works differently. It captures the inflammatory cells before they can enter the tissue and traps them in lymph nodes. It seems safer and it shows promise for Crohn’s Disease, too. Other companies are working on newer versions of it.