Diarrhea can occur in this stage, but constipation is also common. The spleen and liver are enlarged (hepatosplenomegaly) and tender, and liver transaminases are elevated. The Widal test is strongly positive, with antiO and antiH antibodies. Blood cultures are sometimes still positive. In the third week of typhoid fever, a number of complications can occur:
The fever is still very high and oscillates very little over 24 hours. Dehydration ensues along with malnutrition, and the patient is delirious. A third of affected people develop a macular rash on the trunk. Intestinal haemorrhage due to bleeding in congested Peyers patches occurs; this can be very serious, but is usually not fatal. Intestinal perforation in the distal ileum is a very serious complication and often fatal. It may occur without alarming symptoms until septicaemia or diffuse peritonitis sets in. Respiratory diseases such as pneumonia and acute bronchitis
Encephalitis
Neuropsychiatric symptoms (described as "muttering delirium" or "coma vigil"), with picking at bedclothes or imaginary objects. Metastatic abscesses, cholecystitis, endocarditis, and osteitis. Low platelet count (thrombocytopenia) is sometimes seen. Causes
Bacteria
The Gram-negative bacterium that causes typhoid fever is Salmonella enterica subsp. enterica serovar Typhi. Based on MLST subtyping scheme, the two main sequence types of the S. Typhi are ST1 and ST2, which are widespread globally. Global phylogeographical analysis showed dominance of a haplotype 58 (H58), which probably originated in India during the late 1980s and is now spreading through the world with multi-drug resistance. A more detailed genotyping scheme was reported in 2016 and is now being used widely.
Causes
The slowing of the bodys basal metabolic rate associated with hypothyroidism
Pernicious anemia where there is antibody production against parietal cells which normally produce gastric acid. The use of antacids or drugs that decrease gastric acid production (such as H2-receptor antagonists) or transport (such as proton pump inhibitors). A symptom of rare diseases such as mucolipidosis (type IV). A symptom of Helicobacter pylori infection which neutralizes and decreases secretion of gastric acid to aid its survival in the stomach. A symptom of atrophic gastritis or of stomach cancer. Radiation therapy involving the stomach. Gastric bypass procedures such as a duodenal switch and RNY, where the largest acid producing parts of the stomach are either removed, or blinded. VIPomas (vasoactive intestinal peptides) and somatostatinomas are both islet cell tumors of the pancreas. Pellagra, caused by niacin deficiency. Chloride, sodium, potassium, zinc and/or iodine deficiency, as these elements are needed to produce adequate levels of stomach acid (HCl). Sjögrens syndrome, an autoimmune disorder that destroys many of the bodys moisture-producing enzymes
Ménétriers disease, characterized by hyperplasia of mucous cells in the stomach also causing excess protein loss, leading to hypoalbuminemia. Presents with abdominal pain and edema

Risk Factors
Age
It was found that the incidence of achlorhydria in patients under the age of 60 was around 2.3%, whereas it was 5% in patients over the age of 60. In a persons 30s, the prevalence is about 2.5%, and increases to 12% in a persons 80s. An absence of hydrochloric acid increases with advancing age.