والصالة لله الحمد

الله رسول على والسالم

Shigellosis(Bacillary dysentery)

Causative organism:*Shigella sonnei and S. flexneri cause 90% of the cases.*S. dysenteriae has produced epidemic shigellosis.*S. boydii and S. dysenteriae occur more commonly internationally.

Mode of infection:

*The organism spreads by fecal-oral contact; via infected food or water; during travel; or in day care centers, or nursing homes.

Clinical Picture:

*Incubation period: 1- 7 days.

*History:*Acute bloody diarrhea. *Tenesmus.*Passage of mucus. *Fever. *Self-limited course (3 d to 1 wk and rarely lasts as long as 1 mo).

*Physical: *Lower abdominal tenderness.*Normal or increased bowel sounds.*Dehydration (occasional).

Complications:(1)Bacteremia occurs primarily in malnourished children

and carries a mortality rate of 20%. (2)Hemolytic uremic syndrome carries a mortality rate greater than 50%. *Hemolytic uremic syndrome is characterized by acute hemolysis, renal failure, uremia, and DIC.

Investigations: *Fecal leukocytes and erythrocytes *Mildly elevated hematocrit, sodium, and urea nitrogen are

indicative of volume depletion. *Leukocytosis is rare. *Positive findings on stool culture of a fresh fecal specimen.

*Sigmoidoscopy is unnecessary.

Differential Diagnosis:

Amebiasis Cholera Clostridium Difficile Colitis Colon Cancer, Adenocarcinoma Crohn Disease Salmonellosis Ulcerative Colitis Yersinia Enterocolitica

Treatment:*Fluid and electrolyte supplement: ORS are preferable.*General supportive care:

-Treat high fever in children.-Avoid narcotic-related antidiarrheals.

•Co-trimoxazoles 2 tablets /12 hours for 5 days.

•Ciprofloxacin: 500 mg twice daily for 5 days.

*Shigella infection produces a self-limited diarrheal illness that lasts 5-7 days and may not require antibiotics in individuals who are otherwise healthy.

*Antibiotic treatment is recommended for old patients, malnourished children, patients infected with HIV, food handlers, health care workers, and children in day care centers.

AmebiasisDefinition:*Amebiasis is the condition of harboring Entameba histolytica with or without clinical manifestation.

Causative organism:

*Entameba histolytica found in two phasis:

(1)Large trophozoite (pathogenic).

(2)Small trophozoite (commensal).

*Infection occurs by ingestion of Entameba cyst.

Clinical picture:(1)Acute amebic Colitis or Dysentery:

*Unlike bacillary dysentery, tenesmus is rare, abdominal pain and tenderness are not so acute, and no toxic manifestations.

(2)Chronic amebic colitis:

*Bouts of abdominal discomfort.

*Alternating diarrhea and constipation.

*The colon usually distended with gas.

*Sigmoid and even caecum may be palpable.

Investigations:

(1)Stool examination: detect the trophozoite or cyst form.

(2)Sigmoidoscopic examination : to show amebic ulcers.

(3)Serological test: IHA and complement fixation test.

Complications:A. Intestinal:

(1)Perforation of the bowel: lead to localized peritonitis or generalized peritonitis.

(2)Hemorrhage: from erosion of blood vessels or ulcer.

(3)Intussusception: usually occur in caeco-colic part.

(4)Ameboma: mass like tumor in the course of the colon.

(5)Amebic appendicitis and cholecystitis.

B. Extra-intestinal:

(1) Hepatic amebiasis.

(2) Cutaneous amebiasis.

(3) Amebic lung abscess.

(4) Amebic brain abscess.

Hepatic amebiasis(amebic hepatitis & amebic liver abscess)

*It is caused by Entameba histolytica carried from the colon via the portal vein to the liver.

Clinical picture:

(A) Symptoms:

*Fever, rigors, sweating and malaise.

*Pain:- Site: in the right hypochondrium.

- Radiation: right shoulder and back.

- Character: dull aching, stabbing or throbbing.

- Aggravated by: coughing or straining.

- Relieved by: leaning to the left side.

(B) Signs:

*Fever, usually remittent or hectic.

*Marked toxemia.

*Mild jaundice in 10% of cases.

*Liver is enlarged mainly upwards than downwards.

*Tenderness over the right intercostal spaces, and over the right lower ribs posteriorly.

*Edema of chest wall is a late sign.

Investigations:

(1)Stool examination and sigmoidoscopic examination.

(2)Serological test: IHA and complement fixation test.

(3)Blood examination: Leucocytosis (12,000-20,000).

(4)Therapeutic test with dehydroemetine: usually dramatic response occurs after few injections.

(5)Radiological examination:

a- screen show localized bulging and diminished movement of the right cupola of the diaphragm.

b- X-ray: show raised right cupola of the diaphragm.

(6)Liver scanning using radioactive gold, US and CT scans help in localization of the abscess.

(7)Diagnostic aspiration: chocolate-brown fluid (anchovy sauce) will come out cases of amebic liver abscess.

Complications: (1)Rarely becomes chronic. (2)Secondary infection lead to pyogenic abscess.

(3)Rupture of amebic liver abscess may lead to :*Subphrenic abscess. *Amebic lung abscess. *Pleural effusion or empyema.*Generalized peritonitis. *Amebic skin ulcer.

Treatment:(1) Treatment of amebic dysentery:

*Metronidazole 800 mg TID for 5 days with or without diloxanide furoate 0.5 g TID for 5 days.

(2) Treatment of hepatic amebiasis:*Metronidazole 400 mg TID for 10 days with diloxanide furoate 0.5 g TID for 10 days.

*If medical treatment failed, aspiration of the abscess must be done, through the right 9th intercostal space in the mid axially line.

*Open drainage may be done in chronic cases.

MALARIADefinition:*A disease characterized by recurrent attacks of fever with

rigors, enlargement of the spleen and anemia.

Geographical distribution:*The disease occurs throughout the tropics and subtropics

and can occur also in temperate climates.

Causative organism:*Human malaria is caused by any of the following plasmodia:

- P. falciparum (malignant malaria).

- P. vivax (benign tertian malaria).- P. ovale (ovale tertian malaria). - P. malariae (quartan malaria).

*In Egypt, P. vivax is the commonest type and the female anopheles (pharoensis or sergenti) is the commonest vector.

Life cycle of malaria:(1)Asexual phase: (cycle in man)*If infected mosquito bites man, the sporozoites rapidly disappear form the blood stream.*They invade the liver cells and start what is known as pre-

erythrocytic phase.*During this time sporozoites change to trophozoite schizot schizot filled with merozoites. *The diseased liver cells are destroyed merozoites.

*When the merozoites invade the R.B.Cs it give the ring form trophozoite schizont schizont filled with merozoites .

*The diseased R.B.Cs are destroyed merozoites.

*After several generations gametocyte formation occurs with production of male microgametocytes and female macrogametocytes.

(2)Sexual phase: (cycle in mosquito)

*The female mosquito ingests microgametocytes and macrogametocytes from infected man, which unite, in the stomach to form zygote ookinte,

penetrate the gastric wall to form oocyst sporocyst sporocyst contain many sporozoites, then the

sporozoites migrate to the salivary gland.

Incubation period:

*About 10- 14 days.

Clinical picture:(1)Prodromal symptoms: *In the last 2 days of the incubation period. *Headache, generalized aches, malaise and anorexia.

(2)The paroxysm:

*Typical attack occurs every:

* 48 hours in P. vivax and P. ovale (tertian),

* 72 h in P. malariae (quartan), and

* 36 h in P. falciparum (subtertian).

*It passes into three stages:

A-Cold stage:

*Lasting from 15 minutes to one hour.

*The patient feels cold, shivering, and then rigors.

*Rapid rise of temperature sometimes reaching 40o C.

*Nausea and vomiting are common.

B-Hot stage:

*Lasting from 2 to 6 hours .

*The rigor stop and feeling of cold disappear.

*Hotness and the body temperature is still high.

*Headache, dry flushed face, thirst and tachypnea.

*Nausea and vomiting are still present.

C-Sweating stage:

*Lasting from 2 to 3 hours.

*Profuse sweating with rapid fall of temperature.

*Vomiting stop and patient feels well, the patient usually passes into an exhausted sleep.

(3)Spleen:*The spleen always enlarged, fragile and is easily

ruptured by an blow on the abdomen.(4)Liver:

*Liver may become enlarged and tender.

(5)Anemia: Hemolysis and bone marrow suppression.

Complications:*Relapse (in P. vivax and P. ovale).

*Anemia.

*Rupture spleen.

*Nephrotic syndrome (in P. malariae).

Malignant malaria (complicated P. falciparum): *Complicated P. falciparum malaria may take a number of

clinical forms:(1)Cerebral malaria:

*Headache, drowsiness, fits and if untreated passes into coma and death.

(2)Hyperpyrexia:*May occur in association with cerebral malaria where the body temperature is more than 41C. *Hot dry skin, and the patient passes into coma.

(3)Bilious Remittent fever:

*Attacks of epigastric pain, nausea, vomiting, diarrhea and jaundice due to severe liver damage.

(4)Dysenteric malaria:

*Stools containing blood and mucous with nausea and vomiting.

(5)Choleric malaria:

*Profuse watery diarrhea, vomiting and dehydration.

*Shock or acute renal failure may occur.

(6)Black-water fever:

*Acute intravascular hemolysis and hemoglobinuria as a complication of P. falicparum infection.

* Fever with rigor, heavy sweating, nausea, vomiting, jaundice, loin pain and dark urine.

*Mortality rate 20 - 30 %.

Investigations:

(1)Demonstration of the parasite by blood film.

(2)Therapeutic test where the fever responds to anti-malarial drugs.

(3)Enzyme-linked immunosorbent assay (ELISA).

Treatment:*Chloroquine: 4 tables (600mg) orally then 2 tablets after 6

hours then 2 tablet once daily for 2 days.

*Quinine: 2 tablets (650mg) three times daily for 10 days.

*To prevent relapse in P. vivax and P. ovale primaquine in a dose of 7.5 mg twice daily for 10 days is added to any of the above regimen.

*In severe malignant malaria (e.g. cerebral malaria) IV quinine is the drug of choice.

*In chloroquine resistant P. falciparum infection, a combination of quinine and fansidar should be used.

Prophylaxis of malaria for travelers:

*Chloroquine 300 mg once weekly.

*Pyrimethamine 25-50 mg twice a week.

*The drug should start one week before travel and continue for at least 4 weeks after leaving the endemic area.

*If chloroquine resistant P. falciparum is expected fansidar one tablet weekly should be added to any of the

above regimen.

الله الله جزاكـــم جزاكـــمخيــــــــراخيــــــــرا